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02-16-2021, 04:20 PM   #16
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QuoteOriginally posted by puandr Quote
The problem have to be in CZJ lens protruding rear element.
You can visually check this by putting the focus ring at closest focus and slowly screwing the lens on while observing the process from the back with shutter and rear door open (use cable release on "B"). If mounting is stopping by a projecting element or collar, the interference should be visible. If there is potential for mirror interference, that also should be visible.

QuoteOriginally posted by puandr Quote
Today I've screwed Flektogon pretty tight, so the mirror stuck after taking a shot and then turned backwards for 10-15 degrees, until mirror returned in its normal position.
FWIW...you are at risk of damaging your camera, perhaps permanently. If your lens is not mounting cleanly, the solution is to not use that lens on that camera. I have several lenses that do not mount cleanly to my SP F and respecting the incompatibility is one way I avoid expensive repairs or the risk of turning it into a non-working example.


Steve

02-17-2021, 12:44 PM - 1 Like   #17
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Hello. As an occasional user of this combination, a 20mm or 35mm Flektogon on a Spotmatic F, I have to share my advice. Using a east German CZJ lens on this Japanese aperture coupled camera raises a real problem, but it has a simple solution.


The problem is not linked to the protruding rear element of the Flektogon with its aluminium housing. By looking through the 24*36 image field, B set, camera back opened, I find it to be pretty distant to the reflex mirror. Being myself confronted to one of my favourite lenses not mounting to my favourite camera, I found the parts that block the association are diaphragm actuation pin, and aperture coupling lever. When one is about to finish the final turn to mount the lens on the camera, the pin catches the raised end of the L-shaped aperture coupling lever. Continuing to screw on the lens moves the mechanism until it reaches its stop. Its return spring then repels the lens, unscrewing it.


The problem lies in how Pentax has designed their lenses, from the east Germans construction (who have set the M42 standard). And there are minute differences that cause this trouble. On SPF, ES, ES II cameras, Pentax has designed their coupling mechanism with a L shape, in order to have a clearance to let their Takumar diaphragm actuation pin pass just nearby, and let the lens being fitted normally. On a Takumar, I measured with a caliper that the diaphragm release pin is situated about 1.2 mm inside relative to the threads of M42 mount. On an east-German lens, this distance is a tiny bit greater, about 1.45-1.6 mm. The pin being deeper, where the coupling cam lies, it then hits the L shape when the lens is screwed on. On some lens/camera combinations, it passes, on others, it scrapes the coupling lever but still passes, on others it hits and blocks. It is just a matter of a 1/10 mm or so.


But there is a simple trick you can use. On Carl Zeiss Jena and Pentacon lenses, twiddling the lens into manual diaphragm operation deactivates the return spring of the diaphragm pin. You can then either push it with a finger, or let the gravity recess it, by tilting the lens face to the ground. With the pin now recessed, the lens can be screwed without issue. Then you can twiddle the lens in auto mode to use it normally. You just have to remember the trick each time you grab a lens that you know would not pass onto your camera.

Last edited by Praktica*ist; 02-17-2021 at 12:56 PM.
02-17-2021, 04:00 PM - 1 Like   #18
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QuoteOriginally posted by Praktica*ist Quote
The problem is not linked to the protruding rear element of the Flektogon with its aluminium housing. By looking through the 24*36 image field, B set, camera back opened, I find it to be pretty distant to the reflex mirror. Being myself confronted to one of my favourite lenses not mounting to my favourite camera, I found the parts that block the association are diaphragm actuation pin, and aperture coupling lever. When one is about to finish the final turn to mount the lens on the camera, the pin catches the raised end of the L-shaped aperture coupling lever. Continuing to screw on the lens moves the mechanism until it reaches its stop. Its return spring then repels the lens, unscrewing it.
Yep...that is the problem with both the CZJ and Helios 44M lenses mentioned on this thread. If the pin is too long or too fat or not the at the same radius as compatible* Asahi Pentax product, it will not clear the slot in the aperture coupling lever, #4 in the illustration below:


