Extension tube question

[Cashie]

I have a 12mm canon tube & was wondering if I got another one would it stack & make a 24mm? or is there any disadvantage's in doing this.

Would I be better to buy a 25mm one.

The reason I'm asking is because the 25mm is double the price.

Cheers

[jpwone]

Yes it will stack and yes it will give the equivalent of a 24mm tube.

[hollis_f]

For about the same price of the Canon 25mm tube you can get a whole set (12, 20 and 36mm) Kenko tubes. Work just as well as the Canon equivalents. Probably too late for Paul, but worth bearing in mind if anybody else is looking at buying for the first time.

[postcardcv]

For about the same price of the Canon 25mm tube you can get a whole set (12, 20 and 36mm) Kenko tubes. Work just as well as the Canon equivalents. Probably too late for Paul, but worth bearing in mind if anybody else is looking at buying for the first time.

I used to have a set of Kenko tubes and would disagree with this, while they worked fine with a number of my lenses (105 macro and 400 f5.6) they did give problems when used with IS lenses (100-400, 300 f4 and 500 f4). While the allowed the AF to work perfectly the IS went mad, it juddered alot. Needless to say when using with IS lenses I turned the IS off, but this was enough for me to sell them I'll be buying Canon tubes when funds allow. I had the same problem with both Kenko and Sigma 1.4x tcs on my 500 f4 but with the Canon tc it's never been an issue, I don't know what causes it but for me it's reason enough to stick with Canon gear.

[Cashie]

Thanks guys I will probably buy another 12mm tube to make the 24mm then. I dont think I will notice 1mm missing. :-O

[Jamie D]

why dont you buy the 25mm? This will give you options of 12mm, 25mm and 37mm if you combine the two

[Roy C]

I used to have a set of Kenko tubes and would disagree with this, while they worked fine with a number of my lenses (105 macro and 400 f5.6) they did give problems when used with IS lenses (100-400, 300 f4 and 500 f4). While the allowed the AF to work perfectly the IS went mad, it juddered alot. Needless to say when using with IS lenses I turned the IS off, but this was enough for me to sell them I'll be buying Canon tubes when funds allow. I had the same problem with both Kenko and Sigma 1.4x tcs on my 500 f4 but with the Canon tc it's never been an issue, I don't know what causes it but for me it's reason enough to stick with Canon gear.
That is interesting Peter, I have heard before that the Kenko pro 1.4tc can give problems with the 500/4 but never knew stacking tubes could upset the IS. That is good info for the future.

I regularly stack tubes (Jessops) with my 100 macro, 70-200/4 and 400/5.6 with no problems but all of these are none IS lenses.

[Jaff]

Just did a quick check with my 100-400mm with all the Kenko tubes attached and IS only acts funny when the AF is on as well. Turn the AF off and it behaves normally, in truth I find it's the AF that tends to suffer in that case (not surprising really). Better with just the two on.

Conversely I finally tried my dad's taped pins Kenko converter at the wkend and while the AF was pretty damned good actually on the centre focus point, even in what was average light, the IS was going mental and most definitely had to be turned off (my dad experienced the same problem on his 400D). I believe the model of camera has something to do the performance of things like this. I should really try it on my 20D as well to see how well they work together, that won't be possible for a while yet though.

Cheers all B (:

[postcardcv]

I had the problem with the IS when using stacked or single tubes, I've tested it on a number of cameras before finally ditching them - tested on 350D, 400D, 40D, 1D mkII and the problem occurred on all of them.

[Di Stone]

Ok, if this appears a silly question but could someone post a photo of how this set-up works. I'm guessing it is similar to digiscoping whereby the camera is attached to the adaptor then secured to the eye piece of the scope.

Sorry if this seems a daft request but I'm interested in viewing the combinations being used.

Di

[Roy C]

Ok, if this appears a silly question but could someone post a photo of how this set-up works. I'm guessing it is similar to digiscoping whereby the camera is attached to the adaptor then secured to the eye piece of the scope.

Sorry if this seems a daft request but I'm interested in viewing the combinations being used.

Di
Extension tubes are made to fit into the camera just like a lens, you then fit the lens to the tube. Exactly the same method as using teleconverters.