#Lenzfx
40 messages in this thread
<<Actually, with a real camera, a reflection of an object can be in
perfect focus while the object itself is completely blurred. Remember
in the old movies when some fabulous movie star would be sitting in
front of her mirror and her reflection in the mirror would be focused
while the back of her head would not. What you are actually focusing
in on is the light reflected from the mirror's surface, not from the
object causing the reflection.>>
I understand this, but this isn't whats happening in the sample image.
The table is in focus, the wall isn't in focus, and the reflection of
the wall is in focus. I you can come up with a rational explanation
of this phenomena I'd like to hear it. In the example you cite I
would imagine that the mirror she is using would not be in focus, or
if it was then the depth of field is set just beyond the foreground.
In that example the focal distance to the woman's reflection is the
distance from the camera to the mirror plus the distance from the
woman to the mirror. In your sample image the distance to the
reflection on the table is closely related to the distance from the
camera to the wall itself, if not further. I'm no physicist, so I
could be way off base here, but I have been interested in optics and
perception for a few years. If the product works according to
optical physics, put me down for a copy now thanks, scott
Scott,
Here's as rational as I can get :> The focal distance to any light
wave emitted from the surface of an object, either originating from
that object or from a reflection is always a constant, namely the
distance from the point of perception to the object. What you are
seeing any time you perceive a surface is light rays interacting with
the atomic structure of that surface. Whether these light rays come
directly from a light source or are reflected from another object is
irrelevant. So, it is possible to have an out-of-focus object appear
to be in focus in a reflection if the surface of reflection is in
focus. That's why I used the example of a movie star looking into a
mirror. The distance from the camera to the movie star's head is out
of the focal range, but the distance from the camera to the mirror is
in the focal range and you get a crystal clear reflection in the
mirror while the head in the foreground is out of focus.
Aaron
Aaron,
Hope I didn't seem too hostile in my last note, I'm writing under the influence
of a cold.
<<What you are seeing any time you perceive a surface is light rays interacting
with the atomic structure of that surface.>>
Yikes! I didn't think you'd get THAT detailed : ).
<<Whether these light rays come directly from a light source or are reflected
from another object is irrelevant. So, it is possible to have an out-of-focus
object appear to be in focus in a reflection if the surface of reflection is in
focus.>>
I don't believe that this is entirely correct. While it is possible, as in
your movie star example, it is not always that way.
The focus, or non-focus, of the mirror is fairly irrelevant to the state of
focus of the reflection. The image reflected doesn't gain any special
properties because of the location of the mirror. The reflection's state of
focus is solely dependant on a simple equation: the distance from the viewer
to the mirror + the distance from the mirror to the reflected item. The
reflected item's image is treated the same as if it were located at the
resulting distance. Its state of focus and the effects of atmosphere are
calculated the same way.
<<The distance from the camera to the movie star's head is out of the focal
range, but the distance from the camera to the mirror is in the focal range and
you get a crystal clear reflection in the mirror while the head in the
foreground is out of focus.>>
This is NOT why the mirror and the reflection of her head is in focus while her
head is not. As I stated in my last note, it is because the focal range
begins at a distance beyond where her head is and extends to a distance beyond
the distance of her head's reflected image. Why do you think that her head's
reflection is the same size as it would be if it were at a distance equaling
the distance to the mirror + the distance from her head to the mirror? Wasn't
all this figured out 400 years ago by DaVinci et al?
In your sample image the table is in focus, the wall is out of focus. The
distance from the viewer to the table + the distance from the table to the wall
cannot be shorter than the distance from the viewer to the wall. So the wall's
depth is between that of the table top and the reflection of the wall. It
isn't possible to have an out of focus object at a distance between two
in-focus objects.
My friend DrS has a more plausible explanation of why this effect is happening.
He thinks that 3DS will not allow you to apply the depth-of-focus effect before
3DS figures reflections and then allow you to apply the depth-of-focus effect
again to the surface with the reflection on it. I must admit that this is a
formidable task, as you would have to make several calculations for a
reflection of a reflection. This appears to be what is happening in your
sample image. The reflection on the table top is treated as a texture map and
your depth-of-focus effect is applied to the general scene.
This may be the only option which the software allows short of raytracing. If
so, then its a shame. I can't use an effect which only looks realistic if I
don't have any reflections in the scene. My question is: if this is the
reason that this is happening in your sample, then why not just say so? I'm
not implying that you are trying to hide a flaw- maybe you just never noticed
it, or maybe this sample image wasn't created correctly. It's just that your
movie star in the mirror explanation got my dander up- it doesn't explain why
the sample image was incorrect (which it is), it merely dances around the
problem.
If I'm going to spend $300 dollars on a piece of software, then it had better
state what it can or can't do, or you'll get a lot worse notes than mine.
Hope this wasn't too negative (or too lengthy). I was suprised by your quick
and pleasant response and I hope you don't take my criticisms personally. I'm
sure that you know alot more about programming for 3DS than I ever will (or
want to). Some day soon (hopefully), I'll be uploading some of my current
project (a pc playing basketball) and you can feel free to pick it apart at
will!
thanks Aaron!
scott
Scott,
Please relax, take some Nyquil and get some rest. I really don't even want to
argue this with you.
<<In your sample image the table is in focus, the wall is out of focus. The
distance from the viewer to the table + the distance from the table to the wall
cannot be shorter than the distance from the viewer to the wall. So the wall's
depth is between that of the table top and the reflection of the wall. It
isn't possible to have an out of focus object at a distance between two
in-focus objects.>>
If this logic is true, then by every law of triangles that I'm aware of, it
would never be possible for a reflection of an object to be in focus if the
same object is in focus, which is a phenomenon that I witness on a daily basis!
And besides, nowhere in that scene is there an object that is out of focus
between two in focus objects.
And no, I'm not TRYING to avoid any point at all, and in fact your friend is
dead on correct about there not being any access to refraction during 3D studio
rendering. However, the Z-focus module of LenZFX is nothing short of a miracle
in a scan-line renderer. Take for example, the focal capability of LightWave.
