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04-26-2014, 05:12 PM   #1
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ricoh 50mm 1.2 aperture problem

Hi I am new to this website so this may have already been covered, but I have a ricoh kr-10 super and a ricoh 50mm the aperture seems to be broken on the lens. When I move the ring on the lens the aperture does not open or close, but when I move the notch on the back of the camera it will open and close. Can I fix this myself?

04-26-2014, 06:07 PM   #2
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Does the lever feel like there is a spring attached to it?
04-26-2014, 06:25 PM   #3
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yes it does feel like a spring
04-26-2014, 06:48 PM   #4
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If so, excellent equipment, if I may say so. That lens is of top quality.

With the lens REMOVED from the KR-10, you should clearly see the aperture open and close as you rotate the aperture ring in both directions.

With the lens ATTACHED to the KR-10 , the lens will be held fully open by the KR-10, so that you can focus sharply. So when you rotate the aperture ring, you will see no change in aperture.
The KR-10 needs good batteries to operate correctly. It will stop down the lens to your selected aperture, momentarily during exposure process, when you press the shutter release.
The KR-10 does not have a "dof preview", so you can not see this action in the viewfinder.

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04-26-2014, 07:00 PM   #5
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QuoteOriginally posted by wombat2go Quote
Like this?
If so, excellent equipment, if I may say so. That lens is of top quality.

With the lens REMOVED from the KR-10, you should clearly see the aperture open and close as you rotate the aperture ring in both directions.

With the lens ATTACHED to the KR-10 , the lens will be held fully open by the KR-10, so that you can focus sharply. So when you rotate the aperture ring, you will see no change in aperture.
The KR-10 needs good batteries to operate correctly. It will stop down the lens to your selected aperture, momentarily during exposure process, when you press the shutter release.
The KR-10 does not have a "dof preview", so you can not see this action in the viewfinder.
The aperture does not open or close when I move the ring when the lens isn't attached to the camera
04-27-2014, 06:31 AM   #6
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Anyone else have any help?
04-27-2014, 06:44 AM - 1 Like   #7
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Sounds like dis-assembly/repair is required.
Before that, there is a black lever on the lens mount.
normally, off the camera the aperture will be stopped down to the setting of the ring. It will spring open when that lever is moved

On the other side of the mount, there is a slot. In there you should see the top of the coupling lever and it should move in the slot when the ring is rotated.
04-27-2014, 06:59 AM   #8
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If it is a 50f1.2 lens, perhaps it is worth fixing (if indeed broken). If it is a 50f2.0 lens, then perhaps getting another used one may be cheaper than fixing it.

04-27-2014, 08:03 AM   #9
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QuoteOriginally posted by wombat2go Quote
Sounds like dis-assembly/repair is required.
Before that, there is a black lever on the lens mount.
normally, off the camera the aperture will be stopped down to the setting of the ring. It will spring open when that lever is moved

On the other side of the mount, there is a slot. In there you should see the top of the coupling lever and it should move in the slot when the ring is rotated.
Yes when the ring is rotated that coupling lever moves, and when the other lever is moved the aperture springs open like you said. When I move the ring though the aperture does not move unless I move the lever. Do you know how to fix this
04-27-2014, 09:03 AM   #10
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Is it a 1:2 (f/2) lens like my photo above..... or a 1:1.2 (f/1.2) lens?

If it is the f/2, and if you are confident to loosen the screws and take the mount off, I can do the same here and send a photo.

If it is a f/1.2, I do not have that lens. That lens has more value and you might consider getting it repaired ( eg PF member dcshooter)

Bear in mind that if you take the mount off, there is a risk of fiurther damage or some small part getting lost.
04-27-2014, 09:13 AM   #11
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Does the lever move freely or is it sticky or binding? Normally there is a spring that holds the lever in position. If the lever moves freely the spring may have disengaged and it my just be a simple matter to hook it back up.
04-27-2014, 10:24 AM   #12
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QuoteOriginally posted by wombat2go Quote
Is it a 1:2 (f/2) lens like my photo above..... or a 1:1.2 (f/1.2) lens?

If it is the f/2, and if you are confident to loosen the screws and take the mount off, I can do the same here and send a photo.

If it is a f/1.2, I do not have that lens. That lens has more value and you might consider getting it repaired ( eg PF member dcshooter)

Bear in mind that if you take the mount off, there is a risk of fiurther damage or some small part getting lost.
It is the f/2
04-27-2014, 10:31 AM   #13
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Which version is it? There were a few different Rikenon 50/2s.

Someone might have had it apart and put something together wrong. If it is the same as my later model plastic version I could possibly help.
04-27-2014, 10:38 AM   #14
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QuoteOriginally posted by elliott Quote
Which version is it? There were a few different Rikenon 50/2s.

Someone might have had it apart and put something together wrong. If it is the same as my later model plastic version I could possibly help.
I'm not sure which version I picked the camera and lens up from a thrift store
04-27-2014, 10:40 AM   #15
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The front will have either 1:2 meaning F2 or 1:1.2 meaning F1.2
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