Monday, February 2, 2015


If you want to take photos in anything other than auto/preset modes, you have to understand how to set an exposure. Otherwise you're stuck asking people about 'settings' all the time - which seems to be the approach a lot of people actually take. Stop doing that because you're making this way harder than you need to. If you just ask for settings and I say 'ISO 200, f/8, 1/1000' that doesn't mean anything to you other than 'derp I'll just twist knobs until I get those numbers to show up on my camera'. You need to understand what those things do, then it's really easy to figure out the 'right settings' for any random photo you want to take.

Your camera has three knobs, and turning any of those knobs up will make the photo brighter while turning them down will make the photo dimmer. The difference is knob one decreases the in-focus area while it makes the image brighter, knob two makes moving things blur or streak while it makes the image brighter, and knob three makes more noise and less dynamic range while making the image brighter.

Knob one is your aperture, knob two is your shutter speed, and knob three is the ISO. Depending on your camera they might literally be knobs or they might be menu selections, but they always do the same thing.

So here you are, you want to take a photo but you don't know what the settings should be. Assuming this isn't a film camera, just take a photo with any random settings and see what you get. Too dark? Turn one of the knobs up. Still dark? Turn it (or a different knob) up more. Keep doing this until you produce a well exposed image. Image too light? Turn a knob down instead.

A shortcut is to take the first photo in some kind of auto or semi-auto mode then copy the settings into manual mode, this will put you 'in the ballpark'. I like aperture mode for this.

Now that you have a well exposed image, what are the settings? The real question is why should you care? They're just numbers on the screen.

But how do you know which of the three knobs to turn? That just depends on whether you'd rather change the in-focus area, change the amount of blurring on moving objects, or change the amount of noise. As an example, for a typical daytime landscape I probably want a lot of depth-of-field so I want to leave the aperture around f/8 or f/11. I want low noise (and lots of dynamic range) so I want the ISO around ISO 100. But mountains don't move around much so I can flip the shutter speed all over the place without really worrying about getting blur from moving objects.

That's the whole process - you know what side effect each of the three knobs will have on your photo, decide which side effect is the least important, and just flip that knob until the image looks good.

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