It is limited to a focal point of 0 distance from the camera. So the focal
point can never go out into the scene like you can with ZFocus. And to top it
all off, LightWave will render the scene 8 TIMES to achieve this affect! And
it's a raytracer …. And its done directly from within the rendering engine.
Get my point?
Z-Focus is not the only module of LenZFX. It also includes spectacular aura
and starlight effects as well as a proprietary system to create user-definable
lens flares that even make the mouths of ALIAS users water. All completely
controllable by the user through keyframable spline envelopes and automatic
object detection!
LenZFX is a tool just like any other. Just like 3D Studio. None of
this stuff is 100% intuitive. If it was, we wouldn't need animators.
We'd all be playing in holodecks by now. Now this is just my
opinion, but I think LenZFX is about as user-friendly as any of this
complicated mess gets, and its a great tool. If you've decided,
however, that you don't want it on the basis of a liberal amount of
armchair philosophy and one image done with a BETA version of the
software then that's your right. But don't blame me when your 3D
Studio animations compared against the work of a 3DS/LenZFX
professional look like they were done by a 5 year old with a crayon.
Aaron
Aaron, I can say (from using the LenzFX beta) that your optics package is going
to be one of the most valuable tools a 3D Studio animator could have in their
toolbox. The flares package provides control and subtlety beyond what LW, EIAS
and even Alias (yup) offer, and the hilight and glows are going to push
people's creativity as far as it's ever been pushed with 3DS. But my favorite
part of the package is the depth of field control… I've had some experience
with the Wavefront Composer DOF system (this is the closest thing on the market
to the LenzFX DOF), and your way of doing autofocus is much more flexible.
There are always some inherent physical differences between doing things via
scanline rendering instead of with raytracing, but since raytracing takes about
an order of MAGNITUDE more time to compute, any production animator would take
the scanline method ANY DAY OF THE WEEK, or they'd starve while waiting for the
program to finish rendering.
I'm anxiously looking forward to your shipping the package, because I can't
wait to see the work coming back from 3DS animators using it! (I've got a
feeling that LenzFX-style effects are going to be a big assist for anyone
trying to get their work into the '95 3DS Siggraph reel.)
– G
Thank you Gary for your kind response. I'm also really looking forward to
seeing what some talented animators can do with LenZFX.
Just as an aside, the lens flare building capabilites of LenZFX are copyrighted
and if any of the bigger image companies (SGI, SoftImage, Alias) take it and
incorporate it into their packages, I do plan on prosecuting. So, all the 3D
Studio users will finally have something over their smug SGI peers. 🙂 Enjoy.
Aaron
I am absolutely fascinated by the ability to pick (and shape) each individual
secondary flare in the scene. I had a scene with a combination of hexagonal,
octagonal, elipsoidal and circular flares that was completely unnatural, but
totally beautiful! It's great to see that you're working towards protecting
your intellectual property.
– G
Aaron,
I'm really looking forward to your new packages, we're pretty fanatical about
neat IPAS routines! 🙂
Since you mentioned copyrighting your flare building capabilities and I have no
idea what you've got in there, you may want to check out Alias 6, the lens
flares are vastly expanded from 5.1.1 and have been for a long while now. Lots
of neat stuff, including 11 new controls over flares alone, focus effects for
the flares, animated color maps, hexagonal flares, spread control, etc. What
kind of neat new stuff do you have in your package?
If as Gary said your flares allow more control than the new Alias ones do,
you've got quite a nice package on your hands, and I'm anxious to get it in my
hands. 🙂
Paul
Instead of defining your flares by setting a myriad of toggles, confusing
buttons and options, you create your flare using 5 simple color gradients.
These gradients are not only very intuitive, but getting the exact color and
look you want is very easy. Move or change a color on the gradient and you
instantly see its effect in the truecolor preview window. The gradients can
also be animated over time, and incorporate the lights actual color for the
current frame in the gradient! Using this philosophy, I have been able to
emulate several popular lens flares already, including the photoshop flares,
LightWave flares and even Alias flares so that they look even better than the
originals. I don't think anyone will run out of possibilities any time soon.
Secondary flares are created in a similar manner, and can be a circle, octagon,
hexagon or "user-squashable" ellipse. They can be placed anywhere along the
flare's spread. They can even rotate to always face the flare as it moves
through the scene so you can have a bright and dark area of a secondary flare
where the bright area will always be aligned with the flare.
Aaron
WOW!!!!!!
Sounds phenomenal! When do they go on sale?
Paul
<<Sounds phenomenal! When do they go on sale?>>
All four modules are sold as a package. It's in BETA right now, but I expect
it to be released later this week. You can call Digimation and order it now,
and they will send it to you as soon as its set free.
Aaron
First of all, Lenzfx is the long awaited tool for animators & artists to add
realistic touches to their compositions – I can't wait to get my copy <g>!
Second, I have a 35mm photograph of a statue, reflected in a large puddle on
a public square. I had focused on the reflection – the statue is out of focus
and the square is in soft focus. The same analogy is applicable to your
chessboard example correct?
– Phil
Aaron,
I am looking forward to seeing the release version of LenzFX. The flare and
glow abilities appear to be just what I want/need/lust after…. If it does
indeed compare to Alias PAv6 I will be calling to order soon, probably if it's
even just close to Alias….
BUT, regarding this discussion on Depth-Of-Field I must put in my two
cents…..
ASSUMPTIONS:
I. The human eye is our window to the human idea of PERCEPTION.
II. The CAMERA (Lens focal system) is the nearest device yet made to reproduce
the working human eye, but is really a pale imatation.
III. 3D Studio, Lightwave, and ALIAS, ect., use a CAMERA as a metaphor for
simulating a lens-focal-system, which in turn, simulates the human eye, which
in turn leads to our PERCIEVED view of a scene.
IV. 3D Studio, Lightwave, and ALIAS, ect., should then therefore adhere to the
laws of optics for depth-of-field, or we will PERCIEVE a "difference" with an
image which we will PERCIEVE as "not correct" because we are exposed to the
world through our EYES (normal vision) and CAMERAS (Film/Photography) every day
we live. (Unless you are blind and have no vision.)
