Rear cap removal ...Mamiya Sekor Lens

Asha

Asha

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Asha
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I know we've had similar threads before with lenses/ filters etc practically stuk solid but I'm asking if there's a way that I haven't found for getting the rear lens cap of a Mamiya Sekor lens ....It's actually a 90mm RB lens that I use on my RZ67

I've checked against other lenses that I'm attempting to turn the locking ring the correct way but all I'm managing to do is undo the front element or grip so tightly that I've a chance of damaging the aperture / shutter speed rings,

It's not the first time I've found these mamiya rings a little awkward both with the caps and on the RZ body, but never like this,.

So anyone got any bright ideas before i get a hammer to it out of frustration:mad::D
 
Hi @Asha,

If you are unscrewing the front then you may well be turning the ring the wrong way, with the lens facing down turn the rear ring clockwise and it will eventually turn I find one of mine a wee bit stiff at times.
 
Cannot comment from experience but you cry for help got me a Googling and there is history of these caps getting stuck.....................so no idea if these help but found some feedback here:-

http://photo.net/medium-format-photography-forum/00YQxI

https://www.flickr.com/groups/42161461@N00/discuss/72157625119696874/

A few comments relate to the lack of grip and using latex gloves to gain purchase on the cap and the rotating ring i.e. as I read this does not transmit the turning force to the rest of the lens as you describe!

I hope you can sort it without resorting to "extreme measures" ?
 
Box Brownie said:
Cannot comment from experience but you cry for help got me a Googling and there is history of these caps getting stuck.....................so no idea if these help but found some feedback here:-

http://photo.net/medium-format-photography-forum/00YQxI

https://www.flickr.com/groups/42161461@N00/discuss/72157625119696874/

A few comments relate to the lack of grip and using latex gloves to gain purchase on the cap and the rotating ring i.e. as I read this does not transmit the turning force to the rest of the lens as you describe!

I hope you can sort it without resorting to "extreme measures" ?
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Thanks for the links...looks like i'll have to keep "persuading" it and discipline myself to putting it aside as soon as I get frustrated and returning to it when calmer ...It will come off eventually I guess ....I hope!!
 
H'mm my RB rear lens cover is just push on....dunno if it's a genuine Mamiya though or I'm not understanding the problem.
 
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I've got both types, I much prefer the push on ones but they're not deep enough for the WA lenses.
 
steveo_mcg said:
I've got both types, I much prefer the push on ones but they're not deep enough for the WA lenses.
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Yes there is a deeper one for the WA lenses it is one that stays on by turning the locking ring. The earlier RB lenses had push on rear caps.
 
excalibur2 said:
H'mm my RB rear lens cover is just push on....dunno if it's a genuine Mamiya though or I'm not understanding the problem.
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steveo_mcg said:
I've got both types, I much prefer the push on ones but they're not deep enough for the WA lenses.
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Cannyekerslike said:
Yes there is a deeper one for the WA lenses it is one that stays on by turning the locking ring. The earlier RB lenses had push on rear caps.
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I wasn't aware there were two types........I like caps that stay in place and do what they're designed to do but I don't like ones that refuse come off!
 
Well if it's like a Canon breech lock mount you'd swivel the collar one way and just pull the cap off.
 
excalibur2 said:
Well if it's like a Canon breech lock mount you'd swivel the collar one way and just pull the cap off.
Click to expand...

Yes it is much the same but the ring does get stiff and hard to turn sometimes plus it is such a large diameter ring it is difficult to get a hold of.
 
excalibur2 said:
Well if it's like a Canon breech lock mount you'd swivel the collar one way and just pull the cap off.
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Cannyekerslike said:
Yes it is much the same but the ring does get stiff and hard to turn sometimes plus it is such a large diameter ring it is difficult to get a hold of.
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This is the whole point, the darned collar won't budge:mad:

I'm torn between two frustrating little "jobs" to do atm, removing this darned lens cap and getting my old mantlepiece clock to run for more than a couple of minutes....I moved it and it now the pendulum refuses t re-find its "beat" even though, according to the spirit level, the clock is level!:banghead:

