Originally posted by Serkevan The point is that, if you argue that having a lens stuck at f/1.4 is still technically usable, then you don't deserve a lot in the way of logical arguments.
In a more serious note I would argue that spending an extra 1000 bucks on corner sharpness is not really efficient in APS-C land; the FA* 85 and FA77 will do a job almost as good - if not indistinguishably good - for a fraction of the price. Sure, the lens will be gorgeous in crop mode anyway but you're throwing away a lot of the expensive bits
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On another note, a lightly used K-1 won't be much more expensive than a KP (and will probably be cheaper than a K-new); might as well make the D FA* feel right at home.
I generally avoid this kind of discussion.
A lightly used K-P will still be quite bit cheaper than a lightly used K-1. You can play this kind of game all night You can get a lightly used K-P for 1/4 the price of aK1 ii and use the extra money for the lens. It goes on forever.
Quote: In a more serious note I would argue that spending an extra 1000 bucks on corner sharpness is not really efficient in APS-C land; the FA* 85 and FA77 will do a job almost as good
I would argue it's the reduce CA and smooth out of focus areas and transitions not corner sharpness that are the issues. When the DFA 50 1.4 came out I looked at the DA* 55 1.4. I can see the difference. The out of focus areas aren't as smooth. Based on the 10 or so images I take a year the price difference wasn't worth the 50. If I'm shooting a couple portraits a week , 100 a year and maybe 5000 images a year and every one of my portraits looks better because I used the 50 or 85, that's building quality into my work that can only be achieved one way. The cost is divided into a lot more opportunities and it's cheaper per image.
There is nothing inherently efficient or inefficient about the cost of a lens per se. That can only be based on expected personal value and usage, not by looking at the lens. The cost of my DA 35 2.4 per image is very high because I don't like it and rarely use it. It cost me $200, but it wasn't an efficient use of my money, per image.
My DA*60-250, was $1200, but a much more efficient use of my money given it's 10 years old, and I've probably taken 25,000 images with it. And again, looking at our Sigma 18-250, its the out of focus areas and transitions that make every image I've taken with it better compared to the Sigma. We eventually gave the Sigma away, it wasn't a bad lens, unless you have something better. Then it's weaknesses are readily apparent in every shot.
It's alway wise to avoid the scenario I run into with my Sigma 70-300 images. Once I got better lenses all the images taken with it were throw aways. They were only ever good because I didn't understand what was possible. I have images on my hard drive that are blurry to barely acceptable, but would have been stunning with a better lens. You don't get those opportunities back. If what you are doing is portraits, you're going to do better with a lens designed for the purpose. And it's even more critical on APS-c than it would be on FF. With APS-c you magnify those aberrations.