Flashing At High Noon… or Simple Truths About High-Speed Sync
High-speed sync enables daylight flash at wide apertures by changing the way the flash fires.
According to the 1931 song, only “Mad dogs and Englishmen go out in the noon day sun.” Thanks to high-speed sync, flash photographers can now be added to the list. High-speed sync enables shutter speeds way beyond the norm for flash photography. It also opens up a new realm of creative opportunity. Many shooters are intimidated by high-speed sync. In reality, it’s really easy to use if you have the right gear (say a Canon DSLR and a 580EX or a Nikon DLSR and an SB800).
Flash Photography Basics
I think of the amount of the flash as the duration of the flash. A speedlite ["speedlight" in Nikonese] firing at full power emits a longer burst of light than it does when firing at quarter power. When measured in a tiny slice of time, say a microsecond (one millionth of a second), the actual brightness coming out of the flash per microsecond is the same. At full power, the flash is just illuminating for more microseconds than it does at quarter power. [Note to uber-geeks: yes I know that it takes a few microseconds for the flash to reach full intensity and after peak intensity it falls off for a few microseconds, but let's not be too uber.] Looking at this backwards, if you want to freeze motion with flash, then use a high-powered strobe set to a low power setting.
The amount of flash can be controlled by the photographer, by the flash or by the camera. In manual mode, the photographer dials the amount of the flash up and down. [I do this often. To find out when and why, you'll have to wait for a future article. High-speed sync is way cooler than manual.] Some camera-mounted flash units have photo-sensors that will control the duration by measuring the amount of light coming back from the subject. [I think of this as "almost-matic" technology and never use it.] Today’s digital cameras have truly automatic technology in which the camera and the flash talk during the exposure. We refer to this as TTL - Through The Lens - flash. e-TTL in Canonese and i-TTL in Nikonese.
Sync speed is the fastest shutter speed that you can use during flash photography without “screwing up” the shot. If you use a faster shutter speed, a portion of your frame will not be illuminated by the flash. Ever have a flash photo with a dark band along one side? You shot faster than you sync speed. Of course, one shooter’s screw up is another shooter’s creative technique. Check out this video by David Ziser for an alternative look at purposefully shooting faster than your sync speed.
The type of shutter in your camera (or lens) establishes the sync speed. View cameras (remember them?) and most medium-format cameras use lenses that have built-in leaf shutters with metal blades that open instantaneously from the center of the lens. Leaf shutters can synchronize with a flash at any shutter speed [technically, any shutter speed that is longer than the duration of the flash].
Single-Lens-Reflex cameras (film and digital) have shutters in which two curtains move across the focal plane. The interval between the curtains is the shutter speed. Essentially the exposure is a slit moving across the focal plane. For normal sync, SLRs must fire the flash after the first curtain is fully open and before the second curtain has started to close. Most DSLRs have sync speeds in the range of 1/125 to 1/250. At faster shutter speeds, there is no point when the entire sensor is exposed all at once - so normal sync is not possible.
Slow shutter speed = wide curtain gap, normal sync fine
Fast shutter speed = narrow curtain gap, must use high-speed sync
There are also cameras with electronic shutters that enable faster sync speeds (typically up to 1/500). Theoretically, electronic shutters can sync at any speed - but currently there are limitations caused by sensors over-heating… someday this will be really handy technology.
How High-Speed Sync Works
High-speed sync only works with dedicated TTL systems. The camera has to be able to talk to the flash. Further, you have to enable high-speed sync on the flash (Canon) or in the camera (Nikon).
With standard sync, the shutter has to be completely open when the flash fires. So, the camera fires the flash at the instant that the first curtain is fully open (”1st-curtain sync”) or at the instant just before the second curtain begins to close (2nd-curtain sync”). If you’ve ever seen a flash photograph taken at a really slow shutter speed where headlights of a car trail, that’s 2nd-curtain sync. [My cameras are always set to 2nd-curtain sync.]
With high-speed sync, the camera actually changes the way the flash fires. Rather than a single, strong burst, it tells the flash to send out an ultra-fast series of low-power, strobe pulses. Because the strobe pulses are so close together, the light appears to be continuous. So for the duration that the narrow curtain slit is traveling across the sensor, the flash is “always” on.
