Using ND Filters for Strobes and Speedlights

ND Filters, often used to slow exposure times can also achieve great effects with flash.

Being a loyal Pentaxian, one of the biggest limitations to my setup is the flash sync speed of 1/180.
I often wonder where Pentax came up with this exposure and why they hadn’t developed a higher sync speed of 200 or 250 like many of their competitors.
Then I remember my film days and cameras that only had a sync of 125 and realize that even a shutter of 800 is slow compared to the speed of flash.

Flash or strobe work is really the balance of two exposures simultaneously.
Background or intent – exposed with ambient light, controlled by shutter, ISO and aperture plus Subject – exposed by flash, controlled by ISO and aperture.
Shutter speeds don’t really come into play during the flash part of the exposure, as most flash units fire much faster than the top sync speeds in cameras today.

Often, I find the strength of my studio strobes and non-ttl speedlights powerful enough on their lowest settings, that even with a low ISO 100 and the fastest sync speed of 180
I must still use an aperture of f11 or f16 to keep the highlights from blowing out beyond recovery.
When I have my ideal exposure setting for the flash, these small lens openings often cause an undesired effect,
they create a greater depth of field, taking focus away from the subject. Continue reading