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Anonymous
copy pasta from ac
>a. What's perspective/compression? How close things in the foreground look to things in the background >b. Is it dependent on focal length? Not exactly. It's dependent on camera to subject distance. >c. I've heard it's dependent on focal length It's not. Focal length changes apparent subject size, but not perspective >d. Then why does the perspective on a wide angle look different from a telephoto? Because when you shoot with a telephoto, you move away from the subject, and when you shoot with a wide, you move closer to the subject >e. I don't believe you You don't have to! If you have a zoom lens, you can test it yourself! Using the 18-55 kit lens standard on most DSLRs, for instance, emulating a 2x sensor crop factor is easy: 1. Put the camera on a tripod 2. Take a picture at 18mm 3. Without moving anything but the zoom knob, take the picture at 36mm 4. Open up the shot taken at 18mm and take a 2x crop (i.e., half size. Any good image editor should be able to do this) 5. Compare perspective to the 36mm-shot. It'll look the same (although the 18mm will be lower resolution, because you cropped it) >f. I still don't believe you. I've always been told that smaller focal lengths give weird perspective That's a useful rule of thumb, yes, but it's not actually true. As another example, Point & shoot digital cameras have very large crop factors and very short actual focal lengths. By this logic, a Canon PowerShot G9 (with 7.4-44.4mm zoom lens) would only be capable of super-mega-ultrawide to slightly-wide perspectives. >g. But how could a 50mm lens have different perspective when it's on a crop camera as it does on a full-frame camera? It's still the same lens! Because focal length doesn't affect perspective. When you put the 50 on the crop sensor, to get the same picture, you take a few steps backwards to accomodate the crop factor. >h. I still don't get it Then you're hopeless.
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