Canon’s Japan site has a useful diagram here. Fear not, it’s in English.
The upside of high-speed sync is that I can use virtually any shutter speed. The downside is that the output of the flash is greatly reduced. I often have to use several speedlites to get enough light when shooting at high-speed.
Freedom of Aperture With High-Speed Sync
High-speed sync gives me more creative freedom (aka: wider apertures). This is the main reason that I use it. Let’s say that I’ve been commissioned to shoot a portrait of a rising music star and that the only time she’s available is for 20 minutes at noon. Given that the sun is straight overhead, I’ll have to fill her face somehow. If I use a shiny reflector, she’ll squint and probably complain. So, I want to use a fill flash (or two) pushed through a white umbrella to soften the shadows.
With regular sync, the fastest I can shoot on my Canon 5D is 1/160. [Yes, I know the Canon specs say 1/200. But, in my part of the universe, it's really 1/160.] So, under the blazing sun, at 1/160, my widest aperture for a good exposure is f/13. That’s way too much depth-of-field for my portrait style. One option, would be to slap on my Singh-Ray Vari-ND filter and dial in several stops of neutral density. But, then I can’t see the magical expressions on my subject. The better choice is to turn on the high-speed sync on my 580EX (literally a quick button push). Now I can (almost) pick the aperture that I want to use. The reality was that there was too much sun. At 1/8000, the widest aperture I could get was f/5.6 - still, much better than f/13.
Taming The Sun With High-Speed Sync
Another benefit of high-speed sync is that you can overpower the sun with a small speedlite or two. In the photo above, you’ll note that the sky and background (basically, everything lit by the sun) is underexposed. Why? Two reasons. I wanted to make my subject the dominant element (aka: the brightest part of the picture). I also wanted to reduce the competition between the geometry of her arms and the geometry of the lattice. How? I set my overall exposure at -2 EV and my flash exposure at +2 EV. That’s about all the thought I put into it. I let the digital gnomes in my camera do the calculations.
In the following shot, you’ll see the underexposed daylight at left and the effect of the high-speed sync at right.
At left: Daylight only. At right: Canon flash at high-speed sync.
Setting Up High-Speed Sync
On Canon 580-series or 430-series speedlites, your flash must be set to ETTL mode. Then push the H-button until you see the H-icon on the screen. You are now in high-speed sync mode. Frankly, I keep high-speed sync on all the time. I shoot in aperture-priority (AV) mode 99% of the time - meaning that I’m almost always more concerned about controlling depth-of-field than I am about stopping motion. There’s no harm in leaving high-speed sync on. When I dial to an aperture that enables a shutter speed of 1/200 or slower, the camera automatically operates the flash at normal-sync mode - meaning that the full power of my speedlite is available.
On Canon Speedlites: Mode must be ETTL, then push the H-button. That's it. High-speed sync is activated.
On Nikon systems, it’s called Auto FP High-Speed Sync. As I understand it, you activate it in your camera rather than on the flash. Nikon shooters are encouraged to add comments relating to the specifics for their cameras.
Watch High-Speed Sync In Action
Watch this video of Joe McNally shooting high-speed sync in the sand dunes of Dubai. Thanks to the Strobist, David Hobby, for putting it together and launching it on the web.
Why did Joe use so many speedlights? You’ve already learned that high-speed sync greatly reduces the output. So if you have one speedlite and want to double the output (get another stop of light) you have to add a second speedlite. Then if you want another stop of light beyond that produced by two speedlites, you have to add two more speedlites. If you want third stop of additional light, you have to add four to the (one plus one plus two). So for three stops, you went from one light to eight. [Stay tuned... I've decided to round up as many 580EXs as I can and start firing them off en masse for a future article on this most-confusing concept.]
Wireless, High-Speed Sync with RadioPoppers
The opening image was shot using three 580EXs, a 430EX and a mess of RadioPoppers. One 580 was camera mounted with the Popper transmitter. It acted as the Master, but did not fire during the shot. The other three speedlites were mounted ala McNally on a C-stand at camera right and zoomed out to 105mm so that the light was concentrated along the length of the subject.
