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

[tonyowen]

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???

135248135247135246135249

Regards

Tony

[IanG]

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

[djdister]

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.

[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

[tonyowen]

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

[IanG]

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

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

[tonyowen]

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

[ic-racer]

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

[tonyowen]

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

[tonyowen]

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

[Dan Fromm]

Tony, in this context focal spread means the difference in extension between the closest and farthest parts of the subject that you want to be in at least OK focus.

[IanG]

Tony, in this context focal spread means the difference in extension between the closest and farthest parts of the subject that you want to be in at least OK focus.

Taking that a step further getting at least OK focus at f64 you will probably be losing some overall sharpness and definition due diffraction, but it could be a case of getting an image that just wouldn't really work at a wider aperture. There are very occasional times where even using movements f22 or f32 just don't give you enough depth of field.

Ian

[tonyowen]

Ian, thank you
I'm beginning to see the light - pardon the pun!!!
regards

Tony

[ic-racer]

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

As mentioned, focal spread is the distance your focusing standard moves when going from focus on the nearest object you would like resolved and the most distant object. Closing the aperture makes the circles of confusion in the out-of-focus areas smaller, however, it makes the Airy disks of the in-focus areas bigger. Theoretically one could see this on via the ground glass to establish a pleasing compromise between the two effects. However, in practical term,s the ground glass image resolution is poor at small apertures and off axis. Therefore an approximation of sharp and unsharp areas of the final print can be beneficial. The focusing method of Hansma establishes this approximation.

[Jac@stafford.net]

[... Snip good stuff...] Theoretically one could see this on via the ground glass to establish a pleasing compromise between the two effects. However, in practical term,s the ground glass image resolution is poor at small apertures and off axis.

Might aerial focusing help?

[ic-racer]

Might aerial focusing help?

Perhaps. Usually when I look at the un-magnified aerial image at the back of my camera (for example in the cut corners) my eye tends to make the image always look sharp and clear, so it probably needs magnification to see diffraction and defocus. Certainly the magnified aerial image seen in the darkroom when doing enlargements lets one see diffraction effects on grain. But the pattern is always the same; good wide open and progressively mushy as you stop down, making it difficult to know what is actually acceptable in the print. Ideally one would want to duplicate the view of the final print from your target viewing distance. For me it is like looking at a finished print from a distance with a ground glass lying on top of it and trying to tell if it is in sharp or spoiled by excessive diffraction and defocus. Thus I'm a big fan of predicting the final outcome with the Hansma method.

[tonyowen]

a big fan of predicting the final outcome with the Hansma method..
I'm finding this extension of my original query fascinating. For others, like me, who are curious of the curious, I've found (by googling "Hamsma method") a very detailed explanation in LF Forum > Style & Techniques> hyperfocal vs Hasma [Leonard Evens et al, 19th April 2007 18:29].
I will continue to be an avid follower of the route this thread is taking.
regards and thanks
Tony

[ic-racer]

Just to continue on tangents you might find interesting, there is a free on-line book called "Ins and Outs of Focus; An Alternative Way to Estimate Depth-of-Field and Sharpness in the Photographic Image" I use as a reference: http://www.trenholm.org/hmmerk/TIAOOFe.pdf

[tonyowen]

Thank you - found it
It seems to be very thorough - and written by a fellow Canadian
regards
Tony