Correction actually: when you’re using manual flash, it’s your shutter speed that controls your ambient light, not your aperture (strictly speaking of ambient light). Your aperture actually controls how bright or dark BOTH ambient and flash are, not JUST ambient (ISO controls this too). So when it comes to understanding flash durations with manual flash settings, (meaning how much light output the flash emits when you take a shot) think of it like your houses thermostat in the winter. The longer it stays on, the warmer it gets. The shorter it stays on, the not-as-warm it gets. Same with flash durations- the longer the flash stays on during the shot (again, how bright it is, usually notated as a fraction of 1/1, full power) the brighter the flash is for that one picture. The shorter the flash stays on, the darker the flash will be for that one picture (most flashes notate this as, again, a fraction of, say, 1/128). Flash power (aka flash duration) is measured in how long or how short the flash is on for. So, with the house analogy- the longer the flash is on, the warmer the house gets (the brighter the flash). The shorter the flash is on, the not-as-warm the house gets (the darker the flash). Also- not considering any form of high speed sync- the reason why your cameras shutter speed controls ambient light and doesn’t affect your flash power (unlike aperture and iso, mind you) is because most cameras sync speed are around 1/250 or so...whereas most flash’s duration times are from, say, 1/10,000th of a second to maybe 1/60,000 of a second. So cameras at 1/250th can’t even get close to flash’s lowest duration of around 1/10,000th. Therefore, your shutter speed is ONLY affecting how much or how little ambient light you get in the shot, it doesn’t affect flash power at all. So, for flash durations, setting the power manually down to the lowest setting of 1/128th means you get the lowest output/a really fast flash duration of around 1/60,000th of a second or so. And on the flip side, setting the power manually up to the highest setting of 1/1 means you get the highest, brightest output/a really slow flash duration of around 1/10,000th of a second (even though that’s not slow but you get what I mean). Fast duration = low output Slow duration = high output Make sense? Hope this helps! P.S. I love explaining light and stuff
I’ve just started to get into this technical about flash. From what I read so far is that there is a measure called T1 which is 90% of the duration of the flash pulse. I own an AD200 pro Godoy strobe and it’s T1 at full power is 1/220sec. Does this mean that although my camera synch speed on my Nikon D810 can go up to 1/320sec I would get maximum power only when at 1/220sec?
This tip is really clear and visual, many people just think that flashes are just a lamp to illuminate the scene and here Mark really tells and shows how flashes are freezing the motion. Thanks 👍 if anybody don't know how to work with flashes I also recommend to watch a video where Mark explaines rear and front curtain sync
Very nicely thought out. To add a detail to your mentioning of the flash duration, such short times are feasible with speedlights and some strobes but generally at 100% power, duration is between 1/200 and 1/1000 second. If strobes have their longest duration near the 1/200 sec, there is a risk of cutting some of the light short with the camera's shutter. Especially with in-lens leaf shutters.
Pretty good demonstration of one concept; how flash freezes motion, but as someone else commented here, the video is not so much about flash "duration" as the title suggests. I always like Mark's videos but this would have been more complete by showing what happens as you begin to introduce some ambient light with progressively slower shutter speeds and perhaps demonstrating the difference between 1st and 2nd curtain sync and how that choice can affect the appearance of the blur as you blend ambient and flash.
Great vid, but I don't think the title is accurate. I don't think the video explains flash duration so much as it just explains what flash does generally to subjects in motion.
Thanks Mark. I suggest a second more in depth video where you explain that taking a flash photo involves two separate exposures at the same time (ambient and flash). Then go into how to use front and rear curtain sync to intentionally show blur with a sharp subject. (i.e. a moving car or dancer).
The ball doesn't show up because it's darker than the background. Since the background is brighter it's exposing or saturating the darker part of the sensor (where the ball was) after the ball moves effectively erasing it from the sensor with light. Just like film you can't bring back darker objects after it has been exposed to light. If you would do this same thing with a background darker than the ball, you would see the path of the ball and it would look like a smile. This only applies to the ambient light shots. Regardless, this is a good video showing how well flash does when it comes to freeze motion. Thanks for sharing
Helpful video but given the title, I was hoping for more depth regarding flash duration specifically. Although it's not usually as important as other factors, it would be cool to see a video focused on flash duration and show examples of when differences in flash duration can actually matter (e.g. compare cheap and/or long duration strobes with more expensive and/or short duration strobes, or even look at variable-duration strobes if those exist?). Always looking forward to the next video, keep 'em coming!
Nice video! Anyone can get pretty good at photography in ambient light, and then become a total novice when using flashes and actually controlling the light.
Hi nice video this method work with dancers or people in movement ? You got profoto flash, i think it more simple... this method work with other studio flash ? Ty for answers.
Thank you Mark for the good video, you could just go deeper on the Flash settings as they are many we can choose and there is the problem. Thank you anyway for the simple good video.
You did not explained, What if shutter speed is longer like before, i.e. 1/2 second? And what is the FLASH DURATION (different durations), which is the main topic?
can you explain to me way the older flashes are more powerful than the new ones because I tray to use a Sunpak 622 but they over expose the shot do they have more duration because on negative cameras in 35mm zick at 60 of a second I appreciate your answer God bless.
