f64 setting on 4.7 135mm xenar lens and one other query

1] The xenar's aperture lever moves past the lowest numerical setting of f32. (aperture ring at extreme end)

By ‘millimetre rule calculation’, the aperture at the smallest possible aperture setting is f67.5!!! (lens opening at the ’minimum’ aperture).

Is the unspecified and notional f64 aperture a known characteristic of the ‘older’ xenar lens???

2] – The cable release port the xenar lens does not accept my standard conical threaded ended [and stiff] cable release (cable port & cable release) . – [the right angled extension is not threaded at the camera end and I do not see how it can be fitted to the lens panel] -

Was this lens developed for another type of cable release???

Attachment 135248Attachment 135247Attachment 135246Attachment 135249

Regards

Tony

Past f32 the lens will suffer badly from diffraction and you'll lose sharpness, I have the same lens and the aperture on mine can only be set half a stop past f32. My 150mm f5.6 Xenar stops down to f64.

The cable release socket should work with all cable releases but I did have two Jessops cable releases that wouldn't fit most sockets - I had a refund. It's possible there's a bit of the end of a cable release broken off and left in that socket. I received a lens once like that and had to remove the broken metal which came out quite easily.

Ian

You should keep in mind that lenses and shutters are distinctly separate items. Most shutters will stop down beyond the marked settings, but do not perform well at the very smallest aperture, which is why the f/stop scales for distance shooting (as opposed to process or copy work) stop at f/32 or f/64. Also, the type of cable release socket will be native to a particular type of shutter, not the lens.

Thank you,
So, the "f64 setting " should be treated with care.
how did you know there was something there and how did you remove it.
regards
Tony

Thank you - I glad that your reply matches my guesses - It is very nice to get reassurance.
regards
Tony

Quote:

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Originally Posted by tonyowen

Thank you,
So, the "f64 setting " should be treated with care.
how did you know there was something there and how did you remove it.
regards
Tony

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In my case I could see it. I just used a screwdriver and it came out when I twisted it.

The Compur shutter has a tapered cable release socket, the ones on my Copals appear straight. The Compur socket it one piece of aluminium alloy - your second photo seems to shows something brass coloured in the socket.

I'd only use f32 if that was the only way to get long exposures, I wouldn't use f45 or f64, so yes with care. My b135mm Xenar has a something limiting the aperture to half a stop past f32, the click stops could go to f64.

Ian

Eureka - a little "gentle pokem, pushem and twistem!!!!" with a small screwdriver moved something don't know what as there does not seem to be any debris.
The cable released now fits and releases the shutter.
Many, many thanks
This forum seem to be very effective and fast acting.
regards
Tony

If the focal spread is over 8mm, f64 may produce the best image.

Thank you for your response, but I do not know what you mean.
Please clarify, assuming I'm ignorant (which I am not)
regards
Tony

Quote:

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Originally Posted by ic-racer

If the focal spread is over 8mm, f64 may produce the best image.

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Hi ic-racer., I have not heard from you since my reply of yesterday.
In the meantime I googled focal spread but the only thing I've found was a scientific paper from 2006 entitled "Measurement of focal spread, beam divergence and vibration in HREM images"
By 'focal spread' do you mean "circle of confusion"??
I'm really curious about your comment and how it "might/could/will" affect my use of the "f64" setting on my lens.
Please reply
regards
Tony