If you have been following my Lightweight Photography blog you might remember a post I made discussing the Achilles Heal of the GX1. At the time I had been out with my 5D and GX1 shooting waterfalls. Unfortunately I wasn’t able to achieve a slow enough speed with the GX1 to create the images I wanted so I ended up shooting most of my work on the 5D that day.
Since this trip I have purchased a Neutral Density filter from Hoya. The filter is of the screw in type as this limits the chance of light leaking in around a filter holder. It’s also quite convenient as my 3 main lenses (9-18mm, 14-45 and 45-200) are all 52mm diameter so I can attach the filter to any of these.
If you look back to the original post you will see there were a few questions asking about the strength of the filter I am using. I thought therefore I would give some additional information in this post.
The first thing I would like to say is that the filter strength is not the important factor here but the shutter speed is. When I shoot waterfalls I usually like to see the blurring of water to emphasise the movement but I still like some detail in the water. Generally speaking I don’t want to turn the water into a mist so keep my shutter speeds in the region of 0.5 to 3 seconds (as a general rule of thumb). The exact speed is based on factors such as my distance from the falls and the volume of water flowing over the fall. Whilst I can often judge this from experience it’s often a good idea to take a few test shots and adjust the speed if necessary.
The strength of the filter I have chosen is 4 stop (16x). In shaded conditions such as where you tend to find waterfalls, this puts me in the right ball park when shooting at between f/7.1 and f/14. I usually shoot at f/5.6 to f/8 as this is where my lenses are at their best so perhaps I could have opted for a 5 stop filter. I can however attach a square filter holder to the end of my lens and insert one of my ND Graduated filters pulled down so that the dark area of the filter covers the entire image area. This can give me an additional 1, 2 or 3 stops of light reduction which is better than having too strong a filter to start with.
I hope this helps a few of you wanting to achieve longer shutter speeds.