How to choose neutral density (ND) graduated filters for landscape photography

How to choose neutral density (ND) graduated filters for landscape photography

October 18, 2019 71 By Stanley Isaacs


Welcome to this week’s vlog. Now why am I stood in a muddy field in the middle of the French countryside? Well what I thought I’d do this week is, it’s become apparent that on the usual day that I’d do my vlog I’m not actually going to have that much time at all to be able to create the vlog that I want. So I thought that what I would do this week is create a tutorial for those people that have always struggled with neutral density graduated filters and try to give them an understanding of how it is you actually choose the correct neutral density ND grad filter when you’re doing landscape photography. Now why yet another tutorial on using grads? There’s already quite a number of them on YouTube already. Well I’ll tell you. I’ve looked at some of those particular vlog entries and tutorials on YouTube over the last few days and I found them a little lacking in information in actually telling you the correct information you need to be able to choose your correct grad when you’re looking at a scene like the one behind me. Now I’ve chosen this afternoon specifically because of the gorgeous cloud that is up there and also the different tones and tonalities that are in the scene to be able to correctly demonstrate what it is that you need to be able to do to choose those grads. So let’s get going and let’s show you how the first of three methods that I use to be able to choose graduated filters in the field. As I said there’s three different methods that I use in the field to be able to choose ND grads. Now the first is incredibly simple. Here is a Canon 6D and what I do is I just turn on the live view. I look at the exposure of the foreground. Look at the exposure of the sky. Calculate the difference between the two and that’s my ND grad. What I’m going to do now is I’m going to switch between the camera here and I’m going to switch between the live view on here to give you an idea of what it is that I’m doing to be how to choose that particular graduated filter. This is the first and easiest methodology to choosing an ND grad filter. Now what I’ve done is I’ve just all I’ve done is I’ve just turned on the live view on my canon 6D and i’m currently looking at an ISO of 100 and F stop of f 11 at one 50th of a second on the shutter speed. Now that’s giving me a pretty good exposure on the foreground. Now i am going to say right now you’re probably thinking “well it’s a bit dark isn’t it?” Well the sun has just gone behind a huge bank of cloud up in the sky but obviously just for demonstration purposes I’m sure you’ll… by the end of this understand the difference and how you choose these grads. At the moment as I said f11. 1/50th of a second and ISO 100. So how do we determine the exposure for the sky? Well on Canon the live view makes it incredibly easy. You just need to see how many stops difference there is by changing the shutter speed and then you’ll see the difference between the foreground light and the light up in the sky with the blue sky and the white cloud. So let’s just change the exposure. That’s one stop. Two stops. There’s roughly a two stop difference between the foreground light and the light up in the sky. All I do is I take a two stop ND grad. I place it in the filter holder, if I can get it in there, and you will see as I slide it down the difference between the unfiltered sky and the filtered sky. I’m just going to change the foreground exposure just a little bit to 1/40 of a second as it’s gone actually quite dark now and just going to take a shot and see what it looks like. So I’ve taken a shot and doesn’t look too bad. Probably a little couple of little blown the highlights in there as there is some white cloud. Now as you can see the sun is coming back into shot again. If I just change the exposure down again, you’ll see it’s still pretty much a 2 stop grad. That is the first and simplest way to choose a grad. This is method number two. This uses the multi-segment mode metering inside the camera. What that does when you look at the metering mode of your camera will see a square bracket on the top square bracket on the bottom and then a dot in the middle. That’s multi-segment metering mode. There’s a few other names for it but that’s one of the ones that I know. What does that do? When you point your camera at a scene it tries to take readings from all over the scene and then it averages them out and then it gives you the reading that it thinks is the one you’re going to need to take the ideal picture. Now of course we know that doesn’t always happen and sometimes you end up with like a silhouette or things like this. But let’s demystify a little bit of that. What I’m going to do is I’m going to take the camera off the tripod. I’m going to take a meter reading from the ground and I’m going to include various tones on the ground so