I have a 135mm Rodenstock Omeragon from which I tried some prints from my 4x5 b&w negs. However, I feel that the edges remained underexposed and the image seemed rounded at the edges.

Is the 135 recommended for 4x5 negs or is a 150mm absolutely necessary.

And if I stop the 135 down to f 16 will it throw a larger image thereby giving satisfactory prints.

I use a Mercury Argon grid on my homemade wooden enlarger.

Thanks Dileep

-- Dileep Prakash (dileep@abpmail.com), November 18, 2000

Answers

I'd be inclined to agree with you - the 150mm is a fairly safe bet for 4x5, or even a slightly longer lens to allow a comfortable working distance. I use a 100mm for 6x9 and sometimes find this a bit restricting. I have thought that the 135mm would be ideal for 6x9 so a bit limiting for 4x5. On the subject of smaller apertures, you may find that by using such a small stop your enlarging times are long ( a pain if you're holding your arms out whilst dodging/burning) and that lenses dont tend to perform that well at such small apertures. I tend to stick to f8 / f11. Regards Paul

-- paul owen (paulowen_2000@yahoo.com), November 19, 2000.

Dileep,

I might disagree with Paul just a little. While a 150mm lens is ideal for 4x5, a well made 135mm lens (el nikkor, rodagon, or componon s), when stopped down one or two stops, should be pretty close to the performance of the 150mm except in the extreme corners. I can at least say that about a 135mm componon S in comparison to a 150mm el nikkor. I use both lenses on a Saunders 4X5 dichroic enlarger.

-- mitch rosen (mitchrosen@sprintmail.com), November 19, 2000.

Maybe I am just lucky, or not discerning enough, but I use a 135mm lens (Vivitar name on a rodenstock) and make enlargements up 20x24 with no problem. I typically enlarge at f16.

-- Mark DeMulder (mdemulde@usgs.gov), November 19, 2000.

Have you considered your light source may be the reason for edge light fall off? Or the homemade enlarger? The 135mm lens itself should not be a problem.

Burning the edges of all prints is something many people due routinely regardless of edge fall off just to achieve a better balance to the image. So you may need extra edge burn to make up for actual edge fall off.

-- John Hennessy (northbay@directcon.net), November 19, 2000.

I use the Nikkor 135 enlarger lens with negs. 6x9cm to 4x5 and it does a fine job. Used at f11/16 it produces a very sharp evenly illuminated image.

-- Trevor Crone (tcrone@gm.dreamcast.com), November 19, 2000.

The Omegaron is a close to the bottom of the line lens made a a private label lens for Berkey.

It's performance is not typical for a modern, quality lens like a 135 Rodagon but it was designed for 45

-- Bob Salomon (bobsalomon@mindspring.com), November 19, 2000.