Learning to work on lenses - where to start?

Jeff Bannow · Jun 27, 2011

I have a ziploc full of worthless enlarging lenses, and thought it might be nice to learn how to clean them. Is there a good primer on how to go about this? Maybe a walk through with photos from someone who disassembled a lens before?

Any suggestions on needed tools? Suggested practice so I can reassemble this thing when I'm done?

Nicholas Lindan · Jun 27, 2011

http://web.aanet.com.au/bayling/repair.html

Tel · Jun 27, 2011

Jeff,

The thing about lenses is that each manufacturer had its own system for assembly. In general, there are likely to be a couple of threaded rings holding the whole thing together--one on the front and another on the rear. Typically, these will each have two slots or holes directly opposite each other to permit you to use a spanner wrench to turn them. Get a good spanner wrench (like the micro-tools ones) and not a cheap one. I always work on a small tray to keep parts from rolling onto the floor, and I always put a cloth on that when I'm working on a lens. Keep a notepad and pen handy to write reminders for reassembly. I learned from some professionals to use Glass Plus exclusively--it works better than any of the expensive lens cleaners and doesn't harm the coatings.

Many of these lenses are simple designs, especially ones that don't involve shutters. Usually they are composed of two or three elements. I typically remove the front element, clean it carefully with a clean cloth and lens cleaner and then set it down to dry for a few minutes. (You don't want to trap moisture between the elements.) Then I replace the front, remove and clean the back element, and reassemble that. Taking the entire assembly apart at once just increases the chances that you'll forget how it goes together. If there's a middle element you can clean it from the front and the back without removing it: just put a piece of cloth over a cotton swab and clean it with that.

Offhand I can't think of any good books or posts, though I'm sure there are some. I rely on a pretty good mechanical understanding and the knowledge gained from having messed up a lens or two and learning thereby what not to do.

By the way (referencing the joke post in the previous reply) sometimes a yellow shift in lens color can be corrected by exposing the lens to sunlight. The trick is to put a piece of aluminum foil on the back of the lens and open the iris all the way (and the shutter, if it's part of the lens) and place the lens in sunlight (facing the sun) for a day or two, checking the color periodically as you do so. I'm sure this doesn't always work, but I don't know of any other purported cures.

Jeff Bannow · Jun 27, 2011

Nicholas Lindan said:
http://web.aanet.com.au/bayling/repair.html

Jeff Bannow · Jun 27, 2011

Tel said:
Jeff,

The thing about lenses is that each manufacturer had its own system for assembly. In general, there are likely to be a couple of threaded rings holding the whole thing together--one on the front and another on the rear. Typically, these will each have two slots or holes directly opposite each other to permit you to use a spanner wrench to turn them. Get a good spanner wrench (like the micro-tools ones) and not a cheap one. I always work on a small tray to keep parts from rolling onto the floor, and I always put a cloth on that when I'm working on a lens. Keep a notepad and pen handy to write reminders for reassembly. I learned from some professionals to use Glass Plus exclusively--it works better than any of the expensive lens cleaners and doesn't harm the coatings.

Many of these lenses are simple designs, especially ones that don't involve shutters. Usually they are composed of two or three elements. I typically remove the front element, clean it carefully with a clean cloth and lens cleaner and then set it down to dry for a few minutes. (You don't want to trap moisture between the elements.) Then I replace the front, remove and clean the back element, and reassemble that. Taking the entire assembly apart at once just increases the chances that you'll forget how it goes together. If there's a middle element you can clean it from the front and the back without removing it: just put a piece of cloth over a cotton swab and clean it with that.

Offhand I can't think of any good books or posts, though I'm sure there are some. I rely on a pretty good mechanical understanding and the knowledge gained from having messed up a lens or two and learning thereby what not to do.

By the way (referencing the joke post in the previous reply) sometimes a yellow shift in lens color can be corrected by exposing the lens to sunlight. The trick is to put a piece of aluminum foil on the back of the lens and open the iris all the way (and the shutter, if it's part of the lens) and place the lens in sunlight (facing the sun) for a day or two, checking the color periodically as you do so. I'm sure this doesn't always work, but I don't know of any other purported cures.

