Originally posted by climit The smaller the sensor, the less capable. FF offers greater analysis and at least one stop more. A focal reducer is a useable instalation on certain circumstancies but it is bulky and imports elements between the lens and sensor that downgrade the quality of the image.
The smaller the sensor, the more noise. I agree.
Explain what you mean by "FF offers greater analysis" please.
FF does not offer a stop more of light. An f2 lens is an f2 no matter how big or small the sensor is.
I also agree that a focal reducer might be bulky, but if a camera didn't have a mirror, there is a ton of room to play with. I think you could integrate a focal reducer with a mirrorless camera and still have a good looking camera. Of course, the reducer would have to be designed specifically for that camera body or line of bodies in order for it to work out aesthetically, ergonomically, and functionally.
And the degradation of quality I agree with also, but feel that a comfortable compromise can be made between speed/versatility and image quality. I've seen the metabones reviews, and there doesn't seem to be much noticeable degradation of IQ. Anyway, expect that going FF might reduce the quality of the image your lens produces. Not every lens has edge to edge sharpness. Already you can find threads about how sensors will start to outperform the capabilities of todays lenses.
Since I believe you've missed my point in all this:
Because I don't believe we'll get an EVF nearly as good as an ordinary OVF anytime soon, I don't see professionals solely turning to mirrorless. Today, and for the next few years, mirrorless cameras will be enthusiast grade cameras. I think the best idea is to make them as accessible and affordable as possible. The cost alone for a FF sensor would kill that dream. And, especially where Pentax is concerned, less lenses will be available for the new FF format.
I'm only going on and on about a keeping the camera ASP-C sized, because I believe it's an important way to increase the versatility of your lens set. ASP-C effectively (I know this isn't what really happens) zooms your lens 1.6x, but, unlike a teleconverter, it keeps the aperture the same. I think this feature should not be lost but complimented with an excellently crafted telecompressor that will, not only, resurrect the wasted image circle of FF lenses but, also, add a freaking stop of speed to those lenses.
I whole heartedly believe that a photographer should give more care to and spend more money for lenses than cameras. I think lenses are much more important to the overall look of a picture when comparing sensors of a similar size and definition. So, lets just take every one of your lenses and add up the total monetary value of them. Then find the same lenses (if they exist) that are one stop faster and figure out what the price would be to upgrade your whole kit.
I'm sure you get now why I insist that such a focal reducer be made and that APS-C format should not be abandoned just because of all the almost hysterical hype for FF. And I have faith that Pentax can make a speed booster of such quality and precision that it would blow the minds of both enthusiasts and professionals. It would open the door for people who don't have 10 grand to spend on a kit. One could buy an entry level MLC will all the features of a professional DSLR and buy lenses that are far more reasonably priced than what the professionals use. You can buy a 35mm f2.8 and have it become an f2, a 50mm 1.8 would transform into a 1.2, an 85/2 turns into 85/1.4, and so on... You could have a setup with all the capabilities of a pro's but for a fraction of the price.