DIY Lens Servicing....
Can anyone give me a head start for some web links to DIY lens cleaning ?
I'm getting so many lenses with internal fungus/mould that'd I'd like to start having ago at stripping down and cleaning myself.
I'm mostly working with 35mm SLR prime lenses, usually 50mm pentax's and OM zuikos.
Most lenses will have a decorator ring with the name,focal length & aperture information. This ring unscrews anti-clockwise.
I have a selection of rubber stoppers(bungs?) to remove them with. Using the edge of the stopper, hold it against the ring & turn it. sometimes you will have to do this at different points around the ring. Occasionally a drop of alcohol around the edge of the thread may be needed. Don't use too strong a solvent, you don't want to start separating elements.
OK now you have the ring out. Canon FD lenses will typically have a retaining ring held in with three screws for the front element.
Other brands may have a hidden ring with spanner notches under the decorator. Some you will have to remove an outer ring that has lens info on it, these often have set(grub) screws that need to be loosened.
Rear groups are usually screwed into the rear barrel with a spanner.
Microtools has a pretty complete collection that you can look at online & possibly find a source in Britain.
Thanks John - I've had a few goes with some scrappy lenses and am starting to get the feel of it. Not having the right tools is my biggest handicap at the moment so I think a look Microtools is the first step.
It'd be very useful if I could find some web articles showing exploded diagrams and step instructions for dealing with specific lenses.
Some of the lenses I sell on, so it's not worth paying a repairer to do the work as this costs more than the lens is worth.
In my experience there usually is a residual damage to the coating after the haze and fungus are removed. Since the brightness range of negatives is less than that of a typical scene, enlarging lenses tend to do just fine with that residual coating damage.
I went in search of some fungus ladden lenses and for an average of $10 each I got these 3 lenses (shown in the picture below). They are all six-element Schneider Componon f5.6 lenses in Durst mounts. I took them apart and cleaned them. They are all much improved, but still have permanent damage to the coating. Side-by-side comparisons to some new Schneider Componon-S lenses showed nearly identical performance.
Enlarging lenses are pretty easy to get apart. 35mm taking lenses can be tricky. I have taken apart some Rollei QBM lenses, but each brand has its own quirks.
a good tool for unscrewing lenses can be made from a cheap pair of needle nose pliers...I bought a pair about 3 inches long, and ground the points to a flat point (ground the sides in - then flattened the ends a bit)
You need to be a bit careful as you can't lock them, but they've served me well in repairing lenses professionally for the last 15 years...
If you want something that locks try doing the same thing to a pair of metal calipers - the kind used in toolmaking to measure/scribe lines - you can usually find the cheap Chinese ones in stores for $5-10....
Also if you can find a old photocopier (or a friendly technician) the fuser rollers are made of rubber - once you've knocked the metal rod out of the middle you can cut them into 3 inch lengths, and then thin the ends down to the correct size (the advantage of these over commercially available ones is that you hav emore to grip, and more leverage)...
If you find a name ring won't unscrew you will need to drill 2 small holes into the name ring - you can then insert the tips of a fine pair of pliers/lens tool to unscrew them (some can be very tight).
Canon FD name rings - many of the New F1 lenses (the ones with the button to release the breech mount) have a push in lens retaining ring that is glued/clipped in - you need to put the tip of a screwdriver under the inside of the name ring to pop it out....
To remove fungus you can use many things - spit works best, then dishwashing liquid, household bleach, then alcohol - no one things works perfectly, but a combination of 2 can work well.
If you have any specific questions PM me and I'll try to help - I was a Canon Australia camera tech for 5 years, and then worked in other repair shops for a few more years....I'm lucky enough to have learn't from people who worked on Canon rangefinders, RB's and even Rectaflex's when they were new.....
Places like Edmund Scientific, and at one point, Surplus Shed, sell optical spanner wrenches. It's a bar with a fixed spanner and the other side slides to the proper diameter. This is the best method as you won't have to worry about them collapsing and scratching an element.
Also, some lenses are all cemented together. I have had great luck with third-party lenses, they just fall apart. But, a decent lens from Nikon or similar have a tendency to have the retaining rings cemented in. Making it very hard to disassemble. But, older and simpler stuff like an enlarger lens will be easier.
Originally Posted by ic-racer
Aren't coatings only on the outside of the front element ? Since most of the fungus I encounter is usually on the internal glass, there isn't any coating to get damaged ....?
From what I've read there are different 'breeds' of fungus - some more aggressive than others. I guess it depends how long it's been in contact with the glass aswell. I also read that even when the glass has been cleaned there are still spores lurking inside the lens body and workings which can re infest.
Thanks for all the info
The coatings are also on the internal lens elements.
Originally Posted by bill spears
In a modern lens each element is coated on both sides.
Here is some more info on my experience: http://www.largeformatphotography.in...ghlight=fungus
For any DIY camera/lens repairs it's always worth having a look here: http://www.kyphoto.com/classics/foru...tml?1271314577 and using the search facility.
Another website that is very helpful for all things Pentax (including Takumar lenses) is: http://www.mypentax.com/sitemap.html
Once you've done one or two and got a general feel for the way these things are typically put together, then small variations are easy to second guess. I've never found a Pentax lens where the fungus has left any permanent damage, but perhaps that's only because of the particular types, ages or SMC of the lenses I have. Do clean around inside the lens to try to catch any spores lurking elsewhere in the workings, especially around the edges of the retaining rings. I use carbon tetrachloride, which I was told many years ago kills fungus on slides and lenses. Apparently it is also carcinogenic, so may not do much for the health of photographers either if used to excess!