I got this flash, and a new wide angle head for it.. still it seems to be one stop short of the numbers it gives at the back of the flash. I was wondering is this normal, or could i get the full power by relapsing the old capasitators with new ones?
I tested it at iso200, at 2.8m and it says f22 but metered f16, with the new old stock wide angle head and the zoom head that seems to be used.
A mere stop off at wide would actually be good by flash makers standards. Most of them give rather euphemistic numbers - the more serious ones will rate with the zoom at normal coverage, but quite a few will even advertise the figures for the zoom head in the narrowest position.
I know that they guide numbers are usually way off. But i mean the numbers behind the flash, that are given for the wich ever head is in use. The zoom head has 3 positions and it shows different numbers for each position. I would also think that this is such a professional flash, that the numbers would be correct.Originally Posted by Sevo
So i was just thinking that is there any sense in relapsing the capacitators? or are the numbers really one stop short? one stop is twice the power anyhow! So if they say this is a 200w flash.. and it really is just 100w?!
Aleksi, a flash's wattage measures the power going in, not the light put out.
Guide numbers report on light out. The only flashes I've used whose full output guide numbers matched the maker's claims were Minolta brand. This based on tests with a tape measure and Kodachrome and with a Minolta flash meter.
FWIW, my Vivitar 283s with VP-1s produce claimed output from 1/2 power down, are ~ 1/2 stop below claimed output at 1/1 power.
Just measure GNs at the various zoom settings and then use them. FWIW, the 283's fresnels narrow the beam, have little effect on brightness.
That's why they're called "Guide Numbers" it's just a starting point. Then you need to establish your own real value to it.
Sorta-kinda like determining your EI with film.
I know this, i was just wondering does anyone have experience about changing capacitors, does it have any effect at all on the power output of an old flash.
Not sure, but if you do, make sure you discharge them fully by shorting out the terminals before you go anywhere near them. You could have a look at the forums on http://www.cameraaxe.com and hunt down Alan Sailer or Maurice they've made their own air-gap flashguns for high speed photography so should be pretty au fait with messing about with capacitors.
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