[Petey44]

I'm doing some morning outdoor shooting that will involve using my AF360 fgz. The lens is the Sigma 17-50mm F2.8 HSM. WHen using it for fill flash on people subjects, what works the best with the K5? I'm planning on setting it to high speed sync on TTL mode. Most of the shooting will be wide that won't require flash use. When I'm shooting small groups of people, I'll be using the fill. I can either use the pull out white card, or a Stofen diffuser. Any suggestions? Thanks, Peter

[amoringello]

Highspeed sync will eat up so much power you'll need to be within 2-5 feet of your subject. (depending on your shutter speed and how much the flash has to compensate). Of course, if the ambient light is bright enough that you cannot keep your shutter speed below 1/180, you don't have a lot of choices.

You can use ND filter to reduce the light to get your shutter speed back down, but this also reduces flash getting into he camera. So you will waste a lot of flash power to over-power the ambient light and compensating for the ND filter.

My suggestion is learn to adjust flash in manual mode to get the fill you need.

If you don't have time to adjust the flash, I find just leaving in PTTL and setting down -1.5 will get just enough light to fill. A Stofen style diffuser may help soften things a tiny bit, but I find it really just lowers flash output and increases power usage by the flash in an attempt to compensate. I dont find them extremely helpful for softening the flash that much.

I will use something like the Flash Bender or Better Bounce (basically a large 10"x10" a white card behind the flash) and point the flash up.
Just the light reflecting from the card aims forward and lights up the subject.
Again, you lose a lot of light that is going straight up, but you're otherwise going to want to turn down the flash anyway, so this tends to work well. But again you'll need to stay rather close to the subject because the bounce light isn't going to affect a great distance. And the flash power stays rather high.


FYI, my concern with flash power is the six second recycle rate between flashes when the flash fires a full power blast.
I try to keep the flash at -1.0 (1/2 power) or less so I can take two shots when needed or at least not wait so long between them.
But its all a fight of one benefit v.s. another. We can't have everything. :-(

[Petey44]

Thanks for your reply. Yes, I forgot to mention I'll set the flash output to -1 or -1.5. While doing some testing, that seems to work well. More than likely, I'll only be using the flash for 20% of my tasks. I'll have a couple sets of Eneloops. My shot list is mostly stationary objects but I'm sure to have runners during pre/post race activites posing for photos. It will be early morning light, so I need to wait and see what mother nature offers me. I forgot to mention the event is a major 8K race here in Chicago.

[top-quark]

You can overcome loss of flash power from HSS by bumping up your ISO. Since P-TTL doesn't account for loss of power when you're using HSS, you may need to do this anyway.

[amoringello]

But remember ISO; like an ND filter and like Aperture, affects both ambient and flash. If you're HSS is not powerful enough to overpower the ambient light to begin with, up'ing the ISO isn't going to do anything to help that.

[top-quark]

Talking of an ND filter, it does strike me that one might be better than trying to achieve fill-in flash using HSS. I'm guessing that you need HSS so that you can use wide open apertures in daylight. Just use an ND filter to keep the shutter speed at or below 1/180 and you're good to go.