How to change Aperture?

[OK_to_Point]

Hi all, I'm thinking about some extension tubes for my Rebel XS. I've looked for the answer here but was unsuccessful. I have one question.....without the contacts how can you change the aperture. I know you manually focus...Any ideas?.....Thanks...

[inkista]

I have never tried this. But I've read that you put the lens on the camera, set the aperture, hold down the DOF preview button, and keep it pressed while you dismount the lens. Then put it on the extension tubes, and it should still be stopped down where you left it.

Either that, or live with the idea of shooting wide open all the time on the extension tubes.

[OK_to_Point]

I was just thinking about the same thing too. It occurred to me that maybe you set the aperture , then remove it and put the tubes on. So you think it retains the set aperture? I think it's best to know before I buy any tubes....Oh yeah, thanks for the quick reply......

[daft_biker]

Originally Posted by OK_to_Point

So you think it retains the set aperture? I think it's best to know before I buy any tubes....Oh yeah, thanks for the quick reply......

It works with all the Canon bodies and lenses I've used. The lenses stay stopped down until you put them back on a body without the DoF preview button pressed.

[OK_to_Point]

So, if the lens is at f/8 and I turn the camera off, put the extension tube on, put the lens back on, the lens will still be at f/8....is that correct? I really appreciate the help here.....

Originally Posted by daft_biker

It works with all the Canon bodies and lenses I've used. The lenses stay stopped down until you put them back on a body without the DoF preview button pressed.

[daft_biker]

Originally Posted by OK_to_Point

So, if the lens is at f/8 and I turn the camera off, put the extension tube on, put the lens back on, the lens will still be at f/8....is that correct? I really appreciate the help here.....

Close......You don't need to switch the camera off.

The steps I'd use are:
Set f/8 on camera
Press and hold DoF preview button
Remove lens
Release DoF preview button
Fit tubes to camera
Fit lens to tubes
Focus, set exposure and take pic

The iris in EF lenses appears to need a signal to tell it to stop down and another signal to tell it to open up again. The lens will stay stopped down until it gets that second signal to open up and it won't get that second signal on tubes with no electical connections.

Good luck and let us know how you get on

[OK_to_Point]

Thanks alot, daft_biker. I'll let you know how it works.....it may be a week or two till I get them....I really appreciate it.....

[Thunder_o_b]

Get the Kenko tubes, they retain all the functions of the camera and lens. I have been using them for the last 4 years on Canon film T2's and my 50D, they work just fine with the lenses that I have including the MP-E65.

kenko tubes

[Murtasma]

I'm thinking about buying a bellows or tubes and read up on the DoF trick. Has anyone heard or think that this could damage the lens or body? I wouldn't think so but I'm a little scared to try this with an expensive lens and body.

I would get the kenko tubes since they retrain the AF and Aperture selection but there are tubes and bellows out there that give you more magnification for a lot less money so I'm having a hard time making my mind up.

[Thunder_o_b]

Originally Posted by Murtasma

I would get the kenko tubes since they retrain the AF and Aperture selection but there are tubes and bellows out there that give you more magnification for a lot less money so I'm having a hard time making my mind up.

Extension tubes give magnification by increasing the distance between the lens and the film/sensor plain, allowing the lens to be closer to the subject. If the mm of the tubes is the same, they will give the same magnification regardless of whether they have AF and aperture function.

A proper bellows setup is expensive (bellows, rail, mounts, etc) and would cost about the same as the MP-E65, but not knowing what platform you use the 65 may not be an option for you. If you plan to do greater than 5:1 magnification shots and do not wish to get involved with mounting a microscope objective on your body, then bellows are the way to go, but you will still suffer significant light falloff,

I have been told that field work with a bellows setup while not impossible, is far more difficult than using the 65, and the 65 is a very challenging lens to get accustomed to.