understanding flash duration is a really powerful tool for studio photographers so today we're going to break down some really practical demonstrations about how to actually understand exposure time with your strobe and how it affects your shots [Music] hello my name is Jean Lefit commercial photographer and educator and I'm here with Professional Photographers of America to break down in simplistic terms how flash duration affects the exposure in your studio shots now we all know that our cameras can have a certain shutter speed that we set but not a lot of people know that your exposure time also depends on your flash most of the time we're photographing subjects that don't really need a fast flash duration because the general flash duration is going to be faster than 1 250th of a second anyway but in circumstances where you need to use flash with a really fastmoving subject and you don't want there to be too much motion blur you need to understand how the power of your strobe affects flash duration now before we hop into the studio for a practical demonstration I just wanted to let you know that if you're ever looking at the spec sheet for a strobe say you're in the market to buy one and flash duration is a concern for you you'll want to make sure to check the T0.1 score for flash duration not the T0.5 the T0.5 is a little bit more of a lenient test that allows the manufacturers to say that they've reached a much faster flash duration that is actually practical in the studio so look for that T0.1 score to get a more accurate measurement all right with that said let's go ahead and hop into the studio all right so I have a really practical basic demonstration setup here it is nothing beautiful it's not going on my portfolio it's just to show you how the flash duration affects the motion blur of this standard room fan here um I've got two strobes just one to shoot directly off of the fan and then I have one with a yellow gel just to give it some separation from the background again this is nothing uh crazy so don't pay attention to how I'm lighting this but really what we're going to be focusing on is turning this fan on and seeing how the power of these lights um affects the flash duration the camera right now is set at f-22 because these are maxed out at power 10 so I'm going to go ahead and go to low let it catch up to speed let's have a look here so now we can see how much motion blur was introduced this is at 100% scale here and you can see that there is plenty um I have no idea how fast these fan blades are moving i just know this is on power low and we're getting a pretty decent amount of blur i'm going to bump it up to power high just to see if there's a big difference hopefully it's not too annoying in the mic will see and that is how much motion blur we have on high power so it's kind of crazy um you wouldn't think that that much motion blur would occur during the time of an exposed uh flash power and I should mention this is at 500 watts these are 500 W strobe heads so what you're seeing is 500 watts of power being run through the flash tube and dissipated um and it'll vary from model to model depending on your flash model and how much power goes through it uh but in general at high power you can expect motion blur to look kind of like this so I'm going to go ahead and knock this down one stop from power 10 to power nine as well as the background light and that means I need to up the exposure one stop on my camera so 1 2 3 back to ISO 100 here and let's take another test and see what happens to the motion blur there we go it's a little bit less you can kind of see how that's working so let's just work through the power range i think you understand what's happening i'm going to move down to power eight power eight take another shot here there it is yeah we can we can clearly see how the motion blur is getting less and less with each stop of light we take out take the power down again one more stop from 8 to 7 i will need to decrease my aperture to f16 which is one stop up to compensate let's take another shot here and there we go even less so about every time we have the power or remove one stop it's getting about half the amount of motion blur so it's just like controlling the shutter on your camera but we're not relying on the camera shutter we're relying on the flash and what's cool that you'll see when we get into the lower powers is we can get much faster flash durations than our actual shutter speed which is pretty fun so I'm going to drop this down one more time six six and 1 2 3 we're at f11 i'll just take the shot from here there we go again it's getting lower so we're going to go 1 2 3 that's f8 yep even smaller so again we're moving it 1 2 3 take another shot let's have a look at that again motion blur getting a little better not as huge of a difference now because we're getting into smaller increments but let's do the same thing there we go once again even less so let's keep going down one stop so now we're at power two there we go getting pretty tiny on the motion blur there the edge of that fan you look at that highlight on the top blade there it's getting real small but it's still there there we go again and that's looking pretty decent now i don't think it's quite acceptable it's still a little bit blurry but if we zoom in here on the text this is at 200% on my 4K monitor so we're still getting some motion blur and that's okay we can still drop the power on the strobe even more so I'm going to actually take them all the way to the bottom of their power range which is 0.1 which is a very cool thing about the Profoto strobes that I like is the range of these ones goes from 0.1 all the way up some stop at one which doesn't give you a lot of low-end power range control um but because of that I need to go up another stop to ISO 400 here let's have a look now perfect yeah so we can see we've basically froze most of the motion here there's still a little bit of motion blur you can see the sampling here uh on the edge of this blade and just to double triple check that it's not my focus I'm going to stop down this aperture let's go f6 which is two stops and ISO600 just to make sure I've got it all in focus here there we go so we can see exactly what's going on now there's still a little bit of motion blur here you can see at the edge of the fan blade and of course as we come into the center the speed becomes less and less so the motion blur is going to be more exaggerated out here at the end right on these corners we can see how tac sharp the blade is on the ends and how blurry it is right here so we've lowered the power of our strobe as much as we possibly can and we're still getting a little bit of motion blur so what can we do