Getting the Most Out Of Your Camera in Low Light

Getting the Most Out of Your Camera in Low Light

Whether you have a $300 Canon Vixia, or a $19,000 Sony 350K, getting the most out of your camera in a low light situation comes down to one main topic: Exposure.  Exposure is a general term used to describe the lightness or darkness of the image you capture.  If the video is too dark, its “under exposed.”  If its too bright, its “over exposed.”

Your camera’s exposure depends on 3 main factors: iris, shutter speed, and gain.  Lets address each one of these individually.

Iris

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The iris (also known as F-stop or aperture) acts as a gate keeper for light.  It determines how much light to allow through to the camera’s image sensor.  Check out the example to the side.  When you adjust the iris settings, you open or close the gate.    Common iris settings may be f1.4, f3, f8, and up through f22.  It may seem counter intuitive, but the lower the number, the more amount of light is allowed to pass through. 

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Imagine a f1.4 as a skeet choke, f8 as a full choke, and f22 as a .223. 

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The iris setting affects several other attributes of your footage, like depth of field, but we’ll leave that for another time.

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Shutter Speed
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If the iris determines the amount of light getting to the image sensor, the shutter determines how long that light is exposed to the sensor.  Imagine a door opening and closing constantly.  Sometimes 60 times a second.  Often hundreds of times a second.
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The longer that door is open, the more light gets to the sensor, and the brighter the image.  And, the slower the shutter speed, the longer that door is open.
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Shutter speeds are shown like this.  1/60, 1/120, 1/800, etc.  What does this mean?  A 1/60 shutter speed means the shutter will open and close 60 times in one second.  Some cameras, like the AX2000, will even allow you to drop the shutter speed under 1/10!  Sounds great right?  Its not what you think.  Going that low will cause massive amounts of motion blur in the video, making it virtually unusable.  There really is only one use for dropping the shutter speed that low, and that is making sure all animals are out of the field before you get out of the stand.  You can literally see in the dark by dropping your shutter speed that low, and thats one of the key advantages of cameras like the Sony AX2000.

So why would you film with higher shutter speeds?  In addition to exposure qualities, the shutter speed can also affect the “look” of your footage.  Not necessarily the image quality, but the motion of the footage, especially when filming fast motion.  This is also better left for another time.  Keep checking back, and we’ll address these topics soon.
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Gain
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Very similar to ISO on DSLR’s, gain is generally considered a curse word to many videographers.  But, to many outdoor producers, when its in the last minutes of daylight, and that monster you’ve been chasing all year finally steps out of the timber, gain quickly becomes your best friend.
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Gain is the digital amplification of available light.  Its like digital zoom for exposure, and with it comes many of the same downfalls.  The higher your gain setting, the “noisier” your image gets.  When you move from a 0db gain to a +12db gain, your image isn’t as clean anymore.  It looks grainy, and in bad cases, like its snowing.  And honestly, most outdoor television networks won’t allow anything over +12db gain.
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But, not all cameras are the same.  The image from a Canon XF105 at +12db gain will look totally different than an image from a Sony PMW-200 at +12db gain.  The larger sensor of the PMW-200 will outperform the XF105 every time, resulting in a cleaner image.  But, thats also reflected in the price difference.  Check out the video still to the right.  This was filmed with a Sony PMW-200 at +12db gain.

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Is that all?
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So it sounds simple right?  Open the iris, drop the shutter speed, and bump up the gain to the maximum amount allowed, right?  When light is the main concern, pretty much yeah.  But, there is one other aspect to consider if you’re in the market for a new camera.  As a general note, the larger the sensor, the better low light performance.  A 1/4 or 1/3 inch sensor camera won’t match the light gathering ability of a 1/2 or 2/3 inch sensor.  We’ve had users in the industry tell us that filming with a 2/3 inch sensor camera, like the Sony PMW 350K, is almost cheating.  Compared to cameras they were using before, they estimate they gained another 15 minutes of shooting light in the morning and evening, giving them another 30 minutes of filming light each day.  When your lively hood depends on it, thats huge!  Even 1/2 inch sensor cameras like the Sony EX3 or PMW-200, have a huge advantage over the 1/4 and 1/3 inch sensor cameras when it comes to low light performance.
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But, when all else fails you still have one more option.  Get a light.