KL Matt
•
Veteran Member
•
Posts: 5,999
Over half of Pentax FF-compatible lense output is wasted on APSC
Sep 23, 2014
8
So those full-frame compatible K-mount lenses we purchased, they are actually capable of putting out 2.5 times more light and detail than our APSC Pentax bodies can make use of. The rest is simply discarded by the camera body -- sucked up by the black surfaces in the mirror box. Wasted. It might not be exactly 2.5x the detail in lpm or even light once you account for sharpness falling off towards the edges and light fall off, but it would be close for most lenses.
So the advantage of FF is to shoot in half the light, and while you're doing it, get more than double the resolving power for a given pixel density. If a Pentax full frame body comes out that is not considerably larger than the k3, you'll have very little size drawback, particularly on the telephoto end of things, where most of the lenses are already FF compatible or close to it.
That's why FF would be a great thing for K-mount. It would give the K-mount back its title as the system with the best "power-to-bulk ratio" in the world. They maintained that title over decades in the film era on through the Pentax *ist D-series in digital but gave it up rather arbitrarily with the much bulkier k10d. When they decided they wanted it back, it was too late, mirrorless had usurped them on the small end of the APS-C spectrum. The only way to get back home again with the K-mount now is with a FF.
Here's to hoping it will be a K3-level body with nearly identical ergonomics and features, perhaps without the fast frame rate. Having a ff and crop body in my kit would eliminate the need for a teleconverter while at the same time allowing me to shoot events with two bodies - a fast wide like mz FA* 24 on the full frame and a fast 50/55 or my FA 43 on the crop body. Wouldn't it be fantastic to have the flexibility to also swap bodies to get a different effective focal length instead of swapping lenses? Every single FF lens you had would be like two lenses in one. My FA 77 would certainly gain a new life, as would the 31.
If Pentax makes a FF that's 100% compatible with all their lenses and makes it easy to switch back and forth, they're going to have a unique selling proposition when I hear about the difficulties in this respect with other systems.
Matt
... interested in .... photographs? Heh? Know what a mean? Photographs? (He asked him knowingly). Nudge nudge, snap snap, grin grin, wink wink, say no more, say no more, know what a' mean? Know what a' mean?
http://www.pentaxphotogallery.com/home#section=ARTIST&subSection=183820&subSubSection=0&language=EN