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Old Oct 2, 2003, 11:57 PM   #11
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Join Date: Sep 2003
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There are several discussions going on here.

First, as was said earlier, the "ratio" of any zoom lens is the ratio of the minimum focal length compared to the maximum. If one is half of the other, it's a 2:1 zoom. If one is 1/10th of the other, it's a 10:1 zoom.

How big thigs are in the viewfinder.... suppose instead of the viewfinder, you took the video out cable and composed your image on a 36" tv. The picture captured by the camera will be no different than if you composed it on a 1/2" lcd display.

That's all easy stuff. The more complicated part is "bringing things closer", which the lens doesn't really do. Well, it does seem to, but you can just as well use any old lens, and use the darkroom (digital or film) to make that part of the image bigger. Using a longer focal length lens will increase the size of the thing you're shooting on the film or sensor, so grain and stuff won't show up the way it would if you blew up a tiny part of the image.

Try this, or at least think about it. Sit down in your apartment and look at your television set. Now, from one of your eyes, draw an imaginary line to the left side of the set. Draw another imaginary line to the right side. Depending on how close you are to the set, the angle between these two lines will vary. Just for the heck of it, let's say it's 35 degrees.

Now, stay where you are, and take a picture of the tv. When you're done, you can look at the finished image. You can do this if it's on the image screen on the back of your camera, or on paper if you made a printout, or on a computer monitor. When you're looking at the image, do the same imaginary line test, and check (from your eye) the angle between left and right. Your eyes will try to play tricks on you, but the ONLY way that the image is going to look the same as what you saw when you were sitting in your chair looking at the tv, is if the angle is the same as it was back then.

Everyone says that wide angle lenses, or telephoto lenses, distort things. That's misleading. They don't - as long as the viewing angle for the finished image is the same as what you saw when you took the picture.

If you don't believe this, take one photo of something with an extreme wide angle lens, and then take another photo with a telephoto lens. By moving closer or further away from what you're photographing, try to keep the size of the object looking the same. Like, if you're taking a photo of a person, have his feet at the bottom of the frame, and his head at the top. Do this with both the wide angle lens, and the telephoto. While you're doing this, also take note of something a ways behind the person, maybe a tree in the background.

Now, look at the finished images. The one with the wide angle lens will have the person at the right "size", but the tree (or whatever) behind him will look very small. For the one taken with the telephoto lens, the object behind the person will look huge. If you're looking at the finished image on a computer monitor, or maybe an 8x10 enlargement, neither of these is going to look like what you think your eye would see.... to accomplish that, you need to use something like a 50mm lens if you're shooting with a 35mm camera. The reason is because of the angle change I mentioned above.

To fix this distortion, and make things look "normal", you need to hold the photo taken with the wide angle lens only a few inches away from your face. For the other picture, taken with the telephoto, you need to hold the paper many feet away, or stand way back from the monitor.

................of course, once you understand the above, you can use it to your advantage. Knowing that people aren't going to look at things inches in front of their nose, or ten feet away, the image can be distorted, and when you realize how the distortion works, you can make images that use this distortion to make things look differently in an interesting way.

(The above concept works no matter what the camera is, from a pocket size mini-camera, to an 8 x 10" view camera. A "normal" lens for any of these is a lens that will usually produce a viewing angle, as described above, that matches the viewing angle when you were standing there with the camera, looking at whatever you're about to shoot.)
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