Kinky extension tubes... are they any good?

[DocFrankenstein]

I am thinking about trying something new. These tubes go for 130 bucks.

What's the magnification and what are the best lens to use with these tubes?

[robertwgross]

I think that would be Kenko extension tubes.

The effect you get is that you can focus up much closer than with the bare lens, but the amount of the effect depends on the focal length of the lens.

I use a single 12mm tube, and that works fine.

As you get into a deeper extension, it still work fine, but the focus system gets a little squirrelly. The depth of field gets thin, and the whole autofocus mechanism can get unpredictable on some lenses.

However, until an alternative comes along, it works for me.

---Bob Gross---

[Scottes]

They'll rock on your Sigma for macro. You'll easily get 1:1, and since the lens is 2.8 you shouldn't have any problems with AF.

If they look interesting, get them. I love my tubes. I use them all the time.

[MT]

almost afraid to read this thread.

[robertwgross]

I'll bet they don't do kinky in Missouri.

---Bob Gross---
(speaking as a native son)

[MrKickalot]

THEY ROCK!!! There isn't a better $130.00 I have spent yet!! Take all the lenses in your bag and now you have a new use for all of them (except the EF-S ones). Two things though.... 1)forget autofocus... it works but not real well.. Most of the things you shoot Macro on move too fast for the camera to find them... manual focus is much better... and 2)the DOF is pretty thin but still very manageable!! Here is one I took over the weekend... keep in mind that I had the junky 75-300 4.5-5.6 hanging on the end of all 68MM of tubes!!

http://www.fotop.net/allmanphoto/Insects/CRW_5940

All of these are with either my Canon 75-300 4.5-5.6 or my nifty fifty (which is on it's way back to Canon....Focus mech broke... boohoo)

http://www.fotop.net/allmanphoto/Macro

I can't wait to get the money together to get a 70-200L f4.0 to use with it..

[DocFrankenstein]

Nice. What would be the aperture on them if I add a 68mm of extention tubes on my 70-200 2.8 ?

Would I need to use flash to get decent shutter times?

[Spargo]

--NOOB QUESTIONS--
1. Why would I need an extension tube?
2. Would they work with the 18-55 kit lens?
3. Don't they just make it so you can focus closer up?

[robertwgross]

--NOOB QUESTIONS--
1. Why would I need an extension tube?


With a normal lens, you can focus much closer with one than without one. In effect (on the image), this makes a normal lens work to higher magnification.

--NOOB QUESTIONS--
2. Would they work with the 18-55 kit lens?


Not necessarily. I expect that there might be a special one that could accommodate the EF-S lens, but I wouldn't bet on it either.

--NOOB QUESTIONS--
3. Don't they just make it so you can focus closer up?

OK. That works for me.

---Bob Gross---

[DocFrankenstein]

1. Why would I need an extension tube?
If you want to take a picture of a bee so that it takes up the whole frame, you're gonna need either macro lens or a lens with extension tubes.

2. Would they work with the 18-55 kit lens?
MrKickalot says they can't. I beleive him, but also wondering why.

3. Don't they just make it so you can focus closer up?
Yeah, but that's the whole point.

[Spargo]

They would work with the 70-200 f/4L though right? Could they be combined with the 1.4x T-con?

[DocFrankenstein]

I beleive they will. You'll lose autofocus for sure though :?

[Spargo]

Hmm...Guess I'll add it to my wish list. Someday, but first a telephoto and bag. :)

[MT]

no comment

[Scottes]

Not only do tubes allow you to focus closer but they effectively change the lens length and give a magnification just by being on the lens. I took 4 shots with my 100-400 @ 400, no tube, with 12mm. with 20mm, with 36mm tube. I kept the same distance from the subject for every shot.

The 12mm showed a 10% magnification up to 27% with the 36mm.


Also, just having a tube on does NOT mean that you will lose AF "for sure"
My 100-400 is f/5.6 at 400mm, and I can still AF with the 36mm. In bright light I have no issues whatsoever, but as light gets dimmer the lens will have a tendency to hunt a bit before locking on.

[billsh]

Another great benefit of tubes is since they don't have any glass in them, no degredation of the image, which can occur with TC's .

[MrKickalot]

They won't work with the EF-S lenses because they have more lens that is in past the mount on the camera side then regular lenses. They hit something before they reach the mount.

Autofocus does work... just spends more time then I like searching for focus than I like. I like to shoot most of my pictures f11 or higher for get a little longer DOF. They do limit the amount of light to get to the sensor. For instance... I had to drop the spider picture
( http://www.fotop.net/allmanphoto/Insects/CRW_5940 ) to f8.0 to get shutter speeds up to about 1/100th. There was enough light but the tubes restrict it some. Only time I find this to be a problem is if it is breezy out. The bee pictures were in the sun so there was no problem, 1/250th f11.0.

Something I found really amazing about the extension tubes is when you stack them with short lenses. I shot this picture just messing around(shot through slightly foggy glass).

http://www.fotop.net/allmanphoto/Insects/IMG_5493

That is 68mm of extension tubes on my 50mm f1.8. You will notice there is almost no DOF on the mosquito. I had the filter against one side of the sliding glass door at my house and the mosquito was on the other side of the glass. Can you say minimum focus less than 1/2 inch? Just another neat thing to try!

Overall if you like macro then these are nice!! The kit of 3 is just a little more than one Canon tube. They are very versatile because you can stack them to make different combinations.

If you get them we will expect to see pictures!!

Have fun!