The Poppers provided eTTL control without too many hiccups. The biggest issue was making sure that the fiber optic was placed exactly over the sensor. Not a biggie after we figured it out. Using the Poppers enabled me to forget about maintaining a line-of-sight between my Master and Slave units. I could work with my subject without concern for where the rack of speedlites stood. In short, I think RadioPoppers are great. New technology, yes. Rather expensive, yes. A bit buggie, yes. Able to do something that no other gadget can, YES. More on the Poppers to come soon.
RadioPoppers + Canon 580EXs = Wireless, High-Speed Sync
Canon 5D
Canon 5D Mark II
Canon 50D
Canon 24-70 f/2.8L
Canon EF 70-200mm f/2.8L IS
Canon G10
Nikon D700
Nikon D300
Nikon D90
Nikon D3
Nikon 14-24mm f/2.8G ED AF-S
Nikon 24-70mm f/2.8G ED AF-S
Nikon SB-600 Speedlight
41 comments
Syl,
Very clearly explained and quite easy to follow. I like the fact that I can set High Speed Flash on and just leave it be, that the camera / flash combo are smart enough to use it only when the settings require it.
One point for any of us lucky to have that many flash units: if each stop requires doubling the light, wouldn’t we have the progression of 1, 2, 4, 8, 16, … for each additional stop of light?
It will be a while before I can get more than an additional stop anyway, but I’m just curious…
Thanks,
Richard
Richard - Thanks for your question and inspiration. It’s a universal point of confusion among photographers. I blame it on the Inverse Square Law. In this instance, I think we’re talking about the Inverse of the Inverse Square Law. I’ve taken a look at what I originally wrote and have edited it using the new math. You’re right. If you have one light, adding another gets you one more stop of light. If you then add two lights, you have a total of four lights or two more stops of light than you started with. For the third stop, you have to add four. I’m now trying to round up no less than a dozen 580EXs to shoot a demo. Seeing is believing… or at least more fun than doing math.
I wouldn’t say that shooting faster than the max sync speed necessarily screws up the shot — you can use the falloff to your advantage. There’s a great video about it here: http://strobist.blogspot.com/2008/10/great-video-on-overclocking-your-sync.html
Forgot to add — great post otherwise, I hadn’t thought of the flash output setting as more of a duration than a power setting.
Syl,
Nice pics!
So do you STILL like the Radiopoppers? No buyer’s remorse?
Have you seen some of the P1 mods with the fiberoptic cable? Necessary?
http://www.erickochphoto.com/main/ph…oto-geek-alert
I’m thinking about purchasing the RP’s but have read some negative reviews however reviews are so user skill biased, IMO.
BTW- I’m skilled with manual flash but ETTL is so convenient and quick! Extremely undervalued, IMO. And having hi shutter sync and on camera setting without having to walk about is a time saver.
Thx,
Peter
Illkka - Great point about over clocking the sync speed and thanks for the reminder about David Ziser’s video. I’ve appended my article and included a direct link to it. If you’re shooting in a situation with a lot of ambient - outdoors typically - David’s technique is great. Without a broad ambient source - like when you’re indoors - over-clocking may not be so pretty.
Say you don’t have a Quantum strobe and Turbo battery ($1000+ new)… If you’re shooting with a couple of off-camera speedlights rather than the Quantum (the latter being about twice the output of the speedlights - you’d need two or more speedlights), I’d zoom them out to 105mm to effectively snoot them and fire away in TTL high speed sync. The look would be very similar.
Peter - I think the RadioPoppers are great. As I said in my article, “New technology, yes. Rather expensive, yes. A bit buggie, yes. Able to do something that no other gadget can, YES.” I fully expect that Canon or Nikon or some smarter camera company will buy the patents and add this functionality right into their strobes. Someday…
Once you get a sense of how the Poppers work and learn where/how to place the fiber optic ball, you’ll think they are great too. I would not necessarily run out and buy the first generation units right now. Keep an eye on the Popper blog for news about the new models that they’ve been working on. If you have to have some Poppers right away, check eBay. You’ll probably save a bit.
[...] really covered a couple of basics that are worth reading. So without further adeiu, I give you Syl on High Speed Sync. Go and be [...]
[...] really covered a couple of basics that are worth reading. So without further adeiu, I give you Syl on High Speed Sync. Go and be [...]
[...] Source and Read More: pixsylated.com [...]
