Having a difficult time with HSS...

I don't know if its the equipment or the concept of how it works...

I thought ambient light was controlled with shutter mostly, and control the artificial light from the speedlight strictly from the aperture and ISO... but I tried to strictly exposure for the ambiance, and then trying to expose (the subject) with the speedlight with aperture/ISO and kept getting underexposed subject.... not enough power from the speedlight?

I use a wireless trigger YN622C and 430 EXII in this situation... I had a "work around" by over exposing a bit on the background's ambient lightand properly expose the subject... here's a decent shot if you'd like to see the results as well as the EXIF data...

Also the speedlight is at full power... (i think...sorry forgot...)

IMAGE LINK: http://www.flickr.com/​photos/chrisadval/8864​310035/

When in HSS, the shutter does affect flash exposure. The flash is no longer a quick blip; it becomes, in effect, a continuous light source for the duration of the shutter travel. The higher the shutter speed, the smaller the moving slit, hence less light hits the sensor from the rapidly pulsing flash.

Also, I think that in the shot above, the 430 was close to or at max. The 580 or 600 would have given some extra "head room".

The statement that shutter controls aperture is more or less true at or slower than x-sync. In HSS, shutter reduces the flash lighting stop for stop.

In a studio, the ambient lighting can be constant intensity. Outdoors, ambient can vary considerably, and require more output from the flash - Ambient + Flash on subject.

ChrisAdval wrote in post #15977879
I don't know if its the equipment or the concept of how it works...

I thought ambient light was controlled with shutter mostly, and control the artificial light from the speedlight strictly from the aperture and ISO... but I tried to strictly exposure for the ambiance, and then trying to expose (the subject) with the speedlight with aperture/ISO and kept getting underexposed subject.... not enough power from the speedlight?

I use a wireless trigger YN622C and 430 EXII in this situation... I had a "work around" by over exposing a bit on the background's ambient lightand properly expose the subject... here's a decent shot if you'd like to see the results as well as the EXIF data...

Also the speedlight is at full power... (i think...sorry forgot...)

IMAGE LINK: http://www.flickr.com/​photos/chrisadval/8864​310035/
Alexis Wrecks' us - 01 by Chris Adval, on Flickr

Just to clarify, ambient light exposure is always controlled by aperture, shutter speed and ISO, not just by the shutter speed. This is also true for some artificial lighting such as continuous lights and flashes set to FP or HSS mode.

With "normal" flash exposures, i.e. flash or strobe used at or below max sync speed and fired as a quick pulse of light, only aperture and ISO have any affect while shutter speed does not.

How far was the flash from the subject?
HSS dramatically reduces working distance. At the shutter speed you shot at, with a low ISO a 430EX would probably have to be within 5 or 6 feet. As an aside, give some thought to light placement. The shadow from her nose is not good. Light should be higher and, for this type shot maybe even closer to lens axis.

I'd consider trying a two light approach for this sort of shot. But do everything you can to soften the light. Bare bulb/head at close range is NOT pretty.

As for the model.... Her bra is crooked, her hair is no bueno, the pose is boring...

Try and get a logo-less bra, and think of an awesome way to show off her lines, her body.
What that looks like I have NO idea.

Chris, your Speedlite was in the worst possible location for the shot. Look at the shadow of her nose (left side of her face). That was caused by the flash.

If you're going to turn the camera to the "portrait" position, you need to do something to get the flash above the lens rather than out to the side. There are several solutions. One is a flash bracket that keeps the flash above the lens. Another would be to aim the flash at a reflector (probably held by an assistant) and bounce the flash back toward the subject at the proper angle to get pleasing shadows.

dmward wrote in post #15978694
How far was the flash from the subject?
HSS dramatically reduces working distance. At the shutter speed you shot at, with a low ISO a 430EX would probably have to be within 5 or 6 feet. As an aside, give some thought to light placement. The shadow from her nose is not good. Light should be higher and, for this type shot maybe even closer to lens axis.

well for this shot, the flash was about 2-3 feet from the subject, and slightly angled above her pointing straight towards her and flash angled as a strip for to provide more lighting for most of the body...

pyrojim wrote in post #15979202
I'd consider trying a two light approach for this sort of shot. But do everything you can to soften the light. Bare bulb/head at close range is NOT pretty.

As for the model.... Her bra is crooked, her hair is no bueno, the pose is boring...

Try and get a logo-less bra, and think of an awesome way to show off her lines, her body.
What that looks like I have NO idea.

thank you, but I know this, my only equipment with HSS is 1 HSS speedlight, if I use modifiers I am required to use more power, and more speedlights... I've been also playing with garyfong modifier to see if this has any or much effect to soften the shadows... right now I am only trying to master the ability to do HSS photography proficiently. The bikini, was her own modeling name, she wanted to "show it off," at that time I didn't care anything more than to test myself to become as proficient as possible in HSS.

SkipD wrote in post #15979228
Chris, your Speedlite was in the worst possible location for the shot. Look at the shadow of her nose (left side of her face). That was caused by the flash.

If you're going to turn the camera to the "portrait" position, you need to do something to get the flash above the lens rather than out to the side. There are several solutions. One is a flash bracket that keeps the flash above the lens. Another would be to aim the flash at a reflector (probably held by an assistant) and bounce the flash back toward the subject at the proper angle to get pleasing shadows.

I'm sorry, but please don't critique the photo, I am asking on understanding HSS, not lighting portraits... My only focus of this shoot was to get the background light and subject light evenly exposed... and understanding HSS better, and have yet to understand that as I attempt to expose for background I dont got enough power from the 430 EX II, which sounds like I will need an upgrade speedlight to 580 or 600 EX speedlight to achieve what I am trying.

As for the flash above the lens, I doubt will work when I am 10-15 feet away with a 70-200, at 200mm. I know harsh shadows are mostly bad on females... that isn't about this topic please.

First thing to remember about HSS is that it is turning your speedlite into a constant light source.
In order to do that it has to expend the power in the capacitor over a much longer time span. Result is much less power to illuminate the subject since its spread over time.

Canon speedlites, when mounted on the camera will show you the effective range for the speedlite given the shutter speed, ISO and F stop. Do some test shots to get comfortable with what the speedlite can deliver then move it off camera.

The GF modifiers are way too small to be any softening benefit and they steal even more light.

Shot through umbrella or Westcott type softbox are best, but still will use up light you need for the subject. Direct flash, close to lens axis and above camera at least 12 inches is acceptable in many cases. If you need the power its about the only choice.

A good way to determine just how much exposure you loose with HSS is to shoot a test shot at X-Sync that is properly exposed with speedlite and camera manual settings. Then increase the shutter speed 1 click over x-sync, i.e 1/3 stop and make another exposure. You will notice its significantly under exposed.

Take them both into Lightroom and increase exposure on the second shot using the exposure slider until they look the same. If your flash is similar to most the exposure slider will be well beyond one EV and maybe close to 2 EV.

That means that if you could have your flash off camera at 11 feet at x-sync it will now have to be 5.6 ft.

Or, if you could use an umbrella with flash at half power you now will have to use the flash direct at full power. (presuming the umbrella is only reducing exposure 1 EV.)

I don't remember exact settings but the speedlite on camera was providing fill. The camera was probably in Av (my default outdoors) and the shutter speed was probably over 1/200 on 5DII to get the sky a little dark using minus Exposure Compensation.
And it was shot with a wide angle lens. Probably 16-35 at about F4 or 5.6 ISO 100.