If using an adapter will I lose an f stop?
 

If using an adapter will I lose an f stop or two?

Tony B

What kind of adapter?

For a slr lens like a Nikon telephoto.

Check the adapter manufacturer to be sure if not Canon, but with the Canon EF Adapter you get the same f-value as the lens, as long as it is no faster than f/1.6, which is the limit of the CCD block of the XL1.

If using the Canon extender XL 1.6x, as with any teleextender, you lose somespeed. In this casy you multiply the f-value of the lens by 1.6; e.g., F/4.0 becomes f/6.4.