Flash Sync Speed & Auto FP

met

Mainly I shoot natural light and try to pick ideal conditions when doing so, but I know that I need to expand into being able to shoot in any lighting conditions. So the next thing I've been experimenting with is shooting fill flash in harsh lighting conditions. I was getting seriously annoyed when practicing that I couldn't increase my shutter speed on my D80 up past 1/200 when I had my flash on, because I wanted to maintain creative control of my aperture. So I did a little research and some reading that this was due to the flash sync speed. But I also discovered in the menu that I can select "Auto FP". Then I was able to push beyond the 1/200. Am I correct that this is basically a hack around the flash sync speed? My question is - does using this option affect the quality of the pictures? And why do you have to select that in the menu rather than it being the default? Is there a reason not to do it? Thanks

rwells

Go to Neil van Niekerk's excellent website:

You can start here specifically, but study the whole site. You'll find everything you need there
http://neilvn.com/tangents/flash-photography-techniques/6-flash-outdoors/

met wrote: »

Mainly I shoot natural light and try to pick ideal conditions when doing so, but I know that I need to expand into being able to shoot in any lighting conditions. So the next thing I've been experimenting with is shooting fill flash in harsh lighting conditions. I was getting seriously annoyed when practicing that I couldn't increase my shutter speed on my D80 up past 1/200 when I had my flash on, because I wanted to maintain creative control of my aperture. So I did a little research and some reading that this was due to the flash sync speed. But I also discovered in the menu that I can select "Auto FP". Then I was able to push beyond the 1/200. Am I correct that this is basically a hack around the flash sync speed? My question is - does using this option affect the quality of the pictures? And why do you have to select that in the menu rather than it being the default? Is there a reason not to do it? Thanks

Dan7312

It won't hurt the image quality, but the maximum amount of light the flash can produce will be reduced, that's why you only use it when you need to.

The reason you can't normally go beyond 1/200 sec is that at that speed on your camera the second curtain in the shutter starts to close before the first curtain has fully opened. If your camera were to let you take the picture anyhow what you would end up with a black edges on the image. That would be because the first and second curtians of the shutter would be covering part of the sensor when the flash went off.

When you turn on high speed sync (at least what it's called on Canon cameras) it makes your flash do a whole bunch of little flashes, that is act like a strobe light, so the it lights the scene for the entire time it takes for both curtains to open and close.

Richard

Right. I shoot Canon, but I'm guessing that the Nikon Auto FP mode uses high speed sync mode when it needs to. You get less light and greater power consumption, and second-curtain sync won't work, but otherwise there's no problem with it. When using fill in bright light outdoors your other choices are ridiculously small apertures that degrade the image quality with most lenses or using a strong ND filter.

pathfinder

Nice link, Randy - http://neilvn.com/tangents/2010/08/02/high-speed-flash-sync/#more-4308

The OP asked why high speed sync, auto FP is not the default setting, and it is the loss of maximum light intensity from the flash, but if you want to shoot with wide apertures, out of doors, with the flash fairly close to the subject, HSS is great. I leave my flash set up that way unless I really need more pop from it, so that I do not find the flash dialing back my shutter speed slower than I set it to. I hate getting over exposed images because my camera/flash resets my shutter speed to the camera's default flash synch shutter speed without my permission, since I am usually setting my shutter speed myself in manual mode, and get discombobulated when the shutter speed I set is not the shutter speed my camera/flash decides to allow me to have. HSS avoids that issue for me, and I know that if I really need more juice from my flash I can just dial it out of HSS, and reset my shutter speed back to 1/200th and rock on.

Nikon's term for HSS, Focal plane refers back to flashbulbs that were called focal plane flash bulbs, because they did not emit a brief flash of light ( like standard flash bulbs ) but a sustained output of light that lasted ~ 1/2 second allowing one to use a focal plane shutter ( like in an SLR ) at speeds higher than allowed by the native flash synch speed. The HSS mode on an electronic flash does the same thing as Dan described above.

Elaine and I had this discussion a while back

Another post about High Speed Synch

I'm sorry my comments are about the Canon system, not the Nikon system, but the basic issue of spreading the light from the flash over a longer time duration to accommodate a focal plane shutter is the same for both systems. Nikon just calls theirs AutoFP

Ed911

I'm shooting a Nikon D300 and have an SB900...and I use high speed sync all the time with great results. I've shot events outdoors in bright sun light...usually shooting under an opaque tent or in the shade of a tree...and have no complaints. I've had very good luck with it and keep it turned on all the time. I've used high speed sync in Manual mode...if you like that...worked really well...and I've used it in Aperture priority and Program modes...works well everywhere. It does use more power and it does produce less flash...but for events...where you will be close anyway...and don't want to blow out faces, etc., it smokes.

It just takes practice. I highly advise that you go out and find an event that needs volunteer photographers and sign up. I shoot the local MS Bike ride every year...donate my time and images for a good cause and have, literally, hundreds of willing subjects wanting my fill flash photography. You can't ask for a better learning environment.

I don't remember if your camera has Active D-lighting, but if it does, turn it on and set it to normal. It works well outdoors and in combination with high speed sync.

Hope this helped...

met

Thanks everyone for the info. That cleared some things up for me. My major concern was that it wasn't the default for a reason and that my images might suffer by turning it on. I'll definitely go check out that website, too.

Icebear

Oh, an important thing to keep in mind when trying to use Nikon's Auto FP with the built-in pop-gun. It don't work at all faster than 1/320th. Only external flash units (SB 600, 800, 900, SB-R200) work at higher shutter speeds.