Lots of photographers think that professionals use Manual exposure mode all the time, write Jon Adams and Andrew James. But this is not true! In fact, if you use Aperture priority mode and know how and when to use Exposure Compensation, you hardly need Manual mode at all. However, there are a few situations when you can’t do without it, and in this article, we’re going to tell you exactly what they are.
Using studio flash
When it comes to studio flash the first thing to remember is that you need to work in Manual mode so you have total control over the shutter speed and aperture. The next important thing is to know the flash sync speed for your camera. It’s normally either 1/200sec or 1/250sec, but you’ll need to check what it is for your camera model. You can always shoot at a shutter speed that’s slower than your sync speed, but you can’t shoot faster or you’ll run into problems with black bars across the image. These occur simply because the shutter curtain hasn’t had time to clear the frame before the flash is extinguished. To fire the flash, the camera needs to be able to ‘talk’ to it, and this is done via a cable or a wireless connection like a sync lead or a flash trigger. Once set-up, take a test shot at your camera’s sync speed with the aperture at f/8. Depending on the result you get, you can brighten or darken the shot by increasing or decreasing the power of the flash, or by opening or closing the aperture setting.
Shooting at night
If a shutter speed needs to be really long – and we mean 30 seconds or longer – then your camera’s ability to meter light accurately is likely to fail. For this reason, you have to use Manual exposure mode to take long exposures in very low light conditions or at night. For exposures longer than 30 seconds you will need to intervene manually and stop the exposure. this can be done by pressing the shutter button, although it’s best to do it with a cable release to avoid moving the camera while the shutter’s open (as shown below). The most likely occasions when you’ll need to do this are when shooting fireworks, night landscapes, traffic trails or general astrophotography.
Taking images with a 10-stop density filter
While it’s not always necessary to shoot in Manual when using or 10 stop density filter such as a Hoya ND1000 or a Lee Big Stopper, we’d recommend that you do. The reason for this is when you add 10 stops to the exposure time, this will often go beyond the 30 seconds maximum shutter speed that the semi-automatic modes will offer you. The trickiest thing is often doing the 10-stop calculation because of the numbers involved, but it’s a lot simpler than you’d think. Once you’ve made a mental note of the exposure settings without the filter, you just have to count back 10 stops to get the right shutter speed. So if you’ve got a shutter speed of 1/8sec with no filter in place, then 1 stop is 1/4sec, 2 stops is 1/2sec, 3 stops is 1sec, and so on, until you arrive at 10 stops which is 120secs, or 2mins.
A handy conversion to remember is that 1/30sec without a big stopper becomes 30secs with, and 1/15sec becomes 60secs. Anything else, you’ve got 10 fingers to count it off, or you can use a phone app, or the guide supplied with most 10-stop filters, like the one below.
Shooting video footage
You may not be using the video function on your DSLR too often, but if you do feel the urge to capture HD or 4K movies, then you’ll need to work in Manual. This is because shutter speed is king when it comes to capturing smooth video, but you also need to control the aperture to get the depth of field that tells the right story in each scene. To do this you need to shoot at a shutter speed that is double the fps rate at which you’re recording, so if you’re shooting at 25 frames per second (as is normal for UK and European TV) then you will need to set a shutter speed of 1/50sec.
This is fine for indoor use, but go outside on a bright day and try shooting at 1/50sec and you’ll see that your aperture needs to close right down, even at ISO 100. All too often this will be f/16 or f/22 and that won’t give the kind of filmic results that you desire. To hold back the light and allow the use of larger apertures for cinema-style shallow depth of field, DSLR filmmakers rely on variable ND filters which can quickly be adjusted to shut out between 2 to 8 stops of light. Purpose built video cameras like camcorders have ND filters built into the camera body behind the lens. Either way, they’re essential to keep your shutter speed at a constant 50fps. If you’re wondering what happens if you shoot at a shutter speed faster than this, you’ll still capture video, but the motion within it will look jerky and unnatural.
Shooting for Photoshop projects
If you’re looking to combine two or more pictures from the same location and time into the same image in Photoshop – perhaps for a special effect like a levitation shot or a multiplicity selfie – then it’s always best to go Manual to ensure consistent settings between each frame. This is one of the easiest manual setups. All you have to do is frame up on your scene, read off whatever exposure settings you get in aperture priority, then switch to Manual and dial in those same settings. Remember though to set Manual Focus too, as you don’t want your focus point to change if you’re taking a multiplicity portrait. you can see how to put all this together in Photoshop here.
Painting with light
When setting up in a darkened room, you have nothing to give you an exposure reading, so for creative projects like painting with light, manual exposure is the only option open to you. You’ll need to do some trial and error with your light painting to determine the correct aperture, but usually, a setting of around F11 and a shutter speed between eight and 30 seconds will do the job.
You can make your light painting all in one go by tracing your light source around the subject in one exposure, or you can break the subject into smaller chunks with shorter exposures and combine your results into one image using layers in Photoshop. The former is the traditional method, but the latter tends to give more accurate and much more controllable results. To find out how it’s done, see our video here.
All in all, going full manual is rarely needed for general shooting, as modes like aperture priority will get you where you want to go quicker. But for the full creative control required for more unusual projects with difficult or technical lighting requirements, Manual mode is an absolute must.