Thanks - that helps a lot. What would you recommend for a spanner?

Dan Fromm · Jun 27, 2011

Jeff Bannow said:
I have a ziploc full of worthless enlarging lenses, and thought it might be nice to learn how to clean them. Is there a good primer on how to go about this? Maybe a walk through with photos from someone who disassembled a lens before?

Any suggestions on needed tools? Suggested practice so I can reassemble this thing when I'm done?

It really depends on the lens. I have a drawer full of enlarging lenses, most are basic lenses in barrel.

The cells -- front and rear -- simply screw out of the barrel. Very often the only dirty surfaces are the front and rear (that face the paper and negative, respectively). Sometimes the surfaces that face the diaphragm also need to be cleaned.

From here on things really depend on the lens. Most enlarging lenses are tessar types or plasmat types. One cell of a tessar type contains a cemented doublet, no further disassembly needed to clean. The other contains a pair of singlets. If the singlets' inner surfaces are dirty, try simply unscrewing the one that faces the diaphragm. This often works. A plasmat's cells contain a cemented doublet (faces out) and a singlet (faces the diaphragm). Again, very often the singlets simply unscrew.

I wasn't clear. The singlets are often, not always, mounted in disks that screw into the cell. Screw back together to reassemble.

I may not have been clear. Not all enlarging lenses are like the ones I know and had disassembled.

Tools aren't often required, at least with my lenses.

brucemuir · Jun 27, 2011

Jeff Bannow said:
Thanks - that helps a lot. What would you recommend for a spanner?

Look for one that has multiple tips/sizes that you can switch out.
Then you are better prepared.

Maybe some rubber "stopper" type things that will unscrew retaining rings/etc.
These are more handy for slr lenses than enlarger lenses but still good to have.
Also a flat rubber sheet like a mouse pad comes in handy.

Micro tools sells the rubber stoppers but they were out of stock last I was there.

benjiboy · Jun 28, 2011

Nicholas Lindan said:
http://web.aanet.com.au/bayling/repair.html

What this guy has done with this lens s about the most dangerous thing you can do with a lens that is known for having Thorium glass in it which is why it's yellow, and I hope he was wearing lead lined boxer shorts.

Ian Grant · Jun 28, 2011

benjiboy said:
What this guy has done with this lens s about the most dangerous thing you can do with a lens that is known for having Thorium glass in it which is why it's yellow, and I hope he was wearing lead lined boxer shorts.

Ironically the repair to remove the yellowing is UV light or bright sunlight something thewre's no shortage of down under

Ian

Jeff Bannow · Jun 28, 2011

Thanks everyone. Once I've mangled enough small lenses, I'll move on to the big stuff.

paul ron · Jun 28, 2011

You can make a lot of the tools you need. I use straight edges cut to length as spanners, sometimes I have to cut or grind the middle of the span to clear the glass lens but they are much better than spanners because they are more stable n sit low in the notches and allows me to make better handles for em. I've also used E-clip pliers as spanners. They comne in differnt sizes n with removable points I can customise.

No Hub test plugs make great friction bungs and are more redily available at Home Depots n hardware stores and are dirt cheap.

Make your own strap wrench. Noting more than a leather or heavy rubber band attached to a lever.

Get a good set of screwdrivers. Whia is good brand to look for, MicroTools carries lots of camera tools you can shop like a kid in the candy store.

Best way to get started is by doing some homework on the internet looking for repair manuals, sites with experianced repairmen and asking questions as you are doing here. Get some basic tools n cleaning agents, make a clean well lit place to work n rule number one... organize yourself. Also buying or finding junk lenses n taking em appart to experiment on. Once you get some confidence n see how most lenses and camera are built, you'll be a pro in no time at all.

