Hi,
today I tested the 2" 2x barlow lens with the Pentax 75/500.
I used the Canon 350d, ISO 800, 1/200s
http://www.prokyon.startime.at/Bilde...ang8Mai09a.jpg
http://www.prokyon.startime.at/Bilde...ang8Mai09b.jpg
http://www.prokyon.startime.at/Bilde...ang8Mai09c.jpg
f/13 made it possible to get moon and trees sharp.
cheers
werner