there’s all the grass here, the earth and a few bits of dead grass and stuff.So there’s some light tones as well. I’m going to include that. Get a meter reading from the ground. Then I’m going to look up at the sky. Then I’m going to take a meter reading from the sky. Now when I say a meter reading, when I look through the viewfinder of the camera you’ll see, well on this Canon… the Canon 6D, what you’ll see is minus three minus two minus one then there’s the middle then it’s + 1 + 2 + 3. I’m going to put the meter reading in the middle between the minus 1 and the plus one so basically zero. Look at the ground and then i’m going to do the same with the sky. I’m going to take the meter reading from the sky, the meter reading from the ground the difference between the two will then give me the meter reading that i need to determine how many stops of graduation that i need to be able to filter the sky correctly so let’s do that. I’ve set my aperture to f11 and my ISO to 100. Now I need to determine the shutter speed so to determine the…the foreground exposure what I’m going to do is I’ve taken the camera off of the tripod and then I’m going to point it down the ground and then meter for the ground. According to this, it says it’s 1/8 and that’s basically putting the meter in the middle between minus one and plus one…0. If I do the same for the sky. It says it’s 1/60. Now when I’ve metered the sky, I’m looking at there’s the blue sky there; there’s some white cloud and there’s also some grey degradation in that cloud as well. I’ve got plenty of tones for the multimeter segment of the camera to try and determine what it is. If i go back to my base exposure again of 1/8. Now let’s count down so 1/8…it goes to 1/15…1/30…1/60… that’s three stops. So it’s basically saying I need three stops of neutral density graduate filter to determine…to have an evenly balanced image between the foreground light and the light up in the sky. This is the third and methodology that I want to show you as to how i would choose a neutral density graduate filter. This is the methodology that you’ll see printed in a lot of the photography magazines and they’ll be saying to you “if you need to meter for your mid-tone in the foreground, you meter for your mid-tone in the sky. Between the two you should be able to get your neutral density graduate filter.” The problem is, where’s the mid-tone? Now what I’m going to demonstrate now is how you choose those mid-tones, certainly in the foreground but not in the sky, and that will help us to achieve the correct exposure for the foreground and then I’ll demonstrate how to then get the sky and then we can balance the two exposures with a neutral density graduate filter and then we should achieve a balanced exposure in our cameras. When it comes to metering the mid-tones in the foreground there’s a couple of options that you can use to attain your mid-tone reading. Now here I’m stood in the field. There’s green grass around me. Well-lit green grass will give you a good idea of a mid-tone in your foreground. Another one is well worn tarmac. That should give you a good idea of a mid-tone in the foreground but since I’ve got the grass here and let’s just try and see what happens. If I point the camera down at the grass here and take a meter reading it says it’s at f11 iso50 it’s 1/60. So let’s just take a shot. Now I can see from the back of the camera that the foreground is correctly exposed but the sky is certainly overexposed and it needs sorting out. Now what happens if you don’t have well-lit green grass around you? I’ll explain. Now if you don’t happen to be in stood in a field and you’ve got all this lovely well-lit green grass mid-tone around you, what can you do? Well now I’m not sponsored by Lee Filters in any way but I do use Lee Filters for their neutral density graduate filters. Now they do a 10 filter pouch which is and inside there’s this black felt. What I’m going to do is I’m going to take a spot meter reading from the black felt and then if it’s zero it says to me it’s a one-fifteenth of a second something like that if I then adjust the exposure quicken it by two stops two or two and a half stops it should give me a good balanced exposure for the foreground because that’s when you’re putting your camera on zero it’s trying to render everything is grey. So when you’re doing snow things like this you put it in the middle it puts that white snow as grey because it’s under exposed. What I’m going to do is just put this down on the ground I don’t take a spot meter reading from this see what it gives me; check the exposure; adjust it by two stops and then take another picture just to prove that point. OK so… So at the moment is says at f11 ISO50 it’s around one eighth of a second so if i just said by say two to three stops…1/15…one stop. Two stops… 1/30. Three to render it correctly as black. Click an exposure. I can see if I just turn on the histogram on my camera that I’ve definitely got a good exposure for the foreground. So