I need help with a focusing issue...

[hue-e]

Last night I decided to begin my exploration into jewelry photography. As I was sorting out my lighting and popping off test shots, I realized that I'm having a hard time getting everything in full focus. I want these to be pretty sharp.

So I tried moving it back a bit, moving it in close. I tried my best to bring the fstop up nearly as high as I can go. I even tried my smallest extension tube, still about the same.

I think this shot is the best of what I took, but I'm open to suggestions on what I can do to improve the focus on the outter edges of the ring.

Lens: Tamron 90mm f/2.8 (camera was on a tripod)

ISO 400 90mm f/32 1/20sec

[revjvegas]

I think DOF is your enemy here.
If you can back away a little more it may help.

Aside from perhaps going to a tilt-shift lens so you can adjust the focal plane.

[KenJulio]

Just curious, is an f stop of f32 needed? Have you tried f22 or f16 to see if the image sharpens up?

[revjvegas]

Just FYI...

Looking at the EXIF data, you've only got a sliver of focal length to work with.

Subject distance 0.35 m

Depth of field
Near limit 0.34 m
Far limit 0.36 m
Total 0.01 m

In front of subject 0.01 m (49%)
Behind subject 0.01 m (51%)

[KenJulio]

Originally Posted by revjvegas

Just FYI...

Looking at the EXIF data, you've only got a sliver of focal length to work with.

Subject distance 0.35 m

Depth of field
Near limit 0.34 m
Far limit 0.36 m
Total 0.01 m

In front of subject 0.01 m (49%)
Behind subject 0.01 m (51%)

2/5th of an inch...a bit thin :)

.01 meters = 0.393700787 in

[hue-e]

Originally Posted by ken74

Just curious, is an f stop of f32 needed? Have you tried f22 or f16 to see if the image sharpens up?

I had it lower at the beginning.. but I will try in that range.

@ john... I will try backing further away as well.

[revjvegas]

Here's a link to the calculator I used case you'd like to have a look.

Online Depth of Field Calculator

[mdurisseau]

I have to agree...the DOF at those distances is definitely your enemy...

[hue-e]

I'm using a 16" product cube with the hole in it so I can block out all reflections... if I put the ring all the way at the back of it, do you guys think that will be far enough?

@ john, thanks, I'll check that out.

[hue-e]

oh nice.. this thing is pretty helpful. I'm able to kind adjust things until I get a good window of dof.

thanks!