Kenko Auto Extension Tube Set DG (12, 20 & 36mm Tubes) for Canon

[britinozz]

i was wandering can i use these on my canon 50d 100mm 2.8 macro lens for added macro also would i need to or would it be a waste of money.

[DJT]

You could use them. They will give you greater magnification, however keep in mind that they will also reduce you MWD.
I found that I wasn't that into macro when I had mine as well as my macro lens so sold mine.

[Tricky]

Yes, you can use the Kenko tubes on your 100mm macro lens. Using all the tubes together will give you approx 1.8x magnification, rather than the 1x maximum magnification that you currently have at the minimum focus distance.

Bear in mind that autofocus won't work too well (if at all) at 1.8x, largely due to the loss of light (I suspect you'll lose ~ 2 stops of light?). You minimum working distance to your subject will decrease from 15cm to approx 11cm. Given the loss of light, you really need some form of flash to supplement natural light when you've got all the tubes on.

Overall, I'd recommend getting the tubes - they're an inexpensive way to broaden your macro lens' capabilities.

Linked here is an excellent technical site covering popular macro lenses and the impact of tubes etc.

[britinozz]

Thanks for your advise i think i will get them.