Re: Enlarger lens options.

Richard Knoppow <dickburk@[EMAIL PROTECTED]
> wrote:
>     A  high power grain focuser will often show up 
> differences in lenses that are much harder to see in a print 
> but may also introduce its own problems, for instance, some 
> grain focusers are not very well achromitized and will show 
> color fringes due to its own optics which are not present in 
> the image from the enlarging lens.

I made a comparison between some better enlarging lenses for 24x36mm
(Apo-Rodagon 2.8/50, Componon-S 2.8/50, Focotar 4.5/50, Focotar 2.8/40
and Rodagon 4/60) and compared them at about 8x enlargement (20x30cm
paper size). Each was perfectly adjusted using a Peak #1, a glass carrier
and all enlarger planes were adjusted parallel using a laser tool. All 
lenses were closed 2 stops from wide open.

The result: The only one you could distinguish from the others was the old
Focotar 4.5/50. It had a little curvature of field visible at the extreme
edges. That's all... no visible difference for the other lenses.

You can see the differences between the lenses with the Peak #1. The
curvature
of field is readily visible for the two Focotars. The two Rodagon
and the Componon-S were much better and nearly identical. The Apo-Rodagon
was
a little better wide open than the others, but all 2.8 lenses were
unuseable
with this opening (for my view of quality...). Stopped down, all
were excellent.

Martin