When you use a flash, the shutter speed is not that important. Since the flash fires all its power in 1/1000th sec or less, it is not important whether your shutter speed is 1/200th second, or 1/100th, or 1/4 second. Only the ambient light will be affected; not the flash part.
Take this, from a Goldcorp goldmine I shot earlier this year in Timmins, Ontario:
3200 ISO, f/4, and 1/4 second. Handheld.
Why so long? Because I wanted the light at the end of the tunnel to look like, well, the light at the end of the tunnel. And I needed f/4 for depth of field, hence 3200 ISO and 1/4 second.
But Michael, things will be blurry!
Not if they are lit by the flash. 1/1000th sec is 1/1000th sec! And if they are also lit by a little ambient light, then a little ghosting will appear, mainly in the moving parts:
But that is still better than not having any background light. So I shot the goldmine at slow shutter speed, and you should feel free to try the same. Here I did it to capture the hard hat lights:
Use a wider lens, and go slow, even very slow, any time you are using flash and it’s mainly flash lighting the important bits!
Nikon calls it “slow flash” when you use a slow shutter speed while using flash. You engage this in semi-automatic and automatic camera modes (P and A) by pressing the flash button an turning the wheel until you see the word “slow” on the top LCD display in the flash area.
This is a misnomer. The flash is fast – in the order of 1/1000th second. It is the shutter that is allowed to be slow in this “mode” (really just a technique). That is why another, more correct, term for this technique is “dragging the shutter”.
And you want to do that why? As readers here now, you want that in order to allow enough ambient light in, to avoid those dark backgrounds.
But can you use a slow shutter speed when using flash? Surely a shot at, say, 1/30th second will be all blurry?
Not necessarily. While there may be a little ghosting, if your subject is mainly lit by the flash, it will be as though it was shot at 1/1000th second.
That is why “slow flash” is such an unfortunate misnomer: it is”fast flash in a slow shutter image”. Which is why the Willems 444 Rule for indoors flash (400 ISO, 1/40th sec, f/4) usually results in crisp images. Have you tried it yet?
A quick note for you today (and this is the kind of thing my students learn at length in my advanced courses, like the one tomorrow in Mono – there’s still some space).
Every had your camera react unpredictably when using flash? Yeah, I thought so. You flash and then the shutter stays open for a second and it’s all a blur. Or you flash and the background is dark black.
When you shoot indoors, say, and use your flash, your camera behaves differently in different modes – and this behaviour varies per camera.
Aperture mode (A/Av):
- Canon: the shutter will be as slow as needed to expose the background too (caution: this may lead to very long shutter speeds if ambient light is low).
- Nikon: the shutter is restricted to 1/60th of a second or faster (this can be set). But… if you also engage “SLOW” mode, the shutter will be as slow as needed to expose the background too (caution: this may lead to very long shutter speeds if ambient light is low).
Program mode (P):
- Canon: the shutter is restricted to 1/60th of a second or faster.
- Nikon: the shutter is restricted to 1/60th of a second or faster (this can be set). But… if you also engage “SLOW” mode, the shutter will be as slow as needed to expose the background too (caution: this may lead to very long shutter speeds if ambient light is low). .
- Canon is simple: Av = long shutter speeds, P = 1/60th or faster.
- On Nikon cameras, both modes are restricted to 1/60 or faster normally, but either mode can be freed from this by using the “SLOW” setting.
So what is the best mode when using flash indoors?
Ah, that would be Manual. That way the camera does exactly what you want. But we will get to this again another day.
TIP: if you want to try Manual indoors flash, start at 400 ISO, 1/30th second, f/4. And bounce your flash off the ceiling/wall behind you.
So you are surprised that your flash pictures always turn out differently and unpredictably, especially when using automatic (“TTL”) flash?
Then this may help:
A. First, worry about the background, ambient light:
- First, decide “should the background light do any work?”. If you are using an automatic or semi-automatic mode, like P, Av/A or Tv/S, the camera will try to light the background well. so it will not just be the flash doing the lighting.
- Realise that there are limits to the previous: on Canon always in P mode, and on Nikon in P and A when “Slow Flash” is disabled, the camera will limit shutter speed to avoid blur.
- So if you want total predictability of the background, use manual, and set your meter to the desired ambient lighting level (I recommend you start at -2 stops, i.e. the light meter points to “-2”). See a recipe below.
In a typical room, a starting point might be 1/30th second, f/2.8, 400 ISO, and the flash pointed behind you. Auto ISO is not recommended!
B. Then, concern yourself with the flash:
- The foreground is mainly lit by flash, not by your Av/Tv/ISO settings.
- Canon cameras in particular try to avoid overexposing part of the picture, so even a small reflective object in the flash picture can result in a dark, mainly underexposed photo.
- The flash exposure metering is, on most cameras, biased toward your focus points. So the camera looks mainly where you focus.
- If you take a picture of something bright (a bride in the snow) the camera will underexpose it to give you a grey bride. If you take a picture of a dark object (a groom in a coalmine) the camera will overexpose it to give you a grey groom.
- To fix this, you can turn the flash up and down using flash exposure compensation (“Flash Exp Comp”).
- Play with the light: aim your flash at walls or ceilings if you can. and create a “virtual umbrella”.
Try it and see if you get more consistent!
Here’s a typical recent flash picture, of a nice photographer I met recently:
A flash photo - yes really.
Doesn’t look like your usual “deer in the headlights” snap? That’s because I was following my own suggestions above. Note I also used a Honl Photo 1/2 CTO gel, to make the flash light look a bit more like the background Tungsten light. I like warm backgrounds, but I often make them a tiny bit less warm this way.