AO>Scott,<
AO>Please relax, take some Nyquil and get some rest. I really don't even want
to argue AO>this with you.<
He's better now.
SR>In your sample image the table is in focus, the wall is out of focus. The
distance from SR>the viewer to the table + the distance from the table to the
wall cannot be shorter SR>than the distance from the viewer to the wall. So
the wall's depth is between that of SR>the table top and the reflection of the
wall. It isn't possible to have an out of focus
AO>If this logic is true, then by every law of triangles that I'm aware of, it
would never be AO>possible for a reflection of an object to be in focus if the
same object is in focus,
Check out text such as Raymond Fielding's SPFX Cinematography and you will see
that to focus on an object in a mirror, you must measure from the camera to
mirror to object. Add in DOF and I believe your TEST image is not correct.
I find it absolutely incredible that any discussion of depth-of-field has not
mentioned the following items:
1. Focal Length of lens
2. f-stop
3. Distance
4. Light level
It's school time! The following is excerped from CINEMATOGRAPHY revised ed.
1986 by J. Kris Malkiewicz. pub by Prentice Hall.
DEPTH OF FIELD AND CIRCLE OF CONFUSION
If we were to photograph only one distant point, such as a light, the lens
would be in focus when if projects a point onto the film. Because the lens can
be focused for only one distance at a time, objects closer and farther away
will be slightly out of focus. In the above example a second, closer light
would have its image formed behind the film plane and be represented on the
film as a circle. A third light, farther away, would form its image in front
of the film plane and also appear on the film as a circle. These circles are
called "circles of confusion," and they vary in size depending on how far out
of focus they are. The "confusion" is that circles smaller than 1/1000 inch
confuse our eye and are seen as points in focus. This allows us to see
pictures of three-dimensional objects that appear in focus.
We have a range in which objects will appear sharp. It runs between the
closest and farthest objects as circles of confusion smaller than 1/1000 inch.
This range is called "depth of field" (and is sometimes incorrectly called
"depth of focus").
The depth of field varies with the effective diamater of the lens opening and
hence with the f-stop. By '"effective diameter" we mean the actual size of the
iris opening, not the f-stop number…….
…..These general principles govern depth of field:
Greater DOF Less DOF
——————————————————————-
Wide-angle lens Telephoto lens
High f-stop (small Aperture) Low f-stop (wide Aperture)
Subject far away form CAMERA Subject close to CAMERA
Smaller format (such as 8mm) Larger format (such as 35mm)
With greater depth of field more elements in the picture are in sharp focus.
This causes the image to appear harder and of higher contrast. Therefore,
using a higher f-stop number introduces apparently higher constrast.
Depth-of field characteristics for lenses of various focal lenght under
different conditions are available in many publications, such as the American
Cinematographer Manual. (A must have – DrS) Given the focal length and f-stop
and the subject-to-film-plane distance, we can determine the range of the depth
of field and the dimensions of the field of view at that distance.
For each lens and f-stop the chart also gives the hyperfocal distance. This is
the point of greatest depth of field. It is a precalculated figure indicating
that if the given lens at the given f-stop is focused at this hyperfocal
distance, everything from half this distance to infinity will be in acceptable
focus. For example, if for a given lens and f-stop the hyperfocal distance is
20 feet, by focusing at 20 feet we would obtain everything in focus from 10
feet to infinity.
A similar principle is valuable when "splitting the focus" between two objects
at different distances. They will both be equally sharp if we focus for a
point not halfway between them, but a third of the seperation distance form the
closer object. For example, two objects at 10 and 16 feet respectively would
both be equally in focus if you focus for 12 feet. This is often referred to
as the one-third-distance principle……..
_____________________________________________________________________
I will upload diagrams from the above text if you would like to see them.
Based on my earlier assumptions, than LensFX would need to EMULATE a
lens-focal-system in software. It would have to have a software equivilent of
an f-stop and use 3DS's CAMERA focal-length from the KEYFRAMMER. By doing this
than the physics is black and white if you have CAMERA Depth-of-Field,
Hyperfocal Distance & Field of View charts (lookup tables or calculated).
I am curious as to how LenzFX handles the idea of an f-stop?
In Lightwave under the CAMERA menu I do the following:
1. Choose level of Antialiasing (MED or HIGH – Number of passes)
2. Choose Film Size (11 choices)
3. Choose Zoom Factor – Focal Length mm, controlled by Envelope over
time
4. Choose Focal Distance – Variable and controlled by Envelope over
time
5. Choose Lens f-stop – Variable and controlled by envelope over time
AO>And no, I'm not TRYING to avoid any point at all, and in fact your friend is
dead on AO>correct about there not being any access to refraction during 3D
studio rendering.
Thanks! I must be smarter than I look. <BG>
AO>However, the Z-focus module of LenZFX is nothing short of a miracle in a
scan-line
But if it's not a true representation of DOF, I guess I'll be using it for it's
lens flare and it's other stuff. And I'll use Lightwave for my DOF stuff.
AO>renderer. Take for example, the focal capability of LightWave. It is
limited to a focal AO>point of 0 distance from the camera. So the focal point
can never go out into the
WRONG!
AO>scene like you can with ZFocus. And to top it all off, LightWave will
render the scene AO>8 TIMES to achieve this affect! And it's a raytracer ….
And its done directly from
Not quite right, you can actually have up to 16(?) passes. Each pass is a
level of blur (focus). Ask Allen Hastings on the Internet for an explaination
as it's quite interesting what he is doing with this. Do you use Lightwave
regularly? I do, as well as 3DS and others.
AO>Z-Focus is not the only module of LenZFX. It also includes spectacular aura
and AO>starlight effects as well as a proprietary system to create
user-definable lens flares AO>that even make the mouths of ALIAS users water.
All completely controllable by the AO>user through keyframable spline envelopes
and automatic object detection!
This sounds really great! I can't wait to see this stuff work. Sign me up!
