Bought Extension Tubes, how do I use them to their potential?

So, I wanted to try some product shots and of-course some macro, instead of buying a proper lens, I got these Viltrox Extension tubes (automatic). 12mm, 20mm and 36mm set.

Here are the results (first shots). Taken with 5D mark 2 and 85mm f/1.8

Only 1 tube (12mm) on this at f/2.5

IMAGE LINK: http://www.flickr.com/​photos/moinanjum/13293​872493/

IMAGE LINK: http://www.flickr.com/​photos/moinanjum/13293​875483/

I'm not a macro expert by any means (there are some awesome macro shooters on here for sure!), but depending on the amount you want in focus you have to take multiple exposures with different parts of the frame in focus. This can be very challenging with moving objects such as insects, but with a tripod and flowers it can be accomplished quite easily. Good first shots, and good luck in the future!

Just a matter of practice to get used to the lack of DOF and focus difficulties when shooting near 1:1 magnification or above.
Some hints and tips in my signature
Brian V.

Thanks. I've been your fan for a long time LordV, will check out the thread.