Hello, I have some questions about flash photography, Let's say I have a camera with not so high max. flash synchronization 1/100. If I take a portrait in on a sunny day, and I want to balance the ambient light ie. I want the nasty shadows to become milder. For portraits, I have to use an open diaphragm to blur the background. That means I have to use a faster shutter speed. Let's say my camera shows 1/500 shutter speed. In order to be able to use flash I have to decrease the shutter speed, that results in decreased diaphragm aperture which is unwanted for my portrait because I have to blur the background. At these point, I can use a neutral density filter to decrease the exposure at the same opened diaphragm. However, I think it changes the exposure and the effective distance as well(If I am not wrong, it must increase the effective distance) What happens on the shadowed area of the portrait if the effective distance increases? May it cause a too bright or overexposed zone? Can it be a solution for a body with a slower flash synch. speed? If it is not so why are the high flash synch. speeds necessary on the bodies? Sincerely, Yalcin Alimoglu

-- Yalcin Alimoglu (yalcin@teklan.com.tr), August 29, 1999

Answers

Assuming you're using manual exposure setting on the flash. The effective distance has to be increased, however, the ND filter also reduce the extra light, say -2 f-stop (that's why you have to increase it to have correct exposure). Actually, you might have some -ve compensation for less harsh subject.

If you're using TTL (manual mode on aperture and shutter setting to control fill flash i.e. ambient vs flash exposure ratio) instead, just add the ND filter and give some -ve compensation for harsh reason, you'll get what you want.

Normally, even flash sync speed of 1/250s wouldn't help much on this situation, either using slower speed film, or high speed sync or ND filter might help. Or just use a light relector instead of fill flash.

:P

-- Phicol Kwan (phicol@yahoo.com), September 01, 1999.