How Shutter Speed and Aperture Relate to Flash

This illuminating tutorial is guaranteed help you take better photos.

In this information-packed photography class, Karl breaks down the relationships between flash power, aperture settings and shutter speeds.

You’ll learn about:

  • Understanding flash sync speeds
  • The relationship between ambient light and flash
  • The relationship between aperture and flash
  • First- and second-curtain flash synchronization

You’ll learn how each of these can work together to influence the final image.

In this class:

  • How shutter speed works in photography
  • Sync speed vs flash duration
  • Leaf shutter vs focal plane shutter
  • Shutter speed and aperture
  • The impact of ambient light on an image
  • Controlling flash exposure
  • Combining studio and ambient light

If you enjoy this class, check out Understanding Flash Power and Fast-Flash Jelly Headshots.

Questions? Please post them in the comments section below.

Comments

  1. Hi,

    So basically in regular studio photography, I should never really change my shutter speed more or less than 125?

    Thanks

    1. Hi Dave, if that is your maximum shutter sync speed (that is the fastest the camera can synchronise the shutter with flash) on some cameras it’s 1/125th on others it’s more. But whatever it is you should go with as that is the speed that will still work with your flash and cut out the most daylight or ambient light but not cut out any of the flash.

  2. Hello Karl, I have two questions.
    first, If flash speed is lower than the camera shutter speed, then what happened; is the black line still appear in the image or not?
    second, if flash speed and camera shutter speed are the same at a higher value; then what happened, am I get properly exposed image or image with a black line?

  3. I have a Sony A7R4, when I attach the Broncolor highspeed trigger, the camera doesn’t allow me to increase my shutter speed beyond 1/250. Couldn’t find an answer on the internet, do you have solution for this?

    1. Hi, I can’t see a reason for this. If you are in full manual mode then you should be able to set your camera settings to exactly what you like on any camera?

      1. Ahhh, it’s an option in the trigger itself for HS sync , and not the camera itself. Once I turn on HS in the trigger, I can increase shutter speed in my Sony camera. Thank you

    1. Hi, unfortunately we can’t advise on all camera models as there are too many but if it has that feature then it will say about it in the camera manual.

  5. I want to know whether my flash should use front curtain synchronization or rear curtain synchronization in studio shooting？

    1. Hi, First curtain is usually fine. The only time you need second curtain is if your deliberately trying to emulate movement with flash and continuous lighting.

  6. Karl, in your explanation of HSS, you said the flash duration is longer to allow the “scanning” of the image. What effect does the longer duration have on fast moving subjects as discussed in your previous lesson – or would you not use HSS for fast moving subjects?

    1. Hi, it doesn’t have any effect because it allows you to utilise a faster shutter speed instead, so rather than a standard 1/200th for example you can now attain 1/4000th with the shutter speed instead of say 1/4000th with the flash duration. Although the shutter at such speeds is a ‘slit scan’ the resulting laydown of the exposure on the recording medium is still fast enough to counter the effect of the ‘slit scan’ in most cases. Even if we were using fast flash duration instead the light isn’t an instant of total exposure of flash at that one moment, there is a gradual build to a peak of intensity of light and then a gradual fall of light called the tail but it all happens within the t0.1 measured period which may be as fast as 1/10,000th of a second on some flash systems. My preference is still for fast flash durations rather that fast shutter speeds with HSS as you can usually achieve faster crisper shots for very high speed work but even 1/1500th is fast enough for many things.

  7. I had a lot of doubts about this particular topic and yes i am fully satisfied with the content that it cleared almost all by doubts in this specific section . Thank you very much karl. The way you convey each topics with the simplest way possible i really appreciate that .

  8. Thank you very much, Karl!
    I entered this chapter with tons of question marks on my mind but left with an absolute understanding of lighting, aperture, and shutter speed. I can’t wait to reveal more great educational content!

    P.S:
    I’m very happy with my educational experience on this platform with the affordable prices. Professional presentation and neat content organization.

    Furthermore, I really appreciate the other educational contents you do, like challenges, live shows, and member discounts, along with the customer service provided. Thank you very much, bother!

