Long Exposure Photography has been around for some time now but its popularity still remains amongst quite a few Fine Art Photographers. Over the last few years we have seen the introduction of some high density filters which block the light by 10 stops. The B+W screw in filter was very popular about three years ago and then the Lee Big stopper became in such demand that they were fetching ridiculous prices on eBay.
During the summer of 2014, Formatt Hitech introduced yet another ND filter which has a density of 16 stops called the Firecrest and claims to be the first filter that renders no colour cast.
I enjoy doing long exposure work especially with black and white in mind and the only aspect of the process that can be difficult to get your head round is calculating the correct exposure for the density of the filter which you have attached to the lens.
I am the first to hold my hand up and say that I have fallen behind with all this latest singing and dancing mobile technology, in fact I don’t really own a mobile phone. When I say don’t really, I do have a mobile phone but I only carry it with me for emergencies and it’s not one of these smart phones that everyone appears to be carrying around with them.
By not having all the latest mobile apps at my disposal when out in the field, I turn to printed exposure charts to aid me in calculating the correct exposure based on whether I am using a 10 stop or now the new 16 stop filter.
One of the main issues I have found with all these charts which are on the internet is that they are all based on full stop increments and to be honest, I have my camera setup to read in 1/3 stop increments. So you maybe asking why this causes me an issue so let me explain.
Lets assume that my exposure with no filter attached is 1/250th second @ f/8. Because 1/250th is a full stop, I can easily look at the chart which tells me that I need to expose for 4 seconds. So far so good….
But what happens if my exposure with no filter attached is 1/320th second @ f/8?. On the regular charts, they only read in full stops, so do I use the exposure for 1/250th or do I use the exposure for 1/500th?.
Based on the above scenario with a 10 stop filter, it probably would not make an awful lot of difference because 1/250th = 4 seconds and 1/500th = 2 seconds and to be honest the 2 seconds is not going to make and difference in my book.
16 Stops will make a difference though…
Having said all that, if I was using a 16 stop filter, the the difference between using the 1/250th and 1/500th reading from the chart would make a difference, for example.
1/250th second = 4 minutes 22 seconds
1/500th second = 2 minutes, 11 seconds.
That difference of 2 minutes would make quite a bit of difference in my opinion, so hopefully you can see my problem.
I hear you saying that one option would be to set the camera to use full stop increments which would then syncronise nicely with the chart. Yes it would but I like the flexibility of using 1/3 stops.
Why not create a chart that shows you the exposure based on 1/3rd increments and that is exactly what I did. I have created a chart which shows the exposure required based on either 10 or 16 stops in 1/3rd stop increments which sits all the time in my camera bag.
I have included these charts with the latest copy of my Long Exposure Quick Guide eBook which is now available in the online-store. There are 2 versions of the eBook, one is FREE and the other is priced at a modest £2.00. The Free one is just the eBook but the one priced at £2.00 comes complete with the following printable PDF charts.
- 10 & 16 stop in full stop increments sized to A5
- 10 & 16 stop in 1/3 stop increments sized to A4
- 10 & 16 stop in 1/3 stop increments sized to US Letter
- 10 & 16 stop in 1/3 stop increments sized to A5