Metering for Lee ND Grads

Winter in Style
Originally uploaded by thefatcat44

First thing to say is, this is the kind of image which doesn't get many comments on Flickr! Most flickerites are drawn to brightly coloured images, heavily saturated and unnatural. The thumbnails glow and call out 'click on me'.

This type of image, very 'Joe Cornish' (I wish), is exactly as it was the other morning in heavy frost near the Surprise View in Derbyshire. No spectacular sunrise, no zinging colours - just a wonderful calm atmosphere and lovely lilac blue light reflecting off of the frost.

Which leads me to the reason for my post.

I invested in a set of Lee ND Grads in the summer. No amount of blending, HDR'ing or any other jiggery pockery can replicate how they work or the quality they bring to an image.

However, for some reason, they don't come with instructions. I am guessing either everyone knows how to use them properly and I am just a bit thick, or Lee don't care and just make so much money out of these overpriced pieces of plastic they think 'why bother putting instructions in, when wads of cash just keep pouring in without them'. (I mean, £40 for a small adaptor ring of machined aluminium!!! It must cost Lee £1 at most to manufacture).

Then, this week, I got the Lee Filters book, written by the photographers they use in their publicity - David Noton, Joe Cornish, Charlie Waite et al. At the beginning, finally, is a double page where they explain exactly how to meter for the filters to get superb results. I then got an email from a contact of mine with even more help but more of that later.

Lee describe two methods of metering for their ND Grads. The second method is for those with a hand held spot meter. Now at £300 approx for one of those, I don't yet have one, although I can feel one coming, so I won't describe this method just yet - maybe on a future post.

What I will describe is the method all DSLR users can employ. It is going to sound complicated, and I am purposely trying to include much detail, but trust me, once you have done it a couple of times, you will see it is quite straightforward and no where as difficult as it sounds when you write it down. I also include some help from my friend Howard Goff too, towards the end which simplifies things a lot.

1. Set the camera, on the tripod, to manual mode with the filter holder attached but no filters in.

2. Set your desired aperture - for landscapes usually something like f16 or f22.

3. Set the camera to spot metering mode (see your cameras manual for this). In this mode the camera only measures the light in the very centre of the lens, so it is very specific and accurate.

4. Take your first reading by pointing the camera at a mid-tone in the foreground and half depressing the shutter button. A mid tone means, not the brightest part of the ground and not the dark shadows on the ground but a part of your foreground reflecting an average amount of light (In the case of the image above as an example I took a reading from the grass halfway between the millstone and the style, aiming for part of a tuft of grass showing more green than the bluey white of the frost). When you point your camera at your chosen area you need to adjust the shutter speed until your light meter in the view finder centralises. Remember the shutter speed it displays at this setting. This is your 'Base Exposure'

5. Now, leaving the aperture at the same setting, point the camera to a light area in the sky - again, not at a dark cloud or at the sun itself (if this is visible, never point a light meter directly at the sun or look at it through the lens with your eyes) but point at a brightish area - again in the image above I chose the light area near the horizon just above the dark central hill. As you do this again adjust the light meter in the view finder to bring the pointer into the centre by adjusting your shutter speed (the shutter speed will get faster). Note the shutter speed.

6. Now work out how many stops there are between your base reading and the sky reading. Remember that, in the case of Canon cameras and I am assuming Nikons and other makes too, that each 'click' of the shutter speed adjustment wheel is a third of a stop - if there are 9 clicks between the base and sky reading then there is a three stop difference in the light being reflected towards you.

7. So if there is a 3 stop difference, insert 3 stop grad filter and position it correctly with the grad line across where the sky meets the land and set your camera back to the base exposure shutter speed - no matter what your light meter now tells you with the grad in place.

8. Take the shot and it should be well balanced. I usually take additional bracketed shots one third above and below the base reading, just in case.

9. Some photographers would chose a three stop grad in this example as there is a three stop difference, and that is down to taste. However this can cause problems, especially when taking landscapes with water reflecting the light in the sky - either the sea or a lake/river - the water should always be less bright than the light it is reflecting, this is how things are naturally so a one stop difference between the sky and land preserves this effect.

10. In my image above there was a two stop difference between sky and land and so I used a one stop filter, although a two stop could also have been employed.

this method does seem to give consistently good results and saves taking 10 shots and messing about trying to guess which filter to use or which combination of strengths is needed.

You do need to work quickly, especially when the light levels are changing fast at dawn or dusk. It is a bit of a nuisance having to have the camera loose on the tripod mount so you can point it at the appropriate areas to get your readings before finally setting the framing up and locking the tripod head off for the shot.

I am assured by photographers better than me, that you soon develop the ability to look at a scene and think 'mmm, there is a 2 stop difference here' and select the filters without metering.

Now on to the help from my friend, Howard Goff. He has written his own version of the instructions and made them downloadable from his excellent website at http://www.360360.co.uk/equipment_main.html . In this account he also displays a chart of shutter speeds and apertures that you can print off and laminate which help you work out how many stops fall between two readings - brilliant. Please take a look at his instructions and browse his website while you are there - it is well worth it.

He also suggests you take the sky reading first, then the base reading, because you have to return the camera to the base reading for the shot and this makes sense to me and speeds up the process slightly.

I have been struggling with ND Grads since I got them. Sometimes I have hit on the perfect settings, but purely by accident, and I have been having to take heaps of exposures to make sure I get the right one. I hate this finger in the dark machine gun approach.

The correct method takes more time and precision, but it is more satisfying, more reliable and it does yield far better results - so for the true landscape photographer, it is the way to go.

I hope this set of instructions is helpful - please let me know how you get on using it.