Cleaning the Inside of a Lens - Tutorial

Well without any technical knowledge or particular skill, but a love of tinkering and investigating and an essentially 'free' lens that wouldn't have been any real loss had I failed...I decided to tackle trying to clean away some fairly bad fungus growing inside a lens I bought. ; I thought it might be good to document the steps, as though this applies to this particular lens, many lenses share the same assembly, and plus-or-minus minor differences, the tutorial might work just as well with nearly any lens, for cleaning fungus or dust or condensation. ; The lens I was working on was a Konica Hexanon 50mm F1.7 - a super sharp and legendary fast prime I bought used, afflicted with the fungus.

Note that there are two ways to get into a lens - rear element, or front element. ; By all accounts the rear element access is more complex and dangerous, with more chance of losing small parts, throwing off alignment, etc. ; The front element is much more simple by comparison, less risk of damaging things, and less precision needed in reassembly. ; So as long as the area you want to clean is on the inside of the front element or the 2nd element just inside, this method would be preferred.

I've never opened up a lens before, so I dug around for some basic instructions online, and despite my own fears and the warnings of others, it didn't look too challenging.

So, here's what I did - this documents the process for this particular lens, but most lenses will have a very similar construction and similar process:

1. What a horrible documentarian I am! ; I failed to start off with a photo of the actual fungus!! ; I tried massively brightening this first shot and circled where it is - it was a fairly large patch with some spidery veins running off from it - it shows up here as a large dark shadow area, inside the front element:



2. The front name ring that surrounds the front element is simply screwed on - and to unscrew you need a simple spanner wrench...without one of those, often anything rubber with some traction can work the ring off by friction. ; I used the rear element lens cap, with an elastic band pressed between it and the ring - counter-clockwise turns and I felt it loosen pretty quickly:



3. Once that's off, you will see 3 screws inside. ; On the Konica, these held the black metal bezel that makes up the inner lens frame or tube, surrounding the element. ; I've tilted the lens to try to show the tiny little screws inside:


4. Once removed, the outer tube can be grasped, and turned counter clockwise - it unscrews from the lens - it's deeply threaded and takes lots of turns, but was quite easy and comes right off:



5. Now the lens element assembly is sticking out in the open...it too unscrews counter-clockwise, and is now quite easy to grab. ; Once you work it off, the lens element comes off as a single piece with the black surrounding plastic...the rear element can now be accessed:



Here's the actual front element assembly, after a cleaning. ; I carefully wiped the fungus off the lens' element with a damp microfiber towel - not rubbing too hard to avoid abrasions, and turning the towel often to avoid reusing a dirty section. ; I also went ahead and cleaned out the inside of the lens body. ; The aperture blades are fully exposed and accessible from the front like this - I closed them town to minimum aperture to avoid anything falling in by the center elements:



That was it - just put everything back in again in reverse - all quite easily. ; No worries about alignment as everything simply screws back in to its stopping points. ; I was shocked how easy this process was - I might even consider doing something similar with another older lens I have that has quite a bit of dust inside the front element.

Some quickie sample pics afterwards to confirm it was all put together properly and focused correctly and sharp:







Yep...I'd call that sharp and clean! ; Any questions or additional info needed, I'd be glad to share. ; Anyone who's got a junker lens, with bad dust, condensation, oil, fungus, mold, etc - don't throw it away just yet - give this a try if you've got nothing to lose anyway. ; And if you're confident enough, you might even be willing to try it as a maintenance technique on lenses that get a bit too dirty inside. ; I wouldn't recommend getting out there and voiding your warranty on new lenses...but older lenses that need a little care can be restored like new. ; I've gotten past my initial fears of doing so, and will likely work on several other older lenses to clean them up.

 

That's cool Justin! ; Hopefully you got them all without major damage from the fungus to the lens.

 

All in all, it was a no-loss situation even if the fungus had destroyed this lens. ; I went thinking I'd buy 2, maybe 3 lenses for around $70 total - A Konica Hexanon 50mm F1.7, Konica Hexanon 40mm F1.8, and a Vivitar Series One 70-210mm F3.5, all in Konica mount. ; I liked that the Konica SLR adapter for the NEX was one of the thinnest, so some of these primes would be very low profile on the NEX. ; When I got to the guy's house, I found the 40mm F1.8 was pristine, and the Vivitar 70-210 looked solid...but the 50mm had the fungus. ; He had wanted $20 each for the two primes, and $30 for the zoom. ; But then he lays on that he has no need or want for this old camera stuff and would love it if someone would just take it all. ; He pulled out everything he had - which included a Konica T3 SLR body, a Vivitar 28mm F2.8 lens (pristine), a Chinon CM-3 SLR body, a Chinon 50mm F1.9 (pristine), and a Chinon 135mm F2.8 (a little chipped and scuffed on the body, but glass looked fine and aperture worked smoothly). ; Chinon, by the way, was an independent Japanese maker that used Pentax's K mount for their lenses - fortunate for me since I already have a K-mount adapter! ; Plus, 4 filters (2 UV, 2 polarizers), wired cable release, all manuals, cases, boxes, lens caps, etc., flash units...the whole shebang. ; After negotiating, I took everything for $100. ; I really only want/need the lenses, but even there, 6 lenses for $100 would have been a fine deal - even with 1 considered dead for fungus, I was OK with $20 a lens for the other 5. ; So I considered the fungus-infected 50mm a freebie - if I could fix it, great...if not, no loss. ; I had nothing to lose, really.

Fortunately, the fungus was only growing along the surface of the inside of the element, and some on the inside of the casing. ; Absolutely no glass damage, etching, coating damage, nothing. ; It looks like brand new. ; And works like it too - so the deal really worked out!

Funny...my little 2nd camera tagalong which was going to be kit-lens-only and maybe a Pentax adapter on the side for my old K-mount lenses has already grown to a kit of 11 lenses and 2 adapters. ;

 

yes, that is certainly sharp. ; you are a braver man than me, however.

 

Go for it. ; I can't see any reason why not, when you've got no real investment in them. ; As long as you take your time, go step by step and document the steps as you take them, inventory parts and the order they go...you can always stop and put everything back together if you get to a sticking point, and have a professional do it.

I'll be working on a Vivitar Series One 70-210mm F3.5 macro next - it has lots of dust inside the front element, possibly the beginnings of mold (not sure), and the aperture blades are a wee bit sticky - I've already gotten my money's worth many times over with the Konica 28mm, 40mm & 50mm lenses, and Chinon 50mm & 135mm lenses, all of which are gorgeous (now that the Konica 50's been cleaned up). ; So the Viv can now be tackled with no real loss!

 

Understandable - I'm not far off myself. ; Despite having my first SLR in 1977, and having shot film for 20 years before getting into digital, I never really deeply learned or understood photography much then - I was very much a snapshooter - Set to 1/125 shutter, watch the little viewfinder meter, adjust aperture ring to make it go to the center green area, and shoot. ; That's about all I did for 20 years!

 

That's why I make my own chlorine gas autoclave at home. ; ; ;D

 

I can read Mispel...no problem. ; ; Agreed and good advice when dealing with fungus. ; I also treated the lenses (all of them) to a little UV treatment (I have a UV light which I left on them for a few hours each)...and I keep them in a lens cabinet with liberal amounts of dessicant. ; But I do keep them fairly far from eachother in a well aerated space (I've got 3 shelves for lenses, with them on felt lined shelves - the old stuff doesn't sit near my newer stuff).