The 45 is a wide angle design. The corner performance was abismal terrible trash on my condenser enlargers. One day when I was about to give up, I tried it on one of my diffusion enlargers. It worked beautifully. The 40 mm Leica Focotar from my V35 behaves the same way, diffusion only.

I have 4 condensers and 3 diffusion enlargers and the condensers work with nornal lenses just fine.

I can`t explain it, but I have enough systems and lenses to prove it is not a missalligned something or other.