[Ubuntu_user]

@Ubuntu_user: I think I may recognize this lens. Glad to see you're having some fun with it.

Oh yes. It's great!

[Pentaxor]

A 50/1.2 is ok in sharpness. Its purple fringeing is pretty bad in high contrast setting just like most lenses anyway. I find this lens much better shot wide open in the night setting. Colour is quite vibrant doing that.

Da*55/1.4 is good in all paramaters but its background bokeh tends to render double tram track effects quite frequently.

I agree that the 50/1.2 is at it's best during night settings. what I noticed is that it displays this certain glow at night that looks pleasing. it looks soft and at the same time is decently sharp enough wide open that such rendering combination complement each other. it's too bad that I don't own a K-5 and probably wont, but considering the K-5's DR and NR control in the shadows would make images from the 50/1.2 really astounding at such scenario. it's a formidable combination so to speak.

[robgo2]

Very interesting comparison. Overall, I prefer the rendering of the 50/1.2, but I'm not sure that I would want to deal with manual focus. I look forward to seeing the next set of comparison shots.

Rob

[Laurentiu Cristofor]

... the fringing issue you are claim to exist with older lenses like the 50mm f/1.2

To be specific, I just claimed an issue with older lenses in general. I never used the 50/1.2, so I don't really know what older lenses "like the 50mm f/1.2" are like - there is always the odd exception to a rule.

The issue I was mentioning involves both purple fringing and strong LoCA. I believe axl's shot shows LoCA - it is so pronounced that the red component feels like purple fringing. LoCA is also a problem for the Takumar 50/1.4, Cosina 55/1.2 (horrible in strong light), and FA 50/1.4 (it makes it obvious when eyes in portraits are slightly out of focus).

Here are some crops from my collection - I usually throw away the worst offenders, so these are not showing the worst behavior.

Takumar:


Cosina - this is LoCA despite being purplish:


In comparison, lenses that I consider modern do behave better. Nokton 58/1.4, Planar 85/1.4, Samyang 85/1.4 are all showing better control of chromatic aberrations. I suspect coatings may play an important role in this issue as well.

here is a shot with K50/1.2 @1.2, K10D ISO200 +1Ev t=1/2000:
and 100%crop:

Thanks! I really appreciate 100% crops. People always post their better shots and that tends to make even crappy lenses look like great performers.

Of course, such CA issues don't mean that we should stop enjoying old lenses as much as we do, but the thread subject is a comparison with a modern lens and I just think such comparison would be more interesting if it were done in harsher lighting conditions.

If I were to distill my experience with old lenses in one single piece of advice, it would be: beware of CA - it almost never shows in the select images posted in the respective lens clubs, but you'll get it as soon as you take the lens around for a stroll on a nice day. And it's not like modern lenses are devoid of CA, but it's just not as much of a problem as with the old ones.

[Digitalis]

The issue I was mentioning involves both purple fringing and strong LoCA.

pretty much every 35mm SLR lens under 100mm is nowhere near fully apochromatic - that is what causes LoCa, the lack of ability to focus red,green,blue light on the same plane, even the Highly regarded FA31mm f/1.8 Limited is incapable of this. There are a few recent pentax lenses over 100mm that also have this characteristic: the Pentax DA*200mm f/2.8 WR SDM springs to mind.

[Ubuntu_user]

Here's some more comparison shots. Again, this is no scientific test (and not the best subject matter either). The exposure was kept the same for all the shots, also the flash power was kept the same as well.
This definitely shows some interesting results. Let me know your thoughts! From looking at the f/1.2 and f/1.4 pictures from the A 50mm, it makes me feel like it could have been FF just a bit (but then again the A is much softer at f/1.2 and f/1.4 than the DA*). Focus was on the "2.8 2" on the lens aperture ring.

A f/1.2


A f/1.4


DA* f/1.4


A f/2.8


DA* f/2.8


A f/4


DA* f/4


A f/5.6


DA* f/5.6


A f/7.1


DA* f/7.1


A f/11


DA* f/11


A f/16


DA* f/16


A f/22


DA* f/22

[Pentaxor]

Here's some more comparison shots. Again, this is no scientific test (and not the best subject matter either). The exposure was kept the same for all the shots, also the flash power was kept the same as well.
This definitely shows some interesting results. Let me know your thoughts! From looking at the f/1.2 and f/1.4 pictures from the A 50mm, it makes me feel like it could have been FF just a bit (but then again the A is much softer at f/1.2 and f/1.4 than the DA*). Focus was on the "2.8 2" on the lens aperture ring.

