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Poser - OFFICIAL F.A.Q (Last Updated: 2025 Jan 14 12:25 pm)



Subject: Focal Length and face distortion


Muscleguy ( ) posted Thu, 09 January 2003 at 12:30 PM · edited Mon, 13 January 2025 at 7:51 AM

Attached Link: http://www.renderosity.com/viewed.ez?galleryid=310966&Form.sess_id=2832734&Form.sess_key=1042136757

file_40526.jpg

I discovered something while playing with a photoshop postwork tutorial. I had no idea the pronounce effect the focal length had on forshortening and image distortion. I just thought Mike was naturally big jawed. These are identical figures rendered from the face camera set at different focal lengths


-renapd- ( ) posted Thu, 09 January 2003 at 12:39 PM
Site Admin

Muscleguy.. this is well known to photographers (like Paul Hafeli who first posted an extensive tutorial on the subject back at Poser 3 days) and this is why the Poser camera lense has available settings same as any normal camera! :) Hope this is read by many newbies as well so they stop wondering why their models don't look same as the rest they admire around the galleries! :) BTW.. even the default camera needs to be adjusted for a better output.. same with all the rest. :) Rena



[[MyGallery] [MyStore]
"Collect moments, not things."


-renapd- ( ) posted Thu, 09 January 2003 at 12:40 PM
Site Admin

Oh.. Try a real close up of Mike's face at 120 and then you'll see what I mean! :) Rena



[[MyGallery] [MyStore]
"Collect moments, not things."


Muscleguy ( ) posted Thu, 09 January 2003 at 1:23 PM

file_40527.jpg

Body distortions seem worse at very low numbers. I already knew about focal length in theory but never thought much about it in practice. Cool, a new toy!!!!!!


queri ( ) posted Thu, 09 January 2003 at 2:26 PM

I noticed how the texture atches the face better. Look at you first picture. the guy on the right, his texture has a slightly blotchy tone to it because it isn't behaving exactly how we expect a face to confrom itself. The one of the left looks more professionally done-- more what the artist actually meant. I first started correcting my focal lengths for the texture then noticed how much better the actual face looked. Poser 5 isn't quite as bad-- they at least have the default for the face camera at 50mm. But I usually put the face at 120-- we all have favorites-- 120 is my standard camera focus. But some models morphs and textures look their best with even higher numbers-- like 180 200. Play with it and see what you like best. Just never use the default unless you are going for a special effect. Emily


canary3d ( ) posted Thu, 09 January 2003 at 3:06 PM

by the way, if you set up your camera focals the way you like them and then save your preferred state, it'll use your new settings as the defaults as long as you don't use "factory settings."



Stormrage ( ) posted Thu, 09 January 2003 at 3:14 PM

i set my camera's at 400 It really makes a difference in all the characters.


pendarian ( ) posted Thu, 09 January 2003 at 5:03 PM

My camera focals area all set at 100 to start with by default...huge difference and the only way I work now. Pendy


fls13 ( ) posted Thu, 09 January 2003 at 5:52 PM

It all depends on the kind of shot you're looking to make. If it's a close-up, higher is better. But if you keep that high focal length for a wide shot with a few characters, your picture is going to flatten out and background textures will be out of focus.


pendarian ( ) posted Thu, 09 January 2003 at 5:54 PM

I've not found that to be true actually. 100 works for me just fine...I do sometimes lower or raise it, but it just depends on the shot that I'm doing. I've not had any problems with the background textures being out of focus or my images actually looking flattened out.


fls13 ( ) posted Thu, 09 January 2003 at 7:04 PM

I looked at some of your stuff, and you're not getting the out of focus problem because your characters are, for the most part, butt-up against the backdrops, but they do flatten out. I thought Guardian was as it was downloading, until I got to the goat's legs. Then I saw the figure was 6-8 Poser feet from the backdrop. I'm talking about scenes much wider, with multiple characters, 10-20 feet from the backdrop. If you still have the Aria's dream file, try re-rendering with a 35 or even a 25 focal length. I think you'll see what I mean.


wadams9 ( ) posted Thu, 09 January 2003 at 9:03 PM

IMHO, a LOT of otherwise sophisticated 'rosity folk don't know about focal length. Otherwise they would never do the Marketplace thumbnails of their characters in ugly fisheye default 38mm. (I swear we see that more often that not!)