It's fun and will add another phase to your photography hobby that not many know about or care to try.

ic-racer · Jun 28, 2011

For a COMPONON type 6-element lens I proceed as follows:

Unscrew front and rear cells from the barrel.
Each cell has a retainer ring that needs to be removed. I have found heating up the cell helps a lot.
Afer removing the retainer rings the elements come out by tapping the cell. There should be a cemented doublet and a single lens with an air space. So basically two pieces of glass come out of each cell, with a total of 8 surfaces to clean.
Fungus that damages the coating leaves a permanent dullness that won't come off, so I don't try. A gentle cleaning is all that is needed. It "is what it is" after just a gentle cleaning. More agressive cleaning only leads to scratches to add to the permanent damage (if any). The surfaces of brand-new lenses form B&H with life-time warranty is not perfectly clear when held up to light, so I don't expect a fungus lens to get perfectly clear. I got an 80mm from the swap meet that was basically all white on the inner surfaces. It cleaned up OK but still had about 15% residual 'fog.' The side-by-side test with a brand new 80mm Componon-S was nearly indestinguishable when both were stopped down to f16.

With respect to the barrel on the Componon-S large lenses, there is a large circlip (c-clip) that holds the aperture ring in place. Removing this allows access to the click-stop mechanism, that frequently is weak or no longer working. I clean all the goo from the detents and sometimes strengthen the metal piece that rides in the detents.

The aperture can be flushed with naptha, but be prepared to experience solublized oil weep onto the blades and make it worse than when you started, so proceed with caution if you think you need to do that.

ic-racer · Jun 28, 2011

Here is a thread where I show how to dissassemble a silver Componon and clean it up.
http://www.largeformatphotography.info/forum/showthread.php?t=59159

ic-racer · Jun 28, 2011

I have some pictures to post on a major procedure I recently completed. I had two Componon-S 240mm lenses. One had scratched glass and the rest was very clean and good looking. The other had non -scratched, excellent glass with a rusty beat-up barrel. I totally dissassembled each one and build a single excellent lens from the parts. I put the remaining parts togeter and sold them. The 'bad' lens actually worked fine...someone got a bargain.

Jeff Bannow · Jun 28, 2011

Perfect Dale. That will help a lot.

Nicholas Lindan · Jun 28, 2011

benjiboy said:
Thorium

Oh, hell, look at gas mantles...

Everything is radioactive. It's what keeps the Earth alive.

http://en.wikipedia.org/wiki/Geothermal_gradient

Nicholas Lindan · Jun 28, 2011

On a serious note:

I always work on a bath towel (one that has been washed 100 times so all the lint is out of it). It keeps anything dropped from rolling away and keeps scratches to a minimum.

Steve Grimes spanners are rather nice Dead Link Removed

2F/2F · Jun 28, 2011

Hi, Jeff.

I'd check out your local library. I found a pretty good camera repair book at mine. (Wish I could remember the name.) It even covers tool fabrication.

ic-racer · Jul 2, 2011

240MM Componon-S: making one good lens from two.

tkamiya · Jul 2, 2011

I can only speak from my brief experience in fixing EL-Nikkors, Rodenstock something and some cheap 3 element type.

First and foremost.... if it takes more than light "umph" to unscrew, stop! It's not supposed to take "grrrr" kind of force. When you take an element out, be sure to note, which way it is supposed to go back in and what order. I usually take quick photograph to remind myself. I mark lens element with a painter's masking tape to indicate which way is up.

EL-Nikkors unscrew from front and back. All I do is to take a largish rubber balloon, put it on my palm, press hard against it, then twist. I also have a set of small screw drivers. I really haven't needed them. To clean, I use the ordinary lens cleaner and some microfiber cloth. Once clean, I use clean cotton gloves to handle them. A can of compressed air comes in handy as well. As to a work table, I use a very large micro-fiber cloth. Nothing rolls off and nothing gets scratched.

I was actually surprised fairly bad dust and fungus came off cleanly. Then again, I had a Rodenstock that multi-coating was damaged so badly, as I tried to clean, chunks came off. I then used tooth paste to take it all off, re-assembled it, and I gave it away for shipping. (noting what I have done)

Jeff Bannow · Jul 3, 2011

Thanks guys!

Learning to work on lenses - where to start?

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Learning to work on lenses - where to start?

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