Moon Photography help needed (OMD)

Rich

What you need to get the focus spot on is a Bahtinov mask, you can buy them at most astronomy stores

You need one that matches the size of your lens/telescope aperture and focal ratio - they even make them for camera lenses now. Just image a bright star in your viewfinder (you may need iso 12000), put the mask on the end of your lens and manually focus until you get the correct star diffraction pattern.

you will need to use the manual focus enlargement feature to see the diffraction spikes, you will also need a very very steady mount and hand to avoid jiggling the image when focusing as it is very sensitive. In reality a small telescope on a mount with a microfocuser is much easier, my effort was my first go through an 80mm refractor designed with deep space photography in mind (fully corrected for CA and flat field). The other alternative would be an old manual focus lens since they more stiffness than modern autofocus lenses

Once focused on a bright star you can turn to the target of choice e.g. moon and move the iso back down and remembering to remove the mask

http://en.wikipedia.org/wiki/Bahtinov_mask

The other alternative is a steady hand and pot luck at focusing