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11-06-2017, 12:39 AM   #2026
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QuoteOriginally posted by beholder3 Quote
Not.

As any OEM lens it just "needs" to achieve about 90% of the performance of the best lens on the market to be able to be priced at +50% more than 3rd party products (in this case = >1,500 EUR) and still be a good success.

That always was the case and always will be.
You're talking market. I'm talking reputation - not unrelated, but not the same thing either

11-06-2017, 03:32 AM - 1 Like   #2027
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QuoteOriginally posted by Fcsnt54 Quote
You are both Correct and incorrect, it does and does not cover the FF image circle. I Owned the lens, have examples of both with/without heavy vignetting, and that is without the Lens hood. I can post them if need be with no corrections, except for Conversion from DNG to JPEG. To the most part though it does cover the FF image circle.Not sure how the DA or FA 50 are.
I would say that it does cover the circle, but it must be understood that in general, with the exception of extremely high priced lenses, a couple of stops of vignetting is the rule for f1.4 lenses. I would expect the DFA *50 to be better than that, but it doesn't mean that the DA *55 doesn't cover the image circle.

This is the Photozone review of the Nikkor 50 f1.4: Nikkor AF-S 50mm f/1.4 G (FX) - Review / Test Report - Analysis It shows 2 stops of vignetting wide open, which drops to 1 stop a f2. This correlates pretty well with the DA *55's performance.
11-06-2017, 03:44 AM - 3 Likes   #2028
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QuoteOriginally posted by Fcsnt54 Quote
it does and does not cover the FF image circle
Enter the Schrodinger's lens.
11-06-2017, 07:19 AM   #2029
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If the DA*55 didn't cover the full image circle presented by film or the K-1's sensor, vignetting wouldn't be removed simply by stopping down the lens, right? It'd be a hard edge of black that was always present, right?

11-06-2017, 11:33 AM - 1 Like   #2030
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QuoteOriginally posted by pres589 Quote
If the DA*55 didn't cover the full image circle presented by film or the K-1's sensor, vignetting wouldn't be removed simply by stopping down the lens, right? It'd be a hard edge of black that was always present, right?


It covers FF without any serious vignetting from f2.8
EV0.4 at F2 and 0.13 at F2.8 (at APS-C) means that this lens has not any problems at FF.

Last edited by ogl; 11-06-2017 at 11:39 AM.
11-06-2017, 11:39 AM - 2 Likes   #2031
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Old FA50/1.4 is the same

Last edited by ogl; 11-06-2017 at 12:01 PM.
11-06-2017, 12:47 PM - 1 Like   #2032
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Canon 50 f1.2 has 2.74 EVs of vignetting at f1.2 and still has 2 stops at 1.6. Sony 55 f1.8 has 2.8 stops at f1.8.

Even the Zeiss 50 f1.4 Planar has 1.5 stops of vignetting wide open. Just to be clear, it isn't that the DA *55 is perfect on full frame, it is just that the bar is not typically set anywhere near perfection for f1.4 full frame lenses.
11-06-2017, 11:40 PM   #2033
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QuoteOriginally posted by Ascencio Quote
Who has better autofocus primes 85mm 1.4, 35mm 1.4, 20mm, 24mm, 135mm
The problem with some sigma lenses is they don't AF properly on pentax cameras, and calibration with the sigma dock can do little to fix it - for reasons that still remain unclear the Sigma ART lenses have AF issues at certain distances that make them practically unusable for some.

QuoteOriginally posted by Rondec Quote
it is just that the bar is not typically set anywhere near perfection for f1.4 full frame lenses.
It never was a priority in the days of film, most lenses were fast because it made the focus screen brighter - not to satisfy bokeh jockeys who desire infinitesimally thin DOF . It has only been the past decade or so where extreme levels of optical performance have been in demand even at apertures as wide as f/0.95.

QuoteOriginally posted by pres589 Quote
If the DA*55 didn't cover the full image circle presented by film or the K-1's sensor, vignetting wouldn't be removed simply by stopping down the lens, right? It'd be a hard edge of black that was always present, right?
Due to the effects of diffraction, the image circle of lenses actually gets bigger as you stop the lens down. Experienced LF photographers will tell you that.


