Tube question

[MDJAK]

Can someone please explain what a tube is, what lens or lenses it fits on, and exactly what they do? Thanks you.

[DocFrankenstein]

Are you talking about extension tubes?

[CyberDyneSystems]

There hollow tubes,.. the good ones pass the electronic signals through to the camera from the lens so AF still works...

They are simply spacers,. what they do is by moving the lens further from the film plane (CMOS) the focus point shifts and minimum focus distance is decreased,. a lot. At the sacrifice of infinity focus,..

This means that you can move much closer to your subject than would previously have been possible without the tube,. or ring,. and thus increase total magnification. You can use tubes to turn any lens into a close focusing Macro,.. with certain lenses the results are AWESOME! (70-200mmL zooms for example)

It's very affordable way to tunr your lens collection into a nice new set of Macros...

The donwside is that your entire focus range is moved closer,. not just the close end,. so for example,. your infinity focus could end up being as close as 25 feet away,. and anything beyond that completely and totally out of focus range.

[sagebrush]

Any samples of a pic taken using the 70-200L with tubs? Can it achive 1:1 ?

[mbze430]

you would need a few tubes to equal the zoom range of the 200 on the 70-200L to get 1:1. Your best bet, 180mm f/3.5L

[Anders Östberg]

Any samples of a pic taken using the 70-200L with tubs? Can it achive 1:1 ?

Here's a few samples using the 70-200/2.8IS with Kenko extension tubes.
Sorry about the colors, this is from a period when I was maybe a bit heavy-handed on the controls. :)

http://www.andersostberg.com/fotogalleri/albums/userpics/10001/Bug_6003.jpg

http://www.andersostberg.com/fotogalleri/albums/userpics/10001/Bug_5990.jpg

http://www.andersostberg.com/fotogalleri/albums/userpics/10001/Humla_6012.jpg

[sagebrush]

Thanks for sharing your pics. The DOF on the bug shots is more than I expected.

That aughta work nicely.

Sagebrush

[Anders Östberg]

I used f/22 for these pictures, which probably hurts the image quality but it's a tradeoff to get more DOF.

[MDJAK]

Can you tell me how far away you were from the insects in those pictures and whether those are handheld, with or without flash, and exactly what tube you used? Those are great.

[DocFrankenstein]

These are some shots with sigma 70-200 f/2.8 EX and full set of kenko tubes: 12+20+36

http://andrew4137.fotopic.net/p12807897.html

I didn't focus exactly on the pen though:
http://andrew4137.fotopic.net/p12721812.html

http://andrew4137.fotopic.net/c456954.html

It gives you 1:1, but the working distance (from lens to object is about 3 inches)

It will give you 1:2 with working distance of 1.5-2 feet.

Fun stuff

[Anders Östberg]

I can't really remember what tubes I used, anything from the largest in the Kenko set to all three. Distance to the insects probably half a meter or less. Light was mainly quite strong sunlight but I did also use a flash on camera. I used a monopod to help stabilize the lens.

Sorry to be so vague, this was last summer and my memory is going in my old age. :)

[MDJAK]

Your memory is going? Heck, I forgot what I asked you already.:) thanks.

mark

[jbradc]

Any samples of a pic taken using the 70-200L with tubs? Can it achive 1:1 ?
Here is link to a photo taken with my 70-200 F4 L and 25mm extension tube.
http://shp.smugmug.com/gallery/228226/1/8848254/Large
In order to acheive 1:1 you need the amount of extension to equal the length of the lens. Example - to get 1:1 with a 50mm lens you need 50mm of extension.

[MDJAK]

You guys have sure taught me a lot in the short time I've been here.


Let me see if I can continue along these lines and answer my own question that I'm still pondering regarding tubes. (By the way, I'm in awe of all the above posted pics.) Here's the question and my answer: Why would one buy tubes when one can get a "real" macro lens such as the 100mm that I own but have yet to successfully use as I don't have a tripod?

Answer: It is a less expensive route and turns an already existing lens into a macro.

Am I right?

[robertwgross]

Am I right?

Yes, but there are other answers.

If you buy a dedicated macro lens, it works good, but do you want to buy different macro lenses for different focal lengths?

With an extension tube, you can apply it to virtually any EF lens. Granted, there is only a range of focal lengths where it would make good sense.

The extension tube simply takes a good lens and shortens the minimum focus distance where it can be used. The trade-off is that the infinity focus is lost.

---Bob Gross---

[DocFrankenstein]

Answer: It is a less expensive route and turns an already existing lens into a macro.

Am I right?
Pretty much yeah.

In my case, a 100mm macro is not needed. I have 70-200 which is just as fast and I know I won't be doing a whole lot of bug chasing to really need autofocus.

And jewelry doesn't mind me focusing manually. :)

[MDJAK]

Without rereading all the above posts, do I take it that a tube removes the camera's autofocusing ability?

[jbradc]

No, autofocus can still be used when using Canon tubes. I am not sure about 3rd party tubes.

[wolf]

Auto focus works with Kenko tubes and are way cheaper than Canon tubes. They are good quality built tubes also.

[RJSorensen]

Everything works with the Canon tubes . . . the II version even supports EFS lens. They work quite nicely. I have a 25mm and a 12mm Canon II versions. They do cost some more but you know they will work with every thing.

[CyberDyneSystems]

I've been using the $100.00 three tube set from Kenko,. they allow foull aouto focus.

Another reason for tubes is to use them WITH a Macro lens if you have one.

With Tubes,. I can get my 100mm Macro into insane magnification.. waaay beyond 1:1 if I wanted.