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1916
Deleted by topic administrator 11-23-2018 11:36 PM
1915
Adrian Wylie
11-22-2018
09:01 PM ET (US)

And this photo is taken using the 101mm Raptar.
1914
Adrian Wylie
11-22-2018
08:59 PM ET (US)

Don, both the Raptar and Velostigmat 2-inch lenses feature 9-blades in their diaphragms so their bokeh may be similar. The Velostigmat at wider apertures would work especially well for any photos in which you would desire softer corners, such as portraits.

Just in case anyone is interested, here is an image taken with the 35mm Raptar lens from the same spot that I took all the photos from. Sharpness reaches a peak when the lens is stopped down to f/16 or f/22.
1913
dtdinaro
11-22-2018
12:31 PM ET (US)
Raptar is a later lens manufacturing. Soft corners offer a more nostalgic look and extra diaphram blades a better bokeh effect. I would chose the Velostigmat.Sent from my T-Mobile 4G LTE Device -------- Original message --------From: QT - Adrian Wylie <qtopic-22-tjSp7wdBxN3SD@quicktopic.com> Date: 11/22/18 11:37 AM (GMT-05:00) To: QT topic subscribers <qtopic-subs@quicktopic.com> Subject: Clarus Camera Forum QT|[An image was uploaded with this message. Visit the link below.]This may be a first, especially in 2018… the Velostigmat vs. Raptar challenge! Is there are real difference between the two and was it worth paying an extra $52.25 (that’s $500 adjusted for inflation) for the f/2 lens?I tested both lenses at all apertures with Ann Arbor’s Burton Memorial Tower as my subject.  Nothing was scientific in the way this was done… the lighting conditions kept changing, the images were recorded on a roll of Agfa APX25 film that had expired in 2003, and of course my testing instrument was a Clarus Camera.My findings… the 2-inch Raptar at f/2 is somewhat soft with a bit of a zone-plate glow around bright areas in the photo but it does show detail.  In a pinch you could shoot wide open and get a respectable 4x6 print.  f/2.8 shows noticeable improvement and by f/5.6 the corners are looking pretty good.The 2-inch Velostigmat reveals remarkably good center sharpness right out of the gate at f/2.8, in fact its neck-and-neck with the Raptar at every aperture.  But as you scan towards the edges of the images you see what separates the two lenses.  The Raptar offers vastly superior resolution in the corners.  You have to stop the Velostigmat down to f/8 before you get anything that comes close to the Raptar’s acceptable edge performance at f/2.I was surprised that both lenses offered peak resolution at f/16… I couldn’t see any softness due to diffraction.  The two photos included here were both shot at that f-stop. I’m not sure if the web-scans will show how good these images are but there is a lot of detail in the negatives.  In the bottom left corner the Raptar reveals excellent resolution right into the brick work. At f/16 the Velostigmat is also at its sharpest but the corners are still no match against the Raptar.______________________________________Reply by email or visithttps://www.quicktopic.com/22/H/tjSp7wdBxN3SD/m1910To unsubscribe: https://www.quicktopic.com/22/X/tjSp7wdBxN3SDStart your own topic in 20 seconds: https://www.quicktopic.com |QT
1912
Adrian Wylie
11-22-2018
12:14 PM ET (US)

Velostigmat versus Raptar edge detail.
1911
Adrian Wylie
11-22-2018
11:39 AM ET (US)

... and the 2-inch Raptar image at f/16.
1910
Adrian Wylie
11-22-2018
11:37 AM ET (US)

This may be a first, especially in 2018 the Velostigmat vs. Raptar challenge! Is there are real difference between the two and was it worth paying an extra $52.25 (that’s $500 adjusted for inflation) for the f/2 lens?

I tested both lenses at all apertures with Ann Arbor’s Burton Memorial Tower as my subject. Nothing was scientific in the way this was done the lighting conditions kept changing, the images were recorded on a roll of Agfa APX25 film that had expired in 2003, and of course my testing instrument was a Clarus Camera.

My findings the 2-inch Raptar at f/2 is somewhat soft with a bit of a zone-plate glow around bright areas in the photo but it does show detail. In a pinch you could shoot wide open and get a respectable 4x6 print. f/2.8 shows noticeable improvement and by f/5.6 the corners are looking pretty good.

The 2-inch Velostigmat reveals remarkably good center sharpness right out of the gate at f/2.8, in fact its neck-and-neck with the Raptar at every aperture. But as you scan towards the edges of the images you see what separates the two lenses. The Raptar offers vastly superior resolution in the corners. You have to stop the Velostigmat down to f/8 before you get anything that comes close to the Raptar’s acceptable edge performance at f/2.