well if that's all your strobe has that's all the features you have uh then there's nothing else you can do you'll have to figure out something else for your subject but fortunately for me with this particular strobe I actually have a freeze mode now what the freeze mode does is it makes the dump of power faster through the capacitor but it sacrifices color quality which means the hue of the color temperature might shift a little more blue in fact it shifts quite a bit more blue um but it does allow you to get more power out of your strobe while also lowering flash duration so as long as you have your white balance card and after you get everything all set up you make sure you white balance to a gray card then you'll know that your white balance is fine um the trouble is when you start mixing other types of strobes with it you'll get a more blue strobe and a more warm strobe so just make sure that whatever you're doing you know how to manage your color temperatures use color temperature gels if you need to match different lighting um but for me because both of these lights are the same make and model I know that I can just put them in the same power and they're going to function identically so that's what I'm going to do uh if I come up here to my strobe I will take this off and show you here in camera every strobe model is going to be a little bit different i think Profoto is very intuitive but if I click on this I can go down to flash mode here there it is and just click and it goes from normal to freeze so your strobe will probably have a freeze mode unless you're using a speed light that's something else I should mention is that speed lights or on camera flash those little ones that uh go on your camera um those are actually a lower powered flash and sometimes you can get much faster flash durations out of those than in a strobe like this just because of the way they're designed they're low power but they are very effective at fast flash durations just because of the nature of their design all right now I just need to change the background light to also go to freeze mode there we go and we'll keep it on power.1 see what happens all right so we'll see that the color temperature has changed quite a bit it's gone from the nice pure white on the fan there to this kind of bluish color which is uh normal for freeze mode so I'm going to just select the white balance tool here and uh reset that so now they should look pretty much identical um and that looks really nice we're actually getting a very fast flash duration let's look here absolutely no mo motion blur whatsoever the text is very very good looking um yeah it's looking wonderful so I'm going to go ahead and start raising the power to see when the motion blur starts to come back so I'm going to go up to power one take that let's have a look again it's looking really good the text is nice and clear um so we're good to go let's go up another stop so now we're at power two and it still looks really sharp i'm super happy with that definitely nothing to complain about good yeah it's still tac sharp if I hop in here to the text we can see that it's completely legible um we might be getting just a little fuzz here uh that could be also just being slightly out of focus but it's not bad at all if the motion blur is there it's still very minimal hardly noticeable uh but of course it's dependent on your scene and the results that you want now you can see that the color temperature is actually shifted a little more magenta now uh which is kind of interesting that's just part of how the flash mode works it sacrifices that color accuracy so that's why I say as you have the lights set and working properly and you've got them into the right power then take your white balance sample with your your white card because it will shift around with this mode um but let's go ahead and continue to turn it up and see where it gets to a point where we're noticing it so we're going to go up one more stop and I'm going to start stopping down my aperture again to f8 still looking pretty good we are starting to get more motion blur now which is becoming apparent so this blur here is definitely uh getting worse but it's still not bad it's still so much better than without freeze mode which is impressive and you'll also notice that the audible pop from your strobe is going to be a lot u different it's more of a click now because of that burst of energy being so much faster you can actually hear it which is fascinating um but let's go ahead and continue to change this so now we're up to power seven there we go now we really start to see the motion blur on the fan blades and it's still in the center legible but it's getting to the point where I would say this is too much power so it's still impressive it's blocking out the ambient light as it is right now which is really cool actually um so I'm amazed we're able to get up to power what was it six before it became a real problem and again this fan is on fast you know the fastest speeds so I don't think you have any issue at these higher powers with um a normal subject like a a a dancer or water splashes or things like that so let's go ahead and go up one more there we're at f22 at power 8 definitely a lot more noticeable now and now we're starting to see things are getting overexposed because I don't have enough power range on the camera here but the motion blur is really bad now um go up to power 10 max it out on those strobes there and there we go now we've lost all control of freeze mode at this highest power all right there we go so I just ran through the powers real quick with freeze mode off and with freeze mode on and you can see the differences as we worked through it um with power 10 you're always going to get motion blur with a subject moving this fast but it is still significantly better so I'm going to go ahead and show you the difference between let's just say power five on freeze mode and power five on not freeze mode just to see the difference with how this strobe performed all right so here you can see the difference on the left we have the nonfreeze mode flash at power 5 and then this one on the right of the freeze mode on power five and they're both shot at f8 so exposure is similar the only real difference is if I set these to their default white balance you'll see that the one on the right is a lot more blue um but again not a huge deal you just take your white balance tool select something that's white or use a gray card and they should match pretty similarly so that is uh in a nutshell how flash duration works in a practical sense you can memorize the numbers you can look at your flash duration chart for your particular strobe models and all of that stuff but