Cleaning Fungus from any Mirror lens but Sigma 600mm here

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Bought this lens which it transpired had quite a colony of fungus threads....
Rather than get into arguments I sent the seller photos of the issue and we settled amicably on a substancial refund. I then was willing to "take the risk" and strip the lens down and research on the internet revealed similar lenses and implied they were easy to strip down. So I did it, cleaned it... tried but failed to keep the odd specks from  being inside and compromised by removing all the fungus threads, dust will always be there if it's a strip down in any home environment.. but easier to live with than the fungus which can, and probaby will, grow or eat into surface coatings. I but my results up on a photo sharing site which rymes with knicker ;-) take a look.

Mirror lenses have their fans and detractors but are above all fun and give the opportunity to try something different at a relatively low cost...   

Much is made of the restictions of a fixed aperture... by the same people who never deviate from there expensibve lenses sweet spots at f11 ? Much is made of the doughnut shaped so called Bokeh.. but Bokeh is ALL subjective and as far as I am concerned just a matter of taste and if it helps isolate the subject fine... if it distracts then not so... though I believe there is a thing called, photo editing software, that can be employed to reduce or even replicate this anyway.

So Mirror lenses...... good or bad - neither.. just FUN

Cleaning them... probably the simplest EVER process on a lens you will find.

Remove a few screws to take off the mount, [allen key usually] remove the stretchy rubber band around the middle and of all things,  a strip on foil tape... Yes TAPE that holds the focus in line [mark it first so you re-position it exactly where you started, or adjust if there was an issue of back focus. The rest is basic and up to you how much time and effort you want to put in to clean and keep clean before re-assembling.

BIG bonus with mirror lenses is they often focus past infinity [yes I know that's not physically posibble but you
know what I mean]. So id you are adding an adapter to chsange say Minolta MD mount to Alpha you only need the glassless version ! this is MUCH better thsan the glass versions and the glass is not needed you will STILL be able to focus on infinity. This is usual in mirror lenses as it allows for expansion and contraction that there mirror construction is prone to. So another GAIN !  

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