In article <4cs3eh$o3p@nnrp1.news.primenet.com>, reptile@primenet.com says...
>
>A lot of my flash photos have been coming out underexposed. There was
>one in particular that I took from only about 5 or 6 feet away and had
>it set to f/16 and came out pretty "foggy". The chart on the flash
>indicated that this is the right f stop to use for that distance. I
>also noticed that the recycle time was one minute which is far too
>long so I replaced the batteries and it brought down the recycle time
>to about 4 seconds, which is what it should be. I was just wondering
>if the low batteries were causing the pictures to be underexposed. I
>would think that the reason flashes have to charge in the first place
>is to maintain a consistent brightness of the flash when it's used. Am
>I wrong? Do weak batteries cause the flash to be weak?

One problem with using flashes in manual mode (in addition to the manufacturers' inflated guide number ratings on which they base the
exposure scales - you need to test to find out what the guide number
for your flash [with the battery type you use] really is) is that the output power varies with the input(battery) voltage, so it is somewhat irregular. (NiCads help, since their voltage slumps little before they quit,unlike alkalines.) Even when using auto or TTL modes, low battery voltage plus optimistic guide numbers can get you into trouble if you
are at the flash maximum output. BTW, flashes charge because a high voltage is needed to operate the flash tube, not to produce
consistent output level.
Hope This Helps