[...] photography for you). I read the article last night and if you’re into off-camera flash, this article is an absolute must-read. Very well done, and illustrated. Way to go [...]
So how do you do this with, say a Nikon D70?
Fine article. Do you know if the Nikon drops down in to normal synch mode like the Canon?
Everyone seems to jive fine in your article, but you do not make it clear that if you want HS sync off camera, you either have to buy an extended TTL cord (must be custom made), or use the radio poppers since you can only use manual or auto flash via pc cord or the PWs. Since most will eventually want the flash off camera, as you discuss, this is a vital piece of information.
If I missed your discussion of this, please forgive me; I just didn’t see it.
Take care,
Pat
Pat - I shot several hundred frames yesterday in high-speed sync using a Canon 580 as a non-firing master talking to another 580 bolted to the top of a light stand. It was all in e-TTL mode. I freely dialed the flash up and down via the built-in Canon wireless. I ranged up to 30′ from the remote unit without issue. So, for basic setups, Canon high-speed sync does not require any extra gear to go off-camera. Now… IF you want to: shoot e-TTL over a long distance, or put your remote flash where it can’t see your master unit, or shoot in brilliant sunlight, or stuff your remote into a softbox, or (my personal favorite) completely stop worrying about where your remote unit is relative to your master, THEN the RadioPoppers are the answer. I’m a huge Popper fan. Look for a epic post on the Poppers this week or next on PixSylated.
All Nikon Shooters - In our new era of multi-culturalism, I freely confess that I know next to nothing about the workings of Nikon cameras. I’ve been shooting Canon since the early-Reagan years. Hence, I’m the wrong guy to answer your Nikon how-to questions. But… as is often said, “Some of my best friends are” Nikon shooters. I’ll round one or two up and get them to provide the real scoop on Nikon Auto FP.
Isn´t Canon´s TTL-2 flash exposure completely independent from any overall EV adjustment? I can´t understand why one would have to adjust upward (in this example +2EV) the flash exposure, regardless of the overall -2EV adjustment that was made, since this last one would only affect the shutter speed in Av mode, which doesn´t affect flash exposure… Could you explain that +2EV flash setting?
Regarding, “High-speed sync only works with dedicated TTL systems”, for those of us with Pocket Wizards (TTL not available) rather than Radio Poppers (which enable TTL remotely), have you tested Hi Speed Sync with Auto Thyristor mode on the Canon 580 EX II Speedlights?
Its custom function 5 value 3 to enable Auto Thyristor. This effectively puts each speedlight in charge of calculating its own brightness based on a brief preflash, kind of like Through The Flash light metering (which I’ll call TTF just for fun).
Steven - I’ve not explored the Auto Thyristor - which I described as “almost-matic” mode. Couple of reasons. I absolutely hate having to dig into custom functions during a shoot. I may be able to remember them when I’m in the shower, but when a subject is staring back at me? No way. For the same reason, I still use an old 580EX as my master unit. Going from Master to Normal can be done while looking through the viewfinder. With the 580EX II, it’s several buttons-worth of distraction - each way. The other reason is that I embrace the ability in e-TTL to control EV and FEC independently. Please check back in with more comments if you give TTF a go.
WARNING - Long, rambling reply follows
Joe - Great question! Because the answer gets to the heart of why I’ve learned to shoot e-TTL.
Both decisions, an overall EV adjustment and the FEC adjustment, are made for creative reasons. There is no direct connection. It’s not a “have-to” on either one. In hindsight, I see the reason for the confusion with my article. Here’s a long-winded explanation — based on a shot where the sun is illuminating the background and the flash is illuminating the subject.
My first shots are made to establish the amount of depth-of-field. I tell the camera that I’m going to specify the aperture by shooting in AV mode. So, I choose the aperture based on the amount of depth-of-field that I desire and the lens that I’m using. The EV and FEC are zero’d for these initial test shots. Do I care what shutter speed the camera chooses based on my aperture? If I’m shooting with high-speed sync turned on, not at all. [The exceptions would be if I was also using non-TTL strobes (in which case HSS does not apply) or if I wanted to convey a sense of motion (in which case I need a slow shutter speed and 2nd-curtain sync).]