in reality all it comes down to is knowing how much power is going through your strobe and if you have a freeze mode definitely use it but just be aware of the color shifts that should get you a decent understanding of flash duration let's go ahead and just do a quick montage of some real world demonstrations of when you might use this so I've set my little scene up here with this atomizer and you can see I've done a test shot already in Capture One and it's looking really nice and I'm actually kind of surprised because I thought this would take two lights at least but actually I was able to achieve this with one light and then this nice large fill card kind of bouncing the light back into the front and I positioned it just so that that highlight goes over where the water or the the perfume is going to be spraying out and the reason I wanted to do a perfume shot is well because one I'm getting older and now that I'm into my 30s I figure I should probably start buying some nicer cologne instead of like the cheap axe and Old Spice stuff I used to use and I think this will be just a really good example to show how we can use flash duration to get the result that we want out of our motion blur and to freeze the time really well so I have the strobe in the back the one strobe set at power five currently my camera is set at f13 and um the strobe is set in freeze mode so that we can freeze everything um now I've got my uh wireless mouse here ready to go over in capture 1 so I can just click this to hit my shutter which is really nice instead of having to bump the camera because this is such a tight um composition any little bump will shift it a little bit here and there super simple nothing too crazy it could potentially use a top light to kind of separate the top edge of the bottle from the background but I think it looks pretty good as it is so let's go ahead and give it a try and see what's going on so I'm not really sure how I want my hand to come in here i don't I don't know if I want it to really be seen that much if I just want it to be my finger or maybe eventually I just don't want anything at all but let's do this test and see if we can get the spray to happen at the same time trying not to move the bottle so it stays within the plane of focus but let's give this a try ready oh that was way off that was way too late oh and you can see that my hand is blocking a ton of the light coming forward which I should have expected so I'm going to have to just come in here from the top like this depress this down and try to get it as soon as I can there we go that's a pretty good little spray let's have a look at that this is looking pretty cool actually i didn't think there would be this much motion but this little bit of motion actually looks really cool so I'm going to go ahead and do that same shot but I'm going to take my strobe out of freeze mode just to see the difference so the only thing we should see change now is just the color shift all right same thing here we go it's starting to smell really good in here all right let's give this a try little late oh there we go perfect okay let's have a look okay yeah there is a huge difference now let's have a look at this in full screen so with this shot compared to the other one we can see how much more motion blur there is if I go back to that last photo where we got that good spray and I select both we can see the difference so this is the same power of light uh we can see the the difference in color temperature but also we can see the difference in how much detail we get within the spray now the timing I think was very similar on both but we're getting a lot more motion blur so this is filling in this side of the frame really well compared to this one and we're still getting all these little bits here that are actually frozen in time too so it's kind of cool i I like the results of both there's really no right or wrong answer but this is all based on the flash duration let's have a look at those and see if we got anything good oh wow that is so cool looking i was not expecting that wow that is so cool okay I love that look at how that sprays out that is so neat that looks really really cool i love how you can kind of see all that detail now if I wanted it to be even sharper I could drop the exposure or the power of the light even more open up my aperture more but you can see that the liquid in the bottle is already starting to get lower and I don't want it to get so low that it's ugly and so we're running into that issue and I don't have any refill um so we're kind of limited on attempts here but I really like how this looks it's fun there's a little motion it's not too dead um so yeah I'm just going to take a couple more shots see if we can get something really nice and then save the rest of this uh fairly expensive not super expensive cologne but that's basically all there is to it to this particular shot that I'm doing all right there you have it i hope you learned something useful in terms of understanding flash duration again it's a very technical thing but in the real world just practicing it and understanding it isn't too difficult so to recap the key things to understand are the lower the flash power is the faster the flash duration will be in general and if you have a freeze mode you can use it to very great ability to make your higher powers flash even faster as long as you're okay with sacrificing some color accuracy and a quick tip that I forgot to mention during the demonstration if you have your flash duration where it needs to be and you're not getting enough exposure to your subject you can actually stack together multiple strobes and put them side by side or if they're little on camera flashes you can even like tape them together and you will get more light output even though each strobe is still at its lowest power or at the power necessary to get the exposure time that you need so feel free to experiment with that stacking lights together to add more exposure to your scene but before I go be sure to leave a like on this video if you liked it if you learned something new and leave a comment below letting us know what you would like to learn or if you have any questions I'll be down in there answering them for the first week this video goes live so be sure to get those in below and be sure to subscribe to Professional Photographers of America and turn on the bell icon so that you're notified for all our future tutorials we cover everything from photography to lighting to the business side to time management to anything you really need when it comes to photography professional Photographers of America has you covered with that again my name is Jean Lefit and I will see you soon [Music]