Sports Photography Insights

9 09 2010


Light, in terms of its quantity, quality, and colour, is also the most important thing that affects the technical quality of sports pictures. Unfortunately, in most cases for sports action photography, there is not much you can do about any of these factors.

• Quantity – The amount of light illuminating our sports event plays a critical role in our ability to use a high shutter speed to freeze the action. At one extreme we can have an abundance of direct sunshine and plenty of light. At the other, we might have only a little light from a few dim bulbs in a poorly lit sports hall.

• Quality – This describes the light’s nature in terms of direction and softness or hardness. An example of hard light would be direct flash or noon sunshine where the light makes harsh shadows. An example of soft light would be an overcast sky on a cloudy day.

• Colour – Although our eyes are very good at adapting to light sources of many different colors, our cameras are more objective and will record colors accurately for the most part. Late afternoon or early morning light can be a beautiful warm red-yellow color. Light from the sky in open shade on a clear day can be a very cool blue color. Indoors, different light bulb types produce different colors. Tungsten bulbs produce red-yellow light, and some fluorescents can produce green. Different colour light sources can produce different colors in our images and this is why it is important to set the color balance correctly in a digital camera.

Adjusting the Exposure

Exposure is the amount of light that hits the sensor in our cameras and creates an image. In most cases, there is only one exposure that is correct. The amount of exposure must be adjusted to match the sensitivity of the sensor.

Photographers talk about exposure in terms of “stops”. A stop is simply when the amount of light changes by a factor of 2. If the exposure changes by a stop, then it either doubles or is cut in half.

We have two ways of controlling the amount of light that reaches the sensor in our cameras and determines the correct exposure. The shutter speed and the F/stop.

The camera’s ISO setting can also be adjusted to give further control over the exposure.

Shutter Speed

The shutter is a device in the camera in front of the sensor that opens and lets light hit the sensor. The amount of time the shutter is open is called the shutter speed.

Under conditions of low illumination, longer shutter speeds can be used to let more light into the camera to achieve the correct exposure.

Fast 1/1000th sec. shutter speed

Slow 1/40th sec. shutter speed

Shutter speeds are usually given in fractions of a second such as 1/1000th of a second, and full seconds, such as 5 seconds. Short shutter speeds are needed to stop movement and action in the subject. For example, 1/1000th of a second is considered a short exposure and will stop most movement in a fast moving subject. In longer shutter speeds, the shutter is open for a longer period and the subject can move in this time, causing motion blur.

F/Stops and Focal Ratios

The F/stop is essentially an adjustable hole in a diaphragm that is located inside the lens and in front of the shutter and sensor. As the hole gets smaller, it “stops” some of the light from getting in. A larger hole lets more light in allowing a shorter shutter speed to be used, but making focus more critical. For most sports photography under available light conditions, such as night games outside, or games inside gymnasiums, we will end up using the lens “wide open” at its widest F/stop. Lenses that have large apertures are said to have “fast” focal ratios.

The F/stop numbering system is defined by the focal ratio. This is the ratio of the lens focal length divided by the size of the aperture of the lens, or diaphragm when the lens is stopped down to a smaller F/stop. The aperture is simply the effective size of the glass at the front of the lens. Bigger apertures gather more light.

You can have two lenses with the same focal length and different apertures and maximum focal ratios and F/stops. For example, you could have a 300mm f/2.8 lens with an aperture that is twice as big as a 300mm f/4 lens. In this case, you could use a shutter speed that was twice as fast with the f/2.8 lens as with the f/4 lens. This is very useful for sports photography under conditions with poor illumination. Of course the f/2.8 lens will be heavier and much more expensive.

Focal ratios and f/stops can be kind of confusing to beginners because they are counterintuitive and because apertures are never marked on camera lenses. For example, a lens with 300mm of focal length, and an aperture of 75mm would have a focal ratio of 300 divided by 75 which would equal 4, so this lens would be said to be an F/4 lens. These are the numbers used to specify the attributes of the lens: focal length and f/ratio, and are what you can find written somewhere on the lens. Note that F/4 is the specification for when the lens is used wide open at its maximum aperture.