Ok back I go to have another play with the cap, then the clock, then the cap, clock, cap clock , .................:confused::wacky::D
 
Double post
 
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Asha said:
This is the whole point, the darned collar won't budge:mad:

I'm torn between two frustrating little "jobs" to do atm, removing this darned lens cap and getting my old mantlepiece clock to run for more than a couple of minutes....I moved it and it now the pendulum refuses t re-find its "beat" even though, according to the spirit level, the clock is level!:banghead:

Ok back I go to have another play with the cap, then the clock, then the cap, clock, cap clock , .................:confused::wacky::D
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Can't be worse than doing your income tax online :eek:;)
 
excalibur2 said:
Can't be worse than doing your income tax online :eek:;)
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That's a piece of cake in comparison .......I'll eat my words in March when i have to do it myself here:D
 
For my RB 65mm and 180mm they are both push on and stamped Mamiya, so if you get it off, it might be worth getting this sort...maybe the Chinese do em cheap.
 
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excalibur2 said:
For my RB 65mm and 180mm they are both push on and stamped Mamiya, so if you get it off, it might be worth getting this sort...maybe the Chinese do em cheap.
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Could be a good idea Brian ....in the meantime, an if it comes off aint an option.....I can't use the darned thing with it on!!

Blimey this dilema is becoming as dramatic as your 19mm Canon lens :LOL:
 
Asha said:
Could be a good idea Brian ....in the meantime, an if it comes off aint an option.....I can't use the darned thing with it on!!

Blimey this dilema is becoming as dramatic as your 19mm Canon lens :LOL:
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Have you considered asking Miles Whitehead if he has any special hammers he could use?
 
Asha said:
Could be a good idea Brian ....in the meantime, an if it comes off aint an option.....I can't use the darned thing with it on!!

Blimey this dilema is becoming as dramatic as your 19mm Canon lens :LOL:
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Well if the collar moved before the cap was put on then with my Holmes hat on it must be the friction between collar and plastic cap.........so if the collar is allumium? putting the lens in a warm place and in theory the metal would expand more than the plastic and reduce the friction?
 
A bit less than a parrot :)
 
excalibur2 said:
Well if the collar moved before the cap was put on then with my Holmes hat on it must be the friction between collar and plastic cap.........so if the collar is allumium? putting the lens in a warm place and in theory the metal would expand more than the plastic and reduce the friction?
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kendo1 said:
Gas mark 4 for 30 minutes...
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and the genious prize is shared by ^^you two^^:p


I gently warmed the lens as suggested in front of a heater for a couple of minutes, put it on the bed mattress horizontally, left hand on the lens body, right hand around the collar and with all the force i could muster, pushed down very hard whilst at the same time as twisting the collar away from me and hey presto ....it released!(y)

I might add that having dropped and lost / broken things by trying to undo / repair items like this, I now always ensure I'm either on the sofa or better still the bed to ensure a soft landing of delicate parts!;)

Clocks going too now, but strangely it chimed only one chime at 8 o'clock .....now that's the half hour chime :banghead: :crying:
 
Asha said:
Clocks going too now, but strangely it chimed only one chime at 8 o'clock .....now that's the half hour chime :banghead: :crying:
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and now at 8;30pm it's chimed FOUR times!!!!!o_O

I give up, I solve one problem and another arrives:sulk:



kendo1 said:
Yeah!

Next problem is how do you stop it happening in the future?

