When Digital SLRs first came out, many of us were disappointed to note that the standard format was an APS-C sized sensor (later known as "DX" by the Nikon faithful) which was roughly half the size of a traditional 35mm film frame. We had all become so brain washed by the 35mm format that many of us began to agitate for "full frame" on the grounds that we were somehow being short changed by anything less.
Now the 35mm "standard" for small still cameras was an arbitrary one at best and had been originally chosen largely because film of that format was already in use by the motion picture industry and was therefore readily available for use by these subversive "miniature" camera manufacturers. There is nothing intrinsicaly magical about the format but photographers don't always take to change very easily. If we were brought up to believe that 35mm sized sensor surfaces were the REAL fair dinkum article, we were not going to accept "half" sized formats lying down.
As time went on, resolutions increased and general technical improvements arrived, it did indeed become apparent that APS-C/DX sensors were perfectly capable of producing images comparable to the prints and transparencies that 35mm film could produce. For all practical intents and purposes they could do the job, that most of us required, very satisfactorily. What's more, lenses designed for use with 35mm film would still work superbly with DX - especially once it was realised that DX only really utilised the "sweet spot" of such lenses, enabling them to give still better performance than they might have done with film or indeed with the long anticipated "full frame" sensors.
But there WERE thoughtful arguments in favour of full frame/FX sensors. If the performance of "cropped" sensors could compare with 35mm film, full frame sensors might be expected to go one better and perhaps give results that compared to "medium format" film:
a) Full frame sensors would provide more space for a given number of "photo sites". Pixel density would effectively be reduced, thus improving high ISO performance.
b) Full frame sensors could be beefed up to provide much higher resolutions than cropped sensors - for equivalent sensitivities.
c) Larger sensors would mean larger mirrors. Full frame DSLR viewfinders could be expected to be much brighter than their cropped equivalents.
d) Full frame sensors would enable expectations of lens coverage to return to those we enjoyed when using film. Using cropped sensors meant that 28mm focal length lenses (for instance) were nearly "normal" in their coverage. With film and full frame sensors, 28mm lenses would return to genuinely "wide angle" .... the way that God had always intended.
Now all of this sounds very good ... I suppose. In practice however, how much water do these arguments hold?
(a) The first argument is the best one of course. The ability to shoot relatively clean images at 3200, 6400 or even 12800 ISO would be terrific. Imagine being able to shoot low available light images at practical shutter speeds, without tripods. It could be especially wonderful for action photography. In practice however, most people will use flash or not bother at all - few punters can see the point of gloomy images. Noise reduction software routines are also pretty good these days and (if used correctly) will usually go a long way toward effectively increasing high ISO performance for most cameras.
(b) Ultra high resolution sounds good but how important is it really? Good DX bodies can deliver fine, clean 10-12 megapixel images without difficulty. How much resolution do you really need? How big will your prints really be? If you are like me, the lion's share of your output is for internet use anyway. More than about 6 megapixels is effectively pointless.
(c) I have looked through the viewfinder of my brother's very nice Canon 5D mkII. The view is genuinely beautiful. But then again, when I am using one of my cropped sensor DSLRs, the viewfinder has always seemed perfectly satisfactory to me, however less bright it may ACTUALLY be in A/B comparisons with the FF version. Of course the REAL problem comes when you press the shutter. That heavy, oversized FF mirror (with so much further to travel) comes crashing back and forth with such violence that I thought the camera would shake itself out of my hand. However much advantage one gains from the extra resolution and cleaner high ISO performance, I cannot believe that you don't lose pretty much MOST of it with all that thrashing about during the instant of exposure. It's called camera shake.
(d) It is becoming very clear that as resolution increases, the limitations of a given lens become more and more apparent. If their potential advantages are to be fully realised, 21-24 megapixel FF/FX cameras require the use of the best lenses you can find. Given the already horrendous cost of FX bodies, we now must seek out equally expensive lenses. I (for one) simply can't afford it especially when, in a few years time I shall probably have to afford it AGAIN! And even if I COULD afford it, I am saddled with excessively heavy equipment which, I know from experience, will become a literal pain in the neck by session's end.
Don't get me wrong. Cameras like the Canon 5D and its matching L lenses are truly wonderful kit but at the end of the day the files from hires full frame cameras can be almost unworkable. If we care so much about ultimate performance, it makes little sense to shoot anything other than RAW images. The aggravation associated with downloading, editing and storing the resultant 30-40 meg files I just don't want to think about.
Full frame sensors, heavy camera bodies, tank like lenses and massive image files sound like a great idea. All the fashionable people seem to think so. For those photographers in possession of the necessary patience, perseverance, hard drives, gym subscriptions and funding, I am confident they can produce most satisfying product. In practice - for many of us - the concept may be overrated and impractical.
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