The key point to consider is that in an autofocus system, all values must remain known and constant in order for the autofocus function to function. With the accessory bellows, if your lens is misplaced by even a fraction of a millimeter, your focus will be off. What you need is a lens cone for each different lens, and a focusing cam rail for each. To fit the 150mm lens, you'll be after the 5 1/4 (~133mm) lens cone.
My darkroom used to be a meat freezer.
Check and make sure you have a focus track that is marked for something close to 150mm. Unless you really want to preserve accurate focus as you change magnification, it does not have to be exact. But the track follower provides the base position for the lens stage. If the track follower is not present or not close to correct, the focuser will be working out of range with the possibility of vignetting or producing unexpected reflections that cause things like that ring. Or you may not be able to focus it at all.
The proper cone is part of the track design. The longer the lens, the longer the cone. 150mm uses that 5+" cone. The 139mm I used required a 4-3/4" cone, or something like that. I made a 3" cone for the 80mm lens I used for 6x6, etc. I also made a track for that lens by cutting some sheet metal and riveting it to a track for a lens I don't use (but that came on the enlarger that I bought used about 30 years ago). The D3 holds three tracks.
Again, it does not have to be precise unless you really want it to stay focused as you raise and lower the head. That was not a requirement for me. I just wanted the lens to be positioned within the range of the stock focuser.
Rick "who had to figure out the D3 mechanics by reverse engineering" Denney
Good afternoon, Zone. Assuming that this web site is still up to date, active, and that the original owner is still with us, I was able to find some very obscure Omega information from him about two years ago if my memory is correct. He seems to be an incredible resource for info on all things Simmons-Omega. www.khbphotografix.com/omega
Hopefully he will be able to resolve you problems.
Tim
"One of the greatest necessities in America is to discover creative solitude." Carl Sandburg
Good news...
i've purchased the cone linked from Ic-Racer. Today the post-office has delivered the cone, and i take first test. The componon 150 work fine matched with cone and work fine the autofocus system.
Thanks Ic racer... and thanks at all for the contribute.
So following rdenney reasoning i've need of 3" cone for 80mm and which cone for 105 mm????
Originally Posted by rdenney
According to http://www.khbphotografix.com/omega/, which was provided above, you need a 1-1/2" cone for 80 and a 2-1/2" cone for 105.
Again, these do not need to be exact unless you expect the autofocus system to work precisely. I suspect my homemade cone for an 80mm enlarging lens is close to 3", but then the autofocus track for that lens is homemade, too. If you have a track already designed for 80 and 105mm lenses, then use the cones shown in the web page.
I probably would have preferred a D2, but I got my D3 back in the day when even used Omega enlargers were expensive, and that was the deal that came my way.
Rick "who keeps that enlarger for some odd reason" Denney
Posting Permissions
Reply With Quote
Bookmarks