Extension Tubes (Canon EOS, Nikon, d70, lenses)

[Alpha8207]

Hey gang, long time no post over here in Photography!

A question:

I've got a Rebel XT and want a good set of Extension Tubes.

I prefer to buy from B&H or some other reputable, well known site.

Is there anything in particular I should know and could anyone recommend or help me find the 'right' choice?

Thanks guys.

You guys are the best over here.

[kdog]

Here you go: Kenko | Auto Extension Tube Set DG for Canon EOS | AEXTUBEDGC

Your only other real choice is to buy Canon extension tubes, but they're more expensive. I generally stay away from 3rd party accessories, but seeing as how there are no optics in extension tubes, I think the Kenkos are fine.

[RayinAK]

Kenko tubes are of excellent quality. I have a set of them, and paid around $170.00 for the set at B&H.

[Rance]

What do extension tubes do?

[Alpha8207]

Originally Posted by Rance

What do extension tubes do?

I can only answer to my limited understanding but basically they shorten your focal length.

For example, I've got a 300mm zoom that I have to be at least 6 feet from my subject to be able to focus. The extension tube goes between the lens and the camera body moving the lens away from the body....so I can get closer to a subject and focus.

In short, the tubes help turn any lens into a macro lens.

Thanks for all the good advice folks!

I'm going to order shortly and will try and post some of my first pics!

[kdog]

Originally Posted by Alpha8207

I can only answer to my limited understanding but basically they shorten your focal length.

Actually they lengthen your focal length. What you probably meant to say is that they shorten your minimum focus distance. Focal length determines your magnification, and that is actually increased with extension tubes.

BTW, there is a downside to using extension tubes; they affect the lenses ability to focus at infinity. So you wouldn't want to keep one on your lens all the time.

[Rance]

So they increase the amount of zoom or magnification? As well as give you a shorter minimum focus distance?

[Alpha8207]

Originally Posted by kdog

Actually they lengthen your focal length. What you probably meant to say is that they shorten your minimum focus distance. Focal length determines your magnification, and that is actually increased with extension tubes.

BTW, there is a downside to using extension tubes; they affect the lenses ability to focus at infinity. So you wouldn't want to keep one on your lens all the time.

Yep, that's what I meant to say. Don't forget, kdog, I don't know what I am talking about!

Originally Posted by Rance

So they increase the amount of zoom or magnification? As well as give you a shorter minimum focus distance?

No they don't change the magnification, they just reduce the amount of distance you need between the lens and your object of focus.

[kdog]

Originally Posted by Alpha8207

No they don't change the magnification, they just reduce the amount of distance you need between the lens and your object of focus.

Yes they certainly do increase magnification, which is synonymous with increasing focal length.

Here's a link to an article explaining the math if you're interested. How Extension Tubes Affect Magnification

[Alpha8207]

Originally Posted by kdog

Yes they certainly do increase magnification, which is synonymous with increasing focal length.

Here's a link to an article explaining the math if you're interested. How Extension Tubes Affect Magnification

So my 300mm lens will actually be greater than 300mm?

I didn't know that....I thought that was what teleconverters did.

But again, I know not of what I speak!