Omega B8 condensers?
I recently got a B8 for enlarging my 120 negatives from my 'new' Rolleicord. I bought a manual from KBH. I have a question about the condensers. Mine came with the standard (double) condenser as well as the supplementary 13/16" (thicker) lens.
I recall reading a post on here somewhere that I can no longer find, that claimed the supplementary condenser lenses weren't really necessary.
For 2-1/4" square negs the manual advises a 75-80mm lens, with the standard double plus the thinner 5/8" supplementary lens and 1-1/2" lensmount (board).
I have two lensmounts, the flat board for 35 mm negs, and probably the 2" mount--it measures more than 1-1/2" but isn't quite 2", but close to it. I've been using a 90mm Wollensack with the 2" mount and just the normal double condenser, since I don't have the thinner one.
I have no problem enlarging to the 8x8" size I normally use for 120, but the time seems to be really excessive compared to an 8x10 from a 35mm neg with my little Durst. I mean something like 16 seconds or more for the 8x8 with the B8 at F5.6 or 8.0 (it's a 4.5 lens), and 6-8 seconds average for an 8x10 with the Durst at 5.6.
I'm not sure what I'm asking other than for some sort of discussion or guidance on the lensboard depth and the supplementary condensers from somebody knowledgeable about this enlarger--is the manual's advice fixed in stone as it relates to negative size? Do I need to hunt up the thinner B8 condenser and the 1-1/2" lensboard? How does the 90mm lens relate compared to the 75-80mm they recommend? I've read some people recommend a bit longer lens no matter what you're enlarging.
This is all new to me, my little Durst only does 35mm and has a fixed single condenser lens in a filter tray, I only enlarge to 8x10.
Other than the long exposure times, I'm quite happy with the coverage, at least with the relatively small 8x8 print size I do. I also printed several 35mm negs to 8x10"s with the same extended lensboard and the 90mm lens with no supplementary condenser added, and they came out fine too. So???
I use the thinner supplemental condenser and about a 1 3/8 inch cone with an 80 mm lens. I made my own cones as I have yet to find any official ones. I think the approx. 2 inch cone is used with no supplemental condenser and about 105 mm lens. My original complaint was the system was too fast, compared with a homemade enlarger I used many years ago. For 2 1/4 square negatives enlarged to about 6 x 6 inches, I use a 4X ND filter and get times around 16 to 20 seconds at f11. That's with an MG filter and using Ilford MG IV or Warmtone papers. I wouldn't want it much faster, if there was any dodging or burning to do. I can take the ND filter off and jack it up to do 11x11 inch at around the same times.
I don't think the lens and condenser combinations are that critical, as long as you can focus and the light distribution is even.
I have a homemade 2 inch cone and a 105 mm lens but haven't done much with it; it should work for 6x9 cm if I ever want to print stuff from my Brownie Six-20 box camera.
The flat lensboard with a 50 mm and the thick supplemental condenser did a nice 11 x14 print from 35 mm.
I don't know what bulb your Durst uses, the 75 watt jobbies in the B-8 I think are relatively at the low end of the power spectrum.
It doesn't take much of a change in enlarging paper speed or negative density to see large changes in time also.
My thoughts ...
Thanx for your response. Some useful info. I couldn't see doing much larger than 11x14 from a 35mm, so it's good to know I'm set up for that. I was suspecting that when the manual says things like 'you must use' a certain combination of enlarger lens, lensboard (or cone as you say) and condenser combinations they are referring to making enlargements at the upper end of the scale. As I said, I got a satisfactory 8x10 from a 35mm neg using 'all the wrong stuff', for even the 120 neg, at least according to the manual. I haven't actually tried a proper enlargement from 35mm yet, tho I have all I need according to the manual. The Durst is so much easier and lighter to set up in my uber-mini portable darkroom, and I'm just getting going with the 120 film.
As to exposure length, perhaps I'm just used to the faster times from my Durst (that has the 75 watt bulb). I like the time frame of around 6-10 seconds at F5.6 as it's fast for contact sheets and test strips, but allows me to step down a stop or two if I do need a longer exposure for burning and dodging. I have my 35mm negatives nailed 'close enough' so I can usually come pretty close for contact sheets or prints from experience, but the negative density from my Rolleicord is all over the map as I learn about it, I've only shot four rolls so far, and the 'Sunny 16' is working fine, but under other conditions, it's a crap shoot at this point, even with two light meters. But when it's right--what fine pics that old camera puts out! I'm in love.
