Wide Angles lenses on condenser enlargers

[Dave Krueger]

I just noticed that the data sheet for the El Nikkor 40mm f4N lens says it should be used on diffusion enlargers. This is basically a wide angle lens for use with 35mm negatives. Anyone know why the 40mm lens shouldn't be used on a condenser enlarger?

Also, the lens specifies a usable enlargement range of 2X to 20X. What happens if I go bigger than 20X? I assume there's something about the physics of the lens construction that results in some negative effect if you go much beyond that, but I haven't a clue what that would be...

 

[Nick Zentena]

Two things come to mind.

Even my 50mm Nikon needed a recessed board. If you go out of the enlargement range the quality will be lower then normal. The question becomes is it bad enough for anybody to notice.

 

[richard ide]

When a lens is used for magnifications which it has not been optimized for, the first aberation that seems to appear is chromatic. I have done many extreme enlargements and could improve image quality substantially by using a green filter in a lot of cases.

 

[Dave Krueger]

Nick,

I did check the range of movement on the lens board. With my 50 mm lens on there I still have plenty of movement range to bring the lens closer to the negative carrier, so I don't anticipate a problem on the condenser enlarger. On my Chromega, I would definitely need a recessed lens board. I was hoping the problem would be something like diminished edge sharpness or something like that. Since I will almost always be cropping when I go that large, I won't be using the edges of the image field, so it would be nice if the problems occurred out there. haha!

Richard,

I assume a green filter would require that I switch to graded paper, instead of VC paper. I don't anticipate doing many huge enlargements, but it's good to know there's a way to minimize the problem if need be.

 

[Jim Jones]

Another potential problem when using shorter than normal enlarging lenses on condenser enlargers is the mismatch between lens and condensers.

 

[Dave Krueger]

Another potential problem when using shorter than normal enlarging lenses on condenser enlargers is the mismatch between lens and condensers.

How does that mismatch manifest itself in the print?

 

[Jim Jones]

Uneven illumination or vignetting.

 

[David A. Goldfarb]

Another possibility when going outside of the optimal enlargement range could be pincushion or barrel distortion, which would be fairly easy to check for. If you're printing really big, then there are lenses designed for the purpose, such as the Rodagon-G, and given how cheap enlarging lenses are going for these days, and how expensive it is to make huge prints, it would be worth keeping an eye out for one, if that's something you do often.

 

[Lee L]

I was once asked to print an 8x10 inch print from a corner of a 35mm negative at the maximum magnification I could get with an Omega D5-XL enlarger in the lab where I worked.

At that magnification the El-Nikkor 50mm f:2.8 (early 80's vintage) had such bad astigmatism at the corners that I couldn't focus on the grain properly, and the lens made a lousy print from a corner of the frame. I asked the lab manager if they had any other enlarger lenses around, and we scrounged up a Focotar 50mm f:4.5 from one of the cabinets. That improved the corners greatly.

The astigmatism in the El-Nikkor wasn't intrusive at normal 8x10 enlargements from a full 35mm negative, but it made the corners of the frame useless at the higher magnification I needed for the job at hand. As others have noted, lenses are designed for specific degrees of enlargement, and it's best to use them within design parameters.

One reason that wide angle lenses were introduced for enlarging was to get a larger image with a shorter enlarger column. That doesn't mean that they are necessarily better than a longer lens and a taller enlarger column.

I recently got a 40mm f:4(N) El-Nikkor when I bought out a darkroom, but haven't tried it yet. The instructions give a standard magnification of 10x for the 40mm, and a range of 5x to 30x. The 50mm f:2.8(N) EL-Nikkor has a standard magnification of 8x , and a range of 2x to 20x. So perhaps the 40 will work better at greater print sizes.

Lee

 

[Dave Krueger]

Oops. I made a mistake. I just got the 40mm Nikkor and the usable range is 5x - 30x as you say. I I was looking at the wrong lens when I said it was 2x - 20x. In any case, I could be exceeding the 30X range on rare occasions, but would only be using the center of the image field.

I got the lens and noticed it does have light fall off at the corners on my condenser enlarger. On the bright side, it also works on my diffuser enlarger. I didn't think it would work without a recessed lens board. No light fall off at the corners with the diffusion head.

-Dave

 

[Ronald Moravec]

I get fuzzy corners with my 45mm Schneider APO with any condenser enlarger. Glass carriers and well aligned, but all four corner are fuzz. Put the lens on a diffusion machine and it works like a champ. I have tried it on 4 condenser machines and three diffusions all set in my darkroom.

The lens was ready to go in the bin at one point.

 

[Dave Krueger]

I get fuzzy corners with my 45mm Schneider APO with any condenser enlarger. Glass carriers and well aligned, but all four corner are fuzz. Put the lens on a diffusion machine and it works like a champ. I have tried it on 4 condenser machines and three diffusions all set in my darkroom.

The lens was ready to go in the bin at one point.

I experience light fall off in the corners when using the 40mm on my 67SC condenser enlarger, but I didn't actually print any pictures using the entire frame, so I don't know if there is a sharpness issue. I suspect I will see the same thing you do if I were to do that, though.

Since I got the lens specifically to crop down bigger enlargements, I doubt that I will be using the corners of the projected image much. If I need to crop down to the corner of the negative, I will probably just move the negative over so the section I'm printing is more centered in the carrier.

I kinda wouldn't mind having a diffusion head for that 67SC enlarger, but I do have a diffusion 4x5 enlarger and have found that the 40mm works just fine without a recessed lens board. That was a pleasant surprise.

Thanks for the reply.

-Dave