enlarger question

[journeyman]

what is the point of different lenses for an enlarger?

 

[Hertz van Rental]

What do you mean "different lenses"?
There are different qualities of enlarger lens - the more expensive having better resolution and providing more contrast (punch).
There are different manufacturers so that's all about commercial competition.
And there are different focal lengths.
The latter is to do with the various formats.
You get standard camera lenses with various film formats - the one between wide-angle and telephoto. Standard lenses have the same focal length as the film diagonal distance.
35mm = 50mm approx.
6x6 = 80mm approx.
5x4 = 180mm approx.
The same thing works for enlargers.
Using the standard lens for the format you are printing means that the enlarger head works at a reasonable height.
Using an 80mm lens for 35mm negs would act as a telephoto and the enlarger would have to work at twice the height to get a full frame print.
Using a 50mm lens for 6x6 negs would give you a wide-angle effect and the enlarger head would be rather close to the baseboard for a full frame print.
(If you use a condenser enlarger you need to have the right condenser in for the lens/film format.)