How problematic is Balsam separation in a lens

[dimento]

HI guys

I'm looking at buying a cheap 4x5 lens at present which is described by the seller as having some balsam separation. I'm just wondering how problematic it's likely to be.
I've never had a lens with that issue before

I've shot sharp, contrasty images on a lens with haze, another with fungus and rear element scratching, so i'm just wondering what your collective experiences are.

Is the problem likely to increase or accelerate with time?

thanks

D

[Steven Tribe]

Edge separation with Canada Balsam cement remains pretty stable over decades, whilst changes with synthetic lens cement are more difficult to predict. I have seen total separation occur during the stresses of postal transport.

Balsam breakdown can involve displacement of the lenses away from alignment without this being obvious from the outside.

[Kevin Crisp]

Hard to say without seeing it, but Steven is right, this tends to be quite stable. And even a good sized ring of separation makes no difference at typical LF taking apertures in the f:22 range. If the separation is on just one side (not a ring) I'd be more concerned.

[dimento]

Hard to say without seeing it, but Steven is right, this tends to be quite stable. And even a good sized ring of separation makes no difference at typical LF taking apertures in the f:22 range. If the separation is on just one side (not a ring) I'd be more concerned.

thanks guys, without seeing the lens I guess it's safer to side-step it, it's not much cheaper than a non-problematic example so probably not worth the fuss, thanks, D

[EdSawyer]

agreed, unless it's rare or a huge discount, just move on - there's no shortage of most LF lenses so no sense taking on a bad one unless the incentive is there.