Snip:
It depends how far you take the chase for quality. One could argue, for example, that anyone using a Canon DSLR is on the wrong track as these days Nikon and Sony have much better sensors....
Do they really have
much better sensors? Currently, I believe they may have a small advantage in some areas, but is that really noticeable in real-life everyday situations in the photographs they produce? A little more dynamic range may be noticeable to a few camera users (probably in the landscape and wedding photography fields?) but for the rest of us and the viewer/client?
I've just been calibrating a Sigma 100 400 lens as it was front focussing and I think I've now got it about right. To check this I've been pixel peeping and comparing the final results with those on the internet, including some from DSLRs with much higher MP than the one I'm using. The thing that unexpectedly struck me was there isn't a huge difference between the results from my camera and those from some high MP ones. Yes, it's noticeable if you zoom right in, there's more detail and resultant clarity just as I'd expect, however, it's not a
massive difference - in other words, up to around A4 you'd need to put the two images side-by-side and have a good look to notice that one contains more detail. I'm quite glad about this as it's made me more content with the FF DSLR I own and put the urge to 'upgrade' on the back burner for a bit.
Furthermore, the sharpness of the lens and the higher MP of the camera emphasises the point of focus to the extent where you can't get the whole of an object (such as a side-on mallard duck) in focus when it's filling more than around a third of the frame at the smaller apertures you'll probably be using on a telephoto lens in 'average' UK outdoor light. This is great if you can nail focus on the required point every single time, but with that degree of sharpness and resolution any error is going to be very much more evident than it is with less resolution and sharpness.
Compare that to the results from some classic old lenses, where the image wasn't absolutely pin sharp but created the overall impression of sharpness in such a visually appealing way that no-one really noticed or minded. Perhaps the creators of some of those old classic lenses knew a thing or two after all?