Help - Lens will not focus with extension tubes.

[jwbryson1]

I own the Tokina 100mm f/2.8 macro lens. I got a set of Kenko extension tubes for Christmas thinking that when combined with my Tokina lens I could get that much closer to the subject.

However, when I connect the extension tubes (all 3 of them--total 68mm) to the camera and attach my lens to the setup, they will not focus at all. Not in autofocus and not in manual focus.

Am I using them wrong? If I cannot focus close with this set up, can't I focus on objects in the far distance? I have tried both both and there is zero focus. Total blur.

Thoughts? Suggestions?

Thanks.

 

[jriepe]

I've never used extension tubes and probably never will unless I'm wrong in believing they will definitely not allow you to focus to infinity. When I'm out in the field with my macro setup shooting insects and spiders I don't know if I'm going to be inches or feet or yards away from my different subjects therefore if the extension tubes have a very narrow range of focus I would be SOL for many shots. As far as you not being able to focus close up I don't have an answer for that. Have you tried it without the whole set just using one or two?

Jerry

 

[cgipson1]

You are extending the lens out beyond it ability to focus... use one, maybe two tubes.. but three won't work on that lens (or most lenses, for that matter)!

maybe this will help

http://www.dummies.com/how-to/content/how-extension-tubes-work-for-magnification.html

The combination of lense and tubes have to be able to work together to manipulate the focal point onto the sensor. With three tubes, your lens lacks enough adjustment to do this. Most lenses dont have this kind of extreme adjustment available.

 

[Destin]

Also... Extension tubes aren't made to give your lens more reach. Youd need a teleconverter to do that.

Extension tubes will not allow you to focus on far away objects. They are used to allow to to focus on objects CLOSER to the lens than you normally would for the purpose of macro photography.

It sounds like you're trying to use them as a teleconverter, but it just doesn't work that way.

 

[SCraig]

Also... Extension tubes aren't made to give your lens more reach. Youd need a teleconverter to do that.

Extension tubes will not allow you to focus on far away objects. They are used to allow to to focus on objects CLOSER to the lens than you normally would for the purpose of macro photography.

It sounds like you're trying to use them as a teleconverter, but it just doesn't work that way.

I agree with what you say but at one time there was a device that would do both. I have an old Soligor 2X TC in which the optics are removable leaving a 25mm (or so, I never measured it) extension tube. Unfortunately it's for an Olympus OM mount.

 

[jwbryson1]

Also... Extension tubes aren't made to give your lens more reach. Youd need a teleconverter to do that.

Extension tubes will not allow you to focus on far away objects. They are used to allow to to focus on objects CLOSER to the lens than you normally would for the purpose of macro photography.

It sounds like you're trying to use them as a teleconverter, but it just doesn't work that way.

Destin, thanks. I think you nailed it. I incorrectly thought that because that lens can be used as a portrait lens in addition to macro work that by adding the extension tubes I would be able to take portrait shots from that much further away. That's wrong. When I realized that you cannot focus to infinity with them, I tried them that much CLOSER to the subject and it worked. I had it all backwards in my mind.

 

[Destin]

Destin, thanks. I think you nailed it. I incorrectly thought that because that lens can be used as a portrait lens in addition to macro work that by adding the extension tubes I would be able to take portrait shots from that much further away. That's wrong. When I realized that you cannot focus to infinity with them, I tried them that much CLOSER to the subject and it worked. I had it all backwards in my mind.

Gotcha. Glad I was able to help.