megascriler said:What is flash guide number and what difference does it have from the power of the flash?
megascriler said:Then why is it that people here say that the flash of the Fujifilm Finepix V10 is stronger than the flash of the F10 when the F10 has a flash that can reach 6.5m(specs), whereas the V10 has a flash that reaches on 3.5m(specs).
solarii said:Flash range depends on the selected ISO and aperture. There is no fixed range... the guide no.s are quoted for a given ISO. Also note the unit of measure... some quote in feet others in metres.
megascriler said:What is flash guide number and what difference does it have from the power of the flash?
megascriler said:Thanks. I get it now. Then what about the flash distances used by DCResource reviews? It isn't guide number, then what is it? The maximum power of the flash? It says the flash on the F10 reaches 6.5m.
elcap said:A bit confused. Is there a way to convert the flash guide number from 35mm to 105mm for the same ISO no?
MDZ2 said:Don't forget that guide numbers are also referenced to an aperture of F1 so if your lens has a max aperture of F2.8, then inreality, with the iso fixed at 100, you only get 1/3 the distance. ie GN 60 will probably give you a good 20m to work with.
If you are using a long lens, you can always increase the flash power by adding a fresnal magnifier infront of your flash. This will focus the light into a narrower concentrated beam of light. I have actually managed about 40-50m with my Nikon SB26 @400mm F1/5.6, iso100.
It is not that difficult but needs some work only. Some makers will specify both but the concept to convert is to calculate area of exposure. Since you can calculate FOV from focal length, assuming a 3/2 ratio, you can calculate the rest. I'm sure someone on the net has done it...elcap said:A bit confused. Is there a way to convert the flash guide number from 35mm to 105mm for the same ISO no?
You can easily make a magnifier yourself (and it can also be used over your zoom flash to increase the reach)Snoweagle said:Ah something new i've learnt. The flash magnifier i've seen it before, but only in photography books
MDZ2 said:You can easily make a magnifier yourself (and it can also be used over your zoom flash to increase the reach)
basically, you only need the magnifier which you can buy from most bookshop. Just ask for the map reader. They come in a few sizes from about 4"X 2" to about 1/2 A4 size. Should not cost more than $10 for the largest. I got the smallest for about $2
As for mounting it to the flash, you will have to use your imagination as there are just too many ways to do it to mention here.