Macro focussing issues

[crockny]

Hi - I am new to the Canon Macro 100mm lens and have a few questions. Here's my best effort at shooting my orchid:



Camera Canon EOS 7D
Exposure 30
Aperture f/22.0
Focal Length 100 mm
ISO Speed 100

I eventually switched to f/32 but it didn't seem to be any sharper. I'm on a tripod and using a cable release. Strictly ghetto lighting. I don't seem to know where the focal point is to get the whole thing in focus - if I focus on the points at the end of the lip the rest is not in focus and if I focus into the middle the pointy ends aren't entirely in focus ... is this something you learn by trial and error or is there a method to the madness????

[Lolkat]

I have the 60mm 2.8 micro and love taking macro shots. But it can be very frustrating. When you are that close to your subject, even at f32, which is a bit extreme, your dof is still going to be very thin. In order to get the whole orchid in focus, you are just going to have to move further back from your subject. I personally wouldn't routinely shoot at f32 because you may lose some of the sharpness and also will need to use a much lower shutter speed.

[crockny]

So the only way to get more sharpness is to move further away and then crop to what you want? I was hoping to not have to do much cropping ... is f22 about the limit of what you would shoot at?

[sk66]

The only way to get large DOF when shooting macro is to shoot multiple exposures with different focal points and stack them....

If you move further away you will increase the DOF, but you will also loose magnification and NOT be macro any longer....(a lot of stuff called "macro" is really just a closeup)

[Doug Sundseth]

You're using a long lens at a short distance and trying to get deep depth of field. This is not physically possible unless (as SK66 mentioned) you use focus stacking. Your critically sharp depth of field here was probably in the sub-millimeter range, even at F/22.

For more information about depth of field, I recommend you see something like DOFMaster.