Correct Omega D lens cone for 150mm lens?

[James Westfall]

In my research for the answer, I have found a few different ones. (Links below)

I have an Omega Automega D3 enlarger and a Nikkor 150mm lens.

I emailed Classic Enlargers earlier last week but haven't gotten a response yet. Are they still in business? Their site shows a 4 1/2" cone. classic-enlargers.com

KHB shows a 4 1/2" lens cone. khbphotografix.com

Adorama shows a 5 1/4" cone. bhphotovideo.com

B&H shows a 3 1/4" cone. bhphotovideo.com

Someone on Photo.net suggests a 6" cone. photo.net/discuss

And someone here mentions a 4" cone 12 years ago. largeformatphotography.info/


Sorry for all the links but I wanted to show as much info as possible. Can anyone provide a definitive answer or will all of them work, but print size may vary? Thanks in advance for any and all help.

[Bob Salomon]

Why not ask Omega-Brandess? They are the owners of Omega.

[AJ Edmondson]

Print size won't vary... that is governed by lens focal length and height of head (distance between front of lens and enlarging easel). Somewhere around 4 1/2" should be about right, allowing you to use the fine-focus bellows. This does not account for any additional forward displacement due to the various "lens cups" used by Omega.
Joel

[AJ Edmondson]

421-155 5 1/4" Cone (used with a flat disc for lens mounting). If your mounting disc is a "cup" (the one with your 150mm EL Nikkor is) you can subtract the height of the cup can be subtracted. Optimum for your 6" lens would be the 5 1/4" Cone with the flat mounting plate with a 39mm hole. This would be most "adaptable for the autofocus cam.
Joel

[Mark Sampson]

Remembering my experience with them in the 1980s, the autofocus Omegas had shorter bellows than the manual focus versions. Thus they require more precisely-matched lens cones.
(I have an old push-pull D-II, which has a long bellows, and have always used a 2-1/2" cone with my 150mm EL-Nikkor.)
So I'll agree, the 5-1/4" cone is the one you'll want.

[ic-racer]

Some of those links are for the wrong enlarger. When I had a D3 I used this chart from the KHB site below. When I had mine I had a cone and track for 135mm lens, so that is the lens I acquired. Going the other way (trying to find a cone and track for an existing lens) can be very difficult.

[Greg Blank]

I worked for Omega for ten years, I was always doing this sort of research. In short you need the focal distance of said lens between the rear element of the lens regardless of focal length and the negative carrier. Whatever combo has to have that criteria. A longer cone will allow you to make smaller images, some people do reductions from larger negatives. That said the D3 has a short bellows if I recall correctly, therefore most likely you don't want a flat plate for the 150mm lens as a 150 roughly translates to a 6 inch Focal Distance required. Personally I'd probably go with the 5 1/4 if you have at least three inches of bellows which I think you do. The D3 also was made to have specific cam guides that allowed the enlarger to hold focus at one elevation versus the next....meaning if you focused the enlarger then rolled the column up for a big print you remained in focus.......in theory I think!