Compression is Real

Started 11 months ago | Discussions thread
dsjtecserv Veteran Member • Posts: 3,754
Re: It's worse
3

JackM wrote:

Mike CH wrote:

It's worse. He tried to show, at least until he deigns to explain otherwise, that it's a function of focal length and not of position.

He failed.

It's a function of both, obviously.

To be clear, perspective (of which "compression" is one effect) is the size and position relationships among the objects in the field. The framing of the those objects (how wide or narrow a field of view you include them in) is not perspective. Both perspective and framing contribute to the overall look and impression given by a final image. But they are not the same thing, and they are controlled by two independent decisions you make as a photographer.

You choose the perspective of the scene when you choose where to take the picture from. Your choices may be limited -- you may only be able to stand on the sidewalk, or you can't back up without stepping off a cliff, but regardless of how you got there, your position determines the perspective. At that point, your choice of lens cannot alter the perspective.

Once your position is established, you can then make a separate, independent choice as to how to frame the scene, through you choice of focal length. Nothing is dictated -- you can chose short and give a wide view with lots of context, or you chose long and narrow your field of view to just a small part. In either case, the perspective of the scene does not change, just the amount of it that you want to include in the picture.

Now, some people claim that when the choose a long focal length the "have to" move back in order to properly frame their subject, and therefore the focal length determines perspective because it "made me" move to a certain spot. Setting aside the question of why a photographer would feel controlled by his equipment, this argument still misses the point. However you got there, it is the fact that you are at a certain position relative to the subject that determines the perspective; that perspective didn't happen unless and until you actually move to that position. So while you may decide what focal length you want to use first, and then move to the place that gives you the desired framing, it is still the place that gives you the resulting perspective. You are simply giving priority to framing, and accepting whatever perspective results. If that happens to give you "compression" that you like, then you are happy on both counts -- but for different reasons!

Dave

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