Quote Originally Posted by Early Riser
If you are using an Apo-rodagon, and I assume in one of the more common focal lengths, like 50 - 150mm, you are defeating their optical advantage by using them at f11. It is my understanding that the APO-Rodagons are optimised at one stop from wide open, which would be f 5.6 for most of them.
An APO-Rodagon at F11 may not be noticeably better than most other enlarging lenses when all are compared at f11, which is optimum for the non APO-Rodagons but not for the Apo.
This may be so but will the difference be visible in 6-7x enlargement and relevant when stacked up against other factors such as grain emergence?

One thing I found interesting was using an old 150 rodagon at f5.6-f16 for a 20x24 print off a 5x4 neg (I realise that this is a smaller enlargement factor). I could see no difference whatsoever....so I cranked up the column and printed a small section (no Idea what the enlargement factor was but print would prob have been 40+" and again I could see no difference. I therefore concluded that I could use whichever aperture I wanted to give the exposure time I wanted for any print size I wanted The enlarger was wall mounted to a VERY solid wall so I knew I had one hell of a solid mount for this not very scientific test.

If you were using Fuju acros on 6x7 and shot the neg at optimum camera lens aperture off a tripod ....and then enlarged to a very large size using an APO vs a non APO lens at their optimum apertures (on a very stable and perfectly aligned enalreger) then maybe you would see a tiny difference. However I am pretty confident that this difference would be so small and irrelevant as to be not worth thinking about. I cannot prove this however.

This might sound weird coming from someone who has just bought a 72XL and a 110XL. However I bought these for 5x4 & 5x7 because they cover so well and in the case of the 110 are small too. I am very confident that my(sadly departed - did not cover 5x7 well enuff) 203 Ektar from the 50's would easily match them image quality wise (as it matched everything else I have ever owned). Enlarger lenses are no different.

Tom