Originally posted by kernos It seems that that the DFA has a different optical design than the upcoming mega Tokina Opera50mm - two more elements on the DFA if reports are correct.
Nope, it's the same optical formula - designed by Pentax, and licensed to Tokina.
Originally posted by kernos But this lens is big enough for a tripod color, well not quite, but this lens is bigger and heavier than an FA77mm or even an F/FA135mm
It doesn't need a collar, but it's certainly big and chunky... Then again, it has an f/1.4 aperture and - here's the kicker - it's heavily corrected for premium performance across the frame and at all apertures. There's a design cost to that, and unsurprisingly it's in terms of optical forumla. All those elements result in physical size and weight. The FA77 is a great lens, but a much simpler formula.
Originally posted by kernos So I'm wondering outside of bragging rights, who this lens is for that would justify the cost and weight?
Those who want more than anything else currently available offers them. Specifically, an extremely-high-quality, fast apeture, Pentax-branded, all-weather 50mm prime lens with frame-wide sharpness at all apertures, beautiful out-of-focus rendering and transitions, great flare control and minimal aberrations.
I'm a happy owner and user of the old FA50/1.4, but beyond the focal length and maximum aperture, I don't even begin to pretend it offers the same things, or the same level of optical optimisation. You can buy it at a fraction of the cost, but there are good reasons for that...
Last edited by BigMackCam; 08-09-2018 at 05:47 PM.