Extension tube question?

joe.penn · 03-30-2012, 01:05 PM

Originally posted by littledrawe

I don't really want transform these and add contacts. I just don't want the camera to default to f2.5 on every shot.

Sand the base (or foil the contacts), shoot in "M" mode and be done with it, just as I noted in my first post, pretty simple fix - works fine, works fine for many other users, so I am not sure why it wouldn't work fine for you. If you are using your on camera flash and are having exposure issues, stop down the aperture if over-exposing or up your ISO if you are under-exposing.

**Lowell Goudge** · 03-30-2012, 03:59 PM

Originally posted by joe.penn

Sand the base (or foil the contacts), shoot in "M" mode and be done with it, just as I noted in my first post, pretty simple fix - works fine, works fine for many other users, so I am not sure why it wouldn't work fine for you. If you are using your on camera flash and are having exposure issues, stop down the aperture if over-exposing or up your ISO if you are under-exposing.

There is no need to sand the base it is a metal mount. To shoot and have the aperture stop down, yes, shoot in m mode and set the lens using the aperture ring

joe.penn · 03-30-2012, 04:21 PM

Originally posted by Lowell Goudge

There is no need to sand the base it is a metal mount

It's powder coated/anodized, it needs to be bare metal to short the contacts on the body or the foil needs to be used to short the contacts - without doing this the body thinks there is no lens attached and will not stop down the lens even in "M" mode...

Philoslothical · 03-30-2012, 05:04 PM

Originally posted by Lowell Goudge

There is no need to sand the base it is a metal mount.

It's very clear in the picture that it's a black anodized/painted mount on the tubes. Maybe you're looking at the top of them?

Twarp · 03-31-2012, 02:22 AM

Here are some pics of the same set but then by Asahi. There are some differences, the inner diameter of the Kenko set is smaller and the mount which contacts the body is not anodized on the Asahi.

With manual lenses on this Asahi set it works flawless when you use the green button in M-mode for metering with any setting of the aperture ring before hitting the exposure button. You can actually see it quickly stop down to the preset aperture when you press the green button.

Since I don't know what is the effect of the anodized mount I cannot tell if it should be polished to bare metal for this mechanism to work. But you can try...

(I don't see the pics in the preview so here's the link to the album: Twarp's Album: Gear - PentaxForums.com )

littledrawe · 03-31-2012, 06:10 PM

Originally posted by Philoslothical

It's very clear in the picture that it's a black anodized/painted mount on the tubes. Maybe you're looking at the top of them?

Yes the top is bare metal and the bottom is anodized, not sure what the advantage of that was but then again it was before the camera body had contacts so they didn't know is wasn't going to be convenient for me down the road.

Originally posted by joe.penn

Sand the base (or foil the contacts), shoot in "M" mode and be done with it, just as I noted in my first post, pretty simple fix - works fine, works fine for many other users, so I am not sure why it wouldn't work fine for you. If you are using your on camera flash and are having exposure issues, stop down the aperture if over-exposing or up your ISO if you are under-exposing.

I took some 320 grit to the base of the longest section of the tubes and it is seems like it did the trick. I will do the same to the other two sections so I can use them all. Thanks for the info!!

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
auto extension tube question	Classico	Pentax SLR Lens Discussion	16	01-20-2012 09:01 AM
Extension Tube Question	Barron	Troubleshooting and Beginner Help	5	06-22-2011 05:59 PM
m42 extension tube question	gokenin	Pentax SLR Lens Discussion	4	07-23-2010 01:54 PM
Extension Tube Question	eccs19	Pentax Camera and Field Accessories	3	01-29-2009 03:28 PM
Extension Tube Question	twilli53	Pentax SLR Lens Discussion	4	03-04-2007 07:22 AM

03-30-2012, 01:05 PM	#16
joe.penn Veteran Member Join Date: Mar 2011 Location: Maryland (Right Outside Washington DC) Photos: Gallery \| Albums Posts: 2,902	Originally posted by littledrawe I don't really want transform these and add contacts. I just don't want the camera to default to f2.5 on every shot. Sand the base (or foil the contacts), shoot in "M" mode and be done with it, just as I noted in my first post, pretty simple fix - works fine, works fine for many other users, so I am not sure why it wouldn't work fine for you. If you are using your on camera flash and are having exposure issues, stop down the aperture if over-exposing or up your ISO if you are under-exposing.

03-30-2012, 03:59 PM	#17
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,888	Originally posted by joe.penn Sand the base (or foil the contacts), shoot in "M" mode and be done with it, just as I noted in my first post, pretty simple fix - works fine, works fine for many other users, so I am not sure why it wouldn't work fine for you. If you are using your on camera flash and are having exposure issues, stop down the aperture if over-exposing or up your ISO if you are under-exposing. There is no need to sand the base it is a metal mount. To shoot and have the aperture stop down, yes, shoot in m mode and set the lens using the aperture ring

03-30-2012, 04:21 PM	#18
joe.penn Veteran Member Join Date: Mar 2011 Location: Maryland (Right Outside Washington DC) Photos: Gallery \| Albums Posts: 2,902	Originally posted by Lowell Goudge There is no need to sand the base it is a metal mount It's powder coated/anodized, it needs to be bare metal to short the contacts on the body or the foil needs to be used to short the contacts - without doing this the body thinks there is no lens attached and will not stop down the lens even in "M" mode...

03-30-2012, 05:04 PM	#19
Philoslothical Veteran Member Join Date: May 2011 Posts: 1,889	Originally posted by Lowell Goudge There is no need to sand the base it is a metal mount. It's very clear in the picture that it's a black anodized/painted mount on the tubes. Maybe you're looking at the top of them?

03-31-2012, 02:22 AM	#20
Twarp Forum Member Join Date: Jan 2012 Photos: Gallery \| Albums Posts: 77	Here are some pics of the same set but then by Asahi. There are some differences, the inner diameter of the Kenko set is smaller and the mount which contacts the body is not anodized on the Asahi. With manual lenses on this Asahi set it works flawless when you use the green button in M-mode for metering with any setting of the aperture ring before hitting the exposure button. You can actually see it quickly stop down to the preset aperture when you press the green button. Since I don't know what is the effect of the anodized mount I cannot tell if it should be polished to bare metal for this mechanism to work. But you can try... (I don't see the pics in the preview so here's the link to the album: Twarp's Album: Gear - PentaxForums.com )

03-31-2012, 06:10 PM	#21
littledrawe Veteran Member Join Date: Jan 2010 Location: Red Rock Photos: Gallery \| Albums Posts: 2,514 Original Poster	Originally posted by Philoslothical It's very clear in the picture that it's a black anodized/painted mount on the tubes. Maybe you're looking at the top of them? Yes the top is bare metal and the bottom is anodized, not sure what the advantage of that was but then again it was before the camera body had contacts so they didn't know is wasn't going to be convenient for me down the road. Originally posted by joe.penn Sand the base (or foil the contacts), shoot in "M" mode and be done with it, just as I noted in my first post, pretty simple fix - works fine, works fine for many other users, so I am not sure why it wouldn't work fine for you. If you are using your on camera flash and are having exposure issues, stop down the aperture if over-exposing or up your ISO if you are under-exposing. I took some 320 grit to the base of the longest section of the tubes and it is seems like it did the trick. I will do the same to the other two sections so I can use them all. Thanks for the info!!