Beginner Weird extension tube problem.

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Ben
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So I noticed AF didn't work with all three tubes added the other day, so I figured one of them must be the problem.
Tried each individually, and they all work. All combinations of 2 work together, but as soon as all three are together it doesn't work. Any ideas?
 
What was the camera reporting as the max available aperture with the 3x extension tubes stacked?
 
Or, is there enough light getting thru for your AF to work with all 3 tubes attached. Must try my tubes sometime.
 
What was the camera reporting as the max available aperture with the 3x extension tubes stacked?
Not sure where to check that. I can set it wide open.
Or, is there enough light getting thru for your AF to work with all 3 tubes attached. Must try my tubes sometime.
The AF tries to work, but it sounds like it's jammed.
 
Not sure where to check that. I can set it wide open.

The AF tries to work, but it sounds like it's jammed.

If you can set it wide open then you're using the max available aperture. This may be down to the amount of light loss with all 3 tubes attached. When you say "jammed", what do you mean - is it hunting for focus?
 
If you can set it wide open then you're using the max available aperture. This may be down to the amount of light loss with all 3 tubes attached. When you say "jammed", what do you mean - is it hunting for focus?
It won't move, let alone hunt. Like it's trying to but gets caught on something.
Have you tried it with a faster lens?
I will try it with the 50 1.8 when I finish work.
 
Every focal length? VR on or off?
 
So max aperture of f4-5.6 without tubes dependant on focal length. I would think that light loss due to stacked tubes may well cause a lot of AF hunting with that lens, but wouldn't expect it to act like it's jammed/caught on something. Not sure your 50/1.8 will be a good candidate with all 3 tubes assuming they are a standard 12/20/36mm set as the total focal length of the tubes will exceed that of the lens which may cause issues. I tend to use no more than 2 tubes out of a Kenko AF set (12/20/36mm) with an 85/1.8
 
So I noticed AF didn't work with all three tubes added the other day, so I figured one of them must be the problem.
Tried each individually, and they all work. All combinations of 2 work together, but as soon as all three are together it doesn't work. Any ideas?
What camera and lens combo is this?
Panasonic cameras only work with 2 tubes for some reason and so many m4/3 tubes often only come in pairs.
Olympus's own 4/3 rather hitech (they have focus circuits for certain lenses) tubes only work as singles.
Simple tubes work OK though.
 
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aren't you using a bridge camera? (So no extension tubes?)

I use autofocus with close-up lenses on bridge cameras and on telezoom lenses on micro four thirds cameras and a dSLR. I use autofocus with an Olympus 60mm macro on micro four thirds (without extension tubes or close-up lenses).

I just tried various combinations of kit with extension tubes, hand-held, using a variety of subjects. with scene sizes of around an inch and a half to half an inch across (around 1:1.5 to 2:1 in APS-C terms). Working distances were very short compared to what I am used to, as little as a centimetre, perhaps less, for some of the test shots (In fact with the zoom lenses the working distance went to zero as focal length reduced (giving a nice picture of the dust on the front of the lens) and then negative (focusing inside the lens). Only a small range of focal lengths with the zoom lenses gave positive working distances.

Although a bit slower at times than with my usual setups, autofocus seemed usable to me with the following combinations, using live view (which is what I normally use).

Canon 70D (APS-C) with 18-55 and 36mm extension tubes
70D with 18-55, 68mm extension tubes
Panasonic G3 (Micro four thirds) with 12-60, 26mm extension tubes
G3 with 14-42, 26mm extension tubes
G3 with 45-200 , 26mm extension tubes
G3 with 60mm macro, 26mm extension tubes

There are some examples from the 70D test shots in this album at Flickr, all except the first using the 18-55, some with 36mm extension tubes and some with 68mm extenstion tubes. The first was with the Sigma 105 with 68mm extension tubes.

Phase detect autofocus (i.e. using the optical viewfinder) hardly worked at all with the 70D, so much so that it seemed totally unusable to me.
Because of extensive hunting the Sigma 105 macro on the 70D with 68mm extension tubes seemed unusable to me with live view as well as with the optical viewfinder. (I get a lot of hunting with it even without extension tubes, which is one of the reasons I don't use it other than for testing/comparison purposes like this.)
 
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