Omega D2 enlarger - Is it really for 4x5 negatives?

Question

So I bought an Omega D2 enlarger for making 8x10 prints out of my 4x5 negatives at home. I have had two unsolved issues with it that make me question whether it is really suitable for 4x5 printing.

1. Lens length: Originally I had a ~130mm lens on it, but that meant that the edges of my prints were not in focus. So I bought a 180mm lens. However, because the bellows only extend so far, in order to focus the 180mm lens I have to raise the head so high that I crop out a lot of the image. I could have done this with the 130mm lens to crop out the parts that were not in focus, so this is not an improvement.

2. Head circle radius: The bottom of the head has a circle that does not quite allow for a 4x5 negative, meaning the corners of my 4x5s are cut off. I can adjust it so that the loss is fairly small, but I still have to crop a bit of my image to compensate for enlarger vignetting.

Is my setup still incorrect? Are these problems solvable? Or is the D2's ability to print 4x5 negatives exaggerated?

Answer 1

As a rule-of-thumb the focal length lens mounted should be equal to greater than the diagonal measure of the negative to be printed. For the 4X5 negative this works out to 6.4 inches = 160mm (rounded). Think about buying a shorter enlarger lens.

In the meantime, you can mount a camera close-up lens to the 180mm. Such a lens will effectively shorten the focal length.

The math for a +1 added to the 180mm Convert the 180mm to the diopter unit = 1/180 X 1000 = 5.556 diopter power

The +1 is stated in diopter power

Add the two diopter powers = 5.5556 +1.0 = 6.556 system total diopter power

Convert 6.556 to millimeters = 1/6.556 X 1000 = 153mm

To see what a +1 addition will do: Go to the drugstore and buy a pair of +1 reading glasses. Hold one of the lenses under your 180mm and compose and focus. This will show you how a 150mm will behave.

The +1 addition won’t make you happy as the reading glass quality lens will degrade. A photo grade achromatic +1 might suite your need but a 150mm quality enlarger lens is not that expensive.

Answer 2

So I've figured out both issues. The short answer is yes, this enlarger really will work for 4x5.

The longer answer:

1. Lens length: Omega D2 enlargers require you to change the length of your lens cone with the length of your lens. This is why I can't focus with the 180mm lens, since I have a 2 3/4" length lens cone, which works for my 135mm lens.

   Solution: get a longer lens cone, like a 4 5/4".

2. Condenser circle is too small, causing vignetting: My condense has a ring of foam around the bottom. This foam sat inside the condenser circle, blocking part of the light and causing the issue.

   Solution: Remove foam from bottom of condenser. Block light with a small piece of fabric wrapped where the condenser meets the negative holder.