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Are we making models fatter? Or am I beating...
... a dead horse? I hope I'm not... if I am beating a dead horse, then please kindly point me to the old thread! Now the question: Given same exact frame coverage on, let's say, a headshot... 2 images, one taken with, let's say, an 135mm lens and one taken with an 17mm lens, will not look the same. The 17mm will make the model "fatter", correct? Again, this is assuming that you compensate for the focal length by physically moving closer to the model with the wider lenght to equal the frame coverage... Now, many of us shoot with 1.6/1.5 crop cameras... so to conpensate for the distance we are standing from the model, we use wider lenses... So... to put the question in a funny way... are the 1.6 crop cameras making us make the models fatter? Is the difference from, let's say, 56mm in an FF camera and 35mm on an APS-C making the appearence of the model slightly different that it should be? Are there standard lenses that FF users use (e.g. 85mm or 135mm) that the APS-C users are emulating (e.g. 53mm or 84 mm) for distance and therefore changing the "look" of the image? Obviously, the longer focal lenghts wont matter too much, but the wider end? Those used to 50mm focal lengths? 35mm? I ask this question to hear oppinions and experiences from all the working photogs out there... this turned out to a bashing on DPReview, so I hope it won't sink to that level! Thanks a bunch! Aloha!  Sep 22 05 02:12 am Link I wondered about this at one point and after a little bit of geometry on a piece of paper I convinced myself the perspective offered by my 50mm lens was the same as the perspective of a 80mm (85 for practical purposes) lens on a 35mm camera (film or full frame digital). So by using the mutliplier you can related you dslr lens to traditional lens and apply the traditional rules. Regardless of lens.... we can make models fatter. I shot with a model last week and between her posing and my camera angles... yikes. I need to find the book on how NOT to do that again. Sep 22 05 10:55 am Link All about angles, positions, curves, etc, not just so much the lens. True some of the wider lens will have corner distortions, but any good wide angle lens usually have these corrected. Sep 22 05 11:59 am Link On your 1.6x crop at 35mm you will be almost the exact same distance away from the model as a person with a full frame camera and a 50mm lens, this is if your wish to see the exact same framing on both camera bodies. So no your not making anyone fatter by having a cropped sensor! Now on any camera body shooting the model at 135mm versus 20mm will change the perspective and look of the model for sure. The short telephoto lenses 85-135mm are great for modeling work due to the way they compress the images. When your closer with a wider lens it all changes and you lose the effect, but sometimes that desirable. Again nothing to do with the body of the camera, its the distance from the model and your angle that can make a model or part of a model look HUGE! Sep 22 05 12:33 pm Link properlyexposed wrote: You now I had to practice that "distance from the model" to get it right. Apr 12 06 01:44 pm Link Actually, I believe that if you use a wide angle lens on a digital SRL with a "crop factor" to fill the space of say an 85mm lens on a 35mm camera you will get distortion. The crop factor does not magically turn a 35mm lens into a 52mm lens; it is cropping out the middle of the frame. Any distortion you have from the 35mm lens (this is a moderate wide-angle lens) will still be in effect with the digital crop factor. Because a wide angle lens distorts more to the edges and is dependant on the angle you're holding it in relationship to the subject this might not be as noticeable. But it is still there. This image was taken with a 17 - 35mm lens on a Nikon D1x with a 1.5 crop factor. There is very obvious distortion -- the 17mm wide angle didn't become a more moderate 26mm lens.  My advice would be to photograph people with the same lens you would use on a 35mm SLR; just stand back further from your subject. I wouldn't reccomend replacing your 55mm lens with a 35mm lens so your shooting distance can be roughly the same; you will start getting subtle distortion and may indeed make your subjects "look fat." The digital crop factor isn't a teleconverter; it's a digital crop. -P- Apr 12 06 02:07 pm Link I think you've got two questions here. One, do lenses with a 'crop factor' match their 'mathematical twins,' and two, what framing elements make models look fat. I believe that using the 'crop factor' does NOT make the lens behave as it's mathematical twin. For example, an 85mm lens 'medium telephoto lens' on a 35mm film camera has a nice 'compression' effect. a 50mm lens on a dslr with a 1.5 'crop factor' equals the "VIEW" of a 85mm lens... but that does NOT make it a telephoto lens, and therefore does NOT have the nice 'compression' effect. The "view" comes only from the cropping of the sensor. so far, my experiments with my new dslr have me using the 'old' lenses i've always liked, and I have to BACK UP to get the framing I want, again, to get what I want onto the smaller sensor. when I get the dough, i'll go full-frame and give my mind a rest! Unless someone can explain to me that I'm mistaken? second question: models looking fat... I think