High dynamic range

High dynamic range

I have a sneaking feeling I may have blogged about this before – but I can’t find it. And maybe I haven’t: anyway, I’ve spent a while this evening exploring a module of Nik Efex that I haven’t played with before, the HDR Efex Pro 2 filters, to be precise. As far as I can see, there’s no facility to combine frames of the same subject with different exposures, so it’s important to focus on the word ‘Efex’ – what the Nik plugin will give you is the effect of HDR, and not the reality. For that, you will need specialist software, such as Photomatix, or the right part of Photoshop.



I decided to play with the results on an old image of my friend Joceline – and having found several interesting effects, I realised that nudes aren’t quite the thing for a blog on which you can’t set an ‘18’ filter! But I may post one or two in the main gallery soon.

Instead, I went to some equally-old pictures I took poking a camera over the boundary wall of Whitby Abbey (it was closed on the say that I went there with an old friend and his wife). I managed to get a shot of the Abbey with the sun and an interesting sky behind it, and I tried a couple of filters on it. The top image here is a straight image from the RAW file, without adjustments: the second is the result of adjusting highlights, shadows and contrast – Curves users can, I’m sure, achieve a more subtle and nuanced result.



The third image down has the look that many of us associate with ‘HDR’ – and some of us dread. An overall blue tint, and low contrast – the view through an elderly teacher’s glasses, perhaps? There are no rich blacks, and there’s a general feeling of being weak and lacking punch. HDR is for controlling excessive dynamic range, not producing an image that lacks contrast.




Other looks are available in the Nik package, of course, and they aren’t all awful, but I’m not sure that any of them are particularly worthwhile, for most images. The final version is the result of making two files from the original RAW: one plus two stops exposure, the other minus, and combining them in Photomatix. This sometimes works to bring out shadow and highlight detail in images where the contrast range has defeated the sensor.



But all of this is dodging the real question, about proper, five-image HDR. I’ve been meaning to go out and have a bash at doing that – but the weather’s been so grey that the challenge is expanding the contrast range to give impact, not controlling a 16-stop tonal range. And the cold rain has not given me any incentive to put a camera on a tripod to take the necessary repeated shots: a minimum is three images (normal exposure, and plus and minus two stops), and the experts often prefer more images, and sometimes a greater exposure range…

The tripod is necessary to ensure that the field of view is the same, and Aperture priority is the best option, as depth of field needs to remain constant. When the sun shines, I’ll try it! (And blog again.)