Went for a night skate session with my boy, Benfy the other night. We had 2 LightPro 54W 900 LEDs from Dragon Image to light up the park. With no-one else around, Benfy was loving it !
I had my Canon 5D Mark II and decided not to use on camera flash but just the light from my LEDs. This would give me quite dramatic and contrasty exposures which I intended to process as black and white images.
I started shooting at 1/200s, f2.8, ISO 2000 and quickly realised there wasn't enough light from the LEDs, underexposing my images by around 2 stops.
One option to improve the exposure was to bring the LEDs closer. Using the rule of thumb that if I halve the distance between the subject (i.e. Benfy) and the light source (i.e. LEDs), that will increase the exposure by 1 stop. In other words, if the LEDs were 8 metres from Benfy, I could move them closer to 4 metres and this would give me 1 stop more light. Having spent a quite few bucks on these awesome LEDs, I wasn't willing to risk a flying skateboard taking them down, so we left them at a safe distance from the action.
Another challenge was trying to get the focus and limited depth of field right shooting a moving subject at f2.8 in low light. At the same time 1/200s seemed too slow to freeze the action, especially when Benfy was doing flip tricks.
After a couple of test exposures, I decided to settle on 1/320s, closed down to f3.5 for slightly more depth of field and pumped the ISO up to 6400. Also I reluctantly brought the LEDs closer by 2 metres. So in summary, I lost 2/3 stop in light from shutter speed (from 1/200 to 1/320) and 2/3 stop in light from aperture (from f2.8 to f3.5) but gained 1 and 2/3 stop in light from ISO (increased from 2000 to 6400) + 1/2 stop extra light by moving the LEDs closer. After all that, I got 1 more stop of light (I hope my maths is right !).
Alright, so after getting the exposure to where I wanted it to be, away we went with Benfy doing his thing.
This was so much fun and gave me a chance to test the ISO capabilities of the Canon 5D Mark II. Shooting at ISO 6400, there was definitely noticeable noise and grain appearing in the image when viewed at 200%.
The Adobe Lightroom Noise Reduction tool does help to remove the grain and noise. I recommend slight adjustments with the "Color" and "Detail" settings followed by adjusting the "Luminance" slider until you get the desired result.
Another thing to remember is that Sharpening in Adobe Lightroom will have the opposite effect of Noise Reduction so I generally don't touch sharpening if I'm trying to reduce noise.
Shooting at night and photographing a moving subject, faster shutter speeds and greater depth of field was more important to me than the grain introduced with the high ISO. The 5D Mark II ISO can go up to 25600 - I might try this next time as 6400 still gave me an acceptable image for the black and white result I had set out to achieve.
For the final image I did have to increase the exposure by 1/2 stop in Adobe Lightroom and add a small amount of contrast with an S tone curve. Otherwise, everything else in camera...