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11-13-2008, 10:26 PM   #1
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50mm sharpness: Pentax, Cosina, Voigtlander and Tamron

Shots from the following lenses can be found at Pentax 50mm Lens Test. Sorry about the outside link, I couldn't figure a good way to lay them out in the forums since they're too wide and best viewed together.

Pentax-A 50mm f/1.2
Cosina 55mm f/1.2
Pentax FA50mm f/1.4
Voigtlander 58mm f/1.4
Tamron 17-50mm f/2.8

Yes, my LBA has gone out of control thanks to all of you .

I had a hard time getting the Pentax-A 50mm f/1.2 properly focused, so that probably explains some of the variability in those results. I was surprised by how sharp the Voiglander was, but then I'm always surprised by how sharp their APO lenses are.

11-13-2008, 10:51 PM   #2
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So, is there a question in there somewhere?

After looking at the pictures, there seems to be some variation in the distance to target, particularly in the road map shots. Was the Pentax 1.2 not capable of getting in close?

The Cosina showed some nice color & contrast on the map shots with imperceptible PF. The Voight looked nice on the map pictures too.

[LBA Bait] You should pick up a Takumar 50mm 1.4 and have at that test again. [/LBA Bait]

Last edited by TourDeForce; 11-13-2008 at 10:59 PM. Reason: adding review
11-13-2008, 11:14 PM   #3
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Interesting...

Which camera are you using? Are you using auto focus on some of the lenses? Are you manually focusing the manual focus lenses and using auto focus on the the auto lenses?

Lots of variables here. Getting accurate manual focus at f/1.2 (manual lenses) is really hard with a digital camera. The manual focus accuracy is just not that good with modern cameras.

I have gone through all kinds of work in getting accurate focus with a 5D using a Takumar 50/1.4 and a Rokkor 58/1.2. Both of these lenses perform way better than I first gave them credit for...
11-13-2008, 11:15 PM   #4
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@TS

ah thank you.

wonderful thread.

11-13-2008, 11:19 PM   #5
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QuoteOriginally posted by TourDeForce Quote
So, is there a question in there somewhere?

After looking at the pictures, there seems to be some variation in the distance to target, particularly in the road map shots. Was the Pentax 1.2 not capable of getting in close?

The Cosina showed some nice color & contrast on the map shots with imperceptible PF. The Voight looked nice on the map pictures too.

[LBA Bait] You should pick up a Takumar 50mm 1.4 and have at that test again. [/LBA Bait]
No, no question, just thought I'd post the results of the comparison in case anyone was interested. The Pentax 1.2 didn't have any problems focusing closer, but I think the focal plane changes with different apertures. I tried to correct for it in the top set, but not in the map pictures. There's more info on focus shift at diglloyd: A Brief Introduction to Focus Shift. It seems to be a common problem with the the Canon 50mm f/1.2L
11-13-2008, 11:29 PM   #6
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QuoteOriginally posted by Photomaximum Quote
Interesting...

Which camera are you using? Are you using auto focus on some of the lenses? Are you manually focusing the manual focus lenses and using auto focus on the the auto lenses?

Lots of variables here. Getting accurate manual focus at f/1.2 (manual lenses) is really hard with a digital camera. The manual focus accuracy is just not that good with modern cameras.

I have gone through all kinds of work in getting accurate focus with a 5D using a Takumar 50/1.4 and a Rokkor 58/1.2. Both of these lenses perform way better than I first gave them credit for...
All shots were taken with a K20D, using live view to manual focus. I made sure the target was at an angle to make it easier to know where the focus point was. Even then, it was pretty much hit or miss.

Yeah, I have a really hard time with manual focus below f/2.8. I usually rely on the autofocus system when manual focusing, but doesn't seem accurate enough for f/1.2 lenses though. I should really stick to the slower lenses for manual focus.
11-13-2008, 11:31 PM   #7
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QuoteOriginally posted by fearview Quote
@TS

ah thank you.

wonderful thread.
You're welcome, I'm glad you find it useful.
11-13-2008, 11:34 PM   #8
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You could do as suggested and focus at the aperture you intend to shoot. Meter to see what setting the camera wants to shoot, manually stop down the lens, re-focus at aperture, shoot. That should all but eliminate the focus shift problem.

Good read on focus shift too. Thanks for that.

11-14-2008, 11:38 AM   #9
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QuoteOriginally posted by walter Quote
Yes, my LBA has gone out of control thanks to all of you .
If you're really about the Cosina you can still return it!
11-14-2008, 10:22 PM   #10
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QuoteOriginally posted by troyz Quote
If you're really about the Cosina you can still return it!
ha ha, that was a great price on that lens. Thanks! It's a lot nicer and performs a lot better than I expected.

TourDeForce - Thanks, I'll give that a try next time.
11-14-2008, 10:42 PM   #11
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Great test- very enlightening! I am surprised how purely the Pentax 50mm/1.2 performs, I don't believe it is a focus problem since the maps are not flat. Great idea to use the maps for contrast. Surprising is also how sharp and contrasty the tamron zoom already is at its widest apperture.
11-15-2008, 02:29 AM   #12
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If you want to check out a decent test on the 50mm lens range ... check out Carpents extensive test across literally everything 50mm.
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