Why cameras aren’t as clever as they’d like to think (or how I learned to love shooting in manual)

So you’ve got a shiny DSLR camera but you’re still using it on fully automatic mode because you haven’t a clue what all those scary numbers that photographers spout out mean.  We have all been there dear reader – once upon a time, I too ignored those numbers on the screen at the back and just pointed my camera at what I wanted it to take and hoped for the best.  But once it all clicked and I started shooting entirely in manual I couldn’t understand why I’d ever been afraid to try before.  Believe it or not, it’s very simple and easy to understand. and once you get to grips with how your camera ‘thinks’ and what information it’s giving you, your photography will improve beyond all recognition. So let’s think about exposure; say you’re shooting in auto mode and try to take a picture of a snowy field, ever wondered why  it will often turn out too dark?  It’s because your camera sees it as being too bright and will try to underexpose it to compensate.  Likewise a photo of a black cat against a dark background will often be overexposed because the camera sees the whole scene as being too dark. Here’s an example, these are straight out of my camera, with no processing. The first was taken with my camera in fully auto mode with my 50mm lens:


White background with pale shells, and the settings my camera chose were:

1/160 sec shutter speed

f5.6 aperture

ISO 100


Because I could see how underexposed that first shot was, I put my camera in Manual mode, and used: 1/800 sec shutter speed f1.4 aperture ISO 250 I tend to choose the aperture and ISO, then use the shutter speed to fine tune the exposure.

Going back to basics: the shutter speed is the amount of time the shutter stays open; the aperture is how wide or narrow the diaphragm in your lens is; and the ISO determines how sensitive the sensor of your camera is to light.  (Back in the day when everyone used film, you would have to use different ‘speed’ or ISO film for different conditions!) These three elements are the three sides of the exposure triangle and need to become ingrained in your psyche. So how do these things relate to the information on the back of your camera?


M = Manual Mode.

1/1600 = Shutter speed is 1/1600 of a second.  The faster the speed, the less time that light has to reach the sensor.

F1.4 = The F Stop or Aperture. The lower the number the wider the aperture is open and the more light it lets in. F1.4 was the widest aperture on the lens I was using.

ISO400 = This is the sensitivity of you sensor to light. The higher the number the more sensitive to available light your sensor is.

That row of numbers from -3 to +3 is your exposure.  What you’re aiming for is to get the little moving arrow in approximately the centre (this is a little simplistic but it’s what we’ll go with for now).  On a Canon, if the arrow is to the left (or in the minus numbers), the image will appear be darker, if the arrow is to the right, the image will appear lighter.


Here I have the ISO at 200, the shutter speed to 1/200 and the aperture at f1.4; note how the arrow is in the middle.  All things considered this should be a pretty accurate exposure. So there it is, photographic language de-mystified!  It’s all about practice, practice practice… get to know your camera, and think about the exposure triangle until it all becomes second nature. If this has made you decide to try shooting in manual, why not add a link to your images in the comments.  I’d love to see them!


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