Re: Flash compensation range scale on SB24 [v04.n202/2]
Krisada wrote: I am wondering if someone can help explain... Why when I set the compensation of the SB24 say to -2EV (or any negative numbers), the range indicator on the back of the SB24 increases to greater distance? I was expecting it to be less distance if -2EV means I want 2 stop less light from the flash. Is something wrong with my SB24? Nothing is wrong with your flash. If you set -2 EV compensation the amount of light emitted by the flash will be less as controlled by the TTL circuitry but the distance that the flash can be used and still work 2 stops below the non-compensated output level will be twice as far. A -2 EV change in flash exposure is exactly 4 times less light than no compensation at all. Using the inverse square rule, the flash will have exactly twice the usable distance at -2 EV. Example: If your flash has a maximum usable distance of 10 feet at a given f stop and film speed, setting -2 EV will reduce the output of the flash at 10 feet by 2 stops. However the flash's maximum usable distance for -2 EV will be 20 feet. Art Art Searle, [EMAIL PROTECTED], Lake Grove, NY, USA 20 miles east of Nikon USA www.erols.com/w2nra
Re: Flash compensation range scale on SB24 [v04.n202/2]
Negative compensation means you want less light on the subject - so for any given output, the subject must be further away. Using TTL, the output of the flash will be reduced to compensate, but a limit is reached when the flash is at full output. In this case, it will be capable of illuminating a subject which is further away (twice as far for your example -2EV) than with "normal" illumination. Regards John Bean
RE: Flash compensation range scale on SB24
Date: Tue, 19 Jan 1999 12:13:20 + (GMT) From: Krisada [EMAIL PROTECTED] Subject: Flash compensation range scale on SB24 [v04.n202/2] Message: 2 Hi, I am wondering if someone can help explain... Why when I set the compensation of the SB24 say to -2EV (or any negative numbers), the range indicator on the back of the SB24 increases to greater distance? I was expecting it to be less distance if -2EV means I want 2 stop less light from the flash. Is something wrong with my SB24? thank you Krisada Hi, The range indicator on the back of your SB24 shows the distance you can reach if the flash would fire with it's full power (no TTL-sensor interruption). This means: if you need less light (-2EV), then the light can reach (again at SB's full power) longer distance. Example for SB26 (in meters): GN:42 ISO:100 ASA lens: 50mm f-stop:5.6 Max. distance is 42/5.6=7.5 m -2EV = f-stop=2.8 Max. distance=42/2.8=14.3 m The requested EV compensation works at the moment of the exposure, in your case the flash will be interrupted at -2EV situation (the foreground object will be darker). I hope it helps. Bye. Benjamin
