Now much memory the SONY DSC-F505V can support?

Can I use 1G.

Only Memory Stick cards will work (not the newer Pro cards), and only in sizes through 128MB. Here's a compatibility chart:

http://esupport.sony.com/EN/info/mspro-camera.html

None of the Sony models prior to the DSC-F717 (which was introduced in 2002) support the newer Memory Stick Pro formats. So, you're limited to a maximum size of 128MB in your DSC-505V.

The earlier non-Pro versions of Memory Stick cards are gettting very hard to find now (most dealers sold out of cards compatible with your DSC-F505V a long time ago). You can also use the earlier non-Pro Memory Stick duo cards via an Adapter. It looks like B&H still has some in stock.

http://www.bhphotovideo.com/c/produc...ory_Stick.html