1:20 to 1:5 (0.05x to 0.2x)

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Lou Jost
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Re: 1:20 to 1:5 (0.05x to 0.2x)

Post by Lou Jost »

I agree that when stacking, field curvature in no problem at all. I think that's not quite the same thing as distortion correction in a single shot. Distortion correction always does degrade the final image to some degree, while stacking only improves an image. I understand that the proper balance between cost and weight versus performance will vary between persons.

But the inability to use such lenses in the many unusual ways that we use them causes serious problems for us, and I fear the future.

jvanhuys
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Re: 1:20 to 1:5 (0.05x to 0.2x)

Post by jvanhuys »

Hi everyone, I hope the week is treating you well so far.

Small update on my side. I've received the Dokumar and ordered an adapter from RAF camera. In the mean-time I couldn't resist doing a crude hand-held test for copying artwork. I threw together something with some SM2 tubes lying around and I have to give credit to 'simplejoy' once again.

The lens absolutely floored me with the image quality.... There seems to be no distortion or CA and it's slightly sharper than my Makro Symmar 120 HM is at 1:2. This is only a first impression though, so I'm not gonna make any sweeping statements, but the first impression is very strong. I'll hold-off posting any pictures until I get the adapter back, mount it to my setup and photograph paintings or various sizes.

On a side-note the lens is astoundingly heavy. It was so shocking to me that I had to put it on a scale... plus/minus 860grams! It's quite a small lens so I'm not sure what that kind of glass is inside:) Also, from my measurements it is not a M42 mount as mentioned earlier in this thread, but a M48. If I get the adapter and it still doesn't fit I'll post here.

I did stumble upon another lens-series designed by Schneider called the D-clarons (not to be mistaken for the famous G-clarons I suppose). If anyone has shot with these lenses, would you mind sharing your experience here? The tagline that caught my attention was of course this line:
"The D-Claron (Dokumentations-Claron) is a lens family designed for copying of documents onto microfilm."

I'm not sure what microfilm is, but it kinda reminds me of those crazy Zeiss lenses that can do 1200lpmm resolution but also had impossible parameters. I'm hoping the D-clarons are similar to the Dokumar in that it can do magnifications between 1:5 and 1:20 (1:30 in case of Dokumar 47mm f/5.6).

There seems to be a wide variety of focal-lengths too, from 10mm to 210mm. Again, the ones that caught my attention were the 60mm f/5.6 (for 35mm) and the 105mm f/5.6 (for 70mm). Again, I'd appreciate any useful info on these D-clarons. I'm finding it particularly hard to get sample images.

Doppler9000
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Re: 1:20 to 1:5 (0.05x to 0.2x)

Post by Doppler9000 »

jvanhuys wrote:
Wed Apr 05, 2023 5:18 am
…from my measurements it is not a M42 mount as mentioned earlier in this thread, but a M48.
FWIW, the M42 reference clearly stated the mount was not M42, though it seems yours is not even close.
I'm not sure if it's just my particular Dokumar, but it has a thread which is close enough to get into my M42 lens board on my bellows. It's not an exact fit though, so it's a bit loose.

simplejoy
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Re: 1:20 to 1:5 (0.05x to 0.2x)

Post by simplejoy »

jvanhuys wrote:
Wed Apr 05, 2023 5:18 am
Also, from my measurements it is not a M42 mount as mentioned earlier in this thread, but a M48. If I get the adapter and it still doesn't fit I'll post here.
Just to be clear, my Dokumar came with a metal collar around the thread on the barrel which can be seen on the right:
Image

You can check if it's the same thing with yours. It was fixed with two small screws but if you loosen them it should be possible to remove it.

jvanhuys
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Joined: Sun Jan 22, 2023 9:24 pm
Location: Seoul, South Korea

Re: 1:20 to 1:5 (0.05x to 0.2x)

Post by jvanhuys »

Sorry to have misquoted you.

I wish I knew that m48 part could be safely unscrewed :(

You did mention the M42 connection wasn't rock solid, so here's to hoping the M48 adapter is nice and tight.
Thanks for sharing the info about the M48 screw being removable, that's really helpful info for everyone else too.

Chat soon.

jvanhuys
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Joined: Sun Jan 22, 2023 9:24 pm
Location: Seoul, South Korea

Re: 1:20 to 1:5 (0.05x to 0.2x)

Post by jvanhuys »

Hi everyone! Hope the weekend was a rested one.

My Dokumar M48 to E mount adapter from Rafael of RAF camera finally arrived. Why am I using an M48 when the M48 collar can be unscrewed? Because the screws (of my copy) are so brittle that the screws disintegrated after barely touching it with a screwdriver. So I was permanently left with the M48 screw mount. Fine by me!

At any rate, I haven't photographed any large artwork at the intended magnification or with any sort of studio lighting. But I couldn't resists sharing a quick snap I did in my kitchen with very dim overhead lights. This is a tiny tiny corner crop of a postcard sized artwork (closer than intended magnification) but I'm really happy with corner sharpness and CA control.

Unfortunately, despite the MTF curves indicating an almost perfect lens...
- It has slightly less corner sharpness than the centre (I would've expected it to be identical due to slighly larger than 42mm image circle and symmetrical biogon design)
- It has a touch of chromatic aberrations, but interestingly the CA only appears with out of focus objects. In focus, high-contrast areas with ultra-bright highlight pings next to almost black tones, don't seem to create any visible CA I can see when zooming in. This is of course an excellent result.
- It has a yellow color cast which is not present when the same scene is pictured with a different, modern enlarger lens. I have removed the color cast from the attached picture, but left everything else as is from camera without any sharpening or contrast enhancement. I have not flocked the helicoid or adapter and I'm not using a lens hood.

To summarize, first impression is VERY good. But it is not a perfect lens:) Gonna have lots of fun with it though:)
Attachments
dokumar_corner_crop.jpg
dokumar.jpg

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