Sony a900 Manual page 15

• FOCUS
Having made all the necessary menu settings & exposure & drive options, the next aspect in securing a digital image is
focusing. Focusing the image is the most awkward aspect of astrophotography with a DSLR.
• FOCUS
FDA-FL1AM
Type L focusing screen
- SCREEN L
For focal ratios slower than f/4 gridded focusing screen L
should be fitted. Screen L has a clear centre & a focusing
frame with fine chevron marks within the target sections.