A f/1.2


A f/1.4


DA* f/1.4


A f/2.8


DA* f/2.8


A f/4


DA* f/4


A f/5.6


DA* f/5.6


A f/7.1


DA* f/7.1


A f/11


DA* f/11


A f/16


DA* f/16


A f/22


DA* f/22

interesting results you got there. from what it seems, the A is pretty much consistently strong in all apertures in general, has more depth. the DA* perhaps have the advantage at f1.4 and f2 in terms of contrast but gets left at f2.8 and f4. I'm not surprised at all with the performance of the A at f2.8 and f4. I had compared this against the 1.7 and the A seems better at those apertures as well, not to mention a smoother bokeh as well at those stops.

anyway, there is a possibility that you might have some focus error with the A test at f1.2 and f1.4. the image at f1.2 looks to be more in focus than the one at f1.4. another thing to consider is the absence of considerable sharpness at f1.4 of the A50 which would highly suggest the error. as far as my experience with the lens goes, the difference in DOF and sharpness at f1.2 and f1.4 is significantly noticeable.

[Ubuntu_user]

interesting results you got there. from what it seems, the A is pretty much consistently strong in all apertures in general, has more depth. the DA* perhaps have the advantage at f1.4 and f2 in terms of contrast but gets left at f2.8 and f4. I'm not surprised at all with the performance of the A at f2.8 and f4. I had compared this against the 1.7 and the A seems better at those apertures as well, not to mention a smoother bokeh as well at those stops.

anyway, there is a possibility that you might have some focus error with the A test at f1.2 and f1.4. the image at f1.2 looks to be more in focus than the one at f1.4. another thing to consider is the absence of considerable sharpness at f1.4 of the A50 which would highly suggest the error. as far as my experience with the lens goes, the difference in DOF and sharpness at f1.2 and f1.4 is significantly noticeable.

I set the focus once and then left it. So I don't see how the f/1.2 could be sharper then the f/1.4...

[axl]

I set the focus once and then left it. So I don't see how the f/1.2 could be sharper then the f/1.4...

Have you ever heard of focus shift with ultra fast lenses? At f1.2 the focus plane might not be the same as on f1.4 or f2 due to this phenomen

[axl]

This seems to be far more interesting test thenb the first one. I'll say more when I'll see it on the PC as opposed on my phone... Thanks for comparing these two anyway!

[dave9t5]

I set the focus once and then left it. So I don't see how the f/1.2 could be sharper then the f/1.4...

Have you ever heard of focus shift with ultra fast lenses? At f1.2 the focus plane might not be the same as on f1.4 or f2 due to this phenomen

Focus shift is possible, you should definitely refocus at each aperture.

I went through the thread and didn't see mention of the focusing screen that's being used, is it a split-screen (or similar) or the stock screen?

[Blue]

Focus shift is possible, you should definitely refocus at each aperture.

I went through the thread and didn't see mention of the focusing screen that's being used, is it a split-screen (or similar) or the stock screen?

He is using the K-5 so using the stock screen may not be a problem.

[Kennod]

Focus shift is possible, you should definitely refocus at each aperture.

That depends. In Liveview or manual stop down that may be the case, but otherwise the aperture is wide open when focusing using the viewfinder and doesn't stop down until the shutter fires. So changing the Av between shots would not make any difference to AF phase detection or the focus screen.

[Ubuntu_user]

I went through the thread and didn't see mention of the focusing screen that's being used, is it a split-screen (or similar) or the stock screen?

I used liveview and zoomed in (via several presses of the info button). Then focused and refocused and refocused, etc.

[Ubuntu_user]

Have you ever heard of focus shift with ultra fast lenses? At f1.2 the focus plane might not be the same as on f1.4 or f2 due to this phenomen

I never thought of focus shift (see?? I told you it wasn't a scientific test!).