Correlation between enlarger lens focal length and condenser
I have recently bought a Durst M605 enlarger, with a 50mm condenser (Siriocon 50) and 50mm lens (Rodenstock Rogonar). Lens is mounted on Siriotub mount, so it is closer to the negative holder. When I want to enlarge up to 18x24cm format, everything is OK, but for anything beyond that, I cannot place the lens close enough to the negative.
What's even funnier is that on my old Meopta, I could easily enlarge on wall 2m away (so I'm used to having enlargers which can do that. The only thing that seems different is that Meopta has large dual condenser.
I guess now I have two options - I can either find a big condenser for Durst (Siriocon 80), or try to place a lens with shorter focal length (or scavenge Meopta for condenser.
Still, I have seen many instructions that shorter focal length lenses are for smaller film formats, etc. In theory, what can I expect with e.g. 30mm lens? Spherical abberations?
In general, what is normally done in such situations?