Photographing Crystal

[glenafton]

I am photographing my wifes crystal with limited results. I am photographing them indoors using natural light from the front. With some of the larger pieces I seem to have no problem as with the Blue Flower Candleholder. However as can be seen with the small global candleholders I can get the back one in focus with the others to a different degree. Or I can get the front in focus with the rest blurred
The camera is an EOS 550D. lens is the EF-S 17-85 IS USM
The details of the picture are: f stop 7.1 > Exposure 3.2 seconds > ISO 100 > Focal length 64mm > White balance Auto > Manual setting.
My other lenses are 50mm f 1.4 > 50mm f 1.8 > EF-S 18-55 3.5-5.6 IS > and the EF 70-300 4-5.6 IS USM.
Can someone advise me as to where I am going wrong

Glenafton