Originally posted by D1N0 DA
FA
FACTS
Now I see even the schematic is somewhat different - though nothing in the schematics tell us differences in glass or coatings, and the point that the claimed schematics are similar was never contested. Look a bit more closely (not that it really matters). We have measured the front elements and the rear elements - showing very clearly that the ratios are different. Yep, undeniable facts.
---------- Post added 07-18-2017 at 10:43 AM ----------
Originally posted by ChristianRock My DA 35 2.4 is sharp edge to edge wide open. Who am I going to trust, someone on the internet who does not have the lens or my own lying eyes?
The fact is that DA coatings are different than FA coatings - the former being more contrasty hand warmer in general. Also, you can't compare both lenses wide open because one is limited to a smaller aperture. If you compare at similar apertures the results in terms of sharpness and light fall off should be similar.
Well, they aren't similar. Regarding the light fall off, Simon indicated that FA was at 9% at f/2.8 (one stop down); the DA indicated 22% at f/2.4 (wide open), and 11% f/4 (1.5 stops closed). This isn't terribly surprising when you consider that the front objective is around 20% larger! I don't know about warmer, but we have generally seen higher micro contrast in the DA lenses. Possibly mostly related to their newer design.
The sharpness argument on the edges would be more debatable based on sample variation. However, for those of you who read these thorough Lenstip tests, we always get clues about copy quality in the Astigmatism/Coma section. The DA had virtually no corner coma (although Simon was a bit brutal in pointing out that plastic mount lenses often don't hold together well over time and heavy use). The FA had a pretty healthy dose of corner coma not shown in the center, indicating (most likely - all other things being equal) that the lens was slightly decentered. Yet, the FA was the stronger edge performer, especially wide open. I am sure the DA is adequate on the edges, but the FA is really impressive in this regard (keeping in mind that the edge of crop is a long ways away from a FF edge).
I'm just going by the known facts. You would really have to attack the testing methodology of Lenstip to win this argument (claiming that the lens performance is essentially similar), but the light fall off side of it is an especially simple measurement that is not subject to much in the way of sample variation. And that light fall off differential is significant.
Last edited by ScooterMaxi Jim; 07-18-2017 at 08:48 AM.