using high-speed flash sync / Auto FP (model – Aleona)

when you’d use high-speed flash sync / Auto FP

Going to High-Speed Flash sync, ie, over maximum flash sync speed, comes with a penalty. So here’s a solid recipe for when it makes most sense to go to high-speed flash sync / Auto FP.

When you need
either
– shallow depth-of-field, or
– fast shutter speeds,
and
– you have the flash power to spare.

As mentioned in the tutorial on high-speed flash sync (HSS), there is a considerable loss of power in going into high-speed flash sync territory. So you wouldn’t immediately use HSS in very bright light if you are trying to over-power the sun with flash. While the higher shutter speeds brings the ambient exposure down, it brings the effective flash power down faster than it affects the ambient light. So the sweet spot will always be at maximum flash sync speed. Therefore, using HSS shouldn’t just be a default way of working flash.

With this image, the softbox was close enough to Aleona that we were able to get good flash exposure on her, even at a high shutter speed. However, we did remove the one baffle of the softbox.


A fun image taken during an individual workshop today  – our model, Aleona caught-mid-air … with a fast shutter speed and flash, to freeze the movement. Even Jessica, my assistant with the ‘tood, was positively elevated with the experience of photographing Aleona.

camera settings: 1/1000 @ f4 @ 800 ISO

 

summary

Use high-speed flash sync when you need the higher shutter speed OR shallower depth field, AND can afford the subsequent loss in power.

 

equipment used during this part of the photo session

31 Comments, Add Your Own

  1. -cr says

    With these fun shots, it’s hard to focus on the text. :-)
    The more people there are “levitating” in the shots, the more surreal they look. I love it!

  2. says

    I couldn’t levitate to the extent the two girls did. It has something to do with my power-to-mass ratio.

    Also, it’s tough to jump with a Nikon D3 and Nikon 70-200mm f2.8 …. that’s a heavy combo that I had to swing upwards before jumping, just to get some momentum to the camera and lens!

    Neil vN

  3. says

    No one ever seems to mention the use of neutral density filters. It seems to me that this is good way to cut down the ambient light into a range where the flash and camera would not be operating in high speed sync mode. Aside from not having enough hands to juggle a filter along with everything else, am I missing something here?

  4. Motti says

    Hi Neil,

    Funny and refreshing!

    I was under the impression that high speed sync can only go to 1/400 (in the Nikon anyway). I guess it’s the PW that gives you the higher speed sync? Just out of curiosity, would it fair to say that you are using about ten times more flash power this way?

    Cheers,
    Motti

  5. says

    Nope … it’s not due to the PocketWizards.

    Put a speedlight on your camera, and …

    if you have a Canon, hit the lightning symbol on the back of your speedlight, or …

    if you have a Nikon, it is most likely custom function E1 to enable Auto FP mode, …

    and then crank up the shutter speed. See where you end up.

    Neil vN

  6. says

    You can depend on Neil and Jessica for some very good outtakes. :-)

    The reference shot of Jessica near Aleona really is sobering. You aren’t kidding when you state that HSS cuts the effective flash range by half or more. Jessica is really close to the model: 2-3 feet.

  7. says

    Keep in mind that this was shot at 24mm … so there is some spatial distortion.

    For starters, Aleona is a 6’1″ (or 6’2″) Russian goddess / model / dancer. Jessica is … less majestically tall. But in this image, Aleona looks much smaller than Jessica.

    So the softbox wasn’t quite as close as 2 ft, but yes, HSS kills substantial amounts of flash power the higher you go up in shutter speed.

    Neil vN

  8. says

    Neil,
    Two more questions:
    1) Dynamic AF on the Aleona’s eyes? Even though this is not sports photography, Aleona’s eyes are fairly sharp.

    2) Machine gunning the shutter or taking the shot at the height of the jump (anticipation)? I figure machine gunning would be bad since the flash would not have time to recharge.

  9. says

    Pre-focus using Single AF mode. Remember, she is jumping vertically in relation to the camera.