it's a matter of subject distortion in the lens/frame, which is why telephotos are popular in the first place!? But i don't have a clear method here, I'll defer to others... -john Apr 12 06 02:09 pm Link Pat, you said it while I was a-typin'! But I've posted again to say (hijack) NICE PIC!! -john Apr 12 06 02:12 pm Link Like others have said, I compensate for crop factor by backing up rather than using a wider lens. Yes, I believe if you remain the same distance and use a wider lens to compensate on the crop camera you will see more perspective distortion (haven't actually tested it though  ). Whether or not the perspective distortion makes the model look "fat" depends on the composition, it can also be used creatively, like the photo posted by Pat above. I almost never shoot people with less than 50mm unless I'm going for that effect, and usually it's 85 or 135. Apr 12 06 02:49 pm Link When I read the title, the first thing that came to mind was... "Food....is making the models fatter". But I digress. And since the answer is already given by Pat etc...I'll just leave it as that. Apr 12 06 04:06 pm Link It's a matter of public record that models are fatter than 20 or 30 years ago! But that's not because of format changes or digital cameras. Photographers are blameless (unless they pay models too much). Photography is all about rendering a 3D scene onto a 2D surface. Perspective, focus, shading and color are some of the tools. There will always be distortion. It's a question of taste and norms. There are plenty of tutorials around that explain the causes of fattening and compression in photography (perspective distortion). Btw, fattening is the enlargement of near features. For every frame (crop or subject) size there is an almost infinite range of subject-lens distances available. What is important here is the subject-lens distance for a given subject depth. For an individual subject's head (portrait or headshot, subject depth of 10"), the subjective point of balance between fattening and compression is for the lens to be about 5 to 6' distant - irrespective of format, sensor size or focal length. Some may prefer slightly further especially if the subject has a prominent nose or chin, enlargements not normally desired by models. To take advantage of full frame resolution, portrait photographers use 85mm to 105mm lens on a 35mm camera as a compromise between fattening and compression. This corresponds to 57mm to 70mm on a 1.5 factor digital sensor. So irrespective of sensor or film size, once the correct subject to lens distance is determined (perspective), then the focal length is selected (usually by zooming) to fill the frame or crop through magnification. Test this yourself by putting the camera on a tripod and focusing on a head at 6'. Does changing the focal length (by zooming) change the perspective or distortion of the head? No, zooming (unless the lens is crap) only changes the framing or crop. Try any format camera (or even your fingers in a square) - at the same subject distance the perspective distortion remains the same. Once the correct distance is established, cropping can be done before or after with the same effect on distortion. But cropping done before (by the lens) gives you better quality because of limitations in sensor resolution. This is why consumer cameras have moved away from digital zooms back to optical zooms. If a subject is has arms or legs forward or is lying in line with the camera, then the depth of the subject is much greater. Fattening (noticable enlargement of near features) will occur until the camera is moved back. However, the usual reason for posing the subject with a lot of subject depth is to deliberately cause this distortion. Distortion (magnification of near features caused by getting close) is often used to advantage in model torso shots, where the breasts can be made to look a bit larger than life, a feature often appreciated by models. Apr 12 06 05:09 pm Link Well that blows my theory out of the water now, doesn't it? Apr 12 06 05:35 pm Link Gary Davis wrote: It's a bit academic. You soon learn what works and what doesn't for the effects you're after. There is no substitute for years of practice and constant refinement. Apr 12 06 07:23 pm Link Pat Thielen wrote: None of this makes sense together. A 50mm lens on a 1.6x crop camera is essentially the exact same thing (compression/distortion wise) as an 80mm lens on a full frame. There is absolutely no difference in terms of distortion, perspective, or whatever you want to call it. Saying to use the same lens but stand farther back makes no sense and is a BIG waste of resolution. Apr 13 06 03:25 am Link Zulu22 wrote: No, it's not the same thing. When you put a lens on a camera with a crop factor it's the same lens with the center portion cropped out. A 50mm lens is differant than an 80mm, both in distortion and perspective. Mounting one on a DSLR with a crop factor does not magically turn it into an 80mm lens. Focal length is the important consideration here, not subject to distance. And how are you "wasting resolution" by stepping back from your subject with an 80mm lens, rather than putting on a 50mm and not stepping back? What does this have to do with the resolution? Do you somehow lose pixels or something? Apr 13 06 03:38 am Link What with all this technical mumbo-jumbo? A decent lens will just record what is