The image area you choose won't just have an impact on vignetting.
If you look at Nikon FF, for example, the image area you choose may also impact the AF point coverage (wider coverage with crop), the viewfinder display (cropped area visually greyed out), even the the AF-C frame rate (smaller DX files, faster fps), the live view display, and the video mode options too. It may also have an impact on metering.
So Pentax is, I believe, making it pretty clear that the crop mode behaviour will be totally under user control.
---------- Post added 2015-12-12 at 10:26 PM ----------
Originally posted by acoufap I'm anxious about how Ricoh maps the crop modes to storage formats. Will they offer different raw formats for FF and APS-C? If they do so, it will have impact on file sizes and maybe image burst rate.
I think everyone should have a look at a
Nikon D810 user manual. Pentax FF crop modes will no doubt operate very similarly.