    Nope, you can’t machine gun with the softbox, since the flash is firing close to full power.

    With the shot of the three of us jumping, Jeff did fire it at 9 frames per second, with the speedlight firing with every shot. But these were just short blips of light.

    Neil vN

  10. says

    Neil,
    Thanks for the reply! I was too busy being entranced by the freeze-frame photo to realize that Aleona was jumping straight up, so she would still be in the same plane of focus as your pre-focus point. :-)

  11. Ruben says

    1. Do you have to use su-800/speedlight as trigger for HSS to work?
    2. Do you need it for rear sync also?
    3. Or will the new PWs work with both?

  12. says

    1. No, you don’t need an SU-800 or ST-E2 for high-speed flash sync.
    You just need a speedlight and camera that allows it.
    High-speed flash sync need not to off-camera flash. You can use your on-camera speedlight in HSS mode.

    2. Rear curtain sync and high-speed flash sync are completely unrelated.

    You can even say that HSS is the opposite of dragging the shutter. i.e. … a slower shutter speed when using flash. Only THEN can you consider first or rear curtain sync as options.

    In fact, this is made quite obvious on the Canon speedlights, where you have 3 options on your speedlight:
    a. “nothing going on except the flash going off”
    b. high-speed flash sync (the lightning bolt)
    c. rear curtain sync.

    This makes it impossible to consider the notion of having HSS and rear-curtain sync.

    3. The new PWs and the Radio Poppers will work with both modes.

    Neil vN

  13. Jess B says

    To correct, Aleona is 5’11” and I’m 5’7″ – still “less majestic” than Aleona, but not by much!!!

  14. Motti says

    Yes, when the speed light is on the camera body I can go as high as 1/8000, but I did not know that it was possible with a radio trigger (of-camera like you did). Not mine anyway.

    My radio trigger (the cheap version) is capable of shutter speed of maybe 1/160. I was told long ago that the PW can go up to 1/400. I see at B&H site that the new PW you have can go to 1/8000.

    I don’t think that any other radio triggers can do that, I maybe wrong.

  15. says

    Would i be right in saying if you’re using the PW TT system you don’t need to switch HSS on via the flash right? I believe these units intelligently know and take care of business as you select high shutter speeds. If you plug the PW into the computer you can set where the intelligence kicks in.. i think 1/350 is the default setting.

    Also a lot more efficient: “Because the new MiniTT1 Transmitter and FlexTT5 Transceiver communicate through-the-shoe with the camera system, they can control the HSS burst duration. By precisely matching flash duration to the shutter speed, large gains in efficiency are found, as much as 70% in many cases, for both remote and on-camera flashes.”

    Anyway nice to see this is action Neil, it’s certainly a post i’ve been looking forward to seeing.

  16. says

    Since you mention enabling the HSS via the flash, it sounds like you’re talking about the Canon system.

    I’m not sure that HSS would kick in at 1/350 … since with the Canon 5D, the max sync speed is 1/200 and then a 1/350 setting would leave 1/250 as a grey area in terms of the electronics. But then, I haven’t messed around with these default settings at all in the firmware.

    Anyway, the TT5 units take care of enabling the flash to go in to HSS territory.

    There is one caveat though … your first shot, which establishes communication between Master and Slave, needs to be at or below max sync speed. Unlike the Radio Poppers, you can’t already start off in HSS territory.

    Neil vN

  17. says

    If you play with the HyperSync slider in the firmware you can squeeze 1/250 out of the 5Dmk2’s flash sync speed.. I think -300 is the setting and you need only change it on the TT unit which sits on the camera or all it doesn’t hurt.

    I tried it but sometimes you get a very faint dark line from the aperture blades on one side, but only once in a while and it’s very small and easily cropped out.

    The online chart for HyperSync (not to be confused with high speed sync can be found here:

    Thanks for the heads up regarding communication shot, i didn’t know about that.

  18. parv says

    Liked the very first image, especially when Jessica while assisting is also above Earth, which is (normally) unexpected.

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