April 17th 2012 by Andrew S Gibson
If you’ve never used Manual mode on your camera before you may wonder why anybody would use it instead of one of the automatic exposure modes. Most of the time I only use one of three exposure modes on my camera – Aperture Priority (Av), Shutter Priority (Tv) or Manual (M). In this article I’m going to explore why and explain in which situations I would use each one.
I don’t think the fully automatic exposure modes found on non-professional EOS cameras (landscape, portrait and so on) are very helpful. They clutter up the Mode dial and create confusion. They are also very restricted. You have no control over the aperture, shutter speed or ISO, and you can’t use exposure compensation to make the image lighter or darker if the exposure is incorrect.
That’s why I recommend that photographers stick to four Creative Zone modes – Aperture Priority, Shutter Priority, Manual or Program. I personally don’t use Program much but it is very useful in some circumstances.
Why I use Aperture Priority and Shutter Priority
If I’m hand-holding the camera I’ll usually select Shutter priority and set whatever shutter speed is required to prevent camera shake. I control the aperture indirectly by raising the ISO. Sometimes I need to decide which is more important – keeping the ISO low and having a wider aperture than I would ideally like, or selecting a smaller aperture and having an ISO which is higher than ideal. I use an EOS 5D Mark II most of the time, which has good high ISO performance so that gives me a lot of leeway.
An exception is portrait work. Here I often use Aperture priority because I like working at wide apertures. If I need a faster shutter speed to prevent camera shake I just raise the ISO. I used an EF 50mm f1.8 lens on a 40D (it’s an ideal portrait lens on an APS-C camera) at set the aperture to f1.8 to take this portrait. I focused on my model’s eyes and let the rest of the scene drop out of focus.
I like to use Aperture priority when I have the camera mounted on a tripod. That’s mainly for landscape work, or close-up/macro photography. Using a tripod means that I have the luxury of setting whatever aperture I want, and a low ISO, and let the shutter speed take care of itself. I can control the shutter speed indirectly by raising or lowering the ISO. My priority here is controlling depth-of-field.
One case where I might take a landscape photo in Shutter priority mode is if I’m photographing moving water. A waterfall is a good example – I can try a series of shutter speeds and playback the photos on the camera’s LCD screen to see which shutter speed is most effective. Here I used Shutter Priority, utilising the same principle. I set the shutter speed to 1/2 second and asked my model to stay still throughout the exposure so that she was sharp.
I like to use an automatic exposure mode when I’m walking around taking photos, or if the light is changing unpredictably (perhaps the sun is going in and out behind clouds). If I need to adjust exposure I do so by using exposure compensation – the Quick control dial on my camera lets me change it with the camera held to my eye. It’s very quick, and if the subject lacks contrast, or has lots of light tones, I can increase the exposure to give me a good Raw file. I’m so used to working this way that I can do it without thinking – it’s become more or less automatic.
I took the photo above in Shutter priority. I set a shutter speed of 1/180 second so that I could take images without camera shake, and then adjusted the ISO to control the aperture.
Why I use Manual mode
The advantage of Manual mode is that once I’ve worked out the optimum exposure, I can just lock in the ISO, shutter speed and aperture settings, forget about them and concentrate on taking photos. This works if the light levels aren’t changing, or is just changing a little. I glance at the histogram every now and then and adjust if necessary.
In an automatic exposure mode, the camera’s exposure settings are influenced by the way that you frame the scene. As you try out different compositions, the camera’s recommended exposure settings may change, even if the ambient light levels stay the same, depending on the balance of light and dark tones within the frame. This is a nuisance, and using Manual mode avoids dealing with that.
I like to use Manual mode when I’m taking landscape photos. I tend to take landscapes at the end of the day, and I often take a series of images as the sun goes down so I can select the best afterwards. I keep an eye on the histogram – it creeps to the left as the light fades and I normally increase the shutter speed to compensate (or sometimes I open the aperture or raise the ISO, depending on the situation). That’s the approach I used for this photo of Rangitoto Island. The pink cloud was lit by the light of the sun setting in the other side of the sky.
I also like to use Manual mode when I’m shooting portraits with portable flash. I start by working out the exposure for the ambient light. Often, I underexpose the background for dramatic effect. Once I’ve decided on these settings I then introduce the Speedlite and adjust the power manually. It normally takes me two or three test shots to get the exposure right. And once I’ve worked it out, as long as the distance between the flash unit and my subject doesn’t change, I don’t need to change the settings.
There are two advantages to working this way. The first is that, with the Speedlite in manual, the brightness of the flash is the same each time. It doesn’t vary. If I were using automatic exposure, it may vary according to the way that I’m framing the shot.
The other is that I can fire the Speedlite with a Hahnel Combi TF radio flash trigger. The Hahnel unit is less expensive than buying an ST-E2/ST-E3 transmitter or a RadioPopper/PocketWizard trigger. And it works fine for me, so I don’t see any point in doing things any differently.
I don’t like it when photographers say things like ‘you should always use Manual mode’. That’s dogmatic – everybody likes to work their own way and it’s up to you to experiment and find the way that suits you best. For me it’s all about using the metering mode that produces the best results for the situation you’re in.
I explore the topic of exposure in more detail in my eBook Understanding Exposure: Perfect Exposure on Your EOS Camera. Click the link for details.