>When I shot the 800 roll, after every shot, the green light on my 420EX >flash illuminated to tell me that the flash got proper exposure. This >is a nice feature. However, when I used the roll of 100, I got the >green light to illuminate only about half of the time and I could not >figure out why it did or did not light up. ... >I was to the side of the stage, about 25 feet from front and center. >The stage was not well lit. Occasionally an obstruction was in my ... >I used my Elan IIe, 70-200 2.8L lens and the 420EX. I had the flash in >"high shutter speed" mode and used autofocus and manual exposure set on >250 f2.8. Like I said, I used 800 film fine, then had problems with the >100. > >Thanks, > >Richard >Tampa, FL US
I would say: simply because the flash (in FP mode) was not powerful enough for the ISO100 film (with the used aperture, shutter speed and distance). As you may know the flash range decreases dramatically as you switch from "normal" flash mode (where all the flash output is used to expose the film) to FP mode (where only part of the flash power gets on the film, because shutter is open only part of the flash pulse). Now, the FP mode was powerful enough with ISO800 film but when you switched in the ISO100 film which needs eight times more light (I think) FP mode wasn't powerful enough. I believe FP mode is ment to be used mainly as fill flash. Maybe, with ISO 100, you should have used slower shutter speed to be able to use the flash in normal mode and select so small aperture that the ambient light would have been underexposed heavily. This would have resulted in black backgrounds but in any case the flash power would have been high enough and you would also had avoided blurring caused by the ambient light. But let's hope the shots come up fine after all. Vesa _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