I default 55mm distance, 100mm closeup, but of course fls13 is right, you want to play around depending on what you're going for in a particular shot.


pendarian ( ) posted Thu, 09 January 2003 at 9:20 PM

As I said before, it depends on the shot that I'm doing. All I worry about is what it looks like when it's printed as that is where the majority of my images end up, not here. This is more like a test market for me then the end product. Trust me on this, they aren't flattened out in the prints.


_dodger ( ) posted Thu, 09 January 2003 at 9:37 PM

120mm approximates the settings used by most fashion photography view cameras. I haven't gotten a striahgt answer about the lens size Poser assumes at default 100% scale, but the focal and lens size together actually determine the depth of field. In a traditional SLR, the aperture setting (F-stop) determines the functional lens size. From what I can figure based on the fact that a 50mm focal length approximates the human eye according to the documentation, and that an average human eye has a 9mm lens with a 17mm focal length, the lens size seems to be probably 28mm, which would lead to a 48mm focal for human eye approximation. Of course, that's only if they're right. B^)


tasquah ( ) posted Thu, 09 January 2003 at 11:52 PM

.


Muscleguy ( ) posted Fri, 10 January 2003 at 7:04 AM

What would be considered an appropriate focal length for a multifigured scene shot from say 50 feet away.(I know that that is not a real poser unit but you know what I mean)


Muscleguy ( ) posted Fri, 10 January 2003 at 7:08 AM

What would be considered an appropriate focal length for a multifigured scene shot from say 50 feet away.(I know that that is not a real poser unit but you know what I mean) In the group image above the individuals from 25 to 150 look reasonable. I am guessing that the lower focal length might work better if you had several characters not all the same distance from the camera


Muscleguy ( ) posted Fri, 10 January 2003 at 10:03 AM

file_40528.jpg

I think I have it now. This image above shows what fls13 way talking about. The 300mm image looks very flat.


_dodger ( ) posted Fri, 10 January 2003 at 6:23 PM

300 is bordering on being non-perspective (like the side, top, and front cameras). However, it could be very useful for things like logo design. 25 MM increases the drama of the arrangement, but it also sort of creates the illusion the front figure is too far from the back figure to sock him one. 50mm creates a good impressiont that the two are getting ready to box and doesn't leave the viewer feeling that they are too far apart to get the job done. I'd go with something between 50mm and 25mm, to create tension and a real 'fight scene' if that's what you're going for. But you see how different focal length and depths of field lead to different impressions of what's going on. In 2, above, th character are boxing, and the back Mike is maybe takling to his agent behind the ropes. The music is something out of Rocky. In 3, above, the heightened drama from the lower focal length and increased perspective distortion creates a wholly different scenario. I get the impression that the back Mike has just been cornered in a dark alley where the front Mike is about to beat him up or stab or shoot him (you can't see his hands, and it becomes more important that you can't here). The music is something out of a thriller or Batman, perhaps. Much darker. The foreground figure becomes more imposing than the background because the heightened perspective makes him actually bigger on the flat screen, even though we don't think he's bigger, he seems bigger. Also note how the composition shifts between them. People naturally follow arrow-shapes. In the first one, the back Mike is taller, and the outthrust elbow of the front Mike leads the eye to follow the shape from left-to-right. That measn you 'read' the back Mike first. I the middle one, they are about balanced so you focus on both pretty much equally. In the last one, the smaller back Mike leads the eye right-to-left, so you see the front Mike first. This and the size change shifts who is the 'attacker'. The balance of the centre one giving the impression of a 'fair fight', thus the Boxing thing again. ALso note that despit ethe heightened drama of the third one, the composition is goofed up because the back Mike's face is suddenly shoved into the front one's shoulder. That woudl require some adjustment before using it, to avoid the partial-face-cutoff. So, really, it all depends on what will best tell your tale.


fls13 ( ) posted Fri, 10 January 2003 at 7:42 PM

MG, you should put together a turtorial on this.


jval ( ) posted Sat, 11 January 2003 at 10:09 AM

...MG, you should put together a turtorial on this. This one has been around for awhile: http://arcana.daz3d.com/tutorials/jv/jv01/index.html


fls13 ( ) posted Sat, 11 January 2003 at 10:42 AM

Who would go looking for tutorials at DAZ? At least they didn't charge $10 to download the PDF file of the tute. MGs illustrations of the concepts are vastly superior.


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