67 TTL Prism
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Yes. They are forward/back interchangeable. But it's best to match the meter to the body.The meters come in either the old Asahi Pentax model or the newer (1991 onward) PENTAX TTL prisms (with revised metering circuit). The now very old (and frequently bashed) Asahi Pentax TTL meters benefit from a check of the meter for accuracy, drift and 'spikes' (e.g. moving the aperture and/or shutter speed resulting in the viewfinder needle charging either up or down before steadying).
MLU or non-MLU does not matter.
MLU or non-MLU does not matter.
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Generally KEH stuff sold EX+ is in exceptionally good condition. That doesn't mean the meter has been tested or re-calibrated, but working. And sometimes old light seals needs replacement.
That's correct.
If a TTL prism is removed while a lens is attached:
Remove the lens, re-mount the TTL prism, and then re-mount the lens.
This procedure removes and resets all tension from the aperture coupling chain -- the well-known weak spot in the older 6x7 bodies (the chain was improved with the release of the 67 bodies in the early 1990s).
If a TTL prism is removed while a lens is attached:
Remove the lens, re-mount the TTL prism, and then re-mount the lens.
This procedure removes and resets all tension from the aperture coupling chain -- the well-known weak spot in the older 6x7 bodies (the chain was improved with the release of the 67 bodies in the early 1990s).
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That doesn't sound quite right to me. The meter itself just doesn't engage unless you mount the lens afterwards (or partially unlock the lens bayonet
and turn it back). I've never had the chain break; but then, I'm not a Pentax repairman either. I prefer the non-metering prism anyway - a bit less clutter.
and turn it back). I've never had the chain break; but then, I'm not a Pentax repairman either. I prefer the non-metering prism anyway - a bit less clutter.
I have all the manuals too (but read page 6!). You may also notice that nowhere does Pentax tell you in any of the manuals why the chain breaks, and many photographers of the early 6x7 era were none the wiser as to the presence of the chain, what it does and how and why it breaks..
The advisory for the process of removing the TTL prism and lens and replacing came much later, with the release of the improved (a stronger chain) 67.
People are free to mount/dismount in any order they want, and they have done that for decades; it's a risk that has always been there — the body-side coupling is not in the correct position to receive the lens aperture coupling. The chain, by association with the coupling, doesn't break because it's bored, but because it becomes fatigued through stress, and snaps. It is entirely avoidable by reasoned methodology. Actually, I share the view there are lots of places in all of the Pentax 6x7 manuals where advice could be improved with warnings. The manuals are typical of the 1960s — sufficient information to instruct, but a lot left unsaid...
In any case replacement of the chain has become a fairly routine chore. I'm sure Eric the Pentax repairman could tell you that! More people still use published DIY info on the web (e.g. by Bill Peifer).
The advisory for the process of removing the TTL prism and lens and replacing came much later, with the release of the improved (a stronger chain) 67.
People are free to mount/dismount in any order they want, and they have done that for decades; it's a risk that has always been there — the body-side coupling is not in the correct position to receive the lens aperture coupling. The chain, by association with the coupling, doesn't break because it's bored, but because it becomes fatigued through stress, and snaps. It is entirely avoidable by reasoned methodology. Actually, I share the view there are lots of places in all of the Pentax 6x7 manuals where advice could be improved with warnings. The manuals are typical of the 1960s — sufficient information to instruct, but a lot left unsaid...
In any case replacement of the chain has become a fairly routine chore. I'm sure Eric the Pentax repairman could tell you that! More people still use published DIY info on the web (e.g. by Bill Peifer).
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You may also notice the conflict of information in the manual (common throughout all of the 6x7 manuals). On one hand the manual says it's ok to remove the prism and refit it with a lens attached. Later, the manual advised, in point form, of the safe methodology that is the focus of these last few posts! It's this conflict of advice that no doubt confused people and led to them doing as they please (as most would!), with often disastrous results at the least expected time.
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With the ordinary non-metered prism, as well as the folding and chimney finders, there is no integration issue at all, other than the two little pressure springs that keep the device in place.
Exactly. My first 6x7 back in the early 80's had the standard prism and no issues whether I wanted to take the prism off for some reason. This one bought early this year is different since it has the metered prism and I wasn't sure about the sequence.
FedEx delivered the prism today and it's a beauty. Had in been in a box you'd be very hard pressed to tell it from a new one...absolutely perfect. Their rating of EX+ was more like LN+. I've found this to be true with other lens/cameras I've ordered from them in the past. I haven't as yet tried it in lieu of the other meter but will soon. The only difference is this was in newer and just has the Pentax logo on the front whereas my other one is "Asahi Pentax".
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I was under the impression 67II finders are not interchangeable with previous versions, just the lenses.
What on earth are you doing!? I am confused reading the preceding posts and have not got a clear idea of what prism you have for what camera. FWIW, the 67ii prisms are not interchangeable with either the older 6x7 or the newer 67 bodies. Nor can you put a 6x7/67 prism on a 67ii body. What is it you have/have not?? 
I have a 6x7 body with an Asahi TTL metering prism. I bought a "Pentax" TTL prism as a spare and it's not fitting. I do not have a 67II body or prism. The only difference between the prism I have and the new one is the nomenclature on the front. One has "Asahi Pentax" and the new one I bought just says "Pentax".
If it is "LN+", you would not be having trouble fitting this prism! My bet is they didn't check the prism at all.
An up-front point: the prism should easily click into place on any of the 6x7 / 67 cameras. The shape/dimensions never changed from the 60s body to the 1990s body. If it doesn't slot in with consummate ease as the prisms are want to do, it's definitely not "LN+"
Mine was described by the seller (an Estate in VT/USA) as mint (as was the whole camera in toto) and remains so 8 years later. My recently acquired fold-down viewer with hood, with the ancient Asahi-Pentax logo, goes freely in and out.
You should ensure the shutter speed pin on the underside of of the TTL finder matches the slot on the shutter speed dial of the camera. Nothing else I can think of other than some form of damage to the mounting pins or (unlikely) some sort of warpage of the prism body. Send it back.
I think I've discovered the problem. The foam on the underneath side is twice as thick as one the old prism and perhaps is causing this. I looked both prisms over top to bottom and that's the only thing that stands out. I tried pushing the prism on a little harder after finding this but it still won't go.
^Does this sound like someones well intended resealing ( without fully knowing what they're doing ? )
If the foam needs to be compressed on install , then you're probably onto something.
Peter
If the foam needs to be compressed on install , then you're probably onto something.
Peter
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