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09-08-2009, 03:58 AM   #16
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mflens.com forum has an online shop with some very useful tools like lens spanner and different sizes for lens front name plate removal rubbers that work well. I have a set of front plate removal rubbers and their spanner which I can vouch for.

09-08-2009, 04:34 AM   #17
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QuoteOriginally posted by ddhytz Quote
Have you bought anything from them? What is the postage like?
No I haven't. I'm using some DIY stuff, good enough for me
09-08-2009, 05:05 AM   #18
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QuoteOriginally posted by frank Quote
No I haven't. I'm using some DIY stuff, good enough for me
No problem. thinking of buying something, but not sure if they are reliable.
09-09-2009, 02:20 AM   #19
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front ring easily removed!
I found a plastic tape spin perfectly fitting the lens, and I used plumber putty to have a good grip. 2 drops of penetrating oil side the front ring, applied the "putty tool" and... the grip was so strong that I unscrewed the ring applying almost no pressure on it.

But now: I see a ring with two opposite notches... should I remove first the front glass turning it counterclockwise?

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09-09-2009, 03:21 AM   #20
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QuoteOriginally posted by leoalo Quote
front ring easily removed!
I found a plastic tape spin perfectly fitting the lens, and I used plumber putty to have a good grip. 2 drops of penetrating oil side the front ring, applied the "putty tool" and... the grip was so strong that I unscrewed the ring applying almost no pressure on it.

But now: I see a ring with two opposite notches... should I remove first the front glass turning it counterclockwise?
Look at my second picture, unscrewing it will release the whole "front" lens assembly in one piece!

Mike
09-09-2009, 04:45 AM   #21
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wavecurrent,
I am in doubt: unscrewing the GLASS or the notched RING?
IF the second, which tool did you use?

thanks
09-09-2009, 08:36 AM   #22
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QuoteOriginally posted by leoalo Quote
I am in doubt: unscrewing the GLASS or the notched RING?
IF the second, which tool did you use?
This:

09-09-2009, 11:18 AM   #23
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SOldBear, I guess you succeeded in cleaning the blades of yours 24/f2.8.

I beg your pardon SOldBear - frank - wavecurrent, I am still a bit confused (too many generous suggestions!): should I remove the glass before attacking the notched ring (with a manual anti-clockwise rotation of the glass [frank]), or remove first the notched ring (with the Vernier Caliper [SOldbear]), and then detaching the front glass?

thank you again

leonardo

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09-09-2009, 11:58 AM   #24
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Leonardo,

To be honest with you, I don't remember exactly what I did. I did it when my son took the cameras for a trip so I didn't take any photos.

As far as I can remember, I removed the notched ring, then I removed the whole front glass assembly. The rear glass assembly was pretty simple to remove.

But that was not enough. I had to separate the focusing mechanism from the aperture blade assembly. That was pretty simple too but putting it back together is a PITA because there are so many ways to do so, but only one way to achieve correct focus. I had to do it by trial and error. There might be a better way but I didn't know. It took me a few hours and quite a few "not nice" words.

I since sold the lens so I don't have it any more.

Sorry that I'm not much help.
09-09-2009, 02:58 PM   #25
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QuoteOriginally posted by SOldBear Quote
This:

That's exactly what I have and use
09-09-2009, 03:06 PM   #26
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QuoteOriginally posted by leoalo Quote
SOldBear, I guess you succeeded in cleaning the blades of yours 24/f2.8.

I beg your pardon SOldBear - frank - wavecurrent, I am still a bit confused (too many generous suggestions!): should I remove the glass before attacking the notched ring (with a manual anti-clockwise rotation of the glass [frank]), or remove first the notched ring (with the Vernier Caliper [SOldbear]), and then detaching the front glass?

thank you again

leonardo
No, you don't need to remove the very front glass, just find something (like the caliper) to turn the notch ring anti clock, either the whole front glass group will come off together, or you can get it off very easily after that. They you should be able to see the aperture blades assembly.

Before you take the assembly off, better turn the aperture ring left and right, just make sure you know how it works. It'd help when you put it back. Turn the aperture ring to the widest (F2.8) then work from there There should be a ring/plate pressing on the aperture blades, a bit tricky to take it off if it's not fixed by screws, but you'll figure it out.

Like SOldbear, the first lens took me about 3 to 4 hours to put it back, but now I can put that thing back in less than 5min
09-11-2009, 10:29 AM   #27
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I succeeded in dismounting the front lens and reaching the blades, but after opening the barrel, the "sticky blades" problem automagically dissolved!

Cannot say by sure, probably the few drops of unblocking oil I used to unscrew the front ring lubricated the aperture lever pivot - because I finally argued that the problem was there.

Much better! I was afraid of disassembling the blades mechanism...

I took also some short movie, maybe I will put them on youtube.

Thanks to you all for your valuable suggestions, I hope the "fix" will last for a long time.

leonardo
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07-17-2010, 08:17 AM   #28
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QuoteOriginally posted by leoalo Quote
I found a plastic tape spin perfectly fitting the lens, and I used plumber putty to have a good grip.
Good idea.

Inspired by this, I used a cardboard tube from a toilet paper roll some blue tack attached. Nothing else (including rubbers) worked before but this contraption worked like a charm.

To remove notched rings, a pair of tweezers with pointy ends, bent into shape, can work well.

Last edited by Class A; 07-18-2010 at 10:32 PM.
08-04-2010, 01:28 PM   #29
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Thank you very much for these clears explanations.

Nevertheless, I have the same problem (blades are blocked) and I reached to open the lens (same situation as above) but I don't find the way to access the blades...

Do you have any idea ?

Thanks in advance,
Pierre.
08-04-2010, 05:02 PM   #30
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QuoteOriginally posted by pierrot35 Quote
Thank you very much for these clears explanations.

Nevertheless, I have the same problem (blades are blocked) and I reached to open the lens (same situation as above) but I don't find the way to access the blades...

Do you have any idea ?

Thanks in advance,
Pierre.
I don't know if this lens is the same as the Rokinon 28mm that I've taken apart (looks similar), but on the Rokinon, the aperture blade assembly bottom (the part closest to the front of the lens, and the part in the picture above with the pivot points listed) is friction fit into the rear housing. If it is the same, you can press the plate down from the rear of the lens and it should pop right out. The aperture blades will likely go flying when you do this.
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