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Computar DL 65mm f3.5 enlarging lens

John Galt

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I could find very little on the innerwebs about this lens. Although considered an excellent lens they apparently have a penchant for lens separation? Does anyone have any experience with them?

I found two new, still in the bubble and original box, unused examples today at a pawn shop, in a box they brought out from the back with a metric crap-ton of other no-name slr lenses and filters. Boxes have absolutely no outside markings on them. Only after opening the boxes did I see what we had there. Was told I was the first to ask about film cameras for years. . . I may go back and grab them based on the expert opinions here.

Thanks!!!

Edited to add: I don't need them, still getting my darkroom in order. I already found a new El Nikkor 50mm f2.8 and El Nikkor 80mm f4, both new/unused in bubble, for $40 each.
 
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wiltw

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Ctein (who is known for being a bit of a perfectionist in the darkroom) writes in his book, Post Exposure, lists that lens among the 'Ratings of the Best Enlarging Lenses, says that the lens has half-stop detents, is best (sharpness+contrast) at f/4 and met his test standards down to f/7 (smaller apertures diffraction limited),
it has 0.2EV falloff and 0.0% distortion at f/4. He says,
"Slight smearing wide open, but overall image quality as good as Nikkor 63mm. Better corner contrast but a bit more lateral color. Good performance at all magnifications. Also sold as Apo-Computar."​
 
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Patrick Robert James

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The rear elements tend to separate which looks like a rainbow. If they are perfect then the lenses are among the best you can get your hands on. Usable wide open even. I would go back and get them if I were you, but if they are separated, they aren't worth much if anything unless they are recemented. Almost all of them are separated at this point though.
 
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John Galt

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So, if I hold them up to a light source with aperture wide open I will see a rainbow if they are separated? Will it be subtle or pronounced? What would you pay for them?
 

MattKing

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A 65mm lens is very useful for printing 35mm negatives in some 4x5 enlargers - like my Omega D6.
 
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John Galt

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MattKing said:
A 65mm lens is very useful for printing 35mm negatives in some 4x5 enlargers - like my Omega D6.
Click to expand...

Thanks for the reply Matt. I have a Beseler 23C II . . . any advantage of 65mm over the El Nikkor 50mm I already have? I will be doing 35mm and 2 1/4 x 2 1/4.
 

jjphoto

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John Galt said:
So, if I hold them up to a light source with aperture wide open I will see a rainbow if they are separated? Will it be subtle or pronounced? What would you pay for them?
Click to expand...

The rainbow tends to show up when lit with a softbox and might be a bit hard to see with the naked eye if it's subtle. It can look like mottling or haze depending on how bad it is. But yes, light it with a little torch from behind or hold it up to a lght and if there is separation it will be in the rear group (I haven't seen separation in the front of a Computar dL yet).

Mines actually quite clean with no sign of any problems. Maybe the 65's are not prone to separation, not sure, but many other Computar dL's certainly are.

Some info about Computar dL's here: http://www.photocornucopia.com/1057.html

Computar dl 3.5/65: http://www.photocornucopia.com/1074.html
 
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MattKing

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John Galt said:
Thanks for the reply Matt. I have a Beseler 23C II . . . any advantage of 65mm over the El Nikkor 50mm I already have? I will be doing 35mm and 2 1/4 x 2 1/4.
Click to expand...
The 65mm will be good for doing smaller enlargements from 35mm, and larger enlargements from a cropped 2 1/4 x 2 1/4.
The longer focal length (compared to 50mm ) allows you to use the head at a more convenient height when doing small enlargements, and avoids any problems one might encounter with a difficult to fully compress bellows (which is why I use a 60mm Focotar on my Omega D6).
It is also the perfect focal length for 127 and may also give you good results with 6 x 4.5.
Enlarging lenses add flexibility, and don't take up much space.
 

Hilo

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I have the 50/2.8 Computar and like it for its heavy build and larger size. Quality is fine.

John, I sent you a private message or maybe now it is called a conversation, ha
 
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John Galt

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Thank you so much for the replies! I will go back in the next few days and make an offer. I will post here if I get them.
 
