Comparison Flash Speedlite vs Studio Flash
Guide Number GN Calculator, including Conversions
Inverse Square Law
When Shopping - Comparing Speedlight Flash Power Rating using Guide Numbers
The EV Chart
3. What is Soft Light?
Nikon SB910 ken rockwell
Guide number of 34/111.5 (at ISO 100, m/ft., 35-mm zoom head position, in FX format, standard illumination pattern) for high flash output volume
110 shots with throw-away Alkaline.
165 shots with 2,000 mAh eneloop.
190 with 2,600mAh Ni-MH, the kind that run down in a week if you don't use them.
Recycling Time (rated)
2.3 sec. with Ni-MH (2600 mAh) batteries.
3.0 sec. with Oxyride™ (1.5V) batteries.
4.0 sec. with Alkaline-manganese (1.5V) batteries.
4.5 sec. with Lithium (1.5V) batteries.
1/880 sec. at full output.
1/1,100 sec. at M 1/2 output.
1/2,550 sec. at M 1/4 output.
1/5,000 sec. at M 1/8 output.
1/10,000 sec. at M 1/16 output.
1/20,000 sec. at M 1/32 output.
1/35,700 sec. at M 1/64 output.
1/38,500 sec. at M 1/128 output.
What is the Ws in a camera flash?
Nikon SB900 is 76Ws (joules or watt-seconds)
If we compare to the SB900, the Profoto B1 is 6.5 times more powerful, which equals 2.7 stop. So no, the SB900 can never equal a 500Ws strobe... more
The SB800 has a 1400μF capacitor and the normal charging voltage is 330V. The stored energy is 0.5CV^2=76.2J so about 76Ws.
The SB600 has a 1000μF capacitor and is also charged to 330V. The stored energy is 0.5CV^2=54.5J so about 54Ws.
Output Power (Ws): 600
Flash Guide No.(GN): 76
Ok but ¿What happens with the BCPS? Tonight I have measure the BCPS of a Profoto B1 without any lightshaper and have read a 230lxs at 3,16m, so the BCPS is 2300 js.
Tonight I have illuminated the front of an hotel in a place bouncing the B1 (nude, without lightshaper) in the wall in front off the hotel. It is: I have illuminated one side of the place bounthing the light in the opposite wall. I was almost in 1/3 of the lenght of the place, near the bouncing wall. So it was about 15 meters from the B1 to the wall and about 50 meters fom this wall to the opposite. In this, I get a f:2,8 for a ISO 640/29.
With a 1/1000 emission time the illuminance provided by the bouncing in the final wall was about 3300lx.
BUT: if the BCPS of the B1 is 2300js ¿Why I cannot get the same light with a Metz 45 with a BCPS of 4400js?
1m: 8850 lux
2m: 2600 lux
3m: 1280 lux
4m: 650 lux
5m: 450 lux
Studio Flash Explained > Efficiency, Wattseconds, and Units of Measure
Studio Strobes vs. Small Off-Camera Flashes
comparing output: studio lights vs. speedlites / speedlights
Speedlight vs Studio light power comparison
Understanding Watt-Seconds: Ep 239: DIgital Photography 1 on 1
Speedlights vs Studio Strobes
The Ultimate Flash Diffuser Comparison Test
Battle of the Monolights: A Beginner Studio Strobe Review - Alex Koloskov
Home-based Photography Studio: convenience and limitations - Alex Koloskov