I was surprised that both lenses offered peak resolution at f/16 I couldn’t see any softness due to diffraction. The two photos included here were both shot at that f-stop. I’m not sure if the web-scans will show how good these images are but there is a lot of detail in the negatives. In the bottom left corner the Raptar reveals excellent resolution right into the brick work. At f/16 the Velostigmat is also at its sharpest but the corners are still no match against the Raptar.
1909
dtdinaro
11-21-2018
08:45 AM ET (US)
The weakness through time in the focal plane shutter is the silk fabric tapers that rap around the drum. Most all cameras that used this design can be improved by tightening up those tapers.
1908
Rick Oleson
11-21-2018
08:24 AM ET (US)
That's great news! I think mine tested out to around 1/175 or so but it did like to wander .... 175 was probably the high mark rather than the average, and I'm sure it never hit the same number twice. It does fire every time though, which is something.
1907
Adrian Wylie
11-18-2018
01:47 PM ET (US)
“Accurate and strong shutter” I’m thinking there may not be a Clarus that exists that can claim that virtue. And unfortunately the camera that I recently bought on Ebay was no better than the one I was trying to replace. I do give the seller credit for not only giving me a full refund but also covering the return postage.

This got me inspired to see if I could get my faulty body (the camera that is) into better shape. So with some drawings that I found on-line (thank you Rick!) and a video posted by Mike Eckman I got up the nerve to take the top of the camera and clean up the gears along with the viewfinder windows.

One thing I did differently from Eckman’s write-up was that I used a cleaning/lube mixture of dry graphite blended in with lighter fluid instead of the machine oil that he used I don’t use any lube for shutter gears that might leave a gooey residue behind. When I tested the speeds afterwards they are all still a bit slower than the posted speeds, especially the faster speeds with 1/500 clocking in around 1/125. But the good news is that they are all very consistent my new “1/125” speed is never slower than 1/100 nor faster than 1/160. This is a great improvement over what the camera was doing before the cleaning!

Finally I checked the Velostigmat and the three Raptar lenses to see how the actual focusing matched up with the rangefinder view. All are spot on! Even with the shutter imperfections I believe I now have a Clarus body that I can shoot all four lenses with.
1906
Rick Oleson
11-13-2018
10:33 AM ET (US)
Hi - I don't have any idea, I don't have any connection with Camera-Wiki beyond granting permission to use my images.
1905
eastwestphoto
11-13-2018
07:12 AM ET (US)
Rick, Patents were surrendered at Ww2's close. I will try and find were in the book it is discussed. There are countless references online to that event, but not specific to m39 Leitz patents. I thought it was in Perfex cameras? I see your name a lot in camera- wiki.pedia, so a question? Why is so hard to edit a page when a Rare example pops up , like a Katakana marked Konica 1b?
1904
Rick Oleson
11-13-2018
06:32 AM ET (US)
Thanks! I have that book here, can you point out the page? I'm not finding any such reference. My understanding is that German (and Japanese) patent rights became void on declaration of war; the Kardon was commissioned by the government during the war as a direct copy of the Leica IIIa and would have infringed on at least a few Leitz patents, which I also have copies of; but I have not found any patent claiming the M39 lens thread. Assuming that Lahue & Bailey did write that the M39 mount was protected by a Leitz patent, that wouldn't necessarily establish that it was true; if it was, I'd like to read the patent and see just exactly what was claimed. I have a few myself, and none of them were quite that easy.
1903
eastwestphoto
11-12-2018
10:07 AM ET (US)
The American 35mm Vol 1, 1972 by Lahue & Bailey
     Somewhere in this book is a sentence about the E. Leitz 39mm patent infringement and its effect on American cameras.
1902
eastwestphoto
11-12-2018
10:05 AM ET (US)

Eric Truebenbach, Registered US Patent Agent, inventor on 20 patents, portfolio mgr, litigation
Answered Nov 20, 2015
Before WWII, the Germans "Aryanized" the patent system along with the rest of German affairs. This meant that only people of appropriate political and racial purity could apply for patents.

After WWII, the Allies took control of all of the patents, including secret ones for war-related inventions, and used them freely. They didn't put the German patent office back until the early 1950's.

I don't know what happened in Japan, but I daresay it was similar: seizure of all IP as war reparations, followed by eventual re-establishment of a patent office.
1901
Deleted by topic administrator 11-12-2018 04:03 PM
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