Long enlarger lenses, boards w/ extension

[awldune]

I am relatively new to enlarging. I've been working with a Beseler 23C II, enlarging 6x6 with an El-Nikkor 80/5.6 lens.

Recently I tried 6x9, but found that the corners are vignetting. After reading a bit, I gathered that I needed a longer lens, so I bought an El-Nikkor 135mm lens.

When I attached this to my enlarger, I couldn't get the image to focus. After more research, it turns out I need a lens board with extension.

So now I've got a board with about 20mm of extension "cone", but it is still not enough! Don't know what's up with this lens. It

On a whim, I attached my 80mm lens to the extended board, and now it seems to have better coverage. To my surprise, it still has room to focus as well.

Any thoughts?

 

[Jerry Thirsty]

Traditionally the preferred focal length for 6x9 has been the 105mm lens, so maybe the 23CII wasn't designed with enough travel for a 135?

 

[awldune]

When I think about it, getting more coverage with the extension and 80mm doesn't seem to make any sense.

I think I either need a bigger "cone" or a 105mm lens.

 

[Nick Zentena]

Actually it makes sense if you aren't making really large [infinity] prints.

Draw a triangle. At 80mm the width at the wide spot is so large. The more extension the wider the wide spot is.

 

[ic-racer]

When I think about it, getting more coverage with the extension and 80mm doesn't seem to make any sense.

I think I either need a bigger "cone" or a 105mm lens.

I love 6x9, and agree you should pick up a 105.

 

[awldune]

Actually it makes sense if you aren't making really large [infinity] prints.

Draw a triangle. At 80mm the width at the wide spot is so large. The more extension the wider the wide spot is.

Yes, but I think the same effect is achieved by the focusing bellows.

I'll have to see about a 105mm lens. The 135mm El-Nikkor lens I got was such a steal -- mislabeled Ebay listing, went for $9.

I guess I can resell it to help finance the 105mm.

 

[pschauss]

When I had a similar problem with a Russian 105 mm lens I bought s set of 39 mm macro extension tubes from one of the FSU sellers on Ebay. They are designed to be used for thread mount Leicas or Leica copies which use the same diameter and thread as most enlarger lenses. IIRC a set of three or four tubes of various lengths cost me less than an extended lens board.

As an added bonus the macro tubes came with instructions, in Russian, on how to take macro pictures with them as well as a table of focus distance and exposure settings.