« on: February 01, 2013, 06:31:00 AM »
Wondering why would Canon, Nikon would NOT measure actual lenses?It's a numbers game. If they produce ten thousand lenses of a particular lens (I picked that number out of the air - I could be waaaaaaay out on that one...) and each MTF chart has at least eight squiggles, and each squiggle needs at least fifteen points (with zoom, double that - two charts...) that is a lot of points! So which point do you publish? Best? Worst? Average? Median? Mode? I guess simpler not to publish and statistically QA lenses assuring quality is as expected...
I wouldn't think so, I don't thing anyone is suggesting that they QC every lens that rolls off the line with a full MTF curve test. However, Zeiss does publish real, empirical MTF curves for their production lenses, whereas Canon and Nikon choose to publish idealized MTF charts. That choice is likely a marketing decision - it makes their lenses look better (but does Zeiss test a whole bunch of lenses, then publish the best curve? Most likely). In the end, it probably does not matter...but I'd prefer to see real data from a real lens, rather than (not-real) ideal data which a real lens may never match.