Almost all lenses also have a diaphragm inside of them that has a hole that can be made smaller, effectively making the aperture of the lens smaller, and the focal ratio slower. What is confusing is that F/stop numbers are in inverse relation to the aperture. In other words, a smaller F/stop number indicates a larger hole. F/stops usually run in 1/3 of a stop increments. Whole f/stops can run from f/1 to f/1.4 to f/2 to f/2.8 to f/4 to f/5.6 to f/8 to f/11 to f/16 to f/22 to f/32. Also confusing is that every other number doubles the numerical value, but is actually two stops difference which really changes the amount of light by a factor of 4x.

All you really need to know about F/stops is that they need to move in step with shutter speeds. If you stop down a lens one stop letting less light in, then you have to increase the shutter speed by one stop to let more light in to keep the exposure equivalent.


ISO stands for “International Standards Organization” and in photography, ISO is a term that refers to the sensitivity of a sensor as defined by this organization.

ISO can be thought of as the relative sensitivity of the camera sensor to light. A camera with a higher base ISO would be more sensitive to light. Technically, the ISO standard only refers to the base sensitivity. Sensors really only have one level of sensitivity. Sensor output, however, can be adjusted to give the effect of adjustable ISO sensitivities. This is a complicated subject that is beyond the scope of this article, but you can cheat and think of changing the ISO as changing the sensitivity of your camera’s sensor.

ISO settings generally run from about ISO 50 or 100 to ISO 1,600, 3,200 or even 6,400 on the high end. Every time an ISO doubles, that is the equivalent of one stop in F/stops or shutter speeds. Higher numbers allow the use of shorter shutter speeds, although there is a heavy price to be paid, and that is higher noise in the image.

Ideally we want to use the lowest ISO that gives us the highest shutter speed that will stop the action.

In situations with plenty of light, the F/stop can also be adjusted to give the correct exposure. In situations with little light, the lens is used at its widest aperture (lowest F/stop number such as f/2.8) and the ISO is adjusted to give a shutter speed high enough to stop the action.

The Facts About Available Light

In available light situations, such as night football games, or indoor gyms, the amount of light is fixed. You can change the shutter speed, f/stop, or ISO to achieve the correct exposure.

Your primary goal is to use as high a shutter speed as you can because slow shutter speeds won’t stop the action. That leaves adjusting the f/stop and ISO to get a high shutter speed.

At some point, you will not be able to open the lens up any more once it is at its maximum aperture. That leaves only adjusting the ISO.

Increasing the ISO increases the noise in the image. You may reach a point where you find this noise objectionable. What else can you do? Slower shutter speeds result in motion blur and the lens is already wide open.

Your only options at this point are to get a faster lens with a wider aperture to let more light in, or use a camera that has better noise performance at higher ISOs.

For example, if you are using a 70mm to 300mm F/4 to f/5.6 zoom lens for night football, you could get a 300mm f/2.8 lens. If you are using an older camera model, such as a Canon 1D Mark II or Nikon D2H, you could get a Canon 1D Mark III or Nikon D3, both of which have much better noise characteristics at high ISOs.

Unfortunately, these are the facts of available-light sports photography under dim-light conditions. To get good quality, you either need expensive fast lenses, or the latest, most expensive camera bodies. Otherwise you get pictures with motion blur from slow shutter speeds, or noisy images from cameras with high ISO noise.

If you can’t use a faster lens, or a camera with better high-ISO noise performance, you can use a high ISO and try noise-reduction software like Noiseware’s Community Edition (freeware), or Noise Ninja (commercial software).

Focal Length

The focal length of a lens determines its magnification. Longer focal lengths give more magnification and allow you to be farther away from the action.

For some sports, such as cricket and soccer, lenses with focal lengths of 300mm, 400mm or even 600mm may be necessary.

