[ZombieArmy]

Best resolution from 1.4 till f4.0. Rather interesting....

It's actually similar to the Samyang 135mm

Samyang 135mm f/2 ED UMC Lens Review

Although that does gain a little bit at f5.6.

[ffking]

Still need to compare *50 to FA77, but lens and K1ii had to go into intensive care after an accident.

Ugh!! Shame!!!

[ffking]

It's actually similar to the Samyang 135mm

Samyang 135mm f/2 ED UMC Lens Review

Although that does gain a little bit at f5.6.

That brings out one of the major frustrations with ephotozine - they keep changing the way they do they MTF charts, so direct comparisons are difficult - but I suppose that the fact that all these charts seem to rely on the pixel density of the camera attached to the lens makes that too much to hope for anyway

[08amczb]

That brings out one of the major frustrations with ephotozine - they keep changing the way they do they MTF charts, so direct comparisons are difficult - but I suppose that the fact that all these charts seem to rely on the pixel density of the camera attached to the lens makes that too much to hope for anyway

I think "Excelet" is 2500 LW/PH. I would like to see numbers, that would be comparable.

[PJ1]

Before anyone takes this the wrong way, the MTF50 is not everything but ….
ephotozine has tested the DFA* 50 f/1.4,
the Super-Takumar (8 element) 50 f/1.4 (Asahi Pentax Super-Takumar 50mm f/1.4 Model I (8-Element) Vintage Lens Review)
and the FA 50 f/1.4 (SMC Pentax-FA 50mm f/1.4 Review)
on the K-1. So they can all be measured with the same ruler, so to speak.


The DFA* 50 is excellent wide open (centre and edges) and up to f/4. It really is astonishingly good. It is very good after f/4 too, but shows some decline on the MTF chart. The Super-Takumar starts out good in the centre but with soft edges wide open. By f/4 it is almost up there with the DFA* and (according to the MTF) stays up in excellent territory (and above the DFA*) through to f/16. That, too, is astonishingly good. The FA 50 is a good lens (and it will do me any day I need a fast 50 with autofocus) but it does not reach the territory of the other two.


Remember this is only about MTF. There is a lot more to rendition that that. But I think the charts show both why the DFA* 50 sets new standards and why the Super-Takumar deserves its legendary status.

[awscreo]

First time I see a lens that is better at larger aperture values what a beast! Me want one )

[leekil]

Why does the DFA*50 only go down to f/16? I notice the Otus is the same in this respect. (And the Super Takumar, though possibly it is for a different reason.)

[ffking]

Why does the DFA*50 only go down to f/16? I notice the Otus is the same in this respect. (And the Super Takumar, though possibly it is for a different reason.)

I can't remember when I last used anything beyond f/16 - rarely that even - the extra dof isn't worth the IQ loss through diffraction - the sharpness is already dropping off significantly by f/16 with this lens - and you can use filters for longer exposures

[pschlute]

Why does the DFA*50 only go down to f/16? I notice the Otus is the same in this respect. (And the Super Takumar, though possibly it is for a different reason.)

ffking already gave you the answer, but I would ask ...when was the last time you shot at f22 on digital ?

[GUB]

Before anyone takes this the wrong way, the MTF50 is not everything but ….
ephotozine has tested the DFA* 50 f/1.4,
the Super-Takumar (8 element) 50 f/1.4 (Asahi Pentax Super-Takumar 50mm f/1.4 Model I (8-Element) Vintage Lens Review)
and the FA 50 f/1.4 (SMC Pentax-FA 50mm f/1.4 Review)
on the K-1. So they can all be measured with the same ruler, so to speak.


The DFA* 50 is excellent wide open (centre and edges) and up to f/4. It really is astonishingly good. It is very good after f/4 too, but shows some decline on the MTF chart. The Super-Takumar starts out good in the centre but with soft edges wide open. By f/4 it is almost up there with the DFA* and (according to the MTF) stays up in excellent territory (and above the DFA*) through to f/16. That, too, is astonishingly good. The FA 50 is a good lens (and it will do me any day I need a fast 50 with autofocus) but it does not reach the territory of the other two.


