DOF problems

[drt205]

Here is a closeup of a round button polup from my aquarium. Photo taken with my RebelXT with 100mm f2.8 macro with extension tubes. My problem seems to be focus and DOF. I am having problems with getting the entire coral in focus. Any ideas would be appreciated.

[Morca007]

Your aperture is too wide. Use a larger f/stop, right now you are at 3.5, try 5.x.

[Nieton21]

yeah that would help, I would suggest 8 because it seems to be a good number when everything is pretty much in the same field..(i.e. nothing in back or front) also that seems to be a very sharp aperture, at least from my experience. When I shoot something in the same field I usually set it to 8 and feel its better, maybe just me though...neat coral thingies

[drt205]

Thanks. I will try again but will experiment with different focal lengths.

[smc1377]

Does your extension tube have electrical contacts that will allow the camera to talk to the lens? If not, then you can't change a thing when it comes to aperture. The DOF issue just seems to be a side effect of extension tubes.

[drt205]

The extension tubes do have the electrical contacts so I should be able to change settings. I had turned off the auto focus when I took this photo.