AO>LenZFX is a tool just like any other. Just like 3D Studio. None of this
stuff is 100% AO>intuitive. If it was, we wouldn't need animators. We'd all be
playing in holodecks by AO>now. Now this is just my opinion, but I think
LenZFX is about as user-friendly as any AO>of this complicated mess gets, and
its a great tool. If you've decided, however, that AO>you don't want it on the
basis of a liberal amount of armchair philosophy and one AO>image done with a
BETA version of the software then that's your right. But don't AO>blame me
when your 3D Studio animations compared against the work of a AO>3DS/LenZFX
professional look like they were done by a 5 year old with a crayon.
This last sentence is pretty harsh, Aaron. Do you know Scott (SCAATT) Roberts?
I do. For just about 15 years now. In fact I tripped<BG> over his art works
in our apartment for 6 years. His paintings, photographs, sculptures, and
writings seemed very professional to me and he didn't have LensFX when he did
any of them.
…..3DS/LenZFX professional? Give me a break…………..
…..5 year old with a crayon. Sounds like someone here needs to grow a bit.
When you see the work Scott is doing you'll see that he's a bit older than
five. I feel partly responsible for Scott choosing 3DS as a platform and when
I see his work I ALMOST wish I had told him his first choice, the MAC was
RIGHT. You see, now that he's on 3DS I will have to work a bit harder so that
he doesn't grab the whole marketplace up here. <BG>
AO>Aaron >>>
Just speaking my onions,
David.
You are more than entitled to your opinions. But don't use insulting language
like "someone needs to grow a little." If you have a point to make about me,
please phrase it directly. When I made the remark about the 5-year old, you
will notice that the sentence begins with a theoretical metaphor, an if…I
have never seen Scotts work and was saying absolutely nothing about how it
looks.
Your discussion of DOF is indeed educational. As per the image in question, a
scene very similar to that has already been tested with a real 35mm camera, and
the results were exactly the same as in the sample image. So, I guess I just
really don't see your point. Or why you persist in the fact that it isn't
correct. If you, or anyone who you are willing to quote, is actually saying
that a camera, or even our eyes are capable of instantaneously measuring the
complete DISTANCE traveled by a ray of light to infinity, you are wrong. If we
had this technology, can you imagine the military and scientific benefits
alone! Instead, like I pointed out earlier, and even as Kris Malkiewicz writes
in the article you quote, perceived focus is dependant on the intensity and
angle of light rays entering the lens of the camera or our eye, and how the
lens refracts them.
<<Not quite right, you can actually have up to 16(?) passes. Each pass is a
level of blur (focus). Ask Allen Hastings on the Internet for an explaination
as it's quite interesting what he is doing with this.>>
LightWave does have a nice DOF, but its largely unusable because of the time it
takes to render. Imagine rendering a ray-traced scene 16 or even 8 times for a
single image!
<<Do you use Lightwave regularly? I do, as well as 3DS and others.>>
David, if you want to get into some sort of battle of who has the better toys,
you're talking to the wrong guy. Cuz I just really don't care. It doesn't
matter what you've got, but how you use it 🙂
Now take this whole message with a small grain of salt (and maybe a shot of
vinegar) because there's really nothing in this whole thread that's all that
personal.
Aaron
Aaron,
Sorry if MY message came off sounding harsh, that was not the intent.
>>Your discussion of DOF is indeed educational. As per the image in question,
a scene very similar to that has already been tested with a real 35mm camera,
and the results were exactly the same as in the sample image. So, I guess I
just really don't see your point. Or why you persist in the fact that it isn't
correct. If you, or anyone who you are willing to quote, is actually saying
that a camera, or even our eyes are capable of instantaneously measuring the
complete DISTANCE traveled by a ray of light to infinity, you are wrong. If we
had this technology, can you imagine the military and scientific benefits
alone! Instead, like I pointed out earlier, and even as Kris Malkiewicz writes
in the article you quote, perceived focus is dependant on the intensity and
angle of light rays entering the lens of the camera or our eye, and how the
lens refracts them. <<
My point, which I evidently did not convey all that well, is simply this:
I propossed an assumption that the DIGITAL CAMERA of a graphics program like
3DS emulates a lens system simular to a normal camera. This camera is in turn
emulating our vision as seen from our eyes. Following this assumption then the
DIGITAL CAMERA would need to follow the rules of a known optics system, the
camera, and if it didn't we would PERCIEVE a difference because of our
familularity and exposure to said systems every day.
I noticed in the thread that no one talked of a real optics system and DOF and
it's connection to FOCAL LENGHT, LIGHT, DISTANCE, and APERTURE (F-stop). Not
being an expert in optics I qouted a known source so that my ground work
would be correct to the best of my knowledge. Several of the statments in the
thread were off-the-cuff, or appeared to be and were also wrong. Some worked
in a FIXED focal length, FIXED aperture lens system. 3DS is NOT a fixed focal
length lens system. Therefore, any real DOF system would need to consider
idea's like Circle of Confusion, Hyperfocal Distance, and Near/Far lens focus
and Focus Point. In a software emulation I feel you would have to create these
known factors in the system for it to emulate a real scnario. In fact, you
should be able to go to a DOF chart for your lens focal length and use the
figures in that chart to actually place objects an proper distances from the
camera for your setup, if you wanted. In Lightwave you CAN actually do this
very thing.
Making this hypothetical situation, I was hoping you would go into detail on
just how LenZFX use these ideas, if it even does. Either I was so UNCLEAR in
my intentions that you missed that or you did not wish to discuss those
factors.
I still agree with Scott that the reflection is not correct. It APPEARS that
the reflection of wall would be out of the DOF for that setup and hence be
blurred. This is of course based on the output image as I can not look at the
setup.
