The whole concept of shutter speed in regards to studio flash duration seems a bit confusing for many people. So I am going to explain why shutter speeds, when shooting with studio lights, generally don’t matter much to the photo.

First of all, when shooting in the studio, it is generally a dark indoor environment except for a bit of ambient light. So if you are shooting at ISO 100, and an aperture of F/5.6 or higher, then you are going to pick up very little of the ambient light when shooting. That is unless you are using a very slow shutter speed of say 1 second or longer. Thus, it is safe to say if you are using a shutter speed of 1/125th of a second or faster then you are hardly going to pick up any of the studio’s ambient light at all. So in regards to the light the camera sees in the studio, it is as if you are shooting in a pitch black room even though you are not. And what your camera will actually gather in terms of light when you take a photo is really only the light that will come out from the studio flashes.

Now studio flashes generally have a very short duration. What I mean by duration is the amount of time that the light is actually emitted from the studio flash is a very short time, normally in the range of only 1/1,000 to 1/8,000 of a second (depending on brand, type, and model). That is extremely short if you consider that to blink your eye takes much longer at around 1/100 of a second.

DLSR cameras have a limit on the maximum speed that they are able to release the shutter at while still being able to synchronize with the firing of an external flash. That maximum shutter speed is usually between 1/200 to 1/250 of a second. Now, even though the flash’s duration is much shorter than 1/250 of a second, the camera will start opening and closing the shutter before the flash even goes off since the shutter starts to open first and then triggers the flash thereafter. Therefore, actual shutter speed needs to be much slower than the duration of the flash in order to synchronize properly. If the shutter speed is too fast then the shutter curtain will open and close before the flash has a chance to even fire.

Some flashes though, depending on brand and model, have a longer duration, which means it takes a bit longer for the flash to fully emit its lighting power. So in those cases the shutter speed might need to even be a bit slower than 1/200. Some flashes require a sync speed of around 1/160 or even 1/125 of a second in order to properly sync the camera shutter when the light from the studio flash is emitted. Generally, the more expensive the lighting equipment is, then the shorter the duration time is for the flash.

Now why is this important?

Typically, a short flash duration is more desirable because the shorter the duration of the light, the greater the flash’s ability to stop the action and get a sharp picture when shooting a moving subject. For example, freezing the action of a water splash or a model jumping through the air requires a shorter flash duration than a stationary subject. If the studio flash has a long duration though then on action shots you may end up getting a partially blurry picture. And again, this blurring that is occurring would not be based on shutter speed, but the duration of the flash light itself.

Normally when you take a photo outdoors you are using ambient light. Ambient light is what is known as a continuous light source. And when the light is continuous, the shutter speed controls the amount of exposure for the photo as the light is continuously going into the camera’s lens. In the studio it is different. There is very little continuous ambient light and the light we are working with from a studio flash is known as intermittent light because of the fact that it turns on and off very quickly.

This means, when shooting in the studio, if your shutter speed is 1/30th of a second, 1/160th of a second, or anything in between, it makes no difference. Once the light from the flash turns on and off at a minimum of 1,000 of a second there is no more light being emitted, except for the small amount of ambient light, which the camera will not pick up much of if any. So even if the shutter remains open a bit longer with a shutter speed of 1/60, the amount of light being recorded by the camera won’t change much.

So if you were shooting a water splash at 1/30th of a second would you still be able to freeze the splash in the photo? The answer is yes as long as the duration of the flash itself is short enough to stop the movement of the water. This also means that even if your hand is shaking a bit when you are taking the photo it would make no difference as the flash will go on and off before your hand has time to move the camera and have any effect on the picture.

So when if at all does shutter speed in the studio make a difference?

If for example you were shooting in the studio and there was a strong ambient light source from a powerful continuous light source or strong natural light coming in through the window, then you might have to be more careful about shutter speed.

The easiest way to find out if the ambient light in the studio will have any effect on your photo or not though is to set your shutter speed to what you plan to shoot at, say anywhere between 1/60th and 1/125th of a second. Then choose your desired aperture and take a test shot with all the flashes turned off and using only the ambient light in the studio. If the picture resulting on your camera’s preview screen is completely black (as it should be) then this tells you that your chosen shutter speed will have no effect on your photo based on the ambient light in the room.

What does start to have an effect on shutter speed after a certain point though is the aperture setting. For example, if you are shooting a person’s portrait in the studio with a shallow depth of field at an aperture setting of f/2.8. And let’s say there is some bright ambient light in the studio as well. Now in this case shutter speed might matter a bit because with the wider aperture setting there is a chance you will pick up enough of the ambient light to where it starts having a brightening effect on the photo. So a faster shutter speed will help cut out the effect that the ambient light might have when shooting with a wider aperture. Again, you can do a test shot first using only the ambient light at F/2.8 and 1/125th of a second to see if the ambient light will have any effect on the photo at that shutter speed or not. If your test shot is not completely black as it should be then you can try increasing the shutter speed and/or reducing the amount of ambient light in the studio to get rid of the effect of the ambient light. You can also do a test shot with the studio flashes turned on and, if the exposure looks OK, then probably you don’t need to worry about any effect the ambient light might be having at that point.

What does always control the amount of exposure in the studio though is your aperture setting. The wider your aperture setting and the more light your camera is going to take in from the studio flashes. So this is why photographers use a light meter to test the strength of the studio flashes first before they start shooting. This ensures the power output from they flashes matches their desired aperture setting.

If for example you want to shoot at an aperture of F/5.6, the studio flash must be set to emit enough light power for this aperture setting. So as you do your lighting tests with a light meter you will adjust the power on your studio flash either by increasing it or decreasing it to match your aperture setting.

So what happens if you have set your light power already to shoot with an aperture of F/5.6 and then you decide to change your aperture setting later?

Well, say if you increase the size of your aperture 1 stop to F/4, then more of the light coming out from the flash will enter your camera and your picture will become brighter and possibly even overexposed. If you reduce your aperture size 1 stop to F/8 then you are reducing the exposure level and your picture becomes darker. If we were shooting outdoors though we could simply adjust the shutter speed to compensate for any changes in aperture setting. But the studio is different since, as we have been discussing, the shutter speed doesn’t really play a role. So, once your flash lighting output is set to match a certain aperture setting, you will need to adjust the power output on your flashes to compensate every time you change the aperture setting on your camera to something different.

So what is the shutter speed in the studio based on and why should you even shoot between 1/60th and 1/125th and not faster or slower?

In simple terms, you don’t need it any slower than 1/60th. Really even 1/125th of a second is slow enough to capture the studio flash. And if you go too fast then there is a chance that the shutter will open and close before the studio flash has had a chance to emit all of its light completely. So I normally just shoot at 1/125 as a rule of thumb to avoid any shutter synchronization problems.

To sum it up, aperture setting will affect the exposure level of your photo when shooting in the studio with flashes, but generally the shutter speed won’t since you are working with an intermittent light source which has a shorter duration than most shutter speeds you would be using anyway.

Duration in general is a rather important consideration on a studio lighting purchase though. Normally lower priced equipment will have longer flash durations and may not be suitable for stop action studio photography. So before purchasing a studio lighting setup you may want to look into the specifications of the brand and model of the equipment you are planning to buy to see if it will be suitable for your intended photography requirements. For stop action photography a duration of at least 1/2,000 will be needed, but as I mentioned, some flashes have slower durations of only 1/1,000 so be sure to check it out.

This may all sound rather technical, but once you get your head around it is a very simple theory to follow. I hope I was at least able to explain it in a way that was easy enough to understand. But if you have any additional questions about this subject then please feel free to post them below and I will gladly answer them as soon as I can.