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John Galt

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OK . . I went and checked these lenses more closely today . . they both exhibited blotches in the center of the rear element(s) when a small penlight was shined at an angle through them, one was much worse than the other. These blotches are not apparent when looking straight through the lenses at various light sources.

I passed. Too bad, like I said they were NIB/bubble with $190.00 price tags on each. Probably could have snagged them both for $40 if they were in better shape.
 

jjphoto

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I have a couple of lenses with separation which I've found to be OK to use (both Computar dL 1.9/55) but generally separation is 'bad' and has a noticeable effect on image quality and can't be fixed cheaply so is best avoided altogether. You did the right thing.
 

Hilo

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What a pity ! It is bizarre this company got so unlucky with these rear element problems, while intending to produce the highest quality lenses. I had, to try out, three different Computars and I returned them for the same reasons: clear, brownish blotches on the inside of the rear element. A repairman advised against trying to do something.
 

John Wiegerink

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John Galt said:
Never discussed price. I have a great relationship with this shop. Probably could have got them for 10-20$ each because of the blotches.
Click to expand...
You should have probably tried them for that price. You might just be very surprised.............blotches or not!
 
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John Galt

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Thanks for all the very good responses . . . so many smart people here!!! I may reconsider and see what I can get them for . . . sooo . . what do you think I should pay for them?
 

jjphoto

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John Galt said:
Thanks for all the very good responses . . . so many smart people here!!! I may reconsider and see what I can get them for . . . sooo . . what do you think I should pay for them?
Click to expand...

I would buy just one, the best one, and see how it goes. As for price, obviously as low as possible but essentially pick an amount you are willing to loose as the lens might not perform very well. Of course you'll never know for sure without a good one to compare it too. I've had a Computar with separation which was unusable and then I also have a couple with separation that are just fine, but obviously below par compared to a perfect lens. It's a gamble.
 
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John Galt

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Update:

I found myself back in the neighborhood of this shop last week so I stopped in. I asked to see the two Computar f3.5 65mm lenses they had which we discussed above. I am now more educated now on how to evaluated these lenses for mold, haze, separation etc.. He could only find one of the two that he had though (will call if he finds the second one). I checked it again with a bright mini flash light and took a couple pictures with my smartphone. This is what I am seeing . . . not sure if it is separation or haze. It is only visible with a bright light at about a 45 degree angle, it is completely invisible when looking through the lens. It is on/in the rear element. BTW, that orangey thingie at 12:00 high is the reflection of my hand holding the flash light.

What do the experts here think? Regardless, I got this lens for $10, a gamble I was willing to take.




 

Hilo

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It looks different from the stuff I saw in mine (earlier post), but not that different. Does not look like fungus, but I am certainly not an expert there. If you don't get fungus warnings from the others, just try it out . . .
 

John Wiegerink

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I'd say it might be internal fungus, but I really can't tell from that shot. I do know it's almost surely not lens separation. Separation almost always starts on the outside edge of the lens elements. If I had those lenses I'd get my spanner wrench out and pull the rear group. What you see is probably between the front and rear groups and not the lens elements themselves. Could be wrong, but that's what I see. Still, the safest thing to do is what's said above use the damn thing and see. You might be surprised. I've had some pretty ugly enlarging lenses and taking lenses that really shocked me.
 
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John Galt

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Thanks for the reply John Wiegerink. That was the way I was leaning also. How would I go about taking this lens apart . . . can you suggest an online resource to help? Thanks
 

John Wiegerink

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John Galt said:
Thanks for the reply John Wiegerink. That was the way I was leaning also. How would I go about taking this lens apart . . . can you suggest an online resource to help? Thanks
Click to expand...
I can't say for sure, since I don't have that particular lens, but if you look at your last shot of the lens you can see the shiny barrel just behind the threads. That shiny barrel is the rear lens group. Now look and see if there is a break line where that rear group screws into the lens barrel itself. Some enlarging lenses allow you to unscrew that rear group and remove it. Some don't and require a spanner wrench to do the job. First thing to do, if the is a break line, is to try and unscrew it by hand. If that doesn't work you will have to use a "strap wrench" to do it. Go this trial route first and then we or somebody else here might chime in and have an idea. Most of the time I can unscrew mine by hand.
 
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