Sometimes it can be simple: off-camera flash can be really easy. Like in this student’s recent portrait:
Off-camera flash portrait
You can also see how nice the splash of colour is in the background, right?
A matter of choosing manual mode with just the right combination of aperture and shutter speed and ISO to get enough light into the background. And Flash White Balance makes the tungsten light look nice and orange.
My message today: although flash can be done in a very sophisticated manner, it is not always necessary to make it complicated. Often, very simple is all you need. “Off camera” is often enough to just make it work. And an off-camera flash cable, while not cheap, is the simplest way to achieve this.
Here’s a quick start tip for using flash indoors.
First, set your camera to:
- Manual mode
- 1/60th second
- 400 ISO
Now check the light meter in your viewfinder. You want it to read about minus two if you point at a representative part of the room.If it reads higher or lower, adjust aperture and shutter speed until it reads -2. If possible, try to keep the shutter between 1/30th and 1/200th second.
By using this method, your ambient lights shows (avoiding black backgrounds), and it becomes your “fill light”, two stops below the key light. And of course while your ambient is set manually, the flash is still automatic.
And finally: bounce that flash off a wall or ceiling behind you!
“Why are you in Manual exposure mode when shooting flash indoors?”, asks a reader. I thought that would make an excellent blog question.
Well, when I shoot flash indoors I have options. These include:
- S/Tv mode, which is fine because I set the shutter to any value I like, but this has the big drawback that the lens will quite probably not have the aperture value needed to expose well – and also, aperture is the one thing I want to control.
So then next, there’s Aperture mode or Program mode. This works differently on the main brands:
- P: flash speed will not go below 1/60th. This simple engineering decision makes sense, but it can give me dark, “cold” backgrounds. When using a wide lens I want to be able to go slower, like 1/30th, to let in more ambient light.
- Av: now shutter speed can go as low as it needs to in order to light ambient normally. The big drawback: in a dark room this could lead to very slow shutter speeds – even seconds, which would lead to totally blurred images.
- A or P: flash speed will not go below 1/60th. This simple engineering decision makes sense, but it can give me dark, “cold” backgrounds. When using a wide lens I want to be able to go slower, like 1/30th, to let in more ambient light.
- A or P with “slow flash” enabled: now shutter speed can go as low as it needs to in order to light ambient normally. The big drawback: in a dark room this could lead to very slow shutter speeds – even seconds, which would lead to totally blurred images.
So none of those seem quite ideal, do they?
Then there is manual (“M”). In manual exposure mode,
- I can simply set the aperture and shutter speed that I want. The background will be lit accordingly.
- But as long as my flash is set to TTL (Canon calls this eTTL; Nikon calls it iTTL), it is still fully metered and automatic, and the camera varies the flash power to light the flash portion of the photo properly. So “manual” is not manual flash – it is just manual background light.
So for that background light, my starting point is to set manual aperture/shutter speed to give me an exposure two stops below ambient. That means the meter points to minus two when I aim at a representative part of the room. That way I get these advantages:
- Ambient light becomes “fill light”, which is usually 2 stops below the key light.
- If I aim at a brighter part of the room, is it not likely to be two stops brighter, so it will not be overexposed.
- If I aim at a darker part of the room, it is still likely to be light enough to be seen.
So try it next time?
Camera on manual and set time and aperture to a value that gives you -2 stops on the meter. Then bounce off a wall and you get well lit images. Like this one, of two very nice young people at the event I was a forum member at, tonight at UofT’s Mississauga campus:
This also shows that I have taken over 10,000 images with my new 1D Mark IV already. And that I always carry a camera, even when I am a speaker, not a shooter.
If you are new to cameras, let me give you a quick tip for the holidays.
When you shoot pictures of your family, use “slow flash” (enable “slow” on Nikon, or use Av mode on Canon) and an ISO of 400 or even more if it is dark indoors. That allows the background light to show, as well.
You will need flash, too, around the tree. But rather than the popup flash, use an external flash. And above all, do not do this with that flash:
Instead, do this:
That’s right – point the flash backward above you. Your happy snaps (photojournalists call them “grip and grins”) will be infinitely better.
Look at this recent newspaper picture of Elizabeth May, the leader of Canada’s Green Party:
I shot that with a 16-35mm lens set to 33mm on a full frame camera. Exposure was 1/60th second at f/2.8 at 800 ISO, using – what else – bounce flash.The wide angle gives the image depth.
But ignore the technical details and ignore politics. Does this not show what a delightful people-person she is? And a politician who does not hide her wine glass when she sees the press gets full marks for integrity.
This is also a good example of a photo where the foreground is blurred and the background is sharp. That is why you pick your own focus point. If you use the “all focus points are used and the camera picks” mode, you will get the foreground object in focus. Which may not be what you want. Which is why photographers use just one focus point mos of the time.
The other day I shot an event. So that meant dark light, high walls, hard to bounce.
“Crisp” means “bright pixels”, so you will sacrifice some crispness when it is dark.
Still – I never point my flash at subjects when it is the main light. So instead, I bounce. I use the wall or ceiling – but when that is too far (and at 800 ISO “too far” is quite far!), I use a Honl bounce card, or a Fong lightsphere, or I just bounce off my hand:
Um yeah, the theme was “70’s”.
- I was using a 1Ds MkIII and a 16-35mm f/2.8L lens.
- I did not want too much noise so I stayed at 800 ISO.
- I used 1/30th second, f/2.8
- A wide angle lens means that even at f/2.8, I get nice depth of field.
- And the slow exposure means I get some nice background light.
- Flash pointed behind me to the right, and bouncing (I saw a wall not too far).
Everyone else got dark backgrounds; I get this. A fast lens (f/2.8) is quite essential.