QuoteOriginally posted by Praktica*ist Quote
But there is a simple trick you can use. On Carl Zeiss Jena and Pentacon lenses, twiddling the lens into manual diaphragm operation deactivates the return spring of the diaphragm pin.
Yes, that may work on some lenses, but returning the A/M switch to A for use may create a clearance problem for removal. It is important to move the switch back to M prior to removal; depending on lens, it may also be necessary to hold the camera face down to allow the pin to fall out of the way. Tapping the lens barrel a few times sometimes helps. This works consistently with my CZJ Tessar 50/2.8, but not with my Helios 44M or my Rikenon or Mamiya/Sekor lenses. If one has a problem on removal, it may be possible to nudge the pin out of the way from the rear with shutter open on "B".

I am lucky in that I have the option of other M42 bodies that work well with those lenses.


Steve

* No, not all Super-Takumar lenses are compatible. The ST 50/1.4 and ST 55/1.8 (early, "reverse aperture" version) are mentioned specifically in the SP ES and ESII manuals as being incompatible.

Last edited by stevebrot; 02-17-2021 at 04:13 PM.
02-18-2021, 11:57 AM   #19
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Armed with cable release and bulb mode one more investigation was made.
Looks like cause is "Tab for lens orientation" scratches lens barrel. When lens is "almost there" this tab starts to scratch the barrel, barrel moves a bit this tab and then stuck. There is a little scratch on the lens that I didn't noticed before (marked with arrow on first photo).

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02-18-2021, 04:48 PM   #20
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QuoteOriginally posted by puandr Quote
Armed with cable release and bulb mode one more investigation was made.
Looks like cause is "Tab for lens orientation" scratches lens barrel. When lens is "almost there" this tab starts to scratch the barrel, barrel moves a bit this tab and then stuck. There is a little scratch on the lens that I didn't noticed before (marked with arrow on first photo).
The circled part appears to be bent out from where it should be possibly from contact with the lens. The "flipper" appears to be in its extended position. Unless the metering switch is in its "on" position, that part should be stowed out of the way. Note the scratches, probably from the actuator pin on a lens.




Steve

Last edited by stevebrot; 02-18-2021 at 05:14 PM.
03-15-2021, 04:17 AM   #21
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QuoteOriginally posted by stevebrot Quote
The circled part appears to be bent out from where it should be possibly from contact with the lens. The "flipper" appears to be in its extended position. Unless the metering switch is in its "on" position, that part should be stowed out of the way. Note the scratches, probably from the actuator pin on a lens.




Steve
The rewind knobs are colour coded to indicate that some later Pentax lenses are not compatible, my Sv and S1a are too early from memory.
Rewind knobs can fall off and be replaced as well.
https://www.pacificridgephotography.com/Photography/Gear/Asahi-Pentax-SH-Series/
03-15-2021, 11:31 AM   #22
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QuoteOriginally posted by Xmas Quote
The rewind knobs are colour coded to indicate that some later Pentax lenses are not compatible, my Sv and S1a are too early from memory.
Rewind knobs can fall off and be replaced as well.
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The color coding applies to SV (H3V) bodies, specific to compatibility with the eight-element ST 50/1.4 (red "R" are compatible)*. All Spotmatic models (SP F, ES, and ESII included) have a green "R" with the color not being of any significance.


Steve

* Same rule applies to S1a (H1a) and S2 Super bodies

Last edited by stevebrot; 03-15-2021 at 03:51 PM.
03-15-2021, 02:49 PM   #23
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QuoteOriginally posted by stevebrot Quote
The color coding applies to SV (H3V) bodies, specific to compatibility with the eight-element ST 50/1.4 (red "R" are compatible). All Spotmatic models (SP F, ES, and ESII included) have a green "R" with the color not being of any significance.


Steve
My H1a has the later red knob, and if someone wants to send me an eight-element 50mm f1.4, I’ll be happy to prove it works

-Eric

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