To be fair though, this situation arises because we have not yet reached the level of sophistication whereby all the equipment we buy has already been tested in accordance with an international (ISO) MTF standard.
We already have standards for exposure sensitivity. Imagine what it would be like if we didn't. When a camera model deviates from that standard and claims a sensitivity of ISO 100 when it is really ISO 80 or 75, it is usually picked up in a good review. It's something one needs to know.
Fortunately, the true sensitivity of a particular camera model does not seem to vary much from copy to copy.
The same can not be said for lenses. Here is a source of endless dispute. Which lens is sharper than which? There's no definitive answer because the best copy of one lens is often sharper than the worst copy of a much more expensive lens.
Perhaps one could say that the cheaper the lens, the greater the quality variation amongst differnt copies from different batches, and the more expensive the lens the less variation.
Ainīt that the truth!
And perhaps it has become worse since the advent of digital. I canīt remember a time pre-digital when there existed such an animal as a duff Nikkor. I could consult my weekly British Journal of Photography magazine, read reviews of relevant pro lenses from the principal makers and trust what Geoffrey Crawley had to say about them. And buy in confidence.
For purely personal and dumb reasons I exchanged my entire Nikon armoury some years ago in quest of a Pentax 67 ll solution to dwindling stock returns. Just as digital was starting to make its name known. Anyway, on realising my error, I bought back in to the sytem and into some surprises. The 2.8/135 that replaced the vanished 3.5 version wasnīt as crisp; the 1.8/50 that replaced the 2/50 had a wobble in the front as does a replacement one; the F4s would never engage the film under at least three attempts to load (resulting in a return to one of the last F3 bodies in stock). My latest and recent disappointment was the af 2.8/24-70mm that wasnīt useful at the wide end and lasted a month, mostly in a box, until I returned it and took an af 2.8/180 in its place.
Iīm now thinking about a D700, mainly because I want to regain the use of my very good 2.8/24mm Nikkor as a wide, and not just have it be an equivalent to 35mm on the D200 which, otherwise, I find to be a very nice machine/lens combination.
Iīve looked at alternatives for the '24mm wide on FF' within the D200 format, but they all seem to preclude front filters which make them useless in my seaside location. Also, getting back to the point you made about QC, it has become a nightmare and I would hate to have to start doing a regular return-to-dealer routine with a company with whom I enjoy a long and good relationship; easy to piss people off and co-operation is a valuable commodity today...
I donīt condemn people who pixel-peep and test lenses with the help of brick walls; far more realistic a test than any commercial target print. And they do show up lack of good geometry if itīs there. Neither do I accept the argument that film was forgiving and digital isnīt and, thus, no comparison can be made between old expectations and current: my observations are made via scanned 35mm transparencies, so both the old science and the new are up there, side by side on the monitor. And the old with Kodachrome need blush over nothing.
Going out and shooting pictures is all very well, but doing that without confidence in your tools isnīt such fun either, and totally pointless. And that is something that I do find to be a new departure in pro level photographic gear; never felt it in my youth...
Perhaps, if sales slump further, lens makers will have time to reintroduce proper and tight QC and not feel the temptation to push out everything that tumbles off the production line. So I would like to hope!
Perhaps thatīs what will bring the surviving MFD world into line.