that’s how we can get the good meter reading, a spot meter spot meter reading for the foreground exposure. You can get it pretty much every time instead of concentrating on a mid-tone find a dark tone and adjust your exposure by two stops. Put on 0 in the middle, the meter reading adjusted by two stops, quicken the exposure and then you should get a good foreground exposure for your landscape in front of you. Now let’s deal with the sky. When it comes to finding a mid tone in the sky this is always the tricky part because we have blue sky there’s some white… some nice white cloud up there. There’s no real grayish cloud to get a sort of mid-tone reading so what do you do? The easiest thing to do is to tell people to actually head for the white cloud and then adjust the exposure accordingly but that doesn’t always work. But let’s just see what happens when I do take a meter reading from the cloud and adjust the exposure accordingly. So if i take my camera off. If i look at the white cloud it says it f11 at ISO50 it’s 1/500 of a second so if i take an exposure as it’s on zero. It is of course hopelessly underexposed because the camera is trying to render that white cloud as grey. So if I was to look at the image on the back it is indeed grey so what I need to do is the reverse of what i did with the filter pouch where i shortened the exposure I now need to lengthen the exposure to get the white cloud. So if I add in two stops so that brings me to f/11 ISO50 1/125th of a second. If I now take the exposure then the sky is there but the problem is the foreground is dark. What do we do? I’ll explain. OK, so we have various different exposures in our heads at the moment. We’ve got a base exposure. We’re using grass and all sorts of things. How do we choose that ND grad to be able to correctly expose the foreground and the sky? Well this is what you do. You find your correct foreground exposure so we know from what I metered the filter pouch and made it black it was one sixtieth of a second but then I took a meter reading from the sky it’s 1/500 of a second but then I adjusted that and then it made it one 125th and there’s still one stop difference there which made the foreground still dark but the sky was correctly exposed. So how do we then interpret all of these? This is what you do. Get your base exposure so one sixtieth of a second. Meter from the sky, so I had 1/500 of a second and and if you count back that’s three stops of light. However it’s not a three-stop grad you choose it’s actually a one-stop grad. Now why? Because basically you need to leave two stops of exposure above your base exposure to be able to bring in that white and have it looking nicely without the scene being over filtered so I’m just going to put in a one-stop grad and then you’ll see what happens when I put the base exposure at 1/60 of a second; introduce a one-stop grad and you’ll see that everything is perfectly exposed. We’ve got a perfect exposed image in our cameras using neutral density grads. Just watch. What I’ve got here is a Lee Filters 0.3, that’s a one-stop neutral density graduate filter, it’s a hard grad because it’s pretty much a flat horizon back there. What I’m going to do is, trying to see when you use the depth of field preview button to see where the line of the grad is going down over the sky isn’t always easy with a one-stop but, I’m going to put on live view just to be able to see the degradation go down a lot easier and then what you should see is once I put the grad down and then I take my shot What’s happened is at f/11 ISO50 1/60 of a second I’ve ended up, I look at the histogram, a well-balanced exposure using neutral density graduate filters. An exposure that’s done in camera it means that when i get back to the digital workstation that there’s going to be hardly any work to do. Maybe a bit of spot cleaning here and there. But outside of that a well exposed image in camera. That’s how you choose neutral density graduate filters. Now if you are getting to the end of this and you’re thinking “I still don’t understand this or that” please do message me on YouTube and i’ll try to explain in the best way that I can to help you fully understand how you choose those neutral density graduate filters. I don’t know why but there’s a lot of people that want to make it out to be a huge mystery as to how you choose these things or as I’ve had in the past people have said “you just use them creatively” but that teaches you nothing. I’m hoping that what I’ve done with this particular tutorial is helped you choose which grad you use in a particular situation using three different methods. An easy method. One that’s a little bit harder and then harder again using spot metering which is the one, as I said, they try to explain in the magazines and they never quite get it right and people always have the question is “where do I place the tones? How do I do it?” Hopefully the tutorial has explained. As I said, any questions do let me know I’ll be happy to help. Thanks!