Dentist in need!

[rgaut1]

Okay this is probably a really dumb question with a really obvious answer, but I'm desparate....I have a Canon Digital Rebel XTi/EOS 400D that I've purchased 75-300 Macro lens, the 18-55 mm lens, and the 28-80 mm lens for. I've always simply used this camera to photograph my kids at home and various sporting events, but I have a particular case at my dental office that requires a really close up shot of a front tooth for the purpose of getting an accurate shade and contour match for a crown that I am doing on a young lady (the pic is going to the lab who is constructing the crown). I've studied my training video and even in the close up mode everything is still very blurry. I've tried all 3 lenses with no success. Is there anything else I can adjust? Keep in mind, I need a pretty close up shot of this tooth for the lab to see what we are working with.

Thanks for any advice or help!

[i speak in math]

None of those lenses are actually macro lenses. You're gonna need something that can do at least 1:1. Magnification aside, getting an accurate color and lightness is going to be a product of your color balance and exposure (i.e., light) You will want to set up the shot but have a neutral gray card (though a black, gray, white would be more beneficial) in the shot. You can use this for both the exposure and color balance. Make sure you aren't mixing light colors; the light hitting the card should be from a single light source to ensure accurate colors.

[LeeR]

I think I would be trying closeup filters if I were you. The closest focusing distance on your 18-55 is less than 12 inches and with the diopters you should be able to get considerably closer.

[mrteacherdude]

This may seem like an odd question that you have already considered, but does your lab service have some sort of method they can suggest for accurate color/shading match outside of what you normally do?

Otherwise, it sounds to me like you may have a tricky situation with lighting, as noted by I Speak in Math. If you have one available, have you considered the possibility of using a point and shoot? Your DSLR with appropriate equipment and lighting will give you superior results, but with good lighting (like I think you probably have right over your exam chair - unless it causes lots of specular highlights), you can get pretty good closeup (not true macro though) shots with P&S cameras.

LeeR's suggestion of the closeup filters may be the best way to solve your immediate problem of trying to get close, but it almost seems to me that you are having more lighting difficulties, unless you are really needing to get close. The reason I say this is that I have the same camera and same kit lens you do (18-55mm) and I've obtained some pretty decent closeups (not lifesize of course) of relatively small insects with the lens zoomed out all the way. But, the lighting needed to be really good (strong and diffuse) so I could shut down my aperture to at least 8 (one of the sweet spots for my lens, and also for better DOF) and keep my shutter speed down to about 1/50 or faster. IS is good, but I still get blurry pics in crappy light. I find that my photos also come out blurry looking if the light is too strong and direct. If you are using your overhead light, you may be experiencing something like this as well.

I wish I could offer more, but I have no experience in trying to get accurate tooth photos. I do know that in my efforts to get good photos of small quantities of colored solutions, lighting is the trickiest part to getting the color right.

[Thunder_o_b]

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