The most popular Exposure Mode for photographers is often Aperture Priority. It allows photographers to choose the most appropriate depth of field in their images. There are times when freezing the moment, however, is more important than choosing how much detail we want to see in the background. This is where Shutter Priority comes into its own. A starting point for wildlife, that is not even moving that fast, would be a minimum of 1/500 second. The advice to keep the ISO as low as possible has to go ‘out of the window’, as there is no point in having noise-free images if you can’t even make out what sort of wildlife is in the shot. The great thing about large sensors is that they are very forgiving when pushed to high ISO values, and so Auto ISO becomes a great setting to use with Shutter Priority mode when the aperture of your lens cannot be opened any wider. The image of the Serval (above) was captured at /1500 second in the rain, with the aperture of the SEL55210 wide open. This required the ISO to be pushed to 2,500 to achieve an appropriate exposure. With a little bit of care in post, when sharpening and adding noise reduction, the image shows very little signs of the ISO being set so high.
With this image of a Yellow Faced Honeyeater (captured with the SAL70400 lens) the ISO was also pushed to ISO 2,500 (even though the image was captured in the middle of the day). As there was a lot of shade around in amongst the trees I also added flash at 1/4 power (HVL-F60M). Due to the fast shutter speed of 1/500 second the flash is using the HSS mode (high speed sync). The flash serves only to reveal more detail and not to overpower the main light source.
With newer Alpha cameras, such as the A7RII and A6300, it is possible to stay in Aperture Priority and set the Auto ISO Minimum Shutter Speed either to the ‘Faster’ setting or select a precise minimum shutter speed.
So the next time you photograph a moving subject remember to use a shutter speed of 1/500 or faster if you want to freeze the action and let the Auto ISO cover your exposure.