All this talk about "equivalence" is silly

Started Jun 10, 2011 | Discussions thread
Le Kilt Senior Member • Posts: 2,488

silly, and yet you get another discussion going on the subject !
(but I do mostly agree with you)

Howard wrote:

Someone wrote a web page about "equivalence" some time ago. Let me first say that I perfectly understand the concept (it is really about perspective, DOF, framing, etc.), but I think all this talk about "equivalence" is silly, confusing and mostly bogus.

For example, the "equivalence" adherent will say that a 300 f/4 lens is "equivalent" to a 480 f/5.6 lens on a crop camera, or some such. But this has severely limited applicability -- that is, only if you are narrowly concerned about perspective, DOF and want to duplicate exactly the same image as on a FF camera. But this is not the only, or most important concern for most people. Actually, I want to argue that for most people, this is not a concern at all.

Some cases in point:

Case 1: if you want to stop action, in the same lighting condition, with the same ISO, a f/2.8 lens gives you the same shutter speed on a crop sensor or a FF sensor, so to same something like a 300 f/4 lens is "equivalent" to a 420 f/5.6 lens is completely misleading.

Case 2: if your primary concern is reach, then a 300 f/4 lens is decidedly similar to a 480 f/4 lens on a 1.6 crop camera, not 480 f/5.6.

Anyway, I can go on. But I think this "equivalence" talk is very confusing to beginners and causes more harm (confusion) than good (clarification).


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Canon EF 16-35mm F2.8L II USM
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