Focus issue while enlarging 35mm on a 23C

88E30M50 · Oct 18, 2024

I've got two enlargers in my darkroom, a Beseler 23C III and Beseler 67SC. I typically use the 23C for medium format and the 67 for 35mm, but sometimes, I want to do 35mm on the 23C and am running into an issue with the ability of the enlarger to focus. What I'm seeing is that using the standard 50mm Beseler lens that came with the enlarger, I am only able to focus with the bellows almost completely compressed. At that point, the focus knob is hard to turn and once I do manage to get it focused, it quickly loses focus due to, I think, the pressure from the compressed bellows on the lens board. When enlarging medium format with a 105mm lens, the focus is right in the middle of the travel and everything is smooth and stable. On the 67, when enlarging 35mm, the focus is achieved in the middle of the range and it is smooth and stable there as well.

Am I running into a limitation of the 23C for 35mm or is something off that could be adjusted? I've looked the enlarger over and am not seeing anything that might effect the focal adjustment for that enlarger. For those that use a 23C, what lens are you using?

fiddle · Oct 18, 2024

Is the condenser set properly for 35? Knob all the way on top.

VinceInMT · Oct 18, 2024

What size print are you attempting?

88E30M50 · Oct 18, 2024

I've tried playing with the condenser adjustment but didn't see any changes.

88E30M50 · Oct 18, 2024

VinceInMT said:
What size print are you attempting?

This was while working on a 12x18 print with the head height up to 26"

Kino · Oct 18, 2024

"Regular 23C enlargers (non-XL)

35mm negative with 50mm lens: maximum print size is 15 x 22 3/8 inches"

https://www.oresteen.com/bess23c.htm

You should be able to just make that print. Do you have another 50mm lens to try?

If you don't, you can always turn the head and do projection printing. Yes, it's a pain to align and then re-align for normal printing, but cheaper than buying a new lens.

That way you can use a longer, possibly higher quality enlarging lens.

Manual if you don't have one...

http://jollinger.com/photo/cam-coll/manuals/enlargers/beseler/Beseler_23C(newer).pdf

Ian C · Oct 18, 2024

This problem has nothing to do with condenser placement. Your lens is simply too far from the negative to focus due to the location of the first nodal point of the lens relative to the negative. I’ve run into this problem with some 50 mm lenses on my 23CII. The 23C, 23CII, and 23CIII are the same in this regard.

You need the Beseler 8022 lens board with 5/8” (15.9 mm) recess. It places the lens about 15.9 mm closer to the negative to allow focusing with lenses whose construction requires closer placement to the negative than the bellows allow in order to focus properly.

These turn up from time to time on eBay. Be certain to buy a board with the correct diameter hole. That’s most often 39 mm, but there are other sizes. If you buy a board with the wrong size hole, you won’t be able to use it with your lens.

It’s also possible to rework an existing flat lens board by making a recessed spacer mounted to the top surface of the flat board.

Another “workaround” is to find a Beseler 8029 with the 5/8” extended mount. Remove the screws and remount the cup upside-down from the top. Then you have essentially converted it into an 8022 recessed mount. It's inelegant—but it works.

Kino · Oct 18, 2024

Another possibility is that if you have any 3D printing skills, modify this design to the above dimensions;

4x4 Lens board for Beseler 23C (and other) photo enlargers. 39mm Leica lens size opening. by pluckmyeyeout

This is a lens board for a Beseler 23C (and other) enlargers. The 4"x4" base fits many enlargers, and the opening is for a standard 39mm Leica screw mount. You will need a Beseler 39mm Threaded Lock Ring to securely attach your lens... A few notes1) Depending on the material that you use, you...

www.thingiverse.com

ic-racer · Oct 18, 2024

Does your 8021 have the counterbore? I think not all of the 8021 have this. Otherwise, as Ian C mentions above, try the 8022 board,

IOWA CAMERA GUY · Oct 18, 2024

I have serviced literally dozens of 23C’s over nearly 50 years.

The issue you have is that the tension springs on the rails (2 small rods coming down into a box attached to the lens board assembly), have loosened up.

Pull the back cover off the ‘box’ (remove 2 screws on each side of the cover plate, or if no screws, pry off cover GENTLY WITH SMALL SCREWDRIVER BLADE) and there are 2 screws on each rod (A) IN DIAGRAM.

