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SB 600 Flash Drive Help?
Measured Guide Number (GN) in feet, ISO 100: zoom setting of 14mm GN 36 (40 – 1 / 3) 24 mm 64 (56 + 1 / 3) 35 mm, 71 (80 – 1 / 3) 85 mm 100 (110 – 1 / 3) What is a tracking number? Where zoom settings fit into this? Current zoom buttons. Anything else I should know? As you can see, I'm an idiot when it comes to this. Looking to use a Nikon D50 with 35-70mm f2.8 Nikkor 12-24mm F4 or Tokina 17-50mm f2.8 Tamron. Overload of photos … I try to understand a little more. Thanks for all the information too, Steve.
Guide numbers are only one measure of the power of the flash of light, usually always measured at 100 ISO. It is a way to compare power between flash flash units available. You can use the guide number to calculate f stop, but you should know the distance to the subject. For example, if your item at 10 meters, and its guide number is 100, could dividing 100 by 10 and the f stop should be F10. Another example, if the subject was 8 feet away and its tracking number was 71, divide 71 by 8 and your f stop is f 8, (near as possible to respond to 8.8). As ISO speed climbs, so that the guide number. If you have a guide number of 100 to ISO 100, the guide number will double to 200 at ISO 400. The guide number is lower in the broadest ranges of coordination because the flash can cover the greatest area. Thus, in 85mm, the flash only has to illuminate a relatively narrow road in the area. At 14mm, however, the flash should try to illuminate a much larger area, so the guide number will be lower (ie, the distance between the subject and the flash can not be as great as it might with a more telephoto focal length, and 85mm). I can see why modern cameras and flashes dedicated use TTL (through the lens) metering method. The flash automatically the right amount of products based light on the feedback of digital sensor / film plane. I think that Nikon also uses the distance as part of TTL calculations. In case you're using a flash-profit dedicated to a camera without TTL, it is better to use an incident flash meter instead of trying to understand the settings of the flash guide number. The Combined SB600 and D50 is a dedicated camera / flash agreement and deal with the flash output automatically. You should not have problems. Just make sure that the flash is set to TTL mode and manual mode no. Hope some of that made sense! Steve 
Nikkor 35mm f2 with Nikon D90 (Testing)
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