New Full-Frame DSLR to be APS-C switchable

<p>I just read the interview on dpreview. I have known since the appearance of the Pentax D-FA* 7o-200mm f/2.8 lens that Pentax will finally produce a Full-Frame DSLR soon. How wise of them to make it compatible with their DA lenses. I wonder what the MP rating will be. I'm thinking 30- 36 MP to be in line with the resolution of the K-3.</p>

<p>I'd love to have a FF camera that simply uses the APS lenses, providing a square image maybe? Or not caring about the mounted lens at all and letting the user crop the vignetted corners. - Switching to exact APS means not using sensor pixels we 'll pay for.</p>

<p>Well, let's say we have the same pixels in APS-C mode from the new camera that we have from the K-3 or K-5, which have given excellent IQ. To have enough pixels in the FF mode to equal that resolution will require more MPs when spread over that greater area. If one ONLY has DA APS-C lenses and will not be getting FF lenses, there would be no point in acquiring this new camera. </p>

<p>But many of us have a mixture of FF and APS-C lenses. One such I have as an example is the Sigma EX DG 24-60mm f/2.8 which I have found to be a very fine performer. It is full-frame and can be used on both my Pentax DSLR bodies and on my 35mm film bodies. On the DSLRs the crop factor comes out to about 35-90mm f/2.8 equivalent. Great for extending use in the tele range, not so great if my interest happens to be more in the wide angle. With the new FF camera I could switch back and forth as my need indicates. I often carry this lens in conjunction with my DA* 50-135mm f/2.8 as a kit. By using the Sigma in FF mode I would extend the range of my kit to a true 24-60mm with a switchable overlap to the DA* lens's 75-205mm equivelent. That beats other brands' FF models having to tote a much heavier 70-200mm f/2.8 to match up with the Sigma 24-60mm. </p>

<p>Also, the new Pentax (or other brand) 70-200mm f/2.8 on the new camera would be useable either way according to one's needs. Better DOF control as FF, then in APS-c mode as a 100-300mm f/2.8 equivalent for extended tele use.<br>

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<p>I agree with your arguing but: Why stick to the APS constraints instead of a square or almost circular image? Is having that tiny bit of extra card space and writing speed really important enough to even bother with in camera cropping? Sure, sometimes we take the time to frame exactly but I developed a semi messy shooting style, usually printing 8x10"s from 6x6 negs or attempting to cover action with primes. The switching to APSC reminds me of the "digital zoom" old P&Ss & camcorders offered excessively. - I usually disabled it. But of course I agree that 24MP & no postprocessing hassle must be nice to have.</p>

<p>I assume the switch will be to exact APS-C format. There should be no change in picture frame shape. If the FF format is say 36 MP, the APS-c format would be say 20MP, which of course would be spread over a smaller area so resolution would be similar to that of 36MP over the FF larger area. You would not use all of the 36MP crammed into the APS-C area. That would not be a good idea even if possible because such cramming of so many MPs would cause more noise.</p>

<p>You would use all 36MP for full frame when that is appropriate for good design and performance with FF lenses, and less MP as required for APS-C use for good performance there. The issue is to accommodate both lens types with excellent performance in either case, all in one camera body.</p>

<p>Up to now I have stuck with and prefer the APS-C format for DSLR use because I get very fine performance with smaller lighter lenses especially for normal-to-telephoto focal length. But the advantage is reversed for wide angle, and for achieving tighter depth of field. I use 35mm film when I want "full frame", but the new camera may present a desirable alternative.</p>

<p>In regard to having the most flexible uses, I cannot see why one would have to switch to APS-C format with a lens made for APS if that is not desired. Then the photo would simply have edge issues to be addressed in post process. Unless the camera will automatically switch itself!</p>