Problem with M lens and green button

Docrwm · 06-23-2011, 08:48 AM

Just got an M200/f4 lens in from a seller on eBay who said it worked fine on his K-x. Glass is clean and clear. Aperture blades are snappy. However, when I mount it on my K-x, set everything to manual, and press the Green button for metering everything goes black and stays that way. It will take pictures in full manual mode, it's just that the metering will not work with this lens. I've got other M lenses and have never had this happen with any of them. Any ideas?

Last edited by Docrwm; 06-23-2011 at 08:57 AM.

kenafein · 06-23-2011, 08:58 AM

I don't know how to help you, but does it work if you set everything manual without using the green button?

Docrwm · 06-23-2011, 08:59 AM

Originally posted by kenafein

I don't know how to help you, but does it work if you set everything manual without using the green button?

Yes, and I'm getting some very sharp shots once I get the shutter/f/ISO set right.

Adam · 06-23-2011, 09:02 AM

If the aperture blades are snappy then there shouldn't be a problem. Try using the DOF preview button to meter instead, maybe that'll work

Adam
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kenafein · 06-23-2011, 09:06 AM

Originally posted by Adam

If the aperture blades are snappy then there shouldn't be a problem. Try using the DOF preview button to meter instead, maybe that'll work

I've tried using the DOF preview method on my K100D. It's no green button, I'm glad I can use AV mode with my super taks.

JeffJS · 06-23-2011, 09:13 AM

There's a way to use M lenses in Av as well.

Set the lens to its smallest aperture.
Put the lens on the camera.
Press the lens release button and turn the lens until you see the aperture close all the way.
Set your camera to Av and enjoy.

Just remember that the lens is no longer 'locked' on and be careful not to twist it off. The lens mount is tight enough that it shouldn't happen but of course it could.

Docrwm · 06-23-2011, 09:48 AM

Originally posted by Adam

If the aperture blades are snappy then there shouldn't be a problem. Try using the DOF preview button to meter instead, maybe that'll work

Tried this and got a nice image to preview. Thanks. Problem is that the lens is now making the mirror lock up and then stutter. Bad, very bad. I think I have figured out why though. Look at this picture. The piece behind the aperture control is broken off!

Last edited by Docrwm; 05-06-2013 at 08:11 PM.

kenafein · 06-23-2011, 10:14 AM

I hope the guy accepts returns

Docrwm · 06-23-2011, 10:46 AM

Originally posted by kenafein

I hope the guy accepts returns

Apparently not......

Technically his description is accurate. The glass is clear, focus is smooth, and aperture is snappy. Of course there is the minor issue of it having been dropped on its mount and snapped off a piece that prevents it from working properly with a K-x......

kenafein · 06-23-2011, 10:56 AM

Then negative feedback is appropriate. Sorry about your lens.

kenafein · 06-23-2011, 11:16 AM

Originally posted by JeffJS

There's a way to use M lenses in Av as well.

Set the lens to its smallest aperture.
Put the lens on the camera.
Press the lens release button and turn the lens until you see the aperture close all the way.
Set your camera to Av and enjoy.

Just remember that the lens is no longer 'locked' on and be careful not to twist it off. The lens mount is tight enough that it shouldn't happen but of course it could.

My only M series, the 28/2.8, the aperature ring is pretty stiff, it would totally come off. Very interesting tip though! If I come across any other M lenses I will try it.

bobpur · 06-23-2011, 11:20 AM - **2 Likes**

Hi

Don't worry about the plastic piece as it has no part in any aperture use.
Looking at the small arm you can see that there is a scratch mark, that is from the camera control arm. Probably what is wrong is that the lens arm is slightly bent so that it does not engage the camera. just bend it a little towards the outside and it should work fine.
Another option is to completely remove the plastic sticking up and bending the arm towards the inside, that way the lens will work as the Taks. in Av mode.