I've found this to be quite useful :D as it can be used on plastics:
http://www.amazon.co.uk/Liquid-Silk...&qid=1454009085&sr=1-3&keywords=lubricant+sex
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Mmm perhaps that product would work though I think for now I'll try only closing the collar two thirds of the way or so instead of fully when installing the cap
 
Asha said:
and the genious prize is shared by ^^you two^^:p


I gently warmed the lens as suggested in front of a heater for a couple of minutes, put it on the bed mattress horizontally, left hand on the lens body, right hand around the collar and with all the force i could muster, pushed down very hard whilst at the same time as twisting the collar away from me and hey presto ....it released!(y)

I might add that having dropped and lost / broken things by trying to undo / repair items like this, I now always ensure I'm either on the sofa or better still the bed to ensure a soft landing of delicate parts!;)

Clocks going too now, but strangely it chimed only one chime at 8 o'clock .....now that's the half hour chime :banghead: :crying:
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Well my normal method of using a hacksaw wouldn't have worked in this case :D glad it's fixed for poty #1 o_O
 
But seriously :) there must be a way of stopping it from happening again.
 
Try a different protector... erm I'm getting confused!
 
ive got an RZ67 too, to get the rear cap off you dont actually twist the cap, there is a "grippy" collar just above it on the lens that locks it in place. I just twist that and the cap falls off :) Ive only 2 lenses, the 50 and 150 but the method is the same for either.
 
The rear lens caps on my RB67 lenses must be the old ones, as they are push on/drop off types, so I have the opposite problem in that it takes an effort to keep them on!

On the clock front, have you ensured that it's level front to back as well as side to side? We have an old family clock (grandparents' wedding present as I recall) and resetting the time can be a nightmare because the hands and the chimes aren't fully coupled. You have to get the right number of chimes for the hour before the hands can be set going. For example, if you start it just before the hour, it will chime on the hour, but the number of chimes is determined by the chime mechanism. It only seems possible to get them in synch by letting the chimes run down and only winding it up again when the hour matches (sorry if that's clear as mud).
 
I've got an RB 127mm and an RZ 65mm and both use the same caps that work exactly like AshleyC describes. (breech lock, very similar to older canon FD) I tried to see if I could get one to stick but failed.

If it helps, they have the following embossed into the inside of them:
RZ67
RB67 Pro SD
JAPAN
 
AshleyC said:
ive got an RZ67 too, to get the rear cap off you dont actually twist the cap, there is a "grippy" collar just above it on the lens that locks it in place. I just twist that and the cap falls off :) Ive only 2 lenses, the 50 and 150 but the method is the same for either.
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Kei said:
I've got an RB 127mm and an RZ 65mm and both use the same caps that work exactly like AshleyC describes. (breech lock, very similar to older canon FD) I tried to see if I could get one to stick but failed.

If it helps, they have the following embossed into the inside of them:
RZ67
RB67 Pro SD
JAPAN
Click to expand...



Perhaps i'm misinterpreting something with what you guys are saying but I don't think I stated that I was trying to turn the actual cap......the collar turns and yes, the cap falls away from the lens without needing to be turned.

if I only had the one lens and was having this problem then I would consider it an isolated incident, however as it is I have 4 lenses, two RB and two RZ and without much difficulty I can get the caps to stick / make the collar a little difficult to remove, on all of them.
 
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Asha said:
...s I have 4 lenses, two RB and two RZ and without much difficulty I can get the caps to stick / make the collar a little difficult to remove, on all of them.
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You're doing it wrong :runaway:
 
Didn't think you were doing anything wrong, was wondering if perhaps the cap was different. Since I also use an RZ I'd like to find out the cause so if it does happen to mine I know how to remedy it. Maybe dirt gets between the collar and the lens body that causes them to stick. Do the collars rotate completely smoothly with no cap when they are off the camera?
 
Asha said:
Perhaps i'm misinterpreting something with what you guys are saying but I don't think I stated that I was trying to turn the actual cap......the collar turns and yes, the cap falls away from the lens without needing to be turned.

if I only had the one lens and was having this problem then I would consider it an isolated incident, however as it is I have 4 lenses, two RB and two RZ and without much difficulty I can get the caps to stick / make the collar a little difficult to remove, on all of them.
Click to expand...

An idea:- wipe\polish the caps with silicon dashboard cleaner, this makes any surface slippery...even use it on my table so the mouse moves easier....great stuff for cleaning camera bodies as well.
 
I knew I was on the right track. Maybe the wrong department :D
 
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