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10-01-2009, 07:40 AM   #1
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Does sticky/sluggish aperture blades on an M42 lens really matter?

I have one of the Vivitar M42 28mm f2 lenses with oil on the blades.
I hadn't used the lens much but started to try it again recently.

So I'm thinking this really isn't a big deal other than for resale. This is old school shooting and you're focusing wide open, then stopping the lens down to adjust exposure and take the shot. Then opening it up with the aperture ring and doing the same for the next shot. The blades move slowly but still get to the right spot to focus or shoot.

These are not AF or AE lenses and shooting is not rapid fire, so really the slower blades are not an issue. Or am I missing something???

Btw, I've considered cleaning it but those blades are thinner than air and I dont like the idea of messing up a good lens myself, too cheap to have the shop do it.

Note: For those that don't know this, it's usually caused by leaving the gear inside a hot car and the internal lubricants for the lens (aperture ring, focus collar) run down the blades when the oil gets warmer and more fluid.

10-01-2009, 07:45 AM   #2
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As long as they close and open, it doesnt matter. Some lenses get so sticky that they get stuck when you close it down and wont open again in quite a while if they do at all. But if its not that bad, it doesnt affect you att all.
10-01-2009, 08:33 AM   #3
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A lot depends on how you are using the lens. If the lens is adapted onto a K-mount body, sluggish blades are not too much of a problem unless they become stuck. If, on the other hand, you are shooting with a Spotmatic or other M42 body...

Steve
10-01-2009, 09:08 AM   #4
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Peter

I think if they are only sluggish, there is no problem, but note that if they are sticking, then it is possible that some could bend if forced. I have a macro lens where this happened (not pentax but that does not matter for the discussion)

also they may change position after you move the aperture ring and press the shutter making exposure eratic.

As you say, they are thinner than air, but Is it possible to clean them by removing the rear grouping only, and carefully using a q-tip with isopropol alcohol?

10-01-2009, 09:12 AM   #5
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QuoteOriginally posted by Lowell Goudge Quote
Peter

As you say, they are thinner than air, but Is it possible to clean them by removing the rear grouping only, and carefully using a q-tip with isopropol alcohol?
Yes. Worth it? Only if it cause problems.
10-01-2009, 09:40 AM   #6
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I kinda figured as much. The lens is easily opened from the rear and I might give it a try. of course that would only remove the oil from one side but it might be fine if done a couple of times. Steve, yes if used on an M42 camera, that's going to be an issue but on a K mount, it hasn't been yet.... we'll see over time.
10-01-2009, 09:43 AM   #7
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QuoteOriginally posted by Peter Zack Quote
I kinda figured as much. The lens is easily opened from the rear and I might give it a try. of course that would only remove the oil from one side but it might be fine if done a couple of times. Steve, yes if used on an M42 camera, that's going to be an issue but on a K mount, it hasn't been yet.... we'll see over time.
Its only an issue if it does not have a manual/automatic switch. You can use it as on a PK lens if you can put it into manual mode. Or you could just make the pin be stuck depressed. And use it manually.
10-02-2009, 05:14 AM   #8
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QuoteOriginally posted by Peter Zack Quote
I kinda figured as much. The lens is easily opened from the rear and I might give it a try. of course that would only remove the oil from one side but it might be fine if done a couple of times. Steve, yes if used on an M42 camera, that's going to be an issue but on a K mount, it hasn't been yet.... we'll see over time.
note that if you change aperture several times between cleaning, from stopped down to open, and back, all the blades will transfer oil from the front of the blade to the back of the one on top of it at each actuation, therefore it should be possible to remove A LOT of the oil cleaning only from the rear

10-02-2009, 05:18 AM   #9
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Thanks Lowell. I'll try this on the weekend and see how it does. I hope you're right and the rear group removal exposes the blades. I've messed around inside trashed lenses a few times but never with the intent of having the thing work OK afterwards.
10-02-2009, 05:38 AM   #10
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I fixed a Tokina 28mm 2.8 by doing this as described by Lowell.

Has needed revisiting a few times but essentially workswhen required.
10-02-2009, 04:04 PM   #11
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Real good hints, and I might add:

I'd rather use Zippo lighter fluid (meaning: a good clean lighter fluid) to degrease the blades. It tends to bind the grease much better than Isopropyl. Just like Lowell said, rinsing and moving the blades will get ever more grease in the mix. The cotton swabs I use only such: Circular motion along the outside of the housing in the right direction (swab hopping over the steps). Start at full closed aperture and gradually open it up while circling. That way you can not bend the blades very much, cause they are always countered by the housing's guiding.

Apart from cleaning, sticky apertures will get moving better while using them and pretty much worse with colder temperatures.

Good luck with the 28/2 Viv, found it to be real nice.
Georg (the other)
10-02-2009, 06:42 PM   #12
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Well I gave it a try. The rear lens is is fairly easy to remove. Getting at the rear of the aperture blades was not too hard. I cleaned those repeatedly after flicking the blades to try and get the front gease to spread a bit. It seemed to work and the aperture is now more responsive. But it's not like new and that would require getting at the front. I tried to remove the front group but I can't get the group to unseat.

I used Methyl Hyrate (an achohol) that doesn't leave a residue and it might not get all the grease off. I might get some lighter fluid and try that next time.
10-04-2009, 09:44 AM   #13
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I want to say thanks to everyone who offered a tip or comments on doing it themselves.

Final update, I still found the aperture a little sticky and could see residue on the front side. Thinking Lowell was correct and the solvent could get at both sides from the back. I decided to try something a touch risky.

I know Paint thinner will leave a residue but would easily loosen the grease. So I opened the lens again and used that. Coated the rear side and flicked the blades a couple dozen times until the Paint thinner dries. Did that 3 times until things looked good. It removed the grease from both sides. Then I used the Methyl Hydrate to clean the remaining residue from the paint thinner. Each time using a fresh and clean Q tip (gently). It worked. I don't recommend this necessarily to anyone else but I now have a clean set of blades on both sides and the aperture is snappy. I'd say it's a touch slower than brand new and may need another cleaning sometime. But works well now.

I'm amazed I never lost that ball bearing (that gives the click stops for the aperture) after opening the thing 3 times....

Last edited by Peter Zack; 10-05-2009 at 05:30 AM.
10-04-2009, 09:59 PM   #14
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QuoteOriginally posted by Peter Zack Quote
I'm amazed I never lost that ball bearing (that gives the click stops for the aperture) after opening the thing 3 times....
Not a necissarily bad thing to do. I removed it from one of my lenses on purpose to get rid of the steps. Its so much more analog now.
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