Give each one a 1/2 turn CLOCKWISE, do not overtighten, just that simple adjustment (equal turns on all screws to keep the tension the same) and you should be good to go.

Tensioning the springs makes the drive wheels grip the rod with more friction.

It is possible, also, that the drive wheels (B) may be loose on their shaft and need to be tightened. That can be done with an Allen wrench of the proper size, pretty small. Any Allen wrench ’set’ should have the proper sized wrench included. NOTE, THERE ARE 2 SET SCREWS ON EACH WHEEL, SET AT 90-DEGREES APART ON THE COLLAR. TIGHTEN THE VISIBLE SSET SCREW, THEN TURN THE SHAFT TO GET TO THE SECOND SET ON EACH WHEEL.

Diagram attached, should be fairly clear…DO NOT LUBE THE DRIVE WHEELS OR SHAFT RODS, you need friction, not slippage…..DUH!!!

Roger Christian

88E30M50 · Oct 20, 2024

Kino said:
"Regular 23C enlargers (non-XL)

35mm negative with 50mm lens: maximum print size is 15 x 22 3/8 inches"

https://www.oresteen.com/bess23c.htm

You should be able to just make that print. Do you have another 50mm lens to try?

If you don't, you can always turn the head and do projection printing. Yes, it's a pain to align and then re-align for normal printing, but cheaper than buying a new lens.

That way you can use a longer, possibly higher quality enlarging lens.

Manual if you don't have one...

http://jollinger.com/photo/cam-coll/manuals/enlargers/beseler/Beseler_23C(newer).pdf

Thanks Kino. Great info there. I do have a Schneider Kreuznach 50mm that I tried with the same issue.

88E30M50 · Oct 20, 2024

Ian C said:
This problem has nothing to do with condenser placement. Your lens is simply too far from the negative to focus due to the location of the first nodal point of the lens relative to the negative. I’ve run into this problem with some 50 mm lenses on my 23CII. The 23C, 23CII, and 23CIII are the same in this regard.

You need the Beseler 8022 lens board with 5/8” (15.9 mm) recess. It places the lens about 15.9 mm closer to the negative to allow focusing with lenses whose construction requires closer placement to the negative than the bellows allow in order to focus properly.

These turn up from time to time on eBay. Be certain to buy a board with the correct diameter hole. That’s most often 39 mm, but there are other sizes. If you buy a board with the wrong size hole, you won’t be able to use it with your lens.

It’s also possible to rework an existing flat lens board by making a recessed spacer mounted to the top surface of the flat board.

Another “workaround” is to find a Beseler 8029 with the 5/8” extended mount. Remove the screws and remount the cup upside-down from the top. Then you have essentially converted it into an 8022 recessed mount. It's inelegant—but it works.

This sounds like the path that I need to take. Thanks Ian. I'll keep an eye out for an 8022 going forward.

IOWA CAMERA GUY · Oct 20, 2024

You could probably pick up a 40mm EL-Nikkor or something similar for pretty cheap.

That would give you about a 20% maximum image size with the same head height.

Wall-projection printing ‘on a whim’ is more trouble than it is worth.

Just buy a shorter focal-length lens and be done with it.

88E30M50 · Oct 20, 2024

IOWA CAMERA GUY said:
I have serviced literally dozens of 23C’s over nearly 50 years.

The issue you have is that the tension springs on the rails (2 small rods coming down into a box attached to the lens board assembly), have loosened up.

Pull the back cover off the ‘box’ (remove 2 screws on each side of the cover plate, or if no screws, pry off cover GENTLY WITH SMALL SCREWDRIVER BLADE) and there are 2 screws on each rod (A) IN DIAGRAM.

Give each one a 1/2 turn CLOCKWISE, do not overtighten, just that simple adjustment (equal turns on all screws to keep the tension the same) and you should be good to go.

Tensioning the springs makes the drive wheels grip the rod with more friction.

It is possible, also, that the drive wheels (B) may be loose on their shaft and need to be tightened. That can be done with an Allen wrench of the proper size, pretty small. Any Allen wrench ’set’ should have the proper sized wrench included. NOTE, THERE ARE 2 SET SCREWS ON EACH WHEEL, SET AT 90-DEGREES APART ON THE COLLAR. TIGHTEN THE VISIBLE SSET SCREW, THEN TURN THE SHAFT TO GET TO THE SECOND SET ON EACH WHEEL.