Once I figure out my DOF, then I adjust the ambient (background) exposure by dialing in some EV adjustment. The EV adjustment makes the shutter speed faster (for -EV) or slower (for +EV). For me, it’s almost always minus-something so that the background is underexposed - a little or a lot depending upon the scene. Underexposing the background helps saturate the color and encourages the viewer to look at the subject first. Remember, our eyes land on the brightest spot in a photo and scan outward from there. For a portrait, I want the landing spot to be the subject, not some random thing in the background.
I then use the FEC (Flash Exposure Compensation) to control the amount of flash illuminating the subject. In e-TTL mode, the FEC will increase or decrease the duration that the flash is on (aka: change the power level). If I want more light on the subject, I increase the FEC. I often go straight to +2 FEC and then start dialing back in 2/3-stop increments.
If I can do all of this before the subject arrives - by using an assistant or other stand-in - I look much smarter and professional in the eyes of my subject. Sometimes I have to do this on the fly after the subject arrives. So, it really helps to have the above steps in mind. Changing the sequence does not work for me.
Also when I’m often shooting solo, my remote strobe is mounted on a stationary stand. If the subject is moving - relative to the position of the strobe - I constantly change the FEC. Why? When my subject moves to the edge of the strobe path, I need more flash. If he steps towards the strobe, I might need less.
One final thought and then I’ll start turning this in to a real post (thanks for the nudge, Joe). Dialing EV and FEC around via e-TTL is about the only time that I power-chimp. Really. Most times, I’d be perfectly happy if the histogram filled the LCD. I find the histogram to be the best (but not “perfect”) way to make exposure decisions based on highlight clipping when I can’t shoot tethered. Making exposure decisions on the fly when shooting e-TTL is another matter (again assuming that I’m not tethered). For on-the-fly e-TTL sessions, I use the JPEG that the camera throws up on the LCD to make “informed guesses” about how my ambient and subject exposures look. The “informed” part comes from experience gained during previous shoots. PS>I find that a Hoodman Loupe is essential when power-chimping.
As for Nikon gear, it’s dead simple. For what Nikon calls “FP Sync” just put an appropriate speedlight on the hot shoe and select Auto FP in the camera Custom Setting Menu. Not every flash and not every body is capable of FP sync, so check your manual.
FP Sync won’t work with the pop up alone; however, the pop up can act as a commander in Advanced Wireless Lighting mode.
Simply put the remote flash ( SB-800 for example) in remote mode, put the camera in Commander mode, and turn on Auto FP. The wireless remote will sync up to the maximum shutter speed of the camera. No special gear required other than a suitable flash and body combination.
Of course, like all similar schemes, flash output is reduced relative to “normal” flash.
By the way A (automatic) mode, also known as Auto Thyristor mode is a great option which overcomes flash/body compatibility problems which would prohibit normal TTL flash metering. All the metering is done by the flash itself. However, this does nothing for high speed sync. Cameras with normal mechanical shutters are still limited to the X sync speed, usually 1/200 sec or 1/250 sec. Shooting much above these speeds will result in a shutter shadow in A mode.
For more in-depth instructions on setting up the high speed sync, look no further than (go figure) Strobist!
http://strobist.blogspot.com/2008/01/control-your-world-with-ultra-high-sync.html
[...] ARENA POSTS LUCID HIGH SPEED SYNC ARTICLE! [...]
I think I will have to read this a few times to fully digest it. Still, it was neat recognizing where these photos took place.
Thank you! I think you really cleared up the fog for me on this one. I somewhat got it all, but now I really get it. I haven’t been here before, but your on my bloglines now! Hope to see more of this soon.
@Jack - D70 can’t do high speed sync. BUT…it has an electronic shutter. You can use shutter speeds ~ 1/1200 sec. To do this you need either a “dumb” (non-SB) flash or an SB unit triggered in a “dumb” (i.e. on/off) manner, such as PC-sync cord or “poverty wizard” radio triggers. I’ve done this with D70+SB600+radio trigger.
In ref. to the Nikon System’s and in addition to the poster above: I don’t think that the D70 is capable of high speed sync. Also, on the systems that do, automatic high speed sync is activated once the shutter speed is above 1/250 but automatically converts back to normal mode, once the shutter speed is below 1/250.The SB800 has the ability of limited range wireless mode and can be used off camera with an SC-28 remote TTL hotshoe cord. Another alternative is the SU800, which offers complete remote control of the SU800, SB600 and SB-R200’s.