Docrwm · 06-23-2011, 11:34 AM

Originally posted by bobpur

Hi

Don't worry about the plastic piece as it has no part in any aperture use.
Looking at the small arm you can see that there is a scratch mark, that is from the camera control arm. Probably what is wrong is that the lens arm is slightly bent so that it does not engage the camera. just bend it a little towards the outside and it should work fine.
Another option is to completely remove the plastic sticking up and bending the arm towards the inside, that way the lens will work as the Taks. in Av mode.

Thanks for the thoughts. The part that is snapped appears to be metal - is it actually plastic? I do see what you mean about the aperture arm/pin being bent in toward the center of the lens. I'll try to gently bend it so it is more perpendicular to the plane of the mount and see if that resolves this issue.

Docrwm · 06-23-2011, 12:54 PM

Originally posted by bobpur

Hi

Don't worry about the plastic piece as it has no part in any aperture use.
Looking at the small arm you can see that there is a scratch mark, that is from the camera control arm. Probably what is wrong is that the lens arm is slightly bent so that it does not engage the camera. just bend it a little towards the outside and it should work fine......

Absolutely did the trick!

I can use LV and the Green button now with the lens. Thank you very much. I thought the lens was a write-off - glad its not because it seems VERY sharp.

kenafein · 06-23-2011, 01:10 PM

Originally posted by bobpur

Hi

Don't worry about the plastic piece as it has no part in any aperture use.
Looking at the small arm you can see that there is a scratch mark, that is from the camera control arm. Probably what is wrong is that the lens arm is slightly bent so that it does not engage the camera. just bend it a little towards the outside and it should work fine.
Another option is to completely remove the plastic sticking up and bending the arm towards the inside, that way the lens will work as the Taks. in Av mode.

Awesome advice bobpur +1! I will remember this.

06-23-2011, 08:48 AM	#1
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285	Problem with M lens and green button Just got an M200/f4 lens in from a seller on eBay who said it worked fine on his K-x. Glass is clean and clear. Aperture blades are snappy. However, when I mount it on my K-x, set everything to manual, and press the Green button for metering everything goes black and stays that way. It will take pictures in full manual mode, it's just that the metering will not work with this lens. I've got other M lenses and have never had this happen with any of them. Any ideas? Last edited by Docrwm; 06-23-2011 at 08:57 AM.

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06-23-2011, 08:58 AM	#2
kenafein Veteran Member Join Date: May 2011 Location: Southern California Photos: Albums Posts: 4,082	I don't know how to help you, but does it work if you set everything manual without using the green button?

06-23-2011, 08:59 AM	#3
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285 Original Poster	Originally posted by kenafein I don't know how to help you, but does it work if you set everything manual without using the green button? Yes, and I'm getting some very sharp shots once I get the shutter/f/ISO set right.

06-23-2011, 09:02 AM	#4
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	If the aperture blades are snappy then there shouldn't be a problem. Try using the DOF preview button to meter instead, maybe that'll work Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

06-23-2011, 09:06 AM	#5
kenafein Veteran Member Join Date: May 2011 Location: Southern California Photos: Albums Posts: 4,082	Originally posted by Adam If the aperture blades are snappy then there shouldn't be a problem. Try using the DOF preview button to meter instead, maybe that'll work I've tried using the DOF preview method on my K100D. It's no green button, I'm glad I can use AV mode with my super taks.

06-23-2011, 09:13 AM	#6
JeffJS Inactive Account Join Date: Aug 2008 Location: Michigan, USA Photos: Gallery \| Albums Posts: 7,484	There's a way to use M lenses in Av as well. Set the lens to its smallest aperture. Put the lens on the camera. Press the lens release button and turn the lens until you see the aperture close all the way. Set your camera to Av and enjoy. Just remember that the lens is no longer 'locked' on and be careful not to twist it off. The lens mount is tight enough that it shouldn't happen but of course it could.

06-23-2011, 09:48 AM	#7
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285 Original Poster	Originally posted by Adam If the aperture blades are snappy then there shouldn't be a problem. Try using the DOF preview button to meter instead, maybe that'll work Tried this and got a nice image to preview. Thanks. Problem is that the lens is now making the mirror lock up and then stutter. Bad, very bad. I think I have figured out why though. Look at this picture. The piece behind the aperture control is broken off! Last edited by Docrwm; 05-06-2013 at 08:11 PM.

