EF 400mm f/5.6L USM image quality

rodriguezPhoto wrote:

stillviking wrote:

I really love this lens, much better than todays.

I think that film era lenses like this one are built to appeal to a different aesthetic than today's purely digital lenses are. Corner to corner sharpness from wide open is the order of the day for lenses these days. Film era lenses like this one seem to give you the very best they can at center, and not focus too much on perfection at the corners, since film couldn't be guaranteed to be perfectly flat anyway. To me it just seems to make the output more pleasing.

A camera with film has a spring driven rigid sheet in the camera back which presses the film against a frame of 24x36mm which is open to the lens, so it is not less flat than a sensor in a modern camera.

The main issue here is that modern people have much higher requirements to the IQ and modern DSLR / MILF cameras are not below 24MP and most even 30MP while 20 years ago 6-8MP was the mainstream. And indeed lenses are much better and the downside of this is that modern lenses are heavier and bulkier (cf. RF lenses vs EF counterparts with same FL(range) and F ratio). This is against the usual trend that modern consumer electronics is getting lighter and smaller.

Some years ago, Popular Photography commented on the fact that film is not absolutely flat at the film plane because it has acquired a curve or bend from being in the cartridge. While it is held relatively flat against the film plate, the area "open to the lens" can have a tendency to distort. Apparently, this is less of an issue in mid roll frames than towards the end because of tighter curve around the spool and larger format may have more of an issue. See Richardphotolab.com or Photo.net, etc., for more comments.