How to use a flash manually?

[snaggs]

i tried my Nikon SB600 with my Leica today. I can use it, but only in full manual mode.. all I can control is the flash power, i.e. 1/2, 1/4, 1/8, 1/16, 1/32, 1/64.

Any one have a rule of thumb for working out how much flash to use at a given apperture and shutter speed?

Daniel.

 

[dmr]

i tried my Nikon SB600 with my Leica today. I can use it, but only in full manual mode.. all I can control is the flash power, i.e. 1/2, 1/4, 1/8, 1/16, 1/32, 1/64.

Any one have a rule of thumb for working out how much flash to use at a given apperture and shutter speed?

Daniel.

Does this flash have any guide numbers for those various power settings?

 

[Nick R.]

Skaggs, at one time all flashes were manual. All you need for proper exposure is to know the guide number of your flash unit. You should be able to find it in the manual or online. Once you know that, it's just guide number divided by distance to find your aperture. Typically, the guide number is given for 100asa film and, nowadays, it's usually given in meters. So a GN of 40 with the subject at 10meters = f4.
Electronic flash duration is so short that shutter speed doesn't affect flash exposure. However, it is important to consider for the overall look of your photo.

 

[pvdhaar]

Nick's right for GN given for 100 ISO:

GN/distance = aperture

Here's what to do with other film:
For 200 ISO, multiply the 100 ISO GN by 1.4, so GN 40 would become 56
For 400 ISO, multiply the 100 ISO GN by 2, so GN 40 would become 80

 

[snaggs]

Ok, that seems doable in my head! Thanks guys! This should go in a Leica newbie faq.

Daniel.