Sunday 17 March 2013

Lake District 121 - using filters

In the previous post I wrote about camera technique and in this entry I will cover the use of a variety of different filters to either control exposure or to be a little more creative. Whilst using filters does add another process to the taking of an image, my tutor Paul Gallagher is I believe right in expressing the view that the more you can 'get correct' in the camera when taking the shot, the better the RAW negative is to work with when you reach the stage of post processing. It's also true that some effects simply can't be replicated in Photoshop or for that matter any software; for example the use of a polariser.

In the case of the shot below a 2 stop ND hard grad was used to balance and control the exposure as the sky was much brighter than the foreground. Whilst the shot could have been taken without the filter, there would have been the distinct possibility of either blown highlights in the sky or no detail whatsoever in the shadows, neither of which would have been desirable or recoverable in post processing.


Trees
Trees in Newlands Valley

In the second shot below I used a polariser in order to control the amount of reflection coming off the surface of the water, so that the rocks below would be visible. Had this area of the picture just been black, which would have been possible using the polariser, then the foreground interest would have been lost. Paul reminded me that using a polariser had the same effect as a 2 stop ND filter, therefore increasing the exposure time. In this case the exposure was half a second which I think gave the right amount of movement in the water.


Waterfall by Honister Pass
Waterfall study near Honister Pass



In the next shot I used a 10 stop ND filter to slow the shutter speed right down. In the case of this particular shot the exposure time was 60 seconds at f11. I found that some experimentation was required when taking this type of shot, firstly to get a balanced exposure and secondly to create the desired effect. Using a long exposure does give an ethereal appearance to the water as any ripples become merged and therefore lost, and cloud movement is also evident.


Buttermere
Buttermere

It is of course possible to use a combination of filters but more than two at a time can reduce the sharpness of the image as the optical quality of the filters are good but not that good! In the case of the 10 stop ND filter it also produces a strong blue colour cast which is fine if converting to black and white but may not be so easy to lose in post processing if the end result is a colour image. Another advantage of using this filter is that any people or birds entering and leaving the frame during the exposure may not always be recorded by the sensor. The image below would have suffered had the ducks swimming around at the time been part of the finished result!


Elterwater
Elterwater in Langdale

It perhaps goes without saying that a tripod is an essential piece of photographic equipment. for landscape work. None of these shots could have been taken without one. Adjusting the legs and indeed the tripod head can be time consuming in order to achieve the right composition but it does slow the whole process down, and makes you think about what you are doing. This can only be a good thing - as the tortoise said to the hare!



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