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Wrong sized rear element Optar 135mm?

 
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mdanie



Joined: 28 Sep 2014
Posts: 6
Location: UK

PostPosted: Sun Sep 28, 2014 9:07 pm    Post subject: Wrong sized rear element Optar 135mm? Reply with quote

Hello everyone,
I've just bought a Pacemaker Speed Graphic with Optar 135mm lens in a Graflex X shutter. The aperture selector was exceedingly stiff and the blades worn through the paint at the edges. Removing the elements proved that the rear element was binding the aperture blades when screwed in - and as I can compare it to the Optar 135 on my Super Graphic - it is about 1mm too deep. So I guess this is not the correct element for this lens and has been pulled from something else. So, it has the correct diameter and correct thread for Graflex X - but is too deep, plus the lensboard mounting ring does not fit my proper Optar, so is also slightly different. Any ideas what this could be from (no markings, unfortunately)?
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45PSS



Joined: 28 Sep 2001
Posts: 3634
Location: Mid Peninsula, Ca.

PostPosted: Mon Sep 29, 2014 2:58 am    Post subject: Reply with quote

Graflex Corp. under all its names from beginning to end used an engineers rule to lay out their press and Graflex SLR's therefore all camera measurements will be in inch, tenths, hundredths, or thousands of an inch.
1 inch =25.4mm.
Now the 135 Optar is in a #2 Graphex shutter. It has the same mount thread as a #2 Betax shutter which SKGrimes.com shows to be 1.325 inch diameter, 40 threads per inch (TPI). The Graphex is a Rapax rebadged. The Optar is a Raptar rebadged. All were made by Wollensak.
The Optar in your Super is a Rodenstock made lens so it is not unusual for its dimensions to be different.

#2 Graphex full sync shutter with 135mm f4.7 Graphic Optar:
1. Front lens element barrel edge to rear lens element barrel edge mounted in the shutter 1.185 inch/30.1mm.
2. Rear element outer barrel edge to lens element edge (thickest point) .410 inch/10.42mm
3. rear lens inner edge to threaded section on barrel .196 inch/4.98mm, barrel is 1.162 inch/29.52mm diameter.
4. Lens inner edge to barrel edge at the rear of the threaded section .2 95inch/7.48mm
5. Barrel unthreaded outer edge .115inch/2.93mm, 1.289 inch/32.74mm diameter.
6. Shutter rear edge to aperture blades .325 inch/8.25mm.
Rear lens element innermost edge to aperture blade clearance .030 inch/.76mm.
All measurements made with a digital caliper accurate to .0005 inch and may be -.0005 inch of perfect.

Many times due to production tolerances a lens barrel or shutter will be .001 inch from nominal dimensions. Shims are used to space cells for proper fit into the shutter or for correct optical alignment.
It is quite possible that the cell is correct and the shim(s) were left out.

The paint on the aperture blades is bluing, a chemical used to coat and protect metal commonally used on firearms (guns).

If the rear cell checks out make a shim from card stock or a scrap piece of film to get the cell to clear the aperture.
The service manual for your Graphex shutter:
http://www.southbristolviews.com/pics/Graphic/manual-pdf/GraphexShutterService.pdf

Test the tens wide open on a test target for correct optical performance.
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mdanie



Joined: 28 Sep 2014
Posts: 6
Location: UK

PostPosted: Mon Sep 29, 2014 6:24 pm    Post subject: Reply with quote

Thank you so much for all that detailed info 45PSS - and for the correct terms (why do I keep mixing those up?). I'll measure and check ASAP.
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mdanie



Joined: 28 Sep 2014
Posts: 6
Location: UK

PostPosted: Mon Sep 29, 2014 10:49 pm    Post subject: Reply with quote

A quick update. The measurements are careful estimates with rule or analogue micrometer - others I can't do.
1. I get 28.5mm (rear cell screwed right in)
2. 10.65mm
diameters are all obviously standard for the Graphex X shutter.

Interestingly, my estimate of the focal length of this lens using a bulb filament for "focus" is ~150mm (front cell does have the 135mm label) whereas the Super's does correctly estimate to 135mm!

I shall try making a shim and run some proper test shots to clarify what I have here. Thanks again for your suggestions.
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45PSS



Joined: 28 Sep 2001
Posts: 3634
Location: Mid Peninsula, Ca.

PostPosted: Mon Sep 29, 2014 11:29 pm    Post subject: Reply with quote

http://www.ebay.co.uk/itm/Digital-Vernier-Caliper-Gauge-Micrometer-Tool-6-150mm-Electronic-LCD-Display-/171095500315?pt=UK_Measuring_Tools_Levels&hash=item27d616261b
looks identical to mine.

My measurement 1 - your measurement 1 (30.1-28.5) = 1.6mm divide that by 25.4 to get the inch equivalent = .063 inch. Large but not excessive for a shim. I would start with .01 to .025 inch thick shim to get the cell to just clear the aperture blades.
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mdanie



Joined: 28 Sep 2014
Posts: 6
Location: UK

PostPosted: Mon Oct 06, 2014 3:51 pm    Post subject: Reply with quote

Great link - I now own one!
A shim made from sheet film has worked perfectly.
Thanks again for your help.
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