As the focal length of a lens gets longer, the aperture must increase to give the fast focal ratios and f/stops that are necessary for high shutter speeds under low light conditions.

F/Stops and Depth of Field

Depth of field refers to the distance in front of, and in back of, the subject which appears to be in focus.

Depth of field increases as the lens is stopped down and smaller F/stops are used. For example, you will have a larger depth of field for a given lens at f/16 than you will at f/2.8.

Increased depth of field can make focusing seem less critical, but with long focal lengths, it is still very critical. Professional sports photographers usually use very fast lenses with maximum apertures of f/2.8 under available light conditions, and they usually use them wide open. This is done for four reasons:

1. A fast, wide aperture makes higher shutter speeds possible.

2. Fast apertures make the use of lower ISOs possible, resulting in lower noise in the images.

3. Fast apertures with very shallow depth of field will blur distracting backgrounds and make the subject separate more cleanly from the background. This can really help add aesthetic impact to the image.

Focus is extremely critical in super telephoto lenses. The minimal amount of extra depth of field that you get using a 400mm f/2.8 lens at f/4 is not going to help you much if you do not nail the focus in the first place.

ISO and Noise

We have already mentioned how digital cameras really only have one sensitivity. Increasing the ISO speed allows the use of a higher shutter speed by taking advantage of the sensors large dynamic range. Increasing the ISO essentially intentionally underexposes the image and moves the critical image data closer to the noise present in the camera.

Image quality is dependent on the signal-to-noise ratio present in the data. Intentionally underexposing an image by increasing the ISO naturally reduces the amount of signal present and lowers the signal-to-noise ratio. This is the tradeoff we accept for adjustable ISO settings in digital cameras.

White Balance

The colour of light is characterized by its “color temperature”. Color temperature is based on the temperature in degrees Kelvin of a theoretical “black body” that begins radiating light when it gets hot enough.

The lower the color temperature, the warmer the light, that is, the more red it appears. A high color temperature source gives a very bluish light. Some common examples of the color temperature of various different types of light:

• 1,000K – Candles and oil lamps

• 2,000K – Tungsten lamps

• 3,200K – Tungsten studio lights

• 5,000K – Average daylight, electronic flash

• 6,000K – Sunshine with blue sky

• 7,000K – Light overcast

• 8,000K – Hazy sky

• 9,000K – Open shade on a clear day

• 10,000K – Heavily overcast sky

In some cases we will want to preserve the color cast in the image because of the color temperature of the light, such as the beautiful warm glow of the light just before sunset. In other cases, such as with open shade, we may want to change the blue color cast to make it more aesthetically pleasing.

Digital cameras are very good at accurately recording the color of the light. That is why it is important to set the correct white balance in the camera. If you use a daylight white balance setting and you shoot under green fluorescent lights, your images will have a very nasty and ugly green cast to them. Likewise, if you use the daylight setting under tungsten lights, the images will have a red cast.

The latest generation of digital cameras have an automatic white balance setting that does a pretty good job of adjusting for the ambient light color temperature. However the automatic setting usually gets less accurate as the color temperature of the light goes down and gets warmer.

For lighting conditions in situations where the light is not changing, such as in a gym or stadium at a night football game, it is possible to set a custom white balance using a gray card so that the white balance will be accurate.

Colour and Exposure Flicker

Many indoor sports halls and stadiums use mercury vapor or sodium vapor lighting that flickers and changes in both intensity and color as the power cycle goes up and down. This happens too fast to be seen by the eye, but the camera will record it.

If you suspect this is happening, you can test it by shooting a high-speed motor drive sequence of ten frames or so at a high shutter speed. Examine the images on the LCD on the back of the camera and scroll through them quickly and you may see both the exposure and color balance changing.

If this is the case, there is basically nothing you can do except pay your money and take your chances if you must shoot available light. Using a custom white balance will not work in this situation, nor will automatic white balance in the camera. Your only other option is to add artificial light in the forms of strobes as your main lights.

