Etched/pitted lenses

Right will give it a go, many thanks all. The haze you can see is a crescent around the edge of it, maybe not as much as a quarter of the way round, and not too wide, the rest is clear apart from the pits. The photo shows it about as bad as it could have.

To go back a bit - what has caused the haze? It's definitely not a layer of something, I've used a number of solvents and nothing has touched it, I think it's damage to the surface of the lens. I guess there is nothing I can do about it.
 
Agree with Greyscale above, put a hood on it, shoot it and see. Then grab some very fine polish (I've used Mother's chrome polish and Simichrome polish to good effect if you want to risk it.
 
Fungus most certainly does etch grooves into the surface of lens elements; I can't say whether it's actually a digestive process, but the end result is the same as far as the lens is concerned. It might actually be magnesium fluoride that it finds so tasty, as I always seem to see it on coated lenses rather than uncoated ones. The only harmful effect of the etching generally is flare, but it can be severe if a large surface area is involved. I can't think of anything you can do that won't make it worse, other than the black paint trick to prevent light from scattering from the grooves. This makes the lens look pretty bad, though, and it can create little shadow spots on the image. You might just use extra care to keep the lens surface shielded from direct light when shooting.
 
Some results from my test film:
Ten Little Ducks by John Rodriguez, on Flickr
Leaving the Castle by John Rodriguez, on Flickr
Arcade by John Rodriguez, on Flickr
My scanner isn't great, the prints look better. There is noticeable flare (worse in other pictures) where sunlight is involved - one was even indoors at a railway museum, where the light was coming in through a rooflight an I was shooting up at a bridge. A shot of the front of the Mallard (fastest stream train) just below it however was beautiful - deep blue, glossy shine from the paintwork, excellent sharpness and contrast. Same on most pictures, away from incident sunlight, no problem, even reflected sunlight from the back of our house - which is painted off-white - on a very sunny day, erroneously shot at 1/60 f16 on 200ISO, came out free of flare. So, all in, no great problems despite how the lens looks with a flashlight. Thanks all for your help, thought I had best close the loop and tell you my results. I've had another camera (Contessa LKE so very similar) with and without lens prolbems, so I recognise the flare now.
 
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