Diagram attached, should be fairly clear…DO NOT LUBE THE DRIVE WHEELS OR SHAFT RODS, you need friction, not slippage…..DUH!!!

Roger Christian

More good info. I'll adjust and clean the rollers and rods as recommended. I do think that Ian's comment on using the 8022 is the better fix for my focus issue, but this will eliminate the stiff and sticky mechanism while fixing the focus shift issue that I've been seeing as a part of this.

I do appreciate the help from everyone on this and feel that I've got great direction in moving forward on the issue.

IOWA CAMERA GUY · Oct 20, 2024

You could probably pick up a 40mm EL-Nikkor or something similar for pretty cheap.

That would give you about a 20% maximum image size with the same head height.

Wall-projection printing ‘on a whim’ is more trouble than it is worth.

Just buy a shorter focal-length lens and be done with it.

The nice part is that the 40MM Nikkor is also 39mm “LEICA MOUNT BOARD" (if memory serves - been a long time).

So buy a second lens board or use the one you have and swap the lenses.

Of course, I bet if you looked around where you live there is probably a 23C-XL you can get for FREE!

People are likely still dying to ‘get that thing outta here’.

88E30M50 · Oct 20, 2024

ic-racer said:
Does your 8021 have the counterbore? I think not all of the 8021 have this. Otherwise, as Ian C mentions above, try the 8022 board,

Yup. That's the lens board that I have. Off topic question: What are the thumbscrews for?

IOWA CAMERA GUY · Oct 20, 2024

88E30M50 said:
Yup. That's the lens board that I have. Off topic question: What are the thumbscrews for?

88E30M50 · Oct 20, 2024

IOWA CAMERA GUY said:
You could probably pick up a 40mm EL-Nikkor or something similar for pretty cheap.

That would give you about a 20% maximum image size with the same head height.

Wall-projection printing ‘on a whim’ is more trouble than it is worth.

Just buy a shorter focal-length lens and be done with it.

The nice part is that the 40MM Nikkor is also 39mm “LEICA MOUNT BOARD" (if memory serves - been a long time).

So buy a second lens board or use the one you have and swap the lenses.

Of course, I bet if you looked around where you live there is probably a 23C-XL you can get for FREE!

People are likely still dying to ‘get that thing outta here’.

I picked this one up for almost free early this summer. It came with a functional enlarger, several brand new filter kits, several boxes of paper, a very nice grain focuser and some other bits for $50. The guy selling said he had it listed for a couple of years and I was the first one to contact him.

IOWA CAMERA GUY · Oct 20, 2024

The recessed counter-bore allows you to focus some lenses with a shorter back focus for larger size
images.

The larger the image, the closer the lens has to be to the negative (DUH!)

The counter bore only puts the lens a small amount closer to the negative plane, but in some cases it does not take much added ‘movement’ to allow the image to focus.

The counter-bore reduces the lens to negative plane distance just enough in many cases.

xkaes · Oct 20, 2024

88E30M50 said:
Off topic question: What are the thumbscrews for?

Lots of lens boards have them -- not just Beseler. There are there so that you can attach/remove the lensboard from the enlarger without grabbing and pushing/pulling on the lens.

P.S. I never had any trouble at all using a 50mm lens on a Beseler 23CII -- on a flat board.

88E30M50 · Oct 20, 2024

xkaes said:
Lots of lens boards have them -- not just Beseler. There are there so that you can attach/remove the lensboard from the enlarger without grabbing and pushing/pulling on the lens.

P.S. I never had any trouble at all using a 50mm lens on a Beseler 23CII -- on a flat board.

On my 23C, a 50mm lens only focuses at near extreme compression of the focus bellows. I'm going to give Ian's suggestion a shot. Until I find an 8022, I have my 67 that focuses with a 50mm right in the middle of the bellows range, so it's not a show stopper for me.

xkaes · Oct 20, 2024

Maybe it's the 50mm lenses I've used, but I've used them to make LARGE prints. Maybe it has to do with the 23C model I was using or the 50mm lenses I was using. There's no way for me to check, I've moved up to the Beseler 45 & CB7 -- which both have much more bellows than the 23C and work fine with 50mm lenses (even 35mm!).

Good luck.

Focus issue while enlarging 35mm on a 23C

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