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05-25-2014, 12:03 PM   #1
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Tilted Super Tak 50mm F1.4 lens on DSLR?

The adapter I purchased for my camera fit on perfectly except that the numbers for focusing and aperture are not directly at the top meaning the lens is kind of tilted to the right. Would this effect image quality in any way? Thanks!

05-25-2014, 01:29 PM   #2
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I believe that is quite common with the genuine Pentax adapters, at least the newer ones. It has not affected my IQ in any way.
05-25-2014, 04:31 PM   #3
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I like this 'feature' of the 3rd part adapters--you can easily see which aperture you have set as the overhanging 'nose' at the front of the camera is not obscuring your view.
05-25-2014, 05:41 PM   #4
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QuoteOriginally posted by monochrome Quote
I believe that is quite common with the genuine Pentax adapters, at least the newer ones. It has not affected my IQ in any way.
Thanks! Monochrome. Haven't had too much experience with this lens so not sure if the image quality has been affected.

05-25-2014, 05:56 PM   #5
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QuoteOriginally posted by thephototruth Quote
The adapter I purchased for my camera fit on perfectly except that the numbers for focusing and aperture are not directly at the top meaning the lens is kind of tilted to the right. Would this effect image quality in any way? Thanks!
It will not affect image quality. However, if you're off by more than half a turn or so, the lens may no longer focus all the way to infinity (as it will be too far from the film/sensor plane). If you're within a half-turn over or under, it should be fine.
05-25-2014, 06:38 PM   #6
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That was considered a feature by some! Canon had the focus and f-stop indexes rotated by 30* as late as the late '60s. I have two cameras from '68 with that feature and three from earlier.

Perhaps it is designed that way. I have three non-Pentax and one Pentax brand adapters that work that way. Johnyates might be on to something.
05-25-2014, 10:03 PM   #7
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What you have discovered is part of the reason pentax switched to a bayonet mount shortly after introducing open aperture metering on some spotmatic models. Registration of the lens was critical to exposure accuracy

Some of my taks don't line up straight either , don't sweat it
05-25-2014, 10:11 PM   #8
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It is also a "feature" of the lens as much as a feature of the adapter/body. NONE* of my M42 lenses line up on ANY of my M42 bodies and each lens lines up at a different point on a particular body. It is the same story with M39 Leica thread mount too.


Steve

* I take that back. My early, reverse direction, ST 55/1.8 registers properly on the Singlex TLS. Similarly, the Auto-Rikenon 50/1.7 from the Singlex registers properly on the SV. Go figure...

05-25-2014, 10:26 PM   #9
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As I recall all of my Taks line-up near perfect on my Spot F. I'll check a few on Monday.
05-26-2014, 08:17 AM   #10
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The 28, 50 macro, and 105 SMC Taks lined up within a degree or two of perfect alignment. They may have been perfect, they were too close to measure. My Super-Tak 24, was visibly off by as much as 5*. I did not try any other cameras or lenses. My only non-Pentax M42 is a Vivitar 90-180mm. I will that next time I dig it out and post the results.

It does appear that the offset on the adapter is designed, not accidental.
05-26-2014, 08:35 AM   #11
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QuoteOriginally posted by OregonJim Quote
It will not affect image quality. However, if you're off by more than half a turn or so, the lens may no longer focus all the way to infinity (as it will be too far from the film/sensor plane). If you're within a half-turn over or under, it should be fine.
I think they are still completely turned in and the registration distance is unaffected -- just the the threads are not positioned on the adapter so that it lines up straight when it is screwed in.
05-26-2014, 09:25 AM   #12
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QuoteOriginally posted by vonBaloney Quote
I think they are still completely turned in and the registration distance is unaffected -- just the the threads are not positioned on the adapter so that it lines up straight when it is screwed in.
What he said. The registration distance on M42 lenses is determined by the mount face. It make no difference how the lens aligns to the body as long as the face mates to the mount flange on the body.

Another word in relation to the orientation of the lens to body and why they don't consistently match up...consider, if you would, how threads are cut and the nature of the M42 mount. First, the mount is not standardized. It is defined by convention. Second, it is amazing that the lenses line up as well as they do considering that it is not easy to define the point of entry for the thread even with the best dies and taps. Probably the best alignment would happen if the mounting holes are drilled after the threads are cut with the hole position determined by the cut of the thread.

As an aside, the best orientation match on my shelf is with my Vivitar 135/2.8 and one (not both) of my genuine Pentax M42 adapters. With that combination the alignment is good enough for the aperture display per the Judas windows on my K-mount film cameras. Cool, eh?


Steve

Last edited by stevebrot; 05-26-2014 at 09:32 AM.
05-26-2014, 10:07 AM   #13
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I bought a batch of third-party adapters at a good price once (once I decide an m42 is going to be part of the my permanent stable I screw on third-party adapter on it [with the spring removed] so I can mount it bayonet-style easily). I was excited about the deal until they arrived and all the lenses ended up completely upside-down when screwed-in. Sent them back...
05-26-2014, 11:39 AM   #14
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QuoteOriginally posted by vonBaloney Quote
I was excited about the deal until they arrived and all the lenses ended up completely upside-down when screwed-in. Sent them back...
It's no problem to "shim" the adapter until the lens indexes where ever you want it to. I often use a thin rubber band between the adapter and lens base to achieve that 30-degree offset effect. So long as the lens base and camera mount mate normally registration distance is maintained.
05-27-2014, 03:48 AM   #15
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I have about 15 Taks. Some line up and a few do not. I do not believe it makes any difference to IQ.


I could not believe how they could make thread align so well over such a huge amount of production.


If the lens mount seats properly on the adapter the registration distance will be right.
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