Is resolution improved by using an enlarging lens for photography backwards?

I've seen suggestions to mount an enlarging lens backwards when using for macro. Does it improve the resolution or is it for more magnification?

Enlarging lenses are optimized for ratios from 1:3 upwards but not infinity. If you are planning to do extreme macro / blow ups, reverse them. Magnification might be less, since reversing might cost bellows draw? Have there ever been retro focus enlarging lenses? - I 'd doubt but am open.

I think it is just for having a flat field.

The idea behind the lens reversing advice is that lenses are normally used, and designed to perform best, with very asymmetrical conjuggate distances. The distance from lens to film usually is many times smaller than the distance from subject to lens.

When crossing the 1:1 limit, the relation is reversed, and lens to film distances are much larger than subject to lens distances. So, the reasoning goes, a lens should be reversed too, so that it still has the long and short distances on the side it was designed to perform well at.

Around the 1:1 limit, the distances on either side are very similar, so there is nothing to be gained. Not with regular lenses, that are optimized for very asymmetrical distances. Not with enlarging lenses, that are made for more symmetrical distances (so should perform well either way).

 

That's the general idea behind the advice. Doesn't necessarily mean that it works.

 

Resolving power at magnification depends on the f-stop mostly. Don't stop down too much.

So I would keep doing the same way I always do that is mounting the enlarging lens normally as my subject is going to be larger than its image on the sensor. I generally do not shoot with magnification higher than 1:1. Often less.

Thanks for the replies.

 

I was going to build a copy stand setup for camera scanning negs and chromes with a mirrorless. I'd be doing 35mm to 4x5. Maybe an 8x10 neg once in a while. But not too worried about the 8x10. Just want good 35mm and 6x6.