Originally posted by audiobomber I think the argument mainly started because m4/3 shooters don't understand the full ramifications of crop factor. They only understand equivalent focal length. They think the Olympus 12-40mm f2.8 is a 24-80mm f2.8 FF equivalent, when in reality it is a 24-80mm f5.6 equivalent.
It got really heated over at DPR when the Olympus 300mm f4 was announced, and there were several threads showing photos of it beside a huge Canon 600mm f4 FF lens, with price comparisons.
The Oly 300mm f4 is no smaller than a Pentax DA*300. If you shoot them with an EM-1 and K-3, and crop the Pentax image to 16mp and 4:3 aspect ratio, you will have the same image. That is equivalence. Comparing to a 600mm f4 is just ignorance.
I hope at this point people understand that a 300mm lens is the same whatever format you shoot it on. Smaller formats only give more "length" to lenses if they are more pixel dense. But even that gives diminishing returns. From what I have seen of telephoto on the Q shots, the quality begins to suffer, even though there is technically a lot of reach there.
If I post something about my FA 77, I am unlikely to say that it is a 115mm equivalent, because that doesn't mean anything to me. I just like the fact that it has nice rendering and is capable of pretty shallow depth of field. Whether or not it would be better on full frame is meaningless to me. But if I would start a thread about it, there would be folks who would show up to tell how because of the crop factor, it isn't a useful lens, it would be better on full frame, etc.
It just gets a little old. It was a fine lens on film, it is a fine lens on a K3, and it will continue to be a fine lens when the new full frame Pentax comes out. But the comparisons do nothing for me.