Last edited by Digitalis; 11-07-2017 at 06:45 AM.
11-07-2017, 12:46 AM   #2034
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QuoteOriginally posted by Digitalis Quote
The problem with sigma lenses is they don't AF properly on pentax cameras - for reasons that still remain unclear the Sigma ART lenses have AF issues at certain distances that make them practically unusable for some.
What's strange to me is that there are Sigma EX lenses that didn't seem to have nearly the AF issues that others do. I had a 17-70 EX that seemed to focus quite well with my K100D. It feels like Sigma flat out doesn't really iron out all details all the time with their products, at least in this area.


QuoteOriginally posted by Digitalis Quote
Due to the effects of diffraction, the image circle of lenses actually gets bigger as you stop the lens down. Experienced LF photographers will tell you that.
Ah, okay. So basically the DA*55 is on that ragged edge where the image circle it presents to the camera is "just barely enough" and the situation may be acerbated by flying wide open. Okay, cool, thanks.
11-07-2017, 04:03 AM - 1 Like   #2035
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QuoteOriginally posted by pres589 Quote
What's strange to me is that there are Sigma EX lenses that didn't seem to have nearly the AF issues that others do. I had a 17-70 EX that seemed to focus quite well with my K100D. It feels like Sigma flat out doesn't really iron out all details all the time with their products, at least in this area.




Ah, okay. So basically the DA*55 is on that ragged edge where the image circle it presents to the camera is "just barely enough" and the situation may be acerbated by flying wide open. Okay, cool, thanks.
I guess I wouldn't describe it that way. I would say that the DA *55 gives typical performance for an f1.4 lens on full frame. There are some very high quality lenses referenced here that have similar performance to the DA *55. To get better performance will require a much larger lens that is also quite a bit more expensive.
11-08-2017, 06:24 AM   #2036
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QuoteOriginally posted by awscreo Quote
I'm leaning towards the UWA zoom, as I do a lot more landscape work than anything else, and I think it'd be worth my money to upgrade where I need the ultimate performance the most. So UWA first, filter system for it with filters second, then maybe in a year or two - the 50 1.4
There is one other wide angle I am considering now. It is the Rokinon 24mm Tilt/Shift. It is not weather sealed but I have been inspired by what this member, DDoram, has been able to do with it. It could be a great wide angle for my trip out west. Below is a link to some of his pictures; but if you search by user name there are some more.

K1, Rokinon 24mm Tilt Shift: Abraham Lake Alberta - PentaxForums.com

I am going to check Black Friday sales and see what the prices are on the 15-30 and the Rokinon tilt shift. No matter which UWA I get, the 50mm 1.4 will still be my standard focal length lens.

Last edited by JamesDCrockett; 11-08-2017 at 06:58 AM.
11-08-2017, 06:51 AM - 4 Likes   #2037
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QuoteOriginally posted by JamesDCrockett Quote
Rokinon 24mm Tilt/Shit.
I'd stay away from funny smelling lenses.
11-08-2017, 06:58 AM   #2038
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QuoteOriginally posted by beholder3 Quote
I'd stay away from funny smelling lenses.
Way to funny and fixed.
11-08-2017, 07:03 AM   #2039
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The problem with most tilt; shift lenses on Pentax is most lenses can't be shifted up because of the flash overhang. That's a limitation that is overcome if you go for in camera tilt shift. I personally stayed clear of tilt shift on Pentax because of that issue, and because you can't accurately judge focus on on cameras back screen. These days, an iPad will be the way to go if this ever makes it to market.
11-08-2017, 07:29 AM   #2040
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QuoteOriginally posted by normhead Quote
The problem with most tilt; shift lenses on Pentax is most lenses can't be shifted up because of the flash overhang. That's a limitation that is overcome if you go for in camera tilt shift. I personally stayed clear of tilt shift on Pentax because of that issue, and because you can't accurately judge focus on on cameras back screen. These days, an iPad will be the way to go if this ever makes it to market.
I don't know what DDoram did to get these three shots, but I may have to figure it out. Middle one is obviously not about being straight but is about the detail from just past his tripod to the very end of the building and roof on the right hand side of the frame.

K3 and Rokinon 24mm Tilt Shift Lens - PentaxForums.com

K3/Rokinon 24mm Tilt Shift: Old House - PentaxForums.com

K3/Rokinon 24mm Tilt Shift: Edmonton Sikh Temple - PentaxForums.com
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