06-23-2011, 10:14 AM	#8
kenafein Veteran Member Join Date: May 2011 Location: Southern California Photos: Albums Posts: 4,082	I hope the guy accepts returns

06-23-2011, 10:46 AM	#9
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285 Original Poster	Originally posted by kenafein I hope the guy accepts returns Apparently not...... Technically his description is accurate. The glass is clear, focus is smooth, and aperture is snappy. Of course there is the minor issue of it having been dropped on its mount and snapped off a piece that prevents it from working properly with a K-x......

06-23-2011, 10:56 AM	#10
kenafein Veteran Member Join Date: May 2011 Location: Southern California Photos: Albums Posts: 4,082	Then negative feedback is appropriate. Sorry about your lens.

06-23-2011, 11:16 AM	#11
kenafein Veteran Member Join Date: May 2011 Location: Southern California Photos: Albums Posts: 4,082	Originally posted by JeffJS There's a way to use M lenses in Av as well. Set the lens to its smallest aperture. Put the lens on the camera. Press the lens release button and turn the lens until you see the aperture close all the way. Set your camera to Av and enjoy. Just remember that the lens is no longer 'locked' on and be careful not to twist it off. The lens mount is tight enough that it shouldn't happen but of course it could. My only M series, the 28/2.8, the aperature ring is pretty stiff, it would totally come off. Very interesting tip though! If I come across any other M lenses I will try it.

06-23-2011, 11:20 AM - 2 Likes	#12
bobpur Inactive Account Join Date: Jul 2010 Photos: Gallery Posts: 328	Hi Don't worry about the plastic piece as it has no part in any aperture use. Looking at the small arm you can see that there is a scratch mark, that is from the camera control arm. Probably what is wrong is that the lens arm is slightly bent so that it does not engage the camera. just bend it a little towards the outside and it should work fine. Another option is to completely remove the plastic sticking up and bending the arm towards the inside, that way the lens will work as the Taks. in Av mode.

06-23-2011, 11:34 AM	#13
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285 Original Poster	Originally posted by bobpur Hi Don't worry about the plastic piece as it has no part in any aperture use. Looking at the small arm you can see that there is a scratch mark, that is from the camera control arm. Probably what is wrong is that the lens arm is slightly bent so that it does not engage the camera. just bend it a little towards the outside and it should work fine. Another option is to completely remove the plastic sticking up and bending the arm towards the inside, that way the lens will work as the Taks. in Av mode. Thanks for the thoughts. The part that is snapped appears to be metal - is it actually plastic? I do see what you mean about the aperture arm/pin being bent in toward the center of the lens. I'll try to gently bend it so it is more perpendicular to the plane of the mount and see if that resolves this issue.

06-23-2011, 12:54 PM	#14
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285 Original Poster	Originally posted by bobpur Hi Don't worry about the plastic piece as it has no part in any aperture use. Looking at the small arm you can see that there is a scratch mark, that is from the camera control arm. Probably what is wrong is that the lens arm is slightly bent so that it does not engage the camera. just bend it a little towards the outside and it should work fine...... Absolutely did the trick! I can use LV and the Green button now with the lens. Thank you very much. I thought the lens was a write-off - glad its not because it seems VERY sharp.

06-23-2011, 01:10 PM	#15
kenafein Veteran Member Join Date: May 2011 Location: Southern California Photos: Albums Posts: 4,082	Originally posted by bobpur Hi Don't worry about the plastic piece as it has no part in any aperture use. Looking at the small arm you can see that there is a scratch mark, that is from the camera control arm. Probably what is wrong is that the lens arm is slightly bent so that it does not engage the camera. just bend it a little towards the outside and it should work fine. Another option is to completely remove the plastic sticking up and bending the arm towards the inside, that way the lens will work as the Taks. in Av mode. Awesome advice bobpur +1! I will remember this.