Cleaning marks on lenses

[truls]

Often ebay sellers describe lenses having cleaning marks. Here auction number 111409964743, ebay.com, as an example description of lens with cleaning marks.

Will these cleaning marks have an effect in practical photography? Should one skip these lenses or can they be bargains?

[hansz]

Skip.

You will notice the effects mostly when you photograph into the sun.
Repolish/recoating is expensive, only cost effective for very expensive lenses...

[Stephen]

Very subjective, do they mean scratches or damage to the coatings, you cannot trust all descriptions, they may just mean smears, or serious finer scrazes. Most sellers are honest, but may not mean what you take them to mean.
Stephen

[daveh]

Forty years ago I bought, for £1, a Leitz Xenon 5cm f1.5 lens with a "somewhat" scratched front element. I was told by the camera shop that a professional had used it as a soft-focus portrait lens.

I do think it's difficult to describe how much a lens is scratched. Several factors would seem to come into play 1) number of scratches 2) their length 3) their depth 4) their direction 5) whether just the coating or the glass. Of course, we assume these days that all lenses are coated. The Xenon was an uncoated lens, at least in its early production.

[philbirch]

I would interpret cleaning marks as looking as if the coating is smeared. That makes no difference whatsoever to the sharpness of the lens as, remember, the coating is optically clear. Perhaps there may a chance of flare if the sun is in front. Nothing much - BUY IT!

Many fine scratches are different. They will affect the sharpness and reduce contrast considerably - AVOID

Single scratches or chips can be filled with matt black paint. This will have the most minimal effect on sharpness and contrast. If the scratch/chip is on the rear element (and painted in) there could be the possibility of it showing on the image. Left untreated the scratch/chip will have a big effect - CONSIDER.

If you are buying a lens as an investment or to re-sell, I'd avoid any that have marks of any kind.

[Stephen]

The rough rule of thumb for marks like chips not showing is that back elements damage does show on most, and on lens above standard the marks do not show if on the front, with the exception of a retrofocus lens of any type, and that includes a lot of zoom designs. The effective cone focuses close to the front element in these types, which explains why dirt generally shows more on such lenses.
As mentioned before most portrait length lenses, 90mm plus, can be quite scratched up and tatty, with advantage, to give soft focus effect, but like gauze, or smear, rather than true soft focus, which can only be achieved by specially designed lenses such as the Leica types.

[truls]

This was most valuable advice, thanks! I did not buy the lens, I found a better (almost mint) early Ai Nikkor 28/3.5, to my FM and Nikkormat. But later I will consider imperfect lenses with coating issues, depending on usage.