Automatic Exposure

Today’s digital cameras offer a variety of methods for setting the exposure. The most basic is manual exposure where you pick the ISO, shutter speed and F/stop. Once you set them, the camera stays at those settings until you manually change them again. Manual is the best setting to use if the light is not changing.

Other exposure modes are also available such as Tv (Time Value), Av (Aperture Value), and P (Program Mode). In Tv mode, you set the shutter speed and the camera adjusts the aperture to what it thinks is the correct exposure. In Av mode, you set the aperture and the camera picks the shutter speed. In program mode, the camera picks both the aperture and shutter speed.

In most cases you will find that it is better to use manual exposure. Determine the correct exposure and set the shutter speed and aperture yourself. Even though these cameras have sophisticated metering systems and computer analysis, they still can’t tell the difference between a black cat in front of a white wall and a white cat in front of a black wall. Automatic exposure will underexpose the black cat in the first example, and overexpose the white cat in the second.

There are times when automatic exposure can be useful, such as under constantly changing lighting conditions like when the sun is in and out of the clouds and the game action is so furious that you do not have time to manually change the exposure, or when you have a remote camera set up that you cannot access. Another time I sometimes use automatic exposure is when part of the field is in shadow and the other part in brilliant sunshine. This can happen over the course of a football or baseball game as the afternoon progresses. If the quarterback drops back in the sunshine and throws a pass into the shade, you are not going to have time to manually change the exposure.

Some prosumer and amateur model digital cameras also have additional automatic settings. Canon calls them “creative zones”. One is for sports where the camera’s computer will try to use the highest shutter speed in an automatic mode that may also change the aperture depending on how much light there is. In general, you are better off determining the correct exposure yourself and setting it manually. I never use any of these creative zones.

Determining the Correct Exposure with the Histogram

Determining the correct exposure with a digital camera is easy because you can see the results of a test exposure immediately on the LCD on the back of the camera and because you can examine the histogram of the image.

A histogram is a bar graph that represents the distribution of pixels in the image by brightness. The darkest pixels are on the left hand side of the graph and the brightest pixels on the right hand side.

You want to expose your image so that the brightest pixels in the image are as far to the right of the graph as possible without overexposing parts of the image that have important highlight detail.

As with any rule of thumb, there are exceptions. If you are shooting in a back-lit situation, then shadow detail may be more important than highlight detail, and you may have to overexpose the highlights and lose detail in them to record sufficient detail in the shadows. It is up to you to determine what is more important, but it is easy to check with a test exposure.

Raw vs JPEG

Raw preserves all of the original data from the sensor in a high-bit depth. Ideally this is the best way to shoot your images and archive them. JPEG is a lossy format that actually throws image data away to achieve high compression ratios. JPEG is also an 8-bit file format. Don’t let this scare you too much though as the JPEG algorithm does a very good job and most of the data that is discarded is not perceptible visually. I use JPEG every day.

If you get your white balance correct and nail the exposure so that large tonal adjustments are not necessary, you should have no problem shooting JPEG images.

If you are shooting on deadline you are probably not going to have the time to edit hundreds of images and then take the time to do the raw conversion and color and tonal adjustments. Most photographers who work on deadline shoot JPEG file format in the camera.

If you have the luxury of not working on deadline, and you have plenty of memory cards, you can shoot raw file format in the camera, or even raw and JPEG concurrently.

Even if you shoot raw, you should still take the time to get the correct exposure. Even though you have a bit more exposure latitude with raw, your images will be better if you get the exposure correct.

Colour Spaces

Colour management and colour spaces are another subject that is frequently misunderstood and consequently ignored by photographers.

If you really know what you are doing, you should know what color space to use in your camera. If you don’t totally understand colour spaces and color management, then keep it simple and shoot sRGB in the camera and make sure you have your working colour space set to sRGB in Photoshop.



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