little FYI on LF lens cleaning...

ddolde said:

Why not just put them in the dishwasher if you are going this route?

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yer just trying to prod a mythological fire eh?

amusing for me at least.

Thanks for this thread Matt. I'm no longer am all that fearful of cleaning my own lenses. I can't say I'll be pulling apart a $700 leans anytime soon, but I won't be paying $200+ for a cleaning when a lens of mine needs it.

And I lied, it's "carburetor" that I learned was the French word for "don't touch"

-Bob

Nothing wrong with Matt's approach. I took apart my Rodagon G, cleaned it, put it in formaldehyde to prevent fongus formation and put it back together again. All you need is a spanner wrench, patience and careful notes.

Having said that, I would not do it with SS 150 XL.....

Frank Petronio said:

If you read Thomas Mosley's camera repair manuals, he prefers Kleenex and Windex. Seriously.

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Just as an aside, I once "repaired" a Denon CD player with Windex and a cotton swab. Some idiot played CDs that he'd spilled Coke on. I popped the top off and, very carefully, cleaned the laser lens. It took two or three tries, but the player lasted another 8 or so years (until somebody stole it, and for all I know it may still be working). Nice, expensive player, too. Dean

Now while the lens repair crowd is awake, I can ask my little question.

Today arrived a Cooke lens we bought with Ole's help on Tradera. It's a Cooke Speedic, series X, 2.5, 162 mm. Nice lens, great glass. But: there is no movement in the f-stop ring or elsewhere. We've taken the lens apart as far as possible, but one glass element can't be taken out, as the barrel in which it sits is stuck. Won't move, nada. The iris blades seem fine, they even come out a little when tapping the lens barrel. So the problem lies in the two pieces of barrel that won't come apart. And we have no idea what's inside. Probably nothing, not even a thread. Possible diagnosis is that some kind of metal - the aluminum of the ring) has oxidized, laying a thin film between the moving pieces. Haven't got a clue what our next move can be. We've heated the barrel up a bit, no result. Lighter fluid: no result. Even the draconic measure of WD-40: no result (that was probably not a good idea, but hey, it's a frustrating process).

So now what? Does anyone have an exploded view of this lens? Have tips what liquid/oil/grease to soak the stuck b•st•rd in? Mind you that there is still a glass element inside that won't come out. Sending it off to an expensive repair service is not an option.

Sounds like the linkage that activates the aperture blades may be broken, which could be difficult to repair...

Dave

Satinsnow said:

Sounds like the linkage that activates the aperture blades may be broken, which could be difficult to repair...

Dave

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Hi Dave,
thanks for your thoughts. How do I get to this 'linkage'? And what does it normally consist of/look like? Where is it situated in the barrel?

I must add to the description that there is a small headless screw on the outer barrel that easily unscrews. This is partly responsible for opening/closing of the iris blades. I've unscrewd it and then got the iris blades to close a little. But the inner and the outer barrel (if I can call it that) won't move separately from each other. Sheer force of hands won't do much here, also because the barrels are not easy to get a good grip on. That's why I hope for a chemical solution - but if it is a mechanical problem, then I fear I'm truly up sh•t creek. (This is very aggravating - I've always been able to get the better of my gear, can't stand it that this one won't budge... )

PS The Cooke is a sunk-mount lens construction - I've never had one of those open.

Hi there,

medform-norm:

take out your loupe and look for a set screw, ala process lenses, holding the lens cell you can't unscrew. If there is no set screw than it was painted shut. A few drops of acetone at the seam will help.

the headless screw is the linkage between the outer ring and inner mechanism. Remove the headless screw and unscrew the outer ring and remove it**. This will expose the slot in the barrel and you can see the condition of the inner action ring. Now you can ##CAREFULLY## insert a driver and see if you can move the inner ring. It is possible to re-install the ring too far down the threads, you have to check alignment of the inner ring and headless screw.

**most outer rings are threaded, B&L used no threads, the ring is held on by a 'beauty ring' around the front of the barrel. Just remove the front cell and pull the beauty ring straight foward off the barrel, remove the headless screw and turn the ring to the full open position and align the groove with the set screw and pull foward to remove. These were also greased at the factory and the grease dries to cement, a little heat, hair drier, helps loosen them.

Have fun with it.

phfitz said:

Hi there,

medform-norm:

take out your loupe and look for a set screw, ala process lenses, holding the lens cell you can't unscrew. If there is no set screw than it was painted shut. A few drops of acetone at the seam will help.

the headless screw is the linkage between the outer ring and inner mechanism. Remove the headless screw and unscrew the outer ring and remove it**. This will expose the slot in the barrel and you can see the condition of the inner action ring. Now you can ##CAREFULLY## insert a driver and see if you can move the inner ring. It is possible to re-install the ring too far down the threads, you have to check alignment of the inner ring and headless screw.

**most outer rings are threaded, B&L used no threads, the ring is held on by a 'beauty ring' around the front of the barrel. Just remove the front cell and pull the beauty ring straight foward off the barrel, remove the headless screw and turn the ring to the full open position and align the groove with the set screw and pull foward to remove. These were also greased at the factory and the grease dries to cement, a little heat, hair drier, helps loosen them.

Have fun with it.

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Hi Phfitz!

The hairdryer did the trick! Thanks for the help. Once more APUG proves worthwhile and irreplaceable. A good answer within the hour, what can one want more?

Lucky for us, we have a heat gun with very finely regulated temperature and a little LCD display telling you how hot the gun is. Cooke started cooking at 180º Celcius. This was the melting point of the grease, apparently.
From now on, things will be a breeze.....



... we hope (let's not tempt the lens gods).

Tonight I took apart a 150mm g-claron which was hazy as hell and cleaned it with the scooter macgruder method...

just like new!