<< LightWave does have a nice DOF, but its largely unusable because of the time
it takes to render. Imagine rendering a ray-traced scene 16 or even 8 times
for a single image! >>
I use it all the time so I would not say it is unusable. In fact my Company
Logo used DOF on a moving camera and turned out very nice. Computers always
get faster and faster and we just buy more and more to do our work. It's all
part of business. If you want it, you just got to fork out the CASH and go for
it. A recent article in LIGHTWAVE PRO by Grant Boucher of Amblin Imaging gave
first time testing of LW on a DEC Alpha in WinNT. Surprisingly, on the Alpha,
ray tracing was FASTER than non-ray tracing on the same machine! In fact a
scene on a stock 040/28 took 4944secs and on the Alpha took only 353secs.
That's a factor of 14x faster. Speed is no longer a big problem. If you want
it or need it, you can buy it. The MIPS R4400 took 1594secs, MIPS R4600 took
846secs. A Pentium 90 should be about same as MIPS R4400 but was not yet
tested. Imagine 3DS on the Alpha/WinNT!!!!!!!! Boy would that ROCK!
<<Do you use Lightwave regularly? I do, as well as 3DS and others.>>
<<<David, if you want to get into some sort of battle of who has the better
toys, you're talking to the wrong guy. Cuz I just really don't care. It
doesn't matter what you've got, but how you use it 🙂 >>>
Sorry, this is badly phrased. Keep in mind my good buddy is in town form USC
Grad FILM program and we have been playing DOOMII networked til about 5am
nightly. Should read:
I use Lightwave AND 3DS so I feel qualified to speak well on both platforms. I
just wanted to point out that some of what you said about LW was incorrect. I
really don't care which programe works better, as long as they BOTH do what I
NEED.
<<Now take this whole message with a small grain of salt (and maybe a shot of
vinegar) because there's really nothing in this whole thread that's all that
personal.
Aaron >>
Your right. However, I still stand on my comments concerning your Crayola
comment. I do not see your "theoretical metaphor" and think it was off base.
Are we having fun yet!?
Zippy.
DrS
<<Surprisingly, on the Alpha, ray tracing was FASTER than non-ray tracing on
the same machine! In fact a scene on a stock 040/28 took 4944secs and on the
Alpha took only 353secs. That's a factor of 14x faster.>>
Add to that a real-time polygon shader and SGI had better come up with
something real good, real fast or they're looking at a pretty bleak future.
There are already a couple dozen of these cards in the works for NT machines!
Aaron
>> Add to that a real-time polygon shader and SGI had better come up with
something real good, real fast or they're looking at a pretty bleak future.
There are already a couple dozen of these cards in the works for NT machines!
Aaron <<
You said it! There are just amazing speed advances heading towards our
desktops very soon now. I can hardly wait.
"…The future's so brite, I gotta wear shades…."
Later 🙂
David.
<<Based on my earlier assumptions, than LensFX would need to EMULATE a
lens-focal-system in software. It would have to have a software equivilent of
an f-stop and use 3DS's CAMERA focal-length from the KEYFRAMMER. By doing this
than the physics is black and white if you have CAMERA Depth-of-Field,
Hyperfocal Distance & Field of View charts (lookup tables or calculated).>>
Actually, LenZFX Z Focus has a focal plane (since focal-length in 3D Studio is
really nothing more than a field of view, just as with a camera), and an
equivalent for f-stop. I decided to stray from the norms of camera buff
terminology because it is too restrictive. F-stop is really an enhancement or
diminishing of photographic intensity and has very little use for practical
control to a computer animator trying to control scene blur. These are both
controllable with spline-based envelopes. In addition it comes with auto-focus
and object tracking capabilities.
David, no offense, but if you think all of this is sooooo simple, then please
use your knowledge to build the perfect camera or the perfect rendering system
and you will be so fabulously rich that you won't have to bother with what any
of us bozos thinks. Best of luck 🙂
Aaron
>>David, no offense, but if you think all of this is sooooo simple, then please
use your knowledge to build the perfect camera or the perfect rendering system
and you will be so fabulously rich that you won't have to bother with what any
of us bozos thinks. Best of luck 🙂
Aaron <<
Thanks for the explaination of how LenZFX deals with the subjects which I
tossed into this rapidly boiling kettle. The information you offered on how
this product handles the idea of DOF and is informative and helpful.
I don't quite see how you can ignore the "camera buff terminnology" and toss
aside the "lens system metaphor", however. Yes, computer graphics is a
different disipline. But when you look at the fact that most people in CG are
striving towards reality in their images (as in Hollywood work…) then the
image should follow the same PERCEPTUAL principals that we are exposed to
everyday with Painting, TV, Video, Photography, and Film. The method to get
there can be way out of left field, but the end result needs to look correct,
or the viewer will question the output. As I said before, I would like to be
able to use a standard lens DOF chart to check the accuracy of a CG DOF image.
Is this possible with your software?
To the best of my meeger knowledge DOF is a term used only for lens optics and
the human eye. It's a known and PREDICTABLE principal. If your system does
not adhere to this principal, than it is not a true DOF emulation and might
best be termed Computer Graphics Distance Blurring. I have no problem
what-so-ever with a system of CG blurring which does not really emulate a real
DOF scenario. Just tell me that it's not accurate and does not follow the
known DOF principles of optics.
Also, I never said any of this stuff was "soooooo simple." I said it was black
and white, meaning if you had the right data inputs, the math is there to
calculate the correct answer. Implemmenting that data the "correct" way is
no-simple-task. It's not even easy to talk about it.
This whole intellectual discussion (which by the way is why I pay big bucks to
type endlessly at people I have never seen..) began when one person said your
image was not correct to percieved reality as we now understand it. Some
people agreed, others didn't. That's what discussion is all about. If at
least one person in this discussion has gained knowledge that they did not have
before this started, we have done well. If the information they gained is
correct, we have done even better.
Lastly, I would never call any member of this forum a Bozo. Bozo does a show
on WGN in Chicago. The people on this forum are a wonderful collection of
Graphaholics who I respect, even if we don't always agree on all topics 🙂
D O F
o v i
n e n
e r i
David:)
Scott,
I don't mean to swamp you, but you inquired.