  9. Hi,
    If I’m using a continuous light, will slowing down the shutter speed also let in more surrounding/unwanted light?

    1. Hi Juneed, yes absolutely because the other light in the room is also continuous, which is why you should work in a darkened room if shooting with continuous light.

  10. Couldn’t you eliminate the effect of ambient light by finding the aperture that makes the room dark (with only ambient light) and then setting the flash to correctly expose the shot at the next higher f-stop?

    1. Hi, you can always affect ambient exposure with both aperture and shutter speed. But and this is a big BUT, you shouldn’t be approaching your photography that way. The aperture choice is itself a creative decision based on the depth of field look you want in an image so that choice should be made first and then stick to it and adjust everything else you can around it.

  11. Hi Karl. Hope you are doing well. I saw in many answers you tell to make a test about cut out the ambient light. For make this kind of test which settings in my camera should I use? Put the shutter in the max flash sync or less? In my case I have the Sony a7III and it would be 1/250. But I saw you used in 1/60 and you cuted out the ambient ligh. And about ISO? For make this test should I keep it in 100? And about aperture exist a value Rule of aperture for this kind of test? Should I put F8 or if I open it more to F5.6 will be a problem?
    Thanks ✌️

    1. Hi Guigo, we cut out ambient light so that it doesn’t add lighting ontop of our flash lighting (unless we want it to). Ambient light is always different brightness depending on if it is daytime, nighttime, morning, weather, indoors, outdoors etc. So there is not a particular shutter speed that is correct for all of them. If you want to cut out the most you can with your camera then 1/250th is the fastest flash sync speed you have so that is the one you should choose. If you want some ambient light in your picture then choose a slower one (by testing it). If 1/250th isn’t fast enough to cut out the ambient light then you would need to think about reducing your ISO or closing the aperture or using an ND filter. In most cases 1/250th will cut out most of the ambient at f11 but not at f4. There is no rule only the settings that work and allow you to do what you need with light, motion and depth of field.

  13. Hi there, thank you for this tutorial, I figured out that my camera can’t do slow shutter speed with a flash unit because it’s missing a pin in the hotshoe (probably), I’m only able to shoot pictures with flash above 1/250th, if I go below that (which I sometimes want for ambient light to come in also if I’m outdoors, the flash unit doesn’t fire, even if I switch off HSS, I hope to get this fixed with another camera soon, I’m using the Canon EOS 250D now, going to buy the Canon 90D in about 4 months, with that I’m using the Godox AD200 in Manual mode.

    Any way I can still get this working with a work around? You said something about ND filters, but I think that answer was because I didn’t explain it right…

    Anyways, thank you very much for this tutorial, learning a great deal this way 🙂

  15. Hi Karl,

    Can high speed sync be used to make up for a long flash duration? For example is f8 1/200 with a light power that has a 1/4000 flash duration the same as shooting f8 1/4000 with HSS if the light were to only have a flash duration of 1/2000? Hopefully this makes sense.

    Cheers.

    1. Hi Squiggle, no that makes no sense at all. 1/4000th or 1/2000th is much quicker than 1/200th so those very fast flash bursts happen easily within or inside the time of the flash sync. HSS is a different way of working it usually relies on a longer flash burst of like 1/500th of a second so that you can use a faster shutter speed like 1/4000th so what happens is your shutter speed ‘syncs’ with it but it also cuts off a lot of the flash either side so it looses alot of the exposure which is why I’m not a fan of HSS. Like anything though people overcomplicate things. First of all ask yourself ‘what am I trying to do and what do I need it for’? Then from there you test or work out how to solve it. I see far to many photographers getting lost in the specifics rather than focusing on telling the story with their images, what happens is they concern themselves with the technological aspects to the point that it stops them getting on with shooting and creating. First tell me or yourself what it is you’re trying to achieve and why and then let’s go from there.

