Friday, 5 February 2016

Cwm Idwal and 10 stop ND filter photos



On Wednesday this week (3rd February) I had a free day so contacted a good friend and fellow photographer Nathan Roberts of NR Imagery and arranged to visit Cwm Idwal in the Ogwen Valley, North Wales to take some photos.

As I knew I would be taking landscape shots I didn’t see the need to take some of my lenses such as my Sigma 70-200mm and also my Tamron 90mm Macro instead opting only to take my Sony Zeiss 24-70mm f2.8 (A-Mount) and my Sigma10-20mm f3.5 (APS-C sensor lens) along with my Sony A7R and Sony A77ii bodies. I always like to carry two bodies on photo walks just in case one decides not to work.

I also decided to take along with me a couple of 10 stop ND filters. Neutral Density (ND) filters can be used to create very unique looking photos especially when photographing running water. ND filters allow the photographer to use slower shutter speeds for longer exposures. Some of the shots featured in this blog post have shutter speeds of 60 plus seconds and some even as long as 2 minutes in which time a lot of water has flowed through the scene creating a mysterious foamy look.

To use a 10 stop ND filter, I first set my camera for a normal exposure to capture the running water at for example 1/15 second, f10 and ISO 50. I then use the free app LE Calculator on my iPhone to calculate what the shutter speed should then be set to when the 10 stop ND filter is added. At these settings the app calculated that I needed to change the shutter speed to 68 seconds. To do this on a camera you need to select BULB mode or on a Sony camera while using Manual mode rotate the shutter speed dial until it goes one notch further than a 30 second exposure. I then press and lock my shutter remote until the 68 seconds have elapsed then release it and voila we have a unique long exposure of running water.

When taking photos with long exposures like these it’s imperative that you have your camera on a sturdy tripod and use a shutter release cable so that camera shake is reduced a minimum. It was very windy the day these shots were taken but they still turned out ok.

Click to enlarge the photos below. Please leave a comment and share.




















Nathan Roberts trying out one of my ND filters



















A 3 shot HDR photo merged in Lightroom CC



















An 8 shot panorama stitched in Lightroom CC. The end result is a dramatic 68 megapixel image.