<<The image reflected doesn't gain any special properties because of the
location of the mirror. The reflection's state of focus is solely dependant on
a simple equation: the distance from the viewer to the mirror + the distance
from the mirror to the reflected item.>>
I think anyone who's looked through a telescope or a pair of
binoculars would argue the first point. And as for the second, you
are correctly stating the equation for the distance traveled by a ray
of light, but this has absolutely nothing to do with how a camera or
our eye perceives the focal qualities of a scene. For example,
A —————–C
\ /
\ /
\ /
\ /
\/
B
\
\
\
D
A is the viewer or camera, C is an object, B is a reflective object, and D is
an arbitrary point so that CB = BD. When viewing the scene from A, light
travels from C to A by AC and from C to A by CB, BA by reflection from B. Now
it is your contention that since focus is based on the additive property of the
entire length of the rays path, we should be able to bring the reflection of C
on object B into focus by placing the focal point at D. To back up a little
bit, lets assume that object B is not perfectly reflective. Meaning that
object B will add, say 50% of its light reactive qualities to the perceived
reflection, as is the case with a polished desk top. Given our focal point at
D, your theory of focal perception, and object B adding its qualities to the
reflection, what we'd have is a reflection that is in perfect focus (since AD
is our focal range) superimposed upon a surface which is out of focus (since AB
is not our focal range). I'm trying to imagine how this would look but I'm
absolutely certain that it's nothing I've EVER seen in real life.
It's obvious that you've investigated quite seriously into occular physics and
I think you'd find it interesting to read and learn how those theories that
have been around for hundreds of years are put into practical use through
ray-tracing and other fields of computer imaging.
Aaron
>>…what we'd have is a reflection that is in perfect focus (since >>AD is our
focal range) superimposed upon a surface which is out >>of focus (since AB is
not our focal range). I'm trying to imagine >>how this would look but I'm
absolutely certain that it's nothing >>I've EVER seen in real life.
Hello Aaron,
I was going to keep out of this, largely because precise science is often
irrelevant in this field since most of what we do is subterfuge and trickery.
But although it may not detract one bit from the usefulness of your your
software to 3DSers everywhere, there is some confusion here. I work at a
national lab with a group of scientists and optical experts, and I can point
you towards reference material if desired. We run several laser and optics
labs with specialties in fiber optic systems, image processing, and
thermographic imaging.
The case of a partially reflective surface is more complex, however with a
near 100% reflective surface such a mirror at B in your diagram, you do IN FACT
focus on C as if it were actually at D. If you want a simple example, try this
experiment: with an ordinary (focusable) 35mm camera, stand about 2 ft from a
bathroom mirror. Place a piece of tape on the mirror surface for reference and
focus on your reflection in the mirror. Note that when your reflection is in
focus, the tape (and the mirror surface and the mirror frame) are very much out
of focus. In a nutshell, you can treat a plane mirror as a thin lens with a
magnification of unity (check any college physics book.)
Now a partially reflective surface is a different story, depending on to what
extent the reflections are diffuse or specular (you can simulate this to some
extent by placing layers of plastic wrap on the mirror), and when the surface
is not flat, it gets much more interesting.
It is not surprising that there is some confusion here, since the concepts
around virtual imaging are often conceptually challenging. <g> Even simple
lens concepts are difficult, especially when considered relative to the virtual
imaging in the eye. (When faced with virtual imaging calculations involving
compound lenses, I always run posthast down the hall and talk to Dave Sitter,
PhD!)
All this said, I agree with Gary Yost's carefully worded statements,
"There are always some inherent physical differences between
doing things via scanline rendering instead of with raytracing, but
since raytracing takes about an order of MAGNITUDE more time to
compute, any production animator would take the scanline method ANY
DAY OF THE WEEK…"
and
"…your optics package is going to be one of the most valuable
tools a 3D Studio animator could have…"
I agree that the tremendous potential of your program, regardless of the
precise technical tradeoffs involved, will make it one of the most used IPAS
routines yet. The bottom line is not "how did you get there" but "how does the
result look."
JKJ
< what we'd have is a reflection that is in perfect focus (since AD is our
focal range) superimposed upon a surface which is out of focus (since AB is not
our focal range). I'm trying to imagine how this would look but I'm absolutely
certain that it's nothing I've EVER seen in real life.>
PMJI
Ive just done the experiment with a dirty mirror and the computer screen. What
I saw when I focused on the screen was the mirror out of
focus. In additionI saw the dirt on the mirror "double". When I focus on the
mirror I get a double, out of focus computer screen.
As a student of visual perception ( I teach color theory, drawing and design
courses ) Im interested in why an image ( painting or photo for example ) of
the the way things actually look, in this case out of focus and doubled, would
seem so unrealistic. The class example I use is to ask students to focus on
their hand in front of their face and then, without losing focus on the hand
examine the background. It dosnt look real but it is real life.
On the subject of Lens FX I look foward to it. I really like the way XAOS
uploaded a disabled version of Penello. I hope the idea catches on.
Ed
This whole field just fascinates me. There are a lot of visual anomolies
between human perception and the way a camera can look at an object, with the
camera view probably being closer to reality since it is a machine and
therefore objective. And as to the last word, I think that's still waiting to
be heard. It's my opinion that no one really knows whats going on with this
field…if we did, we'd have cloaking devices by now.
Aaron
Hi Aaron
" with the camera view probably being closer to reality since it is a machine
and therefore objective."
Here I have to really disagree. We are the percievers, not the cameras or any
other instruments that we make. Beyond the obvious
lack of stereo vision in all but specialized cameras and images I think there
is a philosophical point to be made about who it is that is
aware of the universe. I am also facinated by the subject . Its interesting to
me, for example, that people think that B+W photos
look "realistic" when as Ansel Adams pointed out they are very abstract.
Ed
EO:<< " with the camera view probably being closer to reality since it is a
machine and therefore objective." >>
EH:<< Its interesting to me, for example, that people think that B+W photos
look "realistic" when as Ansel Adams pointed out they are very abstract. >>
PMJI, but I think that was the point that Aaron was trying to make. As you
point out, people see the same thing differently….subjectively. The camera
therefore possibly being more "accurate", not being influenced by the
post-imaging processing carried out in the brain. Of course, with modern
programmable & AI cameras, that argument has less validity <g>.
