Any opinions on which would be the preferred 50mm?

Cron - Serial Number 391*
Lux - Serial Number 360*

I've dug up some info on the Cron and I see that this version is the preferred one among the Crons, but I haven't been able to find more info on the preferred Lux or info comparing the two.

(it will be mounted on a 5d)

Thanks

I myself would go with the latest Lux with the 60mm filter thread (E60). However, you need to modify either the lens or the mirror on the 5D according to this chart. The latest 'cron is an excellent lens with a very low distortion with great sharpness wide open. I think I would prefer the 'Cron over the 'Lux you listed above, since the lux is an older version, which is said to be not as good as the current lux or cron.

I really like the 60macro (on my dmr). maybe not as crisp as the lux but IMO it gives a smooth detailed look.
I also like how it focuses.

thanks guys

The latest Summilux is one of the best 50 available from anyone. This version has 8 elements (previous had only 7). And it's bokeh is reportedly better than the latest M-series 50 ASPH.

I have this lens and the 60 macro. The 60 is very sharp and flat field but does not have the bokeh of the Summilux. So I would go with the latest 50/1.4.

But if your choice is only an older version, I agree with Peter and would stick with the Summicron, or more likely just go with the 60 macro.