9. • The 35mm film surface area = 36mm x 24mm = a
standard lens=focal length of 50mm.
• Bottom line:
Number to remember is 1.6 if you are a Canon owner
or 1.5 for Nikon.
If you have a different brand, look it up in your manual.
Then apply these conversions to the focal length you
think you need to arrive at what you really need.
If you're converting from 'old money' to new, divide by
1.6, to get back to the old days from the new focal
length, multiply by 1.6.
Old 200mm lens would be 200/1.6 = 125mm on a new
APS-C camera.
New 200mm lens would be 200 x 1.6 = 320mm in old
35mm thinking.
Lens Conversion Factor:
10. • Guide Number
• how powerful does it need to be?
• Will I still be able to do close-ups
with a powerful flash?
• Will I still be able to do close-ups
with a powerful flash?
• Tilt and Swivel
• why do I need swivel?
• What Else do I need to look for?-
light meter,
• Anything Else?
Choosing a Flashgun