Enlarger lenses Beseler 23CII

[68degrees]

I have some questions about enlarging lenses for beseler 23cII. What size do I need? On ebay they talk about threads and diameter and focal length.

SO for example.
35 mm
6x6
6x9

Please advise. are all the lensboards the same for all 23cII?

 

[mwoenv]

The enlarger lenses needed for different formats (these are lens focal lengths):
35mm negative: 50mm
6x4.5 negative: 75 or 80mm
6x6 negative: 80mm
6x7 negative: 90mm
6x9 negative: 110mm

Lenses commonly have a 39mm thread diameter (but some have 25mm)

The 23CII manual indicates the following lens boards should be used (all are 4-inch x 4-inch boards, with openings for 39mm lens thread diameter):
#8021 for 50-60mm lenses
#8023 for 53-90mm lenses
#8029 for 100-105mm lenses

I use one lens board for my 50mm and 80mm lenses (# is not stampled on it so I don't know which it is but it has a slight recess on the pilot light side)

 

[68degrees]

The enlarger lenses needed for different formats (these are lens focal lengths):
35mm negative: 50mm
6x4.5 negative: 75 or 80mm
6x6 negative: 80mm
6x7 negative: 90mm
6x9 negative: 110mm

Lenses commonly have a 39mm thread diameter (but some have 25mm)

The 23CII manual indicates the following lens boards should be used (all are 4-inch x 4-inch boards, with openings for 39mm lens thread diameter):
#8021 for 50-60mm lenses
#8023 for 53-90mm lenses
#8029 for 100-105mm lenses

I use one lens board for my 50mm and 80mm lenses (# is not stampled on it so I don't know which it is but it has a slight recess on the pilot light side)

Thank you very much!!

 

[Dwig]

The enlarger lenses needed for different formats (these are lens focal lengths):
35mm negative: 50mm
6x4.5 negative: 75 or 80mm
6x6 negative: 80mm
6x7 negative: 90mm
6x9 negative: 110mm
...

These are minimum focal lengths. It is perfectly OK to use longer lenses than those on the list although doing so has two issues:

1. Longer that "conventional" will result in reduced maximum print size on the baseboard. This can be overcome by using floor (my preference) or wall projection. For years I used a 150mm EL-Nikkor to print both 6x7 and 3-1/4 x 4-1/4 (Polaroid 667 PN) negatives in addition to 4x5 on my old Beseler 45 (very similar design to the 23cII). I had the enlarger mounted to the wall with a removable baseboard that allowed projection to either a lower shelf or the floor. I could still get 16x20s from the 6x7 negs with no difficultly beyond the bending down to the lower shelf to focus and load the easel. I didn't shoot much 6x7 so it was a reasonable arrangement that saved the expense of an additional lens. If you're going to shoot a range of MF sizes get a lens for the largest (e.g. 6x9) and use it for all MF.

2. The scale on the side of the condensor housing that is used to adjust the condensors for different lenses is calibrated in formats rather than focal length. If you use an 80mm lens to print 35mm you need to set the condensors to 6x6 and not 35mm. Otherwise uneven illumination will result.

 

[68degrees]

These are minimum focal lengths. It is perfectly OK to use longer lenses than those on the list although doing so has two issues:

1. Longer that "conventional" will result in reduced maximum print size on the baseboard. This can be overcome by using floor (my preference) or wall projection. For years I used a 150mm EL-Nikkor to print both 6x7 and 3-1/4 x 4-1/4 (Polaroid 667 PN) negatives in addition to 4x5 on my old Beseler 45 (very similar design to the 23cII). I had the enlarger mounted to the wall with a removable baseboard that allowed projection to either a lower shelf or the floor. I could still get 16x20s from the 6x7 negs with no difficultly beyond the bending down to the lower shelf to focus and load the easel. I didn't shoot much 6x7 so it was a reasonable arrangement that saved the expense of an additional lens. If you're going to shoot a range of MF sizes get a lens for the largest (e.g. 6x9) and use it for all MF.

2. The scale on the side of the condensor housing that is used to adjust the condensors for different lenses is calibrated in formats rather than focal length. If you use an 80mm lens to print 35mm you need to set the condensors to 6x6 and not 35mm. Otherwise uneven illumination will result.

so the scale on the side is if you just use the regular lens for everything?

Also, what will happen if you use the regular lens for 6x9 or 6x6?

 

[68degrees]

The scale on the side of the condensor housing that is used to adjust the condensors for different lenses is calibrated in formats rather than focal length. If you use an 80mm lens to print 35mm you need to set the condensors to 6x6 and not 35mm. Otherwise uneven illumination will result.

ok I see. One lens is 39mm diamter hole and the others are 25mm and I have no lens boards for those. I do have an extra 39mm board but it is too big for the MF lenses. Can I just get some 4" x 1/8" aluminum stock and cut and drill my own? How precise must the center be? criss cross iin the middle close enough ?

 

[Dwig]

... Can I just get some 4" x 1/8" aluminum stock and cut and drill my own? How precise must the center be? criss cross iin the middle close enough ?

Yes to both.

Any 4x4x1/8" material that is opaque and stiff enough to avoid any flex is fine. You just need to be sure that the top side (facing neg) is painted flat black. Black plex will work but needs to be painted or flocked to avoid reflections.

With some lenses you may find that you need to cut a "counter bore". This is a recessed area around the central hole. The problem stems from the lenses having threads that are too short and they don't protrude all the way through the thick lens board. Alternately, if you have a true "flange" (raised lip and 3-4 holes around the edge) rather than the more common "jam nut" (simple flat ring) you could attached the flange to the bottom of the board eliminating the need for the counter bore.

BTW, some of the differences in the Beseler boards is the position and length of the red f/stop illuminator. There is also a Beseler "blank" board which has only a 1/4" hole which is intended for those who need to just a custom hold. Also the 23 series (C, CII, ...) uses the same lens boards as the 45 series (H, M, MX, ...).

Two diagonal lines will cross in the center accurately enough to serve as a guide for cutting the hole.