Ian C
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Short Focal Length Lenses on Omega D5/D6
The D5 and D6 enlargers use a long, tapered bellows. The previous 4” x 5” models had short bellows a and used various lens cones to add distance to position the lens at the approximate correct distance to obtain focus. Then the bellows allow enough adjustment to fine-tune the lens position for correct focus.
The D5 and D6 did away with the lens cones, but this inadvertency created another problem. When the longer bellows are fully closed, the solidly stacked bellows prevents relatively short focal length lenses from being placed at the close distance from the negative necessary for focus.
For example, I cannot use most 50 mm lenses (most often used for 35 mm negatives) for prints of 8” x 10” or larger. I’ve talked with other D5 and D6 owners who face the same limitation.
Other enlargers, such as the DII and D2 use non-tapered bellows that provide sufficient space to install a recessed lens mount partially inside the bellows. These places sort focal length lenses much closer to the negative to allow focusing.
But the D5 and D6 bellows tapers down to a small lens board receiver, making a recessed lens board impossible for the outside diameter of most 50 mm and shorter lenses. It isn’t generally practical to use my D5XL for enlarging 35 mm or smaller negatives. Further down I discuss an exception for a particular lens of small outside diameter.
Other owners claim that they can do so, but only by compressing the bellows (and possibly cracking them at the folds). Too, this can temporarily spring the front of the lens board receiver apart. That will pivot the lens axis to aim it slightly towards the column, misaligning the lens axis and spoiling the focus from front to back.
The D5 and D6 are excellent enlargers for medium format through 4” x 5” negatives. When I need to enlarge 35 mm and smaller films, I use a practical-sized enlarger specifically designed for the purpose.
Adding to this confusion is the fact that Omega lists many lens mounts and negative carriers specifically intended for the D5 and D6 for 35 mm and smaller films. I’ve long wrestled with this problem. I can only speculate.
Here is a partial list of D5/D6 negative carriers that, to me, make no sense because using the appropriate focal length lens to focus is impossible.
423-301, Disc format
423-303, Minox format
423-302, 16mm format (5/16"x7/16")
423-300, 110 format
423-353, 126 Instamatic format
423-304, 35mm Half Frame format
423-352, 35mm Full Frame [Focus possible with a particular lens as explained below]
Here are the lens mounts from the KHB Photographix site:
http://www.khbphotografix.com/omega/LensMountD5.htm
I later acquired a Schneider Componon 1:4/50 #11 291 736. This is a small lens. It uses the M25 x 0.5 mm pitch mounting thread and its outside diameter is small enough that it fits inside the Omega 421-115 RECESSED lens mount. This is the only lens and mount combination that I’ve found that allows the use of a 50 mm lens on the D5/D6 enlargers.
The majority of 50 mm enlarging lenses use 39 mm Leica thread and their outside diameters are simply too large to fit inside any recessed lens mount. This is an old lens and not commonly found in good condition in this era.
Here are the only two recessed lens mounts intended for 50 mm lenses on the D5/D6 enlargers per the list on the KHB site:
421-114 Recessed Oval Plate for 25/35mm Omegaron (use with 421-105) M32.5 x 0.5 mm pitch
421-115 Recessed Oval Plate for 28mm Componon (use with 421-105) M25 x 0.5 mm pitch
Here is the full list of lens mounts and the slide-in plates they mount on for the D5/D6 given on the KHB Photographix site.
http://www.khbphotografix.com/omega/LensMountD5.htm
The same table recommends using the 421-056 flat plate with attached 39 mm Leica flange for 50 mm Componon-S lenses. You’d have to first mount the 421-105 slide-in plate into the slide-in receiver at the bottom of the bellows. Then use the two thumbscrews to attach the 421-056 to the slide-in plate.
The only problem with this is that, even with the bellows fully closed, the lens is too far from the negative to focus a meaningful-sized projection. It might be possible to make a 5” x 7” or smaller print [small prints require the lens farther from the negative], but nothing larger, at least with my D5XL.
My advice, unless you can obtain a Schneider Componon 1:4/50 in good condition and use it with the Omega 421-115 lens plate and 421-105 slide-in lens plate, you should look for an enlarger purposely designed for 35 mm enlarging for that format. Note that this combination requires the two-step mounting procedure described above, because with the lens, mount, and plate, when assembled, will stick up preventing inserting the slide-in plate into the receiver.
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