  16. Hi Karl, my apologies in advance for the silly question; I am still a neophyte. I was wondering why a shorter shutter speed would not allow ambient light in. When you shot the photo of Stephanie at 1/60 of a second, the camera only recorded flashlight. However, if you had shot with no flash at that same speed, the camera would have recorded some ambient light. Probably it would have resulted in an underexposed shot, yet some ambient light would be captured. I must have misunderstood something from your explanation.
    Thanks for the answer and most of all for the outstanding course!!

    1. Hi Max, It would also depend on the aperture. Remember the aperture also dramatically affects the amount of ambient light coming in. So 1/60th at f8 might not let any ambient light in to the camera (in an indoors situation where the light isn’t as bright as outside) but 1/60th at f1.8 would let some ambient light in. The best way to find out is simply do a test shot without the flash trigger to see if any ambient light shows up. Generally speaking though it’s always better to go with the fastest shutter speed you can (that’s called the cameras sync speed) and use that to cut out as much ambient as possible. If you find that even with the fastest sync speed and the desired aperture that you still have ambient light pollution then you must reduce the ambient light pollution.

  17. Hi Karl! Love the way you teach. I just have one question from this class, just to check if I understood everything: If I want to shoot some portraits with movement (someone dancing for example), I can do that with a slow speed on camera if I don’t have ambient light? With natural light I always shoot with high speed, but in studio, is the flash doing that work? Thank you

  18. Hi Karl, the lesson was super clear, I just have one question, what is the difference between High speed sync and Hypersync flash photography? thank you for your time!

  19. Head rush Karl, so easy to understand. I have asked many people to explain this and you made it simple. Thank you

  20. hrachess

    Karl, after watching this whole course, I still have one question (sorry if it sounds little stupid). So I understand that making shutter speed slower in studio while using strobes, just allows more ambient light. But my questions is following. Let’s say you shoot outdoor with 1/10th of even slower shutter speed and hand held, you will most probably get not that sharp images right? so if you do the same but in studio, where is no ambient light, all dark, just a strobe light, but again hand held and slower shutter speed, won’t it have an influence on the sharpness of the image??
    I understand that it’s just burst a of a speed light which is very quick, but if camera is hand held and shutter is still open, won’t it make little blurrier picture? or it will be exactly as sharp as it’s when 1/5th, 1/100 or 1/800… ?
    The reason I’m asking is because I want to understand, in case of shooting water splash or falling object in studio, what real difference will be in terms of shutter speed changes, considering no any ambient light…
    Thanks in advance,
    Hrach

    1. Hi, if you shot in a very dark studio with a fast flash and a slow shutter speed then you could shoot hand held at 1/15th if you wanted to and it wouldn’t make any difference because there was no ambient light to be recorded. The flash would freeze everything but your composition might be poor because you couldn’t see what you were shooting. If it was totally black in your studio it wouldn’t even matter if your shutter speed was 5 seconds long because no light is no light, the only light is the burst of flash which fires with a short duration freezing your subject. However we don’t often work in totally black studios, so it’s always advisable to take a test shot without the flash trigger to see if your camera recorded anything.

      1. hrachess

        Thanks Karl. Just wanted to make sure that I understand the theoretical part correctly, as I don’t have that much experience and tests with studio lights.. Appreciate the answer and your time.

  21. derrick_connell

    My brain hurts but my heart is singing!

    The insights on both high speed sync and second curtain sync are phenomenal. I am off to test both out. I love the effect of the second curtain sync.

  22. Hi Karl!
    I was wondering… in what cases would I need a faster shutter speed (and as a consequence choose first or second curtain) if the freezing motion is based on the speed of the flash?
    Thanks

    1. Hi HC, you don’t need a fast shutter speed if using high speed flash, you can use any shutter speed (up to the sync speed) even very slow shutter speeds as long as you are shooting in a darkish room.

        1. Where you are shooting in a bright room with lots of other light or where you’re modelling lights are on full brightness.

  23. Excellent as usual….I think this is the 5th one I’ve watched in a row! LOL. You stated that HSS is a “work around” for higher shutter speeds. I understand the downside as speed light battery consumption will be quicker. What are the other downsides to it? Color balance issues? Ambient light pollution? Thanks!

