I am all for tools, software and systems that make life as a photographer a little easier. Anything that can keep my simple brain from working too hard and giving me a headache is something I want to try. The difference between getting a shot and missing it can sometimes be quite slim, and when you are using neutral density filters in rising or dropping light, calculating the right exposure time can maximise the chances of ensuring your images are properly exposed.
I regularly use ND filters like the 6 stop, 10 stop and 15 stop in the NiSi Filters product lineup. Pair those with a polariser and grad filters and exposures times can quite often push into minutes. It is not unusual for me to be taking six or seven minute (or even longer) exposures. With a limited timeframe during the times I often shoot (sunrise + sunset) and shifting light there is often a small window of opportunity to get the shots I want.
I have been using and recommending ND calculator apps for quite a while. Now I will say this before anyone leaves a comment about it – I do not require an ND calculator app to work out my exposures times. With experience and a bit of knowledge about how stops of light are calculated across the exposure triangle anyone can do it. But to speed the process up an app can be extremely useful. I have tried just about every app I can get hold of on the iOS app store and even some on Google Play. I keep coming back to the NiSi Filters ND Calculator App and here is why.
NiSi Filters ND Calculator App Interface
There are two basic things you require when calculating exposure times using ND filters and they are the base exposure time calculated by a meter reading without ND filters on the lens + the density and type of filters you will be using to take the exposure. With the NiSi Filters ND Calculator App these two things are laid out extremely intuitively in two fields that can be easily toggled with the requirements.
In the “Normal Shutter Speed” field you simply select the base shutter speed your camera has calculated without any filters on. In the “Choose your Filter” field you select the filter, or combination of filter density you will be using to capture your image. The third field in the “Shutter Speed With Filter” calculation, and this is the exposure time you will need to use to properly expose your scene using the exact same ISO and aperture as you used when doing the initial meter reading for the “Normal Shutter Speed” field.
If you need instructions on how to use the app, there is an option available in the top right corner that takes you to a very useful tips page. This will guide you through the process and will assist you in ensuring you are using the right information to calculate your exposure times.
Number of Neutral Density Filter Calculations
Something that struck me as quite obvious when I first starting to use the app (I personally use Apple devices so I use the iOS version) is the number of variations available within the “Choose Your Filter” field. If you know anything about the NiSi Filters product lineup you would be aware that in Australia the straight neutral density filters available to purchase are the 3 stop, 6 stop, 10 stop, 15 stop and the 20 stop. So why would there be a use for a calculation such as 5 stops or 7 stops? This is a fairly easy answer – the ability to calculate exposures when stacking filters.
As soon as you start stacking ND filters with others filters such as a polariser (generally a 2 stop density) and grad filters your exposure times may vary due to the additional filters. Having the extra stop calculations available in the app can be very useful for this.
Here is a tip if you are stacking your filters – if for example you have a 6 stop ND and a 3 stop soft grad you may need to allow a bit of extra time as shown in the “Shutter Speed With Filter” field depending on how much of your composition you are covering with the grad filter. This is not always a requirement as the grad filter is designed to balance the exposure in certain parts of the scene. But I have found that I occasionally underexpose for a scene if I do not compensate for the additional grad filters being used. I would not add a full 3 stops to the calculation as only part of the grad filter is the full 3 stop in density. But perhaps one extra stop may be required depending on the scene.
NiSi Filters ND Calculator App Store Availability
The NiSi Filters ND Calculator App is developed in house by the team at NiSi Filters Australia & New Zealand. Initially the app was only available on the iOS App Store, but recently has also been launched on Google Play for Android devices. This means the app is now available across a huge percentage of mobile devices. Android apps are much harder to develop due to the combination of possible screen resolutions. If you do not make the app compatible with all of the possible screen sizes you end up with an app that is usable by some and not others.
Thankfully for app developers iOS is much easier and less complicated to develop for. I know the team behind the development will be working to ensure the app is extremely easy to use and constantly updated to suit the requirements of users.
NiSi Filters ND Calculator Review Overview
As mentioned above I have tried many different ND calculator apps over the years. More often the not the interface is too complex or just not intuitive at all. I have used some apps which are limited to the product lines of a specific neutral density filter manufacturer and they don’t allow for the extra calculations for stacking filters. The app is made by photographers so they understand what is required and what isn’t. Overall I would recommend this app to anyone who wants to simplify and speed up the process of calculating expsoures times without giving themselves a headache in the process. You can also use the information available to assist you in understanding the variations in stops of light in cases where any apps are not able to be used, for example when your phone has a flat battery.
You can download the app for free here –