How well does the canon 100L work with theCanon Extension Tube EF 25 II?

Does auto focus still work and how much light is lost? How much closer does that get you?

Hi Butterfly, the AF should still work. I have a set of Kenkos and with them attached I get full AF via my 100L.

Have a look at the image here, you can see the electronic connection points.
http://ecx.images-amazon.com …unVZ5nL._SL500_​AA300_.jpg


As for how close it gets you, I'm not sure of the equation to work it out however it'll be a little closer and you'll lose very little light really. If you're using a flash you'll be fine. If you're using natural light, you'll get a little bit of drop off I guess.

I recently shot some bugs using 3 extension tubes and a 50mm lens reversed on the front. I used flash so was able to get enough light down to the subject.

IanClark wrote in post #15773271
Hi Butterfly, the AF should still work. I have a set of Kenkos and with them attached I get full AF via my 100L.

Have a look at the image here, you can see the electronic connection points.
http://ecx.images-amazon.com …unVZ5nL._SL500_​AA300_.jpg


As for how close it gets you, I'm not sure of the equation to work it out however it'll be a little closer and you'll lose very little light really. If you're using a flash you'll be fine. If you're using natural light, you'll get a little bit of drop off I guess.

I recently shot some bugs using 3 extension tubes and a 50mm lens reversed on the front. I used flash so was able to get enough light down to the subject.

Thank you for the feedback. I was just wondering how much closer I will get for the price. Is it a few inches? Do you still get AF when you stack them or are you completely using MF with no help from AF?

You'll get around 1.36:1 with a 25mm tube and 1.72:1 with 2 of them. You mainly want auto aperture to work when shooting above 1:1. AF becomes increasingly useless as the DOF start getting rather thin and the camera does not know what you actually want in focus. Most macro shooters therefore use MF when shooting above 1:1
Brian V.

LordV wrote in post #15774512
You'll get around 1.36:1 with a 25mm tube and 1.72:1 with 2 of them. You mainly want auto aperture to work when shooting above 1:1. AF becomes increasingly useless as the DOF start getting rather thin and the camera does not know what you actually want in focus. Most macro shooters therefore use MF when shooting above 1:1
Brian V.

Thank you for the information. I was just hoping auto focus would get me close to where I want to be and then I could just fine tune it.

You'll find most people using focus stacking beyond 1:1 as well. Multiple shots taken through the focal planes of your subject then the images staked in a specific stacking program or by hand in Photoshop or similar. That way you can take in focus shots at various points of your subject.

IanClark wrote in post #15774915
You'll find most people using focus stacking beyond 1:1 as well. Multiple shots taken through the focal planes of your subject then the images staked in a specific stacking program or by hand in Photoshop or similar. That way you can take in focus shots at various points of your subject.

Yes I use that technique too. I imagine it is even more important the closer you are to the subject. Is anyone using a special focusing screen or just live view?

Live view as in the LCD Screen? Must admit, I never use the screen for any shot. Always in the viewfinder

butterfly2937 wrote in post #15775019
Yes I use that technique too. I imagine it is even more important the closer you are to the subject. Is anyone using a special focusing screen or just live view?

I meant something like this:
It looks like it might be helpful.
http://www.bhphotovide​o.com …EC_H_Focusing_S​creen.html

For myself, I've never used any other kind of focusing screen other than the one the camera comes with. Can't speak for anyone else in the Macro forum though. . Be interesting to read other peoples take on it.