Remember this is only about MTF. There is a lot more to rendition that that. But I think the charts show both why the DFA* 50 sets new standards and why the Super-Takumar deserves its legendary status.

I actually would prefer the versatility of the Sup tak 8 element. When I think of the subject matter I am likely to be targeting with the lens wide open then softer corners is a bonus. The performance of the 8 element is amazing.
And considering the tests were done by the same reviewer I think it is reasonable to compare them. (As well as his test of the old sup tak 55 f2 -- Asahi Super Takumar 55mm f/2.0 M42 Vintage Lens Review)
I would love to see him do a test on the 7 element sup tak 50 1.4 - it would be very interesting from a historical viewpoint.

[PJ1]

I would love to see him do a test on the 7 element sup tak 50 1.4

I agree. I only recently acquired an 8 element (and I really like it). It would be interesting to see how it really compares with the 7 element version. As good as the DFA* is, I cannot see myself ever buying it. I don't need that much weight in a 50mm prime for the things I do. Also there is a certain sense of satisfaction in using a 50+ year old lens that is outstanding in its own right. But this is getting a bit off the track of the thread.

[monochrome]

Using the 8-element is even more astonishing in the context of having just unmounted the D FA*50.

.:

[leekil]

ffking already gave you the answer, but I would ask ...when was the last time you shot at f22 on digital ?

I am more likely to the be at the wide-open end, but it's less about needing it, and more about a change in the aperture range. Hasn't almost every K-mount lens ever produced by Pentax gone down to f/22 at least? The earliest primes, and the last 5 DFA zooms all went to 22. Why the change now?

[pschlute]

I am more likely to the be at the wide-open end, but it's less about needing it, and more about a change in the aperture range. Hasn't almost every K-mount lens ever produced by Pentax gone down to f/22 at least? The earliest primes, and the last 5 DFA zooms all went to 22. Why the change now?

Sure, and I have plenty of older primes that go to f32. Diffraction has always been an issue at very slow apertures but on film was rarely an issue unless you were creating a big print. On digital where we tend to pixel-peep more diffraction is more noticeable if you go looking for it.

Maybe there is a technical reason due to the construction of the lens that would mean the diffraction at f22 would degrade sharpness to an unacceptable level. Maybe other technical reasons made it more difficult to have f22. Either way the lens was designed "fast" and to produce smooth bokeh and circular oof highlights. f22 is not part of that brief. On a practical note, if you wanted a picture with everything from subject to infinity in focus, you can achieve that at f16 if your subject is 18 feet from you. That is plenty for me.

[cyberjunkie]

I can't remember when I last used anything beyond f/16 - rarely that even - the extra dof isn't worth the IQ loss through diffraction - the sharpness is already dropping off significantly by f/16 with this lens - and you can use filters for longer exposures

In reality the chart shows that diffraction starts to kick in at f/8.
While the new D FA puts to shame the old Super Tak wide open (immensely so at the borders), the latter comes back with a slightly better performance from f/8 to f/16. Which is really impressive.
The D FA is a great lens. It is more or less what I expected, the best fifty in PK mount.
The uncommon 8-elements Super Tak has done much better than I could ever imagine.
Considering its age and the single coating, it shows an impressive performance from f/2.8 to f/16.
looking at the chart, it is effectively two lenses in one.
Reminds me of what I've been told of the Leitz 60mm Macro. Super sharp at mid apertures and beautiful, mellow rendition wide open.
I should try mine at smaller apertures, I have always used it at f/1.4 and f/2 because of the nice mix of (enough) sharpness and some halo.

P.S.
Diffraction is not limited to small apertures. It simply gets stronger and at a certain point outweights the limitation of (certain) aberrations that that are "cut" stopping down. The MTF chart reflects that.
I admit I have no idea on why high performance modern designs are generally more prone to diffraction. Many curves dive down abruptly at f/16, to reach very poor sharpness at f/22.