Achieving Correct Dynamic Range in a Photo
NewsPost Production & Digital Imaging Techniques
Sep 13th 2016
A recent commission for a client to cover some local villages in Kent lead me to Linton. It’s a lovely little village with a old pub, church and views over the countryside.
On this visit I decided to shoot the pub at dusk to capture the lights on the buildings and some nice, inky, blue evening sky above. It also offered me the chance to ‘fill’ the rather unsightly road with some whizzing car trails!
My routine for this kind of shot is to shoot for the sky (to get it while I see it looking good) and then record the exposures needed for the static objects, i.e. the buildings and lights. Normally this takes two, maybe three exposures with Luminosity Masking to blend them together. On this occasion it took 5. Let me show you.
Here’s the shot for the sky at 0.8 seconds.
That’s all fine, the clouds and sky are all well exposed, so I took my next one exposed to capture the tones in the road and buildings which is also fine.
Normally I’d merge these together and that would be that. What I noticed however when I zoomed in on the darker sky shot on the back of my camera was that the highlights in the lights were all very blown out.
I’m not one for over processed, HDR, type images but here I could clearly see all the details and colours in the lamp, wall and pub sign with my eyes and I wanted to capture that in my final shot. I was surprised how fast I had to set the shutter speed in order to properly record them but it demonstrated to me how careful you have to be to accurately record all the tones in the scene so that its looks correct in the final image.
Here’s my first attempt at what I thought would be right. This is a 1/6 second and although the shot seems very dark, the actual bits that I want to have details in are still missing, noticeably so in the wall and the pub sign which is very hot at the top left above the bull.
So I then shot the scene at a 1/13 of a second and although most of the detail was there, some small white ‘hot spots’ were still present, especially in the sign and light which my eyes just didn’t recognise. So I shot again, this time at 1/25 second for an exposure that showed hardly anything on the histogram away from the far left where The Dark Side exists...
This time I’d finally caught all the details and you can see the colours all clearly available to me now for post production merging in this final shot.
Here’s what the shot would look like without the crucial detail in the highlights:
Here’s what it looks like with those nice tones recorded for a full dynamic range that reflects what my eyes could detect.
You might say; 'well, unless you look closely or blow the shot up big, you really cant see these imperfections.' And you'd be right. Except I think that as I have the means to achieve a better reslut (through corrct exposures for the highlights and blending in post production) and because it's 'the right thing to do' to get the shot looking the way I saw it with my eyes, then I really should be doing it. Also, what looks good on the little display on the back of the camera wont translate into a large print so well where these imperfections will be much more obvious, which is reason alone to do it properly.
The blending of these various exposures was all achieved with Tony Kuyper’s Luminosity masks. With these I could accurately select the lightest tones in each part of the shot and paint in the correct tones from the exposures I did to record the highlights. The self feathering nature of the masks meant there was no difficulty in terms of ‘bleed’ from the ‘good’ colours into the far to dark colours that existed everywhere else around these specific little hot spots. In fact the whole process was really quite quick with the V4 panel making what used to be quite a daunting task a real breeze to complete.