    Arjun

    1. Hi Arjun, the main disadvantage is that for HSS to work the flash is actually using longer burn time flash bursts, so usually near full power and there is not much control over the flash power from the flash itself. This has to be done from the camera which reduces the versatility a little.

  24. If a camera doesn’t have a 2nd sync option, is there a way around this? Perhaps and external flash with that setting?

  25. Hi Karl, very clear explanation! Can I confirm that I will also need a HSS enabled flash head aswell as a HSS trigger. So for example I won’t be able to use my old Profoto 600’s to synch above the camera synch even if I swap out my old wireless trigger for a new HSS trigger? Thanks Steve

    1. Hi Steve, yes my understanding is that is correct. I’ve only used HSS once to demo on a broncolor siros ‘how to’ video so I’m afraid I’m not an expert on it. But from what I understand the flash burst actually becomes longer so that light is exposing for the entire time the small slit of 1/8000th passes over the entire sensor. To do this requires the flash in a HSS setting and a capable trigger.

  26. Hi Karl,

    Quick question. I just bought some cheap Interfit studio flashlights with soft boxes. Apparently my camera supports 1/200 sync speed. However, when I choose that shutter speed I can still see the shutter towards the bottom of the image, takes up a bit less than a third of the image. Of course, if I slow the speed down then I don’t have that issue.

    So my question is, am I doing something wrong? The camera definitely supports 1/200 sync speed but it seems I need to make it slower.

    1. Hi Chris, you’re camera is either not supporting 1/200th or the triggering method has a delay problem. I would expect it’s the first, I once had a Canon 5D that was supposed to be 1/200th and I could only ever get it to sync at 1/160th.

      1. Thanks Karl. It seems I have to set mine to 1/125s. There’s a part of me that thinks it’s maybe the trigger as they are not overly expensive lights, this was also on max power so I might try reducing the flash power to see if that makes a difference. Maybe if I try some proper studio lights in the future I might get my answer. Thanks again for responding.

        1. Hi Chris, try an actual sync cable from the camera direct to the lights to figure out if it’s the trigger.

  28. Hello Karl,

    I just want to say that I am absolutely flabbergasted by your online training course. It is amazing. I have learned so much in such a short time.
    That is by far the best money I ever spent. Just like you said in your advert, first invest in yourself and then in your equipment..

    Thanks Karl,

    Keep em coming..

      1. Hello Karl, yesterday during my self portrait shoot I ran into the problem you explained in detail regarding flash sync speed. I was shooting with a fast shutter speed to eliminate the ambient light and I just wanted to light up my face with the flash using the inverse square law. During the shoot I just wasn’t able the see the bottom of my face, it was always dark and then it hit me, I remember your course on sync speed. I was shooting at a shutter speed of 400, and then I found out that my max speed without a high speed flash sync is 320. So I adjusted my f-spot, shallow depth of field had no use here as my back ground was all black. And then I got it to work. Thanks again, I would of never figured that out without seeing your course.

  29. Hi Karl, really loving the courses so far thank you! Does changing the aperture to increase or decrease the flash power then have an effect on the depth of field / background blur?

  30. Hi Karl! I hope you & your team are staying safe due to this hard times. Well, I have a question for you. I have a high sync speed trigger (according to manufacturer 1/8000s), do I have to change trigger in order to let some ambient light in or just a slower shutter speed with same trigger will do? Thank you in advance.

    1. Hi, thank you I hope you are well too. This is one of those questions where I’m afraid you will just have to try it and see. Sometimes 1/8000th is going to be much too fast when you are trying to combine flash with daylight because you will loose all the daylight. Other times you may be in the studio only trying to shoot some fast motion and then it will be fine. But the simplest way of finding out is to take your camera outdoors and put it on a tripod, set up your flash and trigger and just play with it and make a note of each result on a note pad while you test a series of shots and then keep those shots on file for future reference. Have an object such in the 3m range and then look at the results of the light on the object and the further (daylight) background at different settings.

Leave a Comment