Well I've got lots to think about now, many thanks for all your suggestions.

Arthur, I've got one of those Ohnar zoom slide duplicator thingamajigs (T-mount PK adapter) but hardly ever used it. It works but I wasn't terribly impressed when I tried it on my SFX but I dare say that I can tweak the images from my DL and make them much more acceptable - thanks for reminding me, I'll dig it out and have a play

Excellent Matt, I've 'emailed' files to be printed before and the results were pretty good but I've never really thought about converting digital images to slides - I am still quite new to it you see!

Thanks for the links, the service looks very good indeed.

Nots' to worry Mac, I've found it

The sneaky little devil hid it between the sofa cushions, it had been missing for two days and trust me, apart from looking everywhere else, I'd all but taken that sofa apart. I'd removed the cushions, tipped the sofa upside-down and even checked inside the lining underneath and it absolutely wasn't there. I was the last person to use it and no one else had seen it since - whoever said that inanimate objects don't move by themselves?................'coz they bl**dy well do!
If I ever catch that goblin, he'll be well and truly evicted, I can tell you

Anyhow back to matters photographic, I suppose now that digital photography is so much more convenient than film (oh dear), I could try some 'with and without filter' shots to see if there is a noticeable quality difference. If there's nothing obvious at 6.1MP then I shouldn't think it'd visible on standard sized prints. Slide film tends to be more critical and the images are often projected at very large ratios but the quality of the projector lens also has to be taken into consideration - can't wait until digital projectors become affordable

Glad I could be of assistance, perhaps you could return the favour and tell me where the heck the remote control for my VCR has got to........again

Like most people, I normally find it lurking down the side of the sofa but this time, the house-goblin has really surpassed himself!


On the subject of filters, the general purpose UV, Skylight and Polarisers have no real detrimental effect. A reputable manufacturer uses high quality glass which is machined and polished to a very high standard. They are perfectly flat and therefore do not increase the barrel / pincushion distortions that lenses already have. They have no magnifying effect and the screw fit versions are fixed so close to the front element that they are totally invisible to the lens. The only effect is the colour cast or polarising effect that they are designed to produce. They filter out the unwanted rays that would otherwise be detrimental and I can't see how the combined affect of the filter and multi-coating can harm the image.
Harmful colour casts can be compensated for anyway, particularly for digital images.

Special effects filters are good fun and can result in dynamic and exciting images but they should be used sparingly because the effects can become obvious and tiresome but we're not talking about these here!

I've never damaged and had to replace a filter and therefore would not have damaged the lens itself but I'd much rather wipe a greasy fingerprint (we've all accidentally touched a lens' surface or spat on one when trying to blow off some dust - be honest......well I have ) or a raindrop from a relatively inexpensive filter - no matter how tough the coating on the lens is supposed to be.

If there is an optical difference between a lens with or without a UV or skylight filter (in terms of image resolution), then I doubt very much whether the vast majority of users would be able to tell

I think you'll find your keys in your jacket pocket, the one you wore this morning when you nipped out for a paper!

I'm quite relieved that you don't think it is too bad, I've only seen a couple myself and this is the worst one. The element in question appears to be toward the center but with any luck it'll be at the back of the front group or the front of the rear one but either way I suspect a considerable amount of disassembly will be required.
I've just got to find the time to get started but for now, I'm leaving the lens with caps off, in the window sill to help inhibit further growth.

err...no I don't live in Hong Kong but I needed a name for the blog and others I tried weren't available, I rattled off some random letters on the keyboard and it looked like hongkong - so I thought what the heck!
It was my first attempt at a blog and I'll improve the appearance, once I've figured out how to edit the layout (I'm not really happy with it as it is but I think it shows the fungus quite well).

Thanks for looking George and Kim, and for your encouraging comments.

Here's a pic. of the lens in question:


http://hongkongfuey.blogspot.com/

Thanks Kim, the fungus only really affects one internal element and is clearly visible when looking through from front to back.
When I get a chance, I'll have a go at posting an image for you - that'll be an interesting project in itself!
The lens is a one touch zoom with 13-elements in 10-groups and the offending glass looks to be in one of the middle groups - nothing like jumping in at the deep end eh?

If it gets worse, it'll soon affect the image quality but it's not really noticeable through the viewfinder at the moment.

You think the risk of cross-contamination is minimal, that's a relief but I'll certainly be taking the suggested precautions.

Thanks chaps, excellent links Matt

I guess I've got nothing to lose by attempting to take it apart and give it a clean........it'll be an interesting project anyway.

In the meantime, I'll keep it well away from the other stuff and it's only been on a camera for a minute or two - just to see how good (or bad) it was!

I think I'll have a go at cleaning it up and leave it for a while to see if it gets any worse, the image quality appears pretty good as it is, so I think it's worth trying to give it a new lease of life

Folks, is fungus on internal elements really a no-hoper?

I've recently acquired a stonking 75-250mm zoom that is generally in very good condition but at least one internal element is contaminated, it's quite bad but doesn't really affect the image quality.
Being an old lens, it's not worth much and certainly not economical to clean/repair professionally - should I just bin it?
Fungus spores can't be killed by UV-C light because of the multi-coating on the outer elements but keeping the lens dry and well ventilated should prevent further damage but is there really a risk of contamination to my other lenses and equipment?

I guess I should err on the side of caution and throw it away but it seems such a shame