100-400 lens advice

[bottletopburly]

I have been offered. 100-400 canon lens for £100 it does have some fungus marks and I don’t think Autofocus works  , I took some pictures and they’re fine , obviously  Af not working not a  problem for Astro  , is af really a problem for daytime use manual focus works fine ,  can fungus be cleaned off ? what do you think 🤔 buy or not .

[PeterCPC]

You would have to disassemble to remove the fungus.

Peter

[Alien 13]

Its worth a punt in my view, as Peter has mentioned you would have to strip the lens down to do a proper clean with IPA or similar but giving it plenty of fresh air and sunshine (not direct) should stop any more fungal growth.

The lens being an L series should be reasonable easy to dismantle if you can find a guide and spares might also be available for the USM motor and internal wiring if you wanted to get the lens back into tip top condition.

Alan

[PhotoGav]

I would avoid this lens... I believe that lens fungus can spread and you wouldn’t want to pay to infect your other lenses! It looks very marked, which probably won’t show specifically on images, but will affect overall performance of the lens. I never rated this mark I version of the Canon 100-400, it just never seemed to work very well and the push pull zoom on the same ring as twist to focus drove me mad!

Having said all that £100 does seem a steal...

[bottletopburly]

@PeterCPC @Alien 13 @PhotoGavThanks chaps I think I will take a punt on it , my friend believes the auto focus does work though he mainly used manual focus  so it may be that it not switched on I will have a better look later he upgraded to a 600mm lens if memory serves me right so this was collecting dust.

[kirkster501]

Mate, £100 for a Canon lens of that quality?  It'd be rude not to...  Why not research methods to kill the fungus? 

[bottletopburly]

10 hours ago, kirkster501 said:

Mate, £100 for a Canon lens of that quality?  It'd be rude not to...  Why not research methods to kill the fungus? 

Yes I now done deal I think it’s more dust than fungus, found a trick on YouTube that I will do anyway  , lens is fine been out round the local reservoir testing 👍😁

[old_eyes]

11 hours ago, bottletopburly said:

Yes I now done deal I think it’s more dust than fungus, found a trick on YouTube that I will do anyway  , lens is fine been out round the local reservoir testing 👍😁

I think you may have found a winner there!