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09-26-2009, 06:42 PM   #1
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Weird Manual lens problem

I have a manual 50mm f/2 lens that works fine on my film slr, but the aperture ring does not seem to do anything when I have it on my k10d. I can take pictures, but I'm assuming they are all wide open. When I use the lens on my film camera and rotate the aperture ring, it affects the metering. What gives?

09-26-2009, 06:49 PM   #2
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QuoteOriginally posted by columbus Quote
I have a manual 50mm f/2 lens that works fine on my film slr, but the aperture ring does not seem to do anything when I have it on my k10d. I can take pictures, but I'm assuming they are all wide open. When I use the lens on my film camera and rotate the aperture ring, it affects the metering. What gives?
What gives is:

1. You need to set custom function to "aperture ring permitted"

2. You need to use manual mode and either press the green button to meter, or use the (optical) DOF lever to turn on the meter.

3. You will be able to use Av mode, but as you seem to have discovered it will only take shots wide open.
09-26-2009, 06:56 PM   #3
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QuoteOriginally posted by pschlute Quote
What gives is:

1. You need to set custom function to "aperture ring permitted"

2. You need to use manual mode and either press the green button to meter, or use the (optical) DOF lever to turn on the meter.

3. You will be able to use Av mode, but as you seem to have discovered it will only take shots wide open.

I've tried all of these options except the DOF lever. What is this?
09-26-2009, 07:06 PM   #4
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Camera in manual exposure mode. Set the lens to chosen aperture, and press and hold the DOF lever. In the viefinder you wil see the meter bar. Adjust shutter speed or aperture to centre the meter bar.

You should also see the lens stop down as you do this ( as long as you have not set wide open aperture). If this does not happen you have a problem with lens or camera.

What is the make/model of the manual lens ?

09-26-2009, 09:58 PM   #5
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QuoteOriginally posted by pschlute Quote
Camera in manual exposure mode. Set the lens to chosen aperture, and press and hold the DOF lever. In the viefinder you wil see the meter bar. Adjust shutter speed or aperture to centre the meter bar.

You should also see the lens stop down as you do this ( as long as you have not set wide open aperture). If this does not happen you have a problem with lens or camera.

What is the make/model of the manual lens ?
hmmm it still doesn't seem to be working. The lens is an XR Rikenon 50mm.

May I also add that when I look through the rear element of the lens when it is off the camera and rotate the aperture ring, I can't see the iris close.
09-26-2009, 10:07 PM   #6
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QuoteOriginally posted by columbus Quote
hmmm it still doesn't seem to be working. The lens is an XR Rikenon 50mm.

May I also add that when I look through the rear element of the lens when it is off the camera and rotate the aperture ring, I can't see the iris close.
That's normal. The aperture ring itself doesn't move the iris. There should be some sort of lever sticking out the back of the lens. Move that and you should be able to see the iris closing.
09-26-2009, 10:11 PM   #7
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QuoteOriginally posted by Mike Cash Quote
That's normal. The aperture ring itself doesn't move the iris. There should be some sort of lever sticking out the back of the lens. Move that and you should be able to see the iris closing.
Yea, it still does not move.
09-26-2009, 11:48 PM   #8
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QuoteOriginally posted by columbus Quote
Yea, it still does not move.
Was the aperture set on "2" when you tried it? If so, try it again at a smaller aperture.

Also, try this:

1. Put the lens on the digital body and set the aperture to something small, f16 perhaps.
2. Put the camera in "B" mode.
3. Turn the camera around so you're looking into the front of the lens.
4. Press the shutter and hold it down.

You should be able to see for yourself very clearly if it is closing down or not.

09-27-2009, 09:26 AM   #9
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In the Beginner's forum is a sticky thread explaining the use of manual lenses in detail. But it sounds like if the iris doesn't close when the lens is off the camera, then it's probably defective.
09-27-2009, 01:14 PM   #10
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Since none of these suggestions have worked, I assumed the lens is stuck wide open. I opened up the lens and it seems like the spring that pulls the blades to the highest f-stop is not pulling them, so it's stuck wide open. Any suggestions on how to fix this?
09-27-2009, 01:49 PM   #11
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QuoteOriginally posted by columbus Quote
Since none of these suggestions have worked, I assumed the lens is stuck wide open. I opened up the lens and it seems like the spring that pulls the blades to the highest f-stop is not pulling them, so it's stuck wide open. Any suggestions on how to fix this?
Or does anyone know of a disassembly chart of this lens? XR Rikenon 1:2 50mm L
09-27-2009, 02:00 PM   #12
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No direct useful help, but I'll explain why turning the aperture ring affects the metering on your film body but not on your digital body.

It is because the digital has a "crippled mount". If you look on the back of the lens while you turn the aperture ring you will notice a sprotruding piece of metal that moves as you move the ring. This tells the camera what the aperture setting is and that is how the camera knows how much to adjust the shutter speed for a proper exposure. The digital crippled mounts don't have anything that interacts with that part of the lens and has no way to know what aperture you have chosen.

If you shoot some photos with this broken lens on your film camera you should find that they all come back overexposed (except photos where you had the aperture set wide open).
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