I shot the Sony 30mm F/3.5 macro lens for the first time yesterday and found it to work quite well for subjects from about two inches to about twenty-four inches.
The lens is internal focus and in a macro port designed for the lens sits very close to the port glass which allows more room between the glass and the subject. In a standard 18 to 55 zoom port I think the lens would sit to far back in the port to be useful close-up. As Bill has said at 1:1 or even 1:3 the subject would be quite close to the port and lighting would be a challenge.
I was using the Nauticam macro port which works for both the Panasonic M43 45mm macro lens and the Sony 30mm macro. This is a port with the 67mm thread for close-up lenses. While the port works well with the 45mm macro (90mm equiv. in 35mm) and close-up lens it would be pointless with the Sony 30mm macro because it would focus so close to the subject.
The 30 macro of course has greater depth of field than the longer lenses which helps with some fish portraits.
If you shot with a 50mm macro back in the film days and were happy with the results you may feel at home with this lens.
For a $250.00 lens the results are quite good.
Phil Rudin
Camera and housing on loan from NauticamUSA.