visible from a particular standpoint. A 'distorted' picture when something is close (wide angle of view) is actually the real image, but normally when we use our eyes our brain evens this out from prior knowledge (coupled with the stereo ability of having two eyes). And the distortion cannot make people look 'fat' unless its in the horizontal plane more than the vertical plane. Big noses, maybe, but not fat. John Apr 13 06 04:10 am Link Pat Thielen wrote: I read that wrong. I read it assuming that you knew what you were talking about in terms of lens length/distance vs distortion and were saying that you can just take a wider lens and step back farther and then crop the image to get less distortion. Which would work but you would end up with a lower resolution image considering that less pixels would be used. This wont make sense until you understand what I tried to explain in the other thread. Apr 16 06 04:40 am Link Perspective is only a function of distance from the subject and is not a property of or lens characteristic. For fun drop a nice zoom lens on the camera, put the camera on the tripod and take a photo. Then crop the wide angle image to the same field of view as the telephoto image. You will have identical images (except you will loose pixels but this isn't what where discussing here). Next take a fully zoomed telephoto image. Then zoom that lens wide and get closer to fill the frame to the same field of view as the telephoto image. When you compare these two images they will appear very different. It wasn't a function of the lens but where you were standing. If you stand say 7 feet from your model and put four cameras of different format, say a 35mm camera with a 50mm, APS crop factor with 35mm, a 645cm, medium format with a 100mm, a little digicam at 7mm and a 6x6cm with a 85mm lens you will get the same identical images (not considering the shape of the frame) Again it isn't the focal length that creates perspective. It is the distance from the subject that changes the perspective. Now to how we really use our cameras and lenses. You need to kind of get a feel how each lens will look and work on the body chosen. In reality we would say stand at 10 feet and just grab any lens, say a 15mm, and go "I can crop it to look like I took it with a 135mm lens". And we know if we move closer with that 15mm lens to fill the frame like we would standing farther back with a 135mm we're going to start to see distortion from moving closer. If we move back and drop the old 300mm lens on and fill the frame again things will look different. The background will appear closer. Things will appear flatter because we moved back and are now working at a much smaller angle of view of the original scene. As a function of the total distance the background is a much smaller percentage of the total distance. Again it wasn't the lens but the distance that caused the change. Now the real big picture. It all really doesn't matter which way you think about it ... the lens or the distance that changes the perspective. You just need to remember it will happen and how to deal with it. We don't want to make our lovely models look like they have big bums because we blew the perspective. Wanna make a model look like she has a big bum. Go stand 50 feet away grab a 400mm lens. Then have her lean forward so all her nice cleavage shows and take the shot. Now you will see a rather large booty. That was my ramble for the day. Bill Apr 16 06 09:20 am Link Bill Bates wrote: perfect response Apr 16 06 09:27 am Link Zulu22 wrote: The only difference I have found is in dept of field. When I put a 50mm lens on my Fuji S2 I have about the same angle of view as a 85mm on my Nikon N 90 film camera, but with more dept of field. (I still have the same 50mm background sharpness.) Apr 16 06 10:06 am Link Bill Bates wrote: This is exactly what I was saying in a greatly elaborated form. Apr 16 06 03:58 pm Link Zulu22 wrote: Me too :-P Apr 16 06 05:26 pm Link Well, you know what? I'm an idiot. When I read the last post describing the cropping of images something "clicked" and I realized that I was totally wrong about that. I think I may not have quite got what you were saying in the first place -- my apologies. And thanks for explaining your statement about resolution; now that I understand what you meant by "losing resolution" it makes perfect sense and I totally agree with you. Sometimes I realize that I need a new brain. And the really stupid thing about all this is after I figured out what you were saying I also realized that I knew that... I'm not sure how I managed to convince myself otherwise. So, just to get back at my (stupid) brain I'm going to go out tonight and continue to kill it with beer. That'll show it! Peace, -Pat- Apr 16 06 05:34 pm Link eliminate the noise... full frame there... sorry, but someone had to say it. Apr 16 06 05:43 pm Link Pat Thielen wrote: Definately a good thing that you can confess like that but honestly you didn't need to beat yourself up about it so much. Apr 16 06 06:26 pm Link Um, that would be far too obvious. And besides, would kill a great Canon vs Nikon deathmatch that would probably ensue. ;-) Apr 16 06 06:26 pm Link oldguysrule wrote: I would do many erotic things with a donkey for a 5D. Apr 16 06 06:27 pm Link Zulu22 wrote: You call that beating myself up? Dude -- you have no idea...! Apr 17 06 01:10 am Link |