BILL
Bill,
" The camera therefore possibly being more "accurate", not being influenced
by the post-imaging processing carried out in the brain. Of course, with
modern programmable & AI cameras, that argument has less validity <g>."
If a camera atop a tripod is triggered by the motion of a falling tree,
and captures the moment for posterity, but no one ever sees the picture…
did the tree really fall?
\ | /
…………<click>…………………………..\|/ kevin
/|\
/ | \
<< If a camera atop a tripod is triggered by the motion of a falling tree,
and captures the moment for posterity, but no one ever sees the picture…
did the tree really fall? >>
Uhhh…..Yes.
BILL
Yes
<<We are the percievers, not the cameras or any other instruments that we
make.>>
Good point. What I meant to say is that what we perceive can be as much
psychological as physical. And psychological observations aren't very
objective.
Aaron
Scott:
PMJI, but Aaron is correct. When you see an object, you don't really see it,
but rather light rays bouncing off of it and entering your eyes. For all
intents and purposes, the original source of those light rays doesn't matter
(the sun, a lamp, car headlight) — the object COULD be thought of as emitting
the light if you wish. Now, the light that the object reflects is based on its
surface properties. Say the table surface in question was a matte red surface.
You would see a red plane because all other light frequencies are absorbed by
the table, and only the red are reflected. Now, if the table surface were a
perfect mirror, then the light rays reflected to your eyes would actually be
those leaving all other objects in the "field of view" of the table surface,
hence a mirror image, or literally, a _reflection_. Now, because FOCUS is a
concept for eyes and lenses, and not for light rays or surfaces (okay, you
COULD make a case for surfaces, as the qualities of a surface could scatter the
light rays in an out-of-focus-like manner), a reflection of an OUT-OF-FOCUS
item off of an IN-FOCUS item will always be IN-FOCUS.
Now, I think your original problem with the STILL.JPG was that you maintained
that the table is partly out-of-focus, but that ALL of the reflection in it
seems to be IN-focus. While I think this APPEARS to be the case, it is not. If
you ZOOM in on the image in an image editing program, you will see that the
reflection of the edge of the bulliten board BELOW where the stick-pin is
laying is sharp, while where it continues above the pin it is fuzzier (esp.
above the shadow to the table edge. The problem is the area of the table that
is out of focus is so small and dim, and is at the back of the image, there is
just not enough reflection on it to clearly see the reflection un-focused.
Does any of this make sense, or am I just muddying the waters?
Dave
<<If you ZOOM in on the image in an image editing program, you will see that
the reflection of the edge of the bulliten board BELOW where the stick-pin is
laying is sharp, while where it continues above the pin it is fuzzier>>
Jeez David, I didn't know you were gonna go over the image with a fine-toothed
comb! 🙂
Wait til you get my report on the image's pixel-by-pixel deconstruction!<G>
Dave
BTW, I've been reading with interest some of the other posts now in this
thread, and I'm waivering. My FIRST inclination when coming upon this thread
the other day, was that indeed focusing on a reflection WOULD put the mirror
object out of focus, as it appears to be a virtual image an equal distance
behind the mirror as the real object is in front. But, then I thought, well
heck, it's just reflected light rays, just like any other surface, so it should
be in the same focal plane as the mirror. This was the philosophy under which
I wrote my message.
Now it appears that maybe my first instinct was correct. Still, I think that
in the image in question, STILL.JPG, the refelction does look good, and does
blur in the area of the table top that is out of focus, and remind myself that
a semi-mirrored surface is much more nebulous than a perfectly mirrored one.
Well, I think I've sufficiently muddied the waters now, so I'll take my
leave!<g>
Dave
Aaron, David
I apologize for any inaccurate assumptions I may have made, but I did warn that
I was NOT a physicist in my first note. I think I have probably proven that
pretty well by now : ).
<< what we'd have is a reflection that is in perfect focus (since AD is our
focal range) superimposed upon a surface which is out of focus (since AB is not
our focal range). I'm trying to imagine how this would look but I'm absolutely
certain that it's nothing I've EVER seen in real life.>>
<< a reflection of an OUT-OF-FOCUS item off of an IN-FOCUS item will always be
IN-FOCUS.>>
So maybe I am way off base, but if I am then could someone explain to me how
you are able to look at one of those stereogram posters and change your focus
from the image to the reflection on the surface? Maybe I am reading what you
are saying wrong, but your argument seems to say that the reflection would
always be in focus when the reflector is in focus. Another example would be in
a movie when there is a shot of a rear view mirror and the reflection is in
focus while the mirror is not (can't quite remember the specific movie I'm
thinking of).
Also, I don't want to get defensive (I'm sure you think its too late for
that!), but when I said "The image reflected doesn't gain any special
properties because of the location of the mirror," I meant to stress
"location"- I wasn't implying that the surface qualities of the reflector
(color, texture, etc.) wouldn't affect it.
I really didn't mean to impugn (?) the quality of your product. Only that of
your sample image. Please accept my apologies.
Scott "am i flamed yet?" Roberts
Scott,
No hard feelings. I actually love a good heated argument, umm, I mean debate.
Just ask my brother. It's a wonder we BOTH survived childhood.
<<So maybe I am way off base, but if I am then could someone explain to me how
you are able to look at one of those stereogram posters and change your focus
from the image to the reflection on the surface?>>
The poster and the poster's glass case (I'm assuming this is the reflection
you're talking about) are two completely different surfaces.
<<Maybe I am reading what you are saying wrong, but your argument seems to say
that the reflection would always be in focus when the reflector is in focus.>>
Only if your reflecting surface is a perfect mirror. And a perfect mirror is
nearly impossible to find naturally. Most surfaces will at least slightly blur
a reflection, that's why 3DS gives you the reflection blur slider.
