How to Control Your Camera Exposure

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If you want good pictures, take good exposures. A badly exposed photograph can be very hard to appreciate. Since light is the major determining factor in a photograph, how you control it will determine the output of your camera. Unless you want your pictures to be overly bright or vastly dark, a good exposure is start to good photography.

There are three major factors that affect your camera’s exposure. You shutter speed, aperture and ISO.

Shutter Speed

To understand how the following factors interact, think of a bucket being filled with water via faucet. When the bucket gets full, we get the proper exposure. In this analogy, how long the faucet is left open is the shutter speed. If a scene asks for a shutter speed of 1/100 and you use 1/500, that’s like closing the faucet while the bucket is still half-full.

On a sidenote, shutter speed only affects ambient light. Most of the time, It won’t affect studio lights, strobes, etc. At faster shutter speeds, 1/200 above, the camera won’t be able to capture the flash. This is related to its x-sync speed which will be in one of our future articles.

Racing Stars by Andrew Stawarz


How fast water flows out of the faucet also determines how fast the bucket gets full. The more open the faucet is, the faster water flows which mean the bucket gets full faster. The slower the water flows, the slower the bucket gets full. Aperture is the same. When you use an aperture of f/16, you let light enter slowly since the opening is smaller. When you use an aperture of f/2.8, light gets in more since the opening is larger.

Remember that the smaller the value of your aperture, the larger its opening is and the larger the value, the smaller the opening. This information can be confusing at first but it is beneficial if you don’t get confused with the two terms.

Flower Head by vonschnauzer


Bucket size also affects the time it takes the bucket to be full. The larger the bucket, the longer it take and vice versa.  In relation to ISO, higher values means you need less light for the sensor to capture. While a lower ISO value means you have to take more time or widen your aperture opening.  Be wary though, having a high ISO capable camera doesn’t mean you should always use that value. When using a high ISO value, the camera sensor gets hot resulting into noisy data. This is why when using high ISO, your pictures get that grainy film effect which some may or may not like.

… by Seyed Mostafa Zamani

Final Exposure

A scene that needs a setting of 1/500 shutter speed, f/4 and ISO 100 can be exposed in various ways. If you want more depth of field, you can use f/5.6 then a shutter speed of 1/250 and an ISO of 100. The change from f/4 to f/5.6 is one whole stop.  A stop is double of half the light you had before.  Since you decreased the light by closing the aperture to f/5.6, the slower shutter speed of 1/250 is compensated by increasing the light thus getting the same exposure. The same goes for ISO too. ISO 100 to ISO 200 means one stop or double the light. You can use a shutter speed of 1/1000, f/4 then ISO 200 and you will get the same exposure.

Mixing those three together can get confusing at first. Personally, when I’m shooting, I try to use the lowest aperture first. This makes possible the use of faster shutter speed which means no more blurry shots. A shot that is not the sharp is better than a blurry picture in my opinion.

With that in mind, I still prefer shooting in Aperture Priority mode most of the time. Don’t be shy in using the modes in your camera. Those we’re put there for a reason. And no point in using manual mode if you waste them just fiddling with the settings and missing the shot.

Don’t worry if you don’t get all these technicalities at once. Most photographers get stuck in technicalities and they let it control them. This hinders creativity which is the most important part in photography. So don’t cringe if you exposure is off by a third of a stop, that won’t ruin your picture.  Just keep on shooting and capture the light.


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