Photography - Camera Filters (Part 2)
Welcome to the second instalment of our travels through the world of different filters.
The ND (neutral density) filter is another absolute definite for the camera bag of any photographer.
ND Filters come in different strengths most commonly 0.9, 0.6, and 0.3 which stop the exposure down 3 stops, 2, and 1 respectively. Now I know it seems odd because rarely do you have a problem with too much light that you can’t get rid of! However, certain specialist shots require you to stop down further in bright conditions.
First off ND filters come in a couple of variances (putting aside their strength) you can either get graduated or complete. Complete are a full frame of your filter so it will stop the whole frame down X amount whereas graduated filters are, yes you guessed it, graduated! So they will go from clear to grey. Both have their great uses.
Starting with complete ND filters these are used when there is a strong difference between dark and light, for instance a landscape with ground and a bright sky. Our eyes have no problems with this difference in contrast but cameras can struggle trying to expose for both, and what an ND filter will do is balance the brightness, which it does without affecting colour. Very helpful to bring some detail in to sky when usually you would over-expose trying to expose the ground.
NDs will also allow you to do longer exposures in broad daylight/bright conditions. Looking at the picture below it was taken ISO80, F/1.8, shutter speed 1/400. So a quick shutter speed and you can see it’s kinda ugly. The water is neither really sharp nor is it really smooth…it’s just not desirable.
So what can we do? Well, we could shut our f-stop down to f/8 but even that gives us only a shutter speed of around 1/6 which is slow but we can do better. Crack out your tripod and let’s bring on the ND filter. Now your camera might have an inbuilt ND filter which will most likely take the exposure down 2 stops but we will need more. I broke out my Cokin filter and with a shutter speed of 15 seconds, f/8, ISO80 I ended up with this:
The water looks super smooth – and although it’s not the nicest picture (It was very cold and I was in shorts and t-shirt…may have been rushing slightly! Here’s a good example where using ND filters to gain very slow shutter speeds in bright conditions works very well:
I wish I got a shot to show the difference but alas this was a while back! But the water was obviously very choppy flowing fast through the pebbles and rocks, but using an ND filter, I slowed my shutter speed right down and got this smooth, liquid effect.
Ok, so moving on to Graduated ND Filters. As I said before, these filter start clear at the bottom then gradually gradient into the ND grey.
Now I love using these kinds of filter, I use Cokin as it is a slide of filter you use rather than a screw on filter, which gives me the flexibility to shift the filter rather than change my composition. Anyway, I love them because I can get a beautiful exposure on the ground and keep the detail in the sky where it would normally be very overexposed. So, pictured below is the same shot, same f/1.8, ISO80, shutter 1/1000.
However as you can see – exactly the same settings on both, but the 0.9 (3 stop) grad filter meant I could have the ground exposed for and by placing the start of the gradient on the horizon, my sky is stopped down by 3 stops – boom! Much more dramatic and much prettier (especially the ‘fingers of God’ to the right of the picture) But really, this is what sets apart your photos from the rest and it’s all through using an ND filter.