Addendum: Mark, you posted at the same time as I did.. very interesting approach!
My brain hurts!!
Rather than setting up 3 or more strobes to create the portrait that accompanies this article, the smart photographer would place fewer strobes ( or maybe one ) much closer. More power, and better quality from a small hard light source.
The only reason to use many strobes is when you must place your lights far from the subject or you’re using an umbrella or soft box.
High-speed sync reduces your flash power so get accustomed to placing your light closer. The higher the shutter speed the more your output is reduced. And….if you really know what’s good for you, you’ll purchase RadioPoppers. The coolest, most helpful new product in years !
Rex
Rex - To me, smart is about having a vision and knowing how to use your gear to get it captured. The lights were placed as shown because I wanted a long, thin slice of light. I zoomed them out to 105mm for the same reason. To go in “close” with a single, hard source would have created harsh shadows and imposed dramatic falloff that I didn’t want. The closer the light source is to the subject the more the inverse square law comes in to play. Keep the lights way back and the distance between her face and the camera is about the same as that of her knees to the camera. So falloff is effectively zero. Come in close and her face might be twice as close in comparison to her knees. I wasn’t looking to have her face brightly lit with dramatic falloff below given that she’s obviously outdoors on a brightly lit day.
Thanks really nice article.
Syl, sweet site. I think the McNally blog turned me onto you. Anyway, I spent about an hour browsing your site this a.m. You are really doing a phenomenal job with your blog. Thank you sharing in the photographic community. BTW…we adore your neighborhood. Totally dig Paso and the 46! Great piece on off camera HSS flash. I’m a Canon shooter and am eager to see what the next gen. Popper will bring. It would be great if Canon caught up on this off camera flash jazz and made their flashes a bit more Nikonian. Keep up the great work! BTW Killer image up top.m-
Syl,
I re-read my previous post and regret the presumptuous and somewhat rude tone. It wasn’t intended that way.
I enjoyed your article very much and appreciate the website.
Happy to see others using RadioPoppers since I haven’t noticed much advertising and marketing for them.
Rex
[...] the Magnum blog’s list of advice for young photographers. While you’re at it, check out THIS POST at Pixsylated about high-speed flash sync. It’s excellent. I’m increasingly open to the [...]
I just discovered this site, thanks to David from Strobist, and I enjoyed the blog and the comments! Regarding Joe McNally, I think he uses the optical wireless of the flash itself (the flash on the camera seems to be directed toward the other flashes to fire the slaves.) Personally, I tried that and sometimes the optical signal did not reach the slaves. Syl, I wonder, have you, or someone in this blog, tried to use the flashes as master/slave for high-speed sync? I am especially wondering when he uses the umbrella and the flashes are not in direct line with the master. Would an indirect reflection from the umbrella make a difference?
Thanks!
Nice article, very informative. However would like to point out one little thing.. that is that the whole off camera HSS thing was first developed by Minolta in the mid-late 90’s and was a feature in their last film bodies (Dynax 7 & 9) and then followed into the digital SLRs (Dynax 5D & 7D) and lives on today in the Sony Alpha system where it’s available on the entire range.
Much like the Canon/Nikon versions, it’s line of sight except on darker situations and uses the pop-up flash as the master. The new A900 however, does not have a pop-up flash and requires the new HVL-F58AM dedictated strobe as the master. The good thing with the new units is that the power/output of the slaves can be controlled directly from the Master flash, similar (I think) to the Nikon CLS system.
Thanks for the article. It’s good to hear some in depth info about the RPs… been considering them, not sold yet.
[...] learning links for December - Syl Arena has an article about using high speed sync with your small strobes like the Canon 580EX or the Nikon SB-900. You can sync them up to 1/8000 sec! - On the same theme, [...]
Ewen - Great info. Many thanks. I have a hard enough time staying up with Nikon (having spent the past 25 years as a Canon shooter). Nice to see that Sony is nipping at the heals of the other guys. It’s all good for us.
[...] Simple Truths About High-Speed Sync | PixSylated [...]
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