Mark, will you get a ghosting effect or blur if you allow too much ambient light in while also using a flash? I have done some action shots outdoors and I will get a blur after the leading edge of a person (it follows behind them) and I think it is because of me metering too close the ambient value of the light, am I mistaken in my thinking?
Definitely sounds like the shutter speed is slow enough to cause a ghosting effect with ambient. If that isn't an effect that you're intending, adjusting the flash power and shutter speed (something a little faster) possibly could work? Or would rear curtain sync be an option, where the flash fires toward the end?
Flash will only " freeze " action if its contribution to the total exposure exceeds around 70% or there abouts. So if your shutter is too slow to freeze the subject in ambient light, a flash of insufficient power output won't help ( it will likely only act as a fill for shadows ). In those circumstances where you are using flash in bright ambient light you will still need a fast shutter speed to freeze subject motion unless you are really blasting the subject with a very powerful strobe for example. Understanding the ratio between flash and ambient is important when it comes to freezing motion 😉 You could use High Speed Sync, however the power output of most flashes/strobes drops significantly due to the pulsing nature it needs to do to keep up with a faster shutter. In that circumstance you end up with a similar problem of the ambient contributing more to the exposure than the flash and again subject blur occurs. The ball in Marks tutorial " froze " because his flash was contributing 100% of his exposure, his shutter speed eliminating totally all ambient from being a part of the exposure. Hope that helps 😉
The short answer is 'yes'. By lowering ISO, you can reduce the contribution of "available" light (continuous light). Go to an exposure without flash that gives an even black shot without any details. Then add in flash. The trailing blur is because the default flash trigger by the shutter id upon arrival of the first "curtain" in you focal plane shutter on the other side of the frame. Whilst there, the second curtain lingers a tiny bit and departs. Some more pro cameras allow you to move the flash trigger to 'second curtain' where the trigger happens upon departure of the 2nd curtain. The effect to the blur is it now will end the motion with the sharp flash exposure. Mark may have uploaded a video on flash, sync, and focal plane shutters several years ago. It should visualuze this explanation.
Flash curtains confound me... so much can be done with flash and shutter speeds ... I want to learn.... I want to get out of point and shoot. I have a D750 coming on Nov 5th. Rather excited.... I want to learn Light Room and Photoshop... I may never be able to completely explore all aspects of either.... But first I must master lighting
How was the jamon Iberico? Hopefully I'll be there at thebeginning of next year. Try the southern part of Spain and particularly a little town called Mijas and you will never forget my advise. Make sure to take your camera with you.......you should do a program there, get yourself a local model, dress her in whit and see what will happen. Good luck. As always I'll be following you.
= Wrong explanation. = Why is it wrong.? And how does it really work? Read below. 3:12 and 3:30 the ball is not "dodging the light". Remember the light is moving at 300000m/s. It has plenty of time to bounce and hit the sensor before the ball moves 1 millimeter. 3:53 It is not the light has not time to reflect. Proof is if you have shorter shutter speed the ball will be more detailed even though it has less time to print on the sensor. Therefore the explanation of "less time to reflect" is wrong. My guess is Mark wanted to simplify the explanation. But this is not simplification it is simply wrong explanation which prevents to understand how a camera really works. = The sensor and the shutter speed. = In fact the shorter the shutter speed the less motion blur because the ball has smaller movement. Each pixel of the sensor gets many photons during the picture is taken ( the shutter is opened). The mix of those photons on the sensor trigger the signal that makes the resulting image. If a sensor pixel is in front of the wall then it receives only yellow photons (yellow color wave). If a sensor pixel is in front of the ball then it receives only red photons. If the ball has time to move while the shutter is opened then the pixel receives reflected light from both the ball and the wall. The sensor mixes the 2 colors and the resulting picture shows a blurred ball. The shorter the shutter speed the less the ball can move during the frame. therefore the pixel only "sees" the ball (not the wall which is hidden). = What happens with the flash? = Basically Mark killed the ambiant light. Short shutter speed + closed diaph + low iso makes no light on the sensor. Therefore no photon print on the sensor, no color, no image. (Result with the flash would have been different if the ambiant light was not killed) Then the flash triggers. It is much shorter than the shutter speed. It is so short that the ball has barely time to move. The light reflects on the ball, the sensor captures it. Then flash dies before the ball moves. The scene goes dark for the rest of the shutter is opened. The result image is colored pixels of the ball not blurred. = You can freeze movement without flash = In fact you will have the same result without flash but with a much shorter shutter speed. Your problem in this case will be to have enough ambiant light. You may open your diaph (will probably not be enough by itself), add powerfull light (summer mid day sun, or cinema projector), raise your iso (will generate noise). In fact when you have shorter shutter speed you allows less time for photons to react on the sensor. Therefore you need to compensate the reduced amount of light by orher variables (more light from the lens or more light in the scene or more sensibility of the sensor). = diaph and iso = When you open your diaph you have more light coming through the lens. And when you increase iso you make the sensor more reactive to received light ( sensor needs less light to trigger the signal which will become a pixel on the result image).
