Mountain bike photography tips.
There are three variables to play with in order to control the brightness of a photograph:
- Exposure time
- Sensor ISO setting (signal amplifcation factor)
Increasing any of these will make a photograph brighter. If one is turned down then either of the other two can be turned up to compensate. The photographic “stop” system was designed so a notch up or down by a stop resulted in a doubling or halving of the image lighting. The film speed ISO numbers went up by factors of 2, the exposure times by a factor of 2 and the lens f number in 1.4 multiples rounded to convenient numbers. e.g.: as f/1, f/1.4, f/2 etc (f number is lens focal length divided by the aperature diameter, the area of the aperture goes with f number squared (pi r squared), the square root of 2 is approximately 1.4).
See my article on sensor size and crop factor for more information.
With mountain bike photography there is generally the requirement of capturing action in low light. A long exposure leads to blurring so this normally has to be kept down below around 1/250th of a second. A high ISO value tends to increase the noise in the image. Good compacts can produce tolerable results at ISO 800 but it’s better to be down around 400. Therefore it’s best to crank the aperture wide open. This is expressed as the F number which is the focal length of the lens divided by the aperture diameter. A low F number means a wider aperture which is good news. Such lens are described as “bright”.
In practice I always run with the aperture as wide as possible and trade off the ISO noise versus the shutter speed. Lenses tend to be sharper when stopped down a bit but I have to trade sharpness with image noise. Reducing the aperture size also narrows the depth of focus which can be used to create artistic effects like someone’s face in focus and the background out of focus. This is generally hard to achieve on a compact due to the small aperature diameters. Sometimes you might want blur – you can pan with movement and blur the background, or you might want to blur the water on a waterfall.
I shoot in standard jpg and use the GIMP free editor to tweek photos. I generally crop, adjust the brightness curves and fiddle with hue and saturation until I like the look of a photgraph more. I’ve never bothered with RAW and my aim is to get photographs good enough to start with to save editing time. I will make an exception if a photograph excites me and I think I can get more from it.
For most of 2010 through to 2015 I used a pair of Canon S90 compacts for my photographs. In 2015 I considered the top performing cameras in the compact market. See my index of all recent camera posts for the conclusion.