<<Another example would be in a movie when there is a shot of a rear view
mirror and the reflection is in focus while the mirror is not>>
A focal effect is actually due to the differing angles that light enters a
camera or your eye, and the lens element composition and placement in the
camera (in the case of a camera) or the shape of your cornea and eyeball (in
the case of your eye). Light coming from different depth planes of a scene
generally reach your eye at different angles and thereby gives the classic
depth-of-field focus effect. However, it is easier for us to think of focal
effects based on distance rather than a bunch of angles and lens refractions.
Early cameras were pretty simplistic though and often relied on the exact
center of an image to be the focal point and then blurred the edges of the
image. This is probably what you're seeing in the rearview mirror example.
Aaron
>>So maybe I am way off base, but if I am then could someone explain to me
>>how you are able to look at one of those stereogram posters and change
>>your focus from the image to the reflection on the surface?
Personally Scott, I'm convinced that those stereogram deals are the emperor's
new clothes! Person A says, "Hey, look at this and you'll see a 3D-whatever!"
Person B, not wanting to admit that try as he might, he can't see ANYTHING,
says, "Oh yeah, I see it! Neat!" He then proceeds to tell HIS friends, etc.
<G>
Really, based on some new messages in this thread, I'm not really convinced
that I know what _I'm_ talking about anymore. It now seems to me that the
question of should the mirror AND the relection both be in or out of focus will
depend on the depth of field of the lens and the distance between the mirror
and the object being reflected — ie if you focus past the mirror onto the
reflection, which is some virtual distance behind the mirror plane, and the
mirror itself then lies outside the focal range, then the reflection is IN
focus, but the mirror itself OUT of focus.
One thing I know for sure is _I'm_ out of focus, and I wish I remembered more
from my jr. high science class when we spent quite a bit on time on lenses and
virtual images!
Dave
>>Does any of this make sense, or am I just muddying the waters?
No, Yes. <G>
I do a lot of rack focus effects with a camera and sometimes do effects like
capture surrounding reflections in peoples sunglasses. Here is how it always
works in the real world. The focus can either be the surface of the mirror
eg. scratches/printing/frame/ even dust and dirt on the mirror surface, or, it
can be a distant reflection of the world surrounding seen as an image in the
mirror. The only time it is possible to focus in on both is when the camera is
receiving enough light to allow for greater depth of focus where the range of
focus includes the distance between the mirror and the light path to the real
world surrounding the mirror that is being reflected. To facilitate this
greater depth of focus I use a wide angle lens and shoot the mirror surface up
close. To achieve the rack focus effect I use the telephoto lens and then vary
the focus ring over time. Telephoto has a much tighter depth of focus.
This is not a complicated issue for a cameraman but I guess it is for people
knowledgeble in the laws of optics physics and virtual reality experts. <BG>
Jeez, look what I started.
When I first made an inquiry about the reflection in the sample image, it
wasn't to start an argument. I am merely a serious, PROFESSIONAL animator (I
really doubt that any animations that I have done would look like "they were
done by a 5 year old with a crayon" no matter what they may be compared with)
who wants to make sure that the tools that he spends money on are up to the
quality standards of my clients. I also happen to have spent over ten years
studying almost every aspect of visual perception I could get my "hands" on,
from perception to photography. I am NOT an expert on math, raytracing, or
computers and don't claim to be.
I questioned my views when I read your responses and when several people posted
in support of your theory, with none in support of me. To me this is what
someone who is concerned with the truth does (David Rhoten, for example : )).
I did several experiments to test out if I was being stupid (as I admit I often
am) and spent WAY too much time pondering it, in the obsessive way which is my
very own. I wondered if I was confusing the problems of representing how we
2-eyed creatures see a reflection (kind of floating on a separate focal plane)
with how the 1-eyed camera sees it. I am glad that you gave me this
opportunity to reconsider all of this, as I should have done more of before
responding to your first response.
In the end, however, I am convinced that either we are talking about different
things, or that you are mistaken. What may have happened is that I confused
the issue by arguing it incorrectly. I suggest that anyone really interested
in this should read the messages posted by JKJ and Don Landis for some much
more clear explanations of the phenomena than I could have written. What some
people may be mistaking for seeing a mirror and its reflection at the same time
is the way that the human eye can change focus from one to the other so quickly
that its almost imperceptable. The camera doesn't have this same ability.
As for your comment, <<And as to the last word, I think that's still waiting
to be heard. It's my opinion that no one really knows whats going on with this
field…if we did, we'd have cloaking devices by now.>>, I am sure that the
field of optics has probably progressed far beyond the point of our
discussions. If a serious scientist got ahold of this thread, he'd probably
think that it was WRITTEN by 5 year olds with crayons <G>.
BUT, regardless of this, the value of your product has been proven. If it
takes this much discussion just to prove that the reflection in STILL.JPG is
incorrect, then it probably will go unnoticed by anyone viewing animations made
with it. From the beginning, all that I wanted to know was whether you could
fix it. Now its up to me to decide whether its worth the money, and after the
glowing endorsements of Mr. Yost and JKJ I'd probably say yes. Would there be
any way that you could upload a flic of the depth of focus effect MOVING? If I
could look at that (with the things in focus and the angle of reflectance
changing) it would eliminate any hesitations I still have.
respectfully, and friendly-ly,
scott "Nyquil" roberts
Hah! Good, as I think I came up with a similar statement in one of my more
recent posts, regarding the importance of the distance between object and
reflector, and the current depth of field!
Dave
Scott, Actually the reflection would be in focus, just like it is in the sample
image. Think about it, the wall is out of focus to the camera – not the
table… The reflection of the wall in the table would have to be in focus
since the table is in focus. This seems so simple to me, I can't understand why
you don't get it. It is right…
Dave Mennenoh
<< Actually the reflection would be in focus, just like it is in the sample
image. Think about it, the wall is out of focus to the camera – not the
table… The reflection of the wall in the table would have to be in focus
since the table is in focus. This seems so simple to me, I can't understand why
you don't get it. It is right…>>
It may seem simple to you, but it actually is a very complicated subject. Just
because the initial responses to my views were negative doesn't make them
right. Have you thought this out? Have you went to a mirror or reflective
surface and experimented to make sure that it works like you think? I have,
and I stand by my initial observations.
scott