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06-06-2009, 03:25 AM   #1
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3x1000mm

I have been playing with 3 1000mm lenses on my K10D.

MC MTO-11CA 10/1000 (russian maksutov mirror lens)
SMC PENTAX REFLEX 11/1000
SMC PENTAX 1:8 1000mm

And these are not very common, so maybe others would like to see how they perform.

All on a sturdy tripod : Berlebach UNI6 (no head, but I used the leveling mechanism for aiming instead)
Because it takes some time to swap these lenses (and mirrors) the lighting conditions are unfortunately not exactly the same.
My test object is a 'Bobcat' on the roof of a building.
This is the uncropped frame :



The grid and the bright sky (white sunlit clouds) behind it, will make it extra tough for these lenses.

Here 100% crops :

1 MC MTO-11CA 10/1000 :


2 SMC PENTAX REFLEX 11/1000 :


3: SMC PENTAX 1:8 1000mm @ F11:


4: SMC PENTAX 1:8 1000mm @ F8:


5: SMC PENTAX 1:8 1000mm @ F8 + Yellow K2, and the color adjusted afterwards:


Anybody doubt the need of APO/ED tele lenses ?
And the air turbulence is probably a more resolution limiting factor than the lenses.

George

06-06-2009, 04:01 AM   #2
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air turbulence/heat distortion is a surprisingly problematic issue for super telephoto lenses, my 400mm f/2.8 from canon that I use on my 1DsMKIII it can cause some serious image quality issues...and you can't do a thing about it.
06-06-2009, 04:25 AM   #3
Dom
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Interesting, the reflex lenses seem to do better.
06-06-2009, 04:29 AM   #4
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reflex lenses are basically immune to chromatic aberration, but the downside is that they often have lower contrast compared to their glass counterparts due to the fact that multicoating a mirror to prevent internal reflections would be a bit counter-productive in a mirror lens ;-)

06-06-2009, 04:31 AM   #5
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Interesting glasbak.

Thanks for taking the time to do this comparison. It must be fun to play with lenses of that focal length. Actually, the first uncropped shot doesn’t look too bad and would have been impossible with any a shorter lens. Like most photographers without access to such glass I hadn’t considered issues such as turbulence. I have a K 300/4 and M 400/5.6 and no question purple fringing and chromatic aberrations are an issue with the older telephotos. I suspect this is even more so with super telephotos. There is no doubt APO/ED glass is a great advantage. That being said the old glass can still deliver some pretty fine images.

If you had the time, or inclination, it might be fun to see how these lenses perform under less challenging conditions. Under ideal conditions how good is that SMC Pentax K 1000/8?


Tom G
06-07-2009, 06:57 AM   #6
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QuoteOriginally posted by Digitalis Quote
air turbulence/heat distortion is a surprisingly problematic issue for super telephoto lenses, my 400mm f/2.8 from canon that I use on my 1DsMKIII it can cause some serious image quality issues...and you can't do a thing about it.
Yeah, that is quite true. I have the 400/5.6 and it really gets affected too.

How's the 2.8? I checked them out and they are just too damned enormous to lug around comfortably when hiking The 5.6 is about as big as I'd ever want to go.

As to the tests; that is the worst CA I have ever seen.
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