Originally posted by photoptimist As long as you never consider buying a camera with a different format, use a camera with a different format*, or try to learn aperture-choice techniques or effects from photos taken with a different format, you don't need to worry about equivalence.
Equivalence in those cases is learned as accumulated background information. There's no need to even formally give it a name. It would seem, that folks who favour the formal approach take the position that those who handle equivalence informally are in some way deficient.
Every body uses equivalence. The issue is not who uses it. The issue is who actually uses crop factor in their day to day work?
I carry up to three sensor sizes all the time. I have never once taken an image with my K-3 at 50mm, then thought, I should take this at 70mm with the K-1.
Did you catch that?
It should have been 75mm. The only 75mm lens I own is MF and I don't have an adapter for it.
So even for the math heads, equivalence doesn't get you out of having to try out lenses.
Simple fact. People don't own enough lenses to make equivalence a real thing. The equivalent of my 40XS is 60mm. I think Sigma made one of those once.
IN this situations it simply doesn't work.
Maybe it's time for some real world examples of how you used equivalence out in the real world, as opposed to all these hypotheticals.
MY point would be not that equivalence doesn't exist.
MY point is it's better understood by understanding the different lenses in your lens bag, which you have to do anyway and how they affect images on different formats.
The whole mathematical step is unnecessary except for ball park numbers that have to be adjusted for lens characteristics.
And if you have zooms, it's next to useless. The whole thing about composition is getting the framing you want. One UWA zoom, one standard zoom, and one telephoto zoom and you are covered.What do you need equivalence for?
The "rookies need it" argument is also counter intuitive. Rookies deal with a lot of issues, I'm not at all certain that studying equivalence formally even helps. But I'd be happy to hear any real world experiences that would suggest different.
The funny thing to me is that the guys pushing equivalence theory, are assuming, if you don't buy into the math, you don't know equivalence. My point has been you can understand equivalence without mathematical formulas, and you will have a better understand it, if you simply understand your gear. Because it's small part of the question, if I like 35mm on APS-c what do I shoot on a K-1. There are many factors way more complex than equivalence needed to answer that question, and the design and characteristics, that are much harder to understand are more important than the very simplistic "equivalence" method of looking at the decision.
If you want to tell folks 50mm or 55mm on FF is the same as 35mm on APS_c feel free. But that doesn't mesh with my experience. SO I'd consider it misleading. I love my 55 on FF. I really never liked 35mm on APS_c. Forget equivalence. Learn your gear. You'll learn every thing you need to know about equivalence along the way. IN the end it comes down to, I like this lens on this system, and it's way to simplistic to claim equivalence is more than peripheral information.
I don't like it not because I don't believe it is true, I don't like it because I see it as overly simplistic to the point of being misleading, in many situations. There is simply no situation where I would recommend equivalence as the main point of focus in lens selection. It's one of those things you might want to consider in a ball park kind of way, like a quick calculation in your head, but it's not enough to give you definitive help in lens selection. And in many cases, I have my SMC 50 1.4, My FA 50 1.7, my FA 50 2.8 macro, my DA* 55 1.4, my 18-135, a Tamron 17-50, my 28-105, my FA 35-80 and so on and so forth. The big part of lens selection is not equivalence.
And the corollary to that is I get really tired of people who think they are experts on lens selection because of a very simplistic mathematical formula.
Originally posted by photoptimist Equivalence is only useful when working across formats to answer the question of which focal length and aperture do you use if you use a different format.
Have you ever used it for that? I frequently carry three formats. I look through the lens and zoom to the framing I want. I look up focal length in the exif. I generally make up my mind which format to use before I pick up the cameras. I've never once though out in the field. Oh look I'm using 50 on APS_c . I'm going to change to FF and then I need 75mm, so I can take this shot not only with the format that best suits it but also with the format which theoretically at best can match it, but will never exceed it."
I don't do that. Do you?
---------- Post added 01-25-19 at 11:04 AM ----------
Originally posted by Rondec
Not exactly the same framing, but the big thing to me, is that you can actually take similar photos between formats.
That is covered by "All cameras take pictures." I think if there's one thing everyone knows it's that they can take their pictures with a little camera or big camera and for most images, the format will make little difference. You get your snapshot. In the end you won't care what it was taken with.
I'd find it curious if there were people who thought you couldn't take similar pictures on different formats. Is that even thing? What I hear is "I can take that same picture with my cell phone." It's the guy who knows why you shoot what format and when that is knowledgeable. The whole idea of a kit lens is that the camera come with a lens that allows it to take practically the same images as every other camera on the market with it's kit lens. You can figure out mathematically why they are the focal lengths they are, but it won't change anything. The camera companies do it for you. They did the math to save you the trouble. But you can still do the "trouble" thing if you want.
Last edited by normhead; 01-25-2019 at 09:30 AM.