Originally posted by Paul the Sunman Fascinating insight. Thanks! I'm not sure if such subjective and artistic design philosophies are given much weight these days; one gets the impression that the new Sigma "Art" lenses are designed to hit the best possible numbers. I may be wrong. But perhaps that is the inevitable result of high-resolution digital sensors and pixel peeping.
A lot of people just care about numbers nowadays... and those who don't, have a huge market of old lenses to choose from. It's hard to sell a new lens that doesn't cater to the "sharpness" crowd...
I do think these new Sigma lenses are made worrying mostly about sharpness numbers, but I'm sure they do take the rendering into consideration up to some point at least. But the bokeh tests that I've seen don't lie - it's not the "one lens to rule them all". It's one option, and a very good one at that. But if sharpness isn't your main concern, as a lot of people here claim, then it's your lens (as a side note - it's funny to see all these people worrying about sharpness across the frame, and when you look at what they use, it's zooms and even superzooms... but I digress...)
Back to the technological aspects...
Originally posted by MadMathMind The only real "technology" that has changed has been manufacturing capability.
Well, to be totally fair, coatings did have changes recently, and that can be considered a technological gain. In the 90s there were the "ghostless" coatings, and then after that came the "nano" coatings. And I'm sure there's been other aspects that aren't as exciting to talk about.
Sharpness, however, has nothing to do with technology, except for the coatings part, which does come to play. Even more so in the aspect of "perceived sharpness" due to high contrast wide open. But most of the sharpness itself seems to be pure optics.
Originally posted by MadMathMind Pretty much anything can be made. That's not an issue. But making it affordable for consumers to purchase...that's the trick. The FA31 was designed for late 1990s manufacturing capability. The new Sigma is made for 2014 abilities. Precision and automation is much better now than it was 15 years ago.
Some manufacturing processes don't change quite as much as we think they do.
And also, the manufacturing changed completely since these FA Limiteds were introduced - they used to be made in a factory in Japan, now they are assembled in Vietnam.
So my question is, are you just saying this because you are guessing, or do you have insights on how the manufacturing of optical lenses has changed, and more specific, what changes happened when Pentax moved its factory to Vietnam?
Originally posted by MadMathMind The FA lenses were also designed for film cameras, where chromatic aberrations are far less noticeable. At that time, correcting so stringently for CA was a waste of money; all it would do is make the lens more expensive for no gain for consumers. But now it matters.
While I agree with you that this is the case, I don't agree it's a problem. Software gets rid of that with one click (well sometimes one click, plus a sliding bar... lol)
For example, my Tamron 70-300 which everybody thinks is a "purple fringe monster" (I see it called that a lot), has much less fringing than some of my manual prime lenses like the SMC-A 135mm f/2.8. And it's so easy to get rid of it, it doesn't bother me.
Now OOF fringing, however, is a different issue, but it doesn't seem to be a problem for these Pentax lenses designed since the 90s.