20 Sep Exposure Triangle in Photography – Fred Smith

exposure triangle, and how the elements work, shutter, aperture, isoI’m Fred (Omega) Smith and this is my “Digital Photography Blog”. The intension of this Blog is to refresh, instruct or to give a different perspective on the fundamentals of photography. I am starting this Blog at the beginner’s level, so for the beginner it will be explanatory, for the hobbyist it might be a refresher and it might give the professional Photographer a new or different perspective, since they live this day in and day out.

Exposure Triangle in Photography – Shutter

If you remember my last entry, I went over the “Shutter”, it controls the duration of time that your sensor is exposed to the light. You can use that duration to your advantage, if you want to freeze a moving object, you would use a fast shutter speed of around 1/500 of a second or quicker. If you wanted some motion blur in your image you could shoot at 1/30 of a second, which seems fast, but it relatively slow when you factor in the shake of you hands or the movement of you body, which affects the image at this speed.

Exposure Triangle in Photography – Aperture

The Aperture controls the quantity of the light that enters your camera. Think of it like a hole, but a hole that gets larger and smaller. The larger the hole is, more light is allowed to pass through. The aperture is valued kind of like the gauge system called Focal Stop, f/1.8 is large and f/36 is small.  Also an aperture of f/1.8 will have a shallow Depth of Field (what’s in focus) where as an aperture of f/36 will have a more deeper Depth of Field. Depth of Field is also controlled by how close or far you are to your subject. When transitioning from your camera’s automatic modes to its creative modes there are a few steps that can help you, if you do not feel very comfortable using manual mode. The Aperture priority mode works by allowing you set the aperture and the camera finds a shutter speed that will give you a properly exposed photograph. There is also a Shutter priority mode, where you choose the shutter speed and the camera chooses an aperture that will give you a properly exposed photograph.

Exposure Triangle in Photography – ISO

The ISO controls the camera’s sensitivity to light. It’s kind of like your eyes, if you have been watching TV in the dark and someone turned on a bright light, you’ll most likely squint because you eyes have adjusted to the low light conditions, making the more sensitive to light.  ISO number 100 is a low sensitivity value, which works great in situations with a low of ambient light, like outdoors on a sunny day. An ISO number of 6400 is a high sensitivity value and it works good for low light conditions. The down side to using high ISO numbers with a low to mid level DSLR is that the images can  have a grainy look to them. It’s called “Digital noise” or “Artifacting”. That noise deters people from shooting with high ISO with those cameras. The Aperture setting, Shutter speed and ISO value work together to make a balanced photograph. .  The balance is based on your personal preference, some people may like their photographs brighter, darker, with more contrast or with more saturation. None of those preferences are wrong, the key is controlling the settings so that the photograph comes out exactly how you intended. The automatic settings may get you the results that you want, but the camera is trying to balance out the greys in the image, to be 18%.  You may want your percentage of greys to be higher or lower.

Exposure Triangle in Photography – Example

When your lighting condition change, so should your setting. If you’re taking photographs indoors and then went outdoors, on a sunny day, chances are it’s going to be a lot bringer outside than it was inside. If you have not changed any of your settings and then you starting snapping away, you indoor photos will look a lot different than your outdoor ones. To balance out the exposure you will have to ask yourself a few questions. Are the lighting conditions are brighter out here? If so, you will have to adjust your settings. Do I need my ISO at a high sensitivity?  Since you’re moving to brighter conditions you will most likely have you ISO set to a low sensitivity.  Could I speed up my shutter speed to get less ambient light? Since it’s brighter outside,  a faster shutter speed could also help to reduce the ambient light. Can I change my aperture to a higher F/stop number so that less light is hitting the sensor?  That could also be a way to balance out your photograph if the exposure is still coming out too bright. Although that will change my depth of field, having more things in focus. For every stop of light added, a stop needs to be taken away, or vice versa to keep the balance. For the ISO a stop is 100 to 200, for Shutter speed a stop is 1/125 to 1/250 and for the Aperture a stop is F/4 to F/5.6. So basically every increment on your settings that lets you adjust it high or lower, is a stop.

All right, that’s it for this entry. Now that you know about the “Exposure Triangle” you can use these three elements to get a balanced exposure, especially if you did not intent to have an underexposed (too dark) or overexposed (too bright) photograph. Find a style of your own and become comfortable shooting and making adjustments with the ambient like available to you.

Fred is one of Calgary photographers at Kallos Studio. He loves shooting in outdoors as a Calgary wedding photographer. He does many personal portrait work in his free time and keeps busy with in-studio work at his Calgary studio and provides these free online photography tips. Follow his work on Kallos Studio YouTube as well as the portfolio featured at Kallos Studio.

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