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D.I.Y lens repair


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Alan7140

Another vote for older technology, straight-forward design with no electronics, plastic or glue, just sound engineering and construction.

My 4/300 Carl Zeiss lens (circa 1976) became very stiff to focus and the aperture wasn't closing properly during operation, both of which are common enough problems in lenses of this age whereby the organic grease used originally breaks down and loses its viscosity as well as spreading to areas where it isn't wanted (such as the aperture blades. This required an almost complete strip-down, cleaning out of old grease and replacement with a modern Lithium grease to fix the problem. Starting from scratch with no manual or instructions, the lens was easy enough to disassemble (as in the first photo) and clean and reassemble again with little more than two jewellers screwdrivers, a pair of tweezers, Scotch 700 solvent and some cotton buds, and is now working like new again. Cost was effectively near zero, and total time taken was about two hours.

 

iVc4VjW.jpg

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Another vote for older technology, straight-forward design with no electronics, plastic or glue, just sound engineering and construction. My 4/300 Carl Zeiss lens (circa 1976) became very stiff t

Yes, Hugh, made by WD40. I spray it into a small container first (A 400gm glass Mocona jar lid with the plastic insert removed) and let it sit for an hour or so to allow the propellant residue to evap

Thanks Alan.    I now have a can of said lithium grease.  Micro Tools have a 10 gram container of their #10 grease for around "only" $US40 each plus postage, so the lithium alternative sound

crowecg

I'm sure you are right - there will be modern lenses out there which are impossible to dismantle, although photographic equipment is perhaps not quite at the point of other consumer electronics that are cheaper to replace than to repair.  Or perhaps they are with the extreme tolerances needed for the crazy digital resolutions of the high end cameras these days.

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Hugh_3170

Nice work Alan.  Is the white lithium grease one of the thin spray can type ones that you get from car accessories shops?  I think that I can see such a can in the background of your photograph.

 

I have a micro Nikkor - 55mm f/2.8 which needs a similar treatment to your Zeiss.  It has quite longish helicoids, so I cannot afford to use a grease thar is too stiff or the whole business is liable to bind up on me - not that this issue is a problem right now.  Quite the reverse in fact as the old gease is now much more a liquid than a grease and the iris is distinctly oily and slow to work! :(

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Alan7140
17 hours ago, Hugh_3170 said:

Nice work Alan.  Is the white lithium grease one of the thin spray can type ones that you get from car accessories shops?  I think that I can see such a can in the background of your photograph.

 

I have a micro Nikkor - 55mm f/2.8 which needs a similar treatment to your Zeiss.  It has quite longish helicoids, so I cannot afford to use a grease thar is too stiff or the whole business is liable to bind up on me - not that this issue is a problem right now.  Quite the reverse in fact as the old gease is now much more a liquid than a grease and the iris is distinctly oily and slow to work! :(


Yes, Hugh, made by WD40. I spray it into a small container first (A 400gm glass Mocona jar lid with the plastic insert removed) and let it sit for an hour or so to allow the propellant residue to evaporate and the bubbles to dissipate and let the grease stiffen up a bit, then apply it in a smooth layer to both surfaces. Apparently it resists breaking down and migrating, which is where the old organic grease failed so badly. I have found that applying too can be detrimental, however, and applying too much gets really messy, so only experience will be your guide as to how much to use.

 

I had used Inox "Premium Grade Machinery Grease, High Temp - EP Food Grade" on a previous lens' helicoid for its advertised non-migratory properties, but it stiffened up too much in a very short time and I had to remove it. That lens with Lithium grease is still as smooth as butter over two years later, however.

 

The old grease liquefying is also what causes aperture blades to bind, and it only takes the slightest amount. Thankfully in this aperture assembly I didn't need to disassemble the blades and was able to remove it by spraying Scotch 700 solvent into the removed assembly and mopping up the brown residue up as it drained out when opening and closing the blades until it ran clear. Don't panic when the blades bind up solidly when closing the aperture just after you've wet them - the solvent evaporates pretty quickly and they will free up as you gently wipe them. You'll have to apply it numerous times, though. If it's easily accessible you are probably be just as well served by disassembling the blades and soaking them in lighter fluid to clean and degrease them; in this instance the assembly looked too difficult for me to tackle, with a couple of very obviously plastic levers embedded that looked ripe for breaking with the slightest misstep, so I opted for this more time-consuming and less fiddly process instead.

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Hugh_3170

Thanks Alan. 

 

I now have a can of said lithium grease.  Micro Tools have a 10 gram container of their #10 grease for around "only" $US40 each plus postage, so the lithium alternative sounds better to me - especially if you have gotten over two years with it in service without it playing up.

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Alan7140

I think the main thing to do is to thoroughly clean all the old grease off the threads. Cross-contamination of that with the lithium grease would very likely have an effect with resistance building up in the grease with use.

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CarreraS

If you want lessons in dismantling modern lenses, take a peak at the work of Roger Cicala and friends on the Lens Rentals blog ..

 

for example .. a geek article .. https://www.lensrentals.com/blog/2020/06/the-great-flange-to-sensor-distance-article-part-ii-photo-cameras/

 .. https://www.lensrentals.com/blog/2020/01/finally-the-nikon-z-24-70mm-f2-8-s-lens-teardown/

 

all good clean fun ! Nice to come in from a day preparing my car for hillclimbs up on my 2 post lift and relax with one of these .,. ;)

 

cheers, Maurice

"Wild things are always faster"

from 'Two Dogs' by Philip Hodgins

Wild-Things@btconnect.com

www.Wild-Things-Photography.com

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