I'm curious about how you made another cone. I started making one from a plastic marine battery switch, which works out about 1-1/2" deep and is large enough to just fit on a flat plate (lensboard) to slip in, but I got sidetracked making a new lens mount disk--the smaller disk the lens itself mounts to--for the 50mm setup. I got a hodge podge of stuff with this enlarger (no lenses) and mating things up to make working stuff has been an interesting challenge. I really like the enlarger, altho it's a bit of a monster to be 'portable'. I'm planning a permanent darkroom, so it will have a proper home eventually.
Very nice work! I'm a handy do-it-all-guy, so not afraid to jump in to a challenge, but I also don't like to reinvent the wheel, unless it needs it <grin>.
From your pics it appears what you've done is extend the smaller lens mounting plate, which is why I guess you call it a cone. Having only my flat plate and 2" deep one to go by, I assumed the entire lensboard had to be extended, it hadn't occurred to me to go your route.
The plastic cup I was working with is about 5.25" in diameter and 1.5" deep and already has a flange around the rim, so I had planned to simply epoxy that to a new square plate, the large plate that actually slides in and out--which I'd have to make too--this would have more or less duplicated the factory 2" board in style and design. If I can get by with a smaller apparatus like yours based on the small flat plate, then I'll certainly go that route, a bit less work fersure since I can use the large flat plate holding the 50mm now. Thanx for the ideas!
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Originally Posted by Mike Keers
That's it. Somewhere along the way, I obtained some "parts lists" for tthe B-8. Those show "Lens Mounts" --
Flat, with 39mm Leica thread
Recessed Lens Mount (for 35 mm Omegaron)
Lens Cone 1 1/2" for 75-80 mm lenses
Lens Cone 2" for 90 - 105 mm lenses
And then there's "Lens Disks" and an assortment of flats with various hole diameters and one "Recessed Lens Disk for 28 mm Companon." The list I have has a bunch of "(replaced by 421-xyz)" notations, so perhaps over its production history they made some changes in the lens board configuration.
My B-8 was acquired via ePrey and was all set for 35 mm and nothing else, so I just extrapolated away like crazy. I've been checking the Omega listings on ePrey for close to 3 years and have yet to see any of the cones, mounts, etc. for the B8 series. (The D-series, plenty.) I was able to come up with the thinner supplemental condenser and a bunch of negative carriers over that time, though there have been darn few condensers.
Having wrestled with homemade contraptions in my earlier history, this is like suddenly having a Leica or whatever. So far my biggest prints from 6x6 have been 11x11 inches, and they look really good, grain sharp to the corners, so I assume when I get the darkroom a bit more usable 16 x 16 should be decent. I doubt I'll ever go much bigger than that, just too much $$$$ tied up in getting big trays and all, plus the darkroom is too small and framing is too expensive!
Anyway, good luck getting yours going.
Looking for a condenser for Omega B8
I picked up a B8 in good shape but need a condenser for it - help and thanks!
Originally Posted by Mike McMullen
Do you mean the main condenser, which is a pair of plano-convex lenses in an aluminum barrel? Or one of the supplemental condensers?
I don't have any extras, and I long ago stopped following the ePrey listings for Omega so I'm not sure what the chances are these days. They were certainly not common, but did show up from time to time. I believe the condensers for the B7 and maybe a couple of earlier models are compatible also.
KHB Photografix might have something
Classic Enlargers is another possibility
If it's just the glass lenses, no cones/mounts/etc. with some luck and the required dimensions, it might be possible to find generic replacements at Edmunds or Surplus Shed.
If you are only looking for the supplemental lenses, you can probably get by without them. You'd have to check how even the lighting comes out corner to corner, but other than that the only likely negative effect is a bit less light output.
I don't know if the C67 will fit however, the part numbers and items I have as follows:
Originally Posted by Mike McMullen
473-124 Heat Absorbing Glass for condenser lamphouse
472-053 Standard Condenser for condenser lamphouse
472-054 Auxiliary Condenser for 35mm and smaller formats
Yes, the main condenser - and thanks much for the references!