Concert photography is war. Concert photography places photographers in the most challenging and uncontrollable myriads of conditions. Our world is that of apertures in excess of F2.8 and ISO’s north of ISO1600. To further challenge the concert photographer and their gear, dim washes of light in single hues of red, blue, or green are often employed during the 9-12 minute shooting limit of the first three songs. While this makes for great audience presentation, it can leave a digital photographer both metaphorically and literally Seeing Red.
Photographers deal with this scenario in different ways. The most common of which is conversion to black and white. While I respect any artists creative embellishments, my personal choice is to take the shot as it is presented.
While not an expert on camera sensor technology and the associated processing algorithms, the technical basics of what happens when you press the shutter and why solid washes of primary additive colors are a problem for modern DSLR sensors are as follows.
Modern DSLR’s contain an image sensor. This sensor is comprised of silicon divided into millions of little buckets commonly referred to as pixels. These pixels capture the image in monochrome. To understand the color makeup of the image, a filter is overlaid upon the image sensor. The most common of which is a Bayer Filter. When the shutter is pressed, light falls upon the filter which sorts the values of the red, blue, and green light into the pixels/buckets underneath it. Due to the sensitivity of the human eye to green, there are twice as many green sections of the filter as there are red or blue. Meaning in practical terms, 50% of the pixels filter green, 25% filter blue, and 25% filter red.
Next, the camera tallies up the amount of data in each bucket and through interpolation of the data via some very complex algorithms determines the color values for each pixel by assessing the amount of data in each pixel and its immediate surrounding pixels to determine both color and shades of color within the color space. The accuracy of such is determined by the bit depth supported by the camera. Within my Nikon D700 for example, I have JPG (8-bit or 2^8), 12-bit RAW (2^12), and 14-bit RAW (2^14) color accuracy options. Of course, RAW 14-bit (2^14) is my personal option for the highest degree of accuracy and the greatest latitude in color possible from the camera.
Finally, the camera applies its own internal and user adjustments to the captured colors and levels and writes its interpretation of the image to the storage medium. In the case of JPG files, this is the final output. In the case of RAW files, the RAW image data as captured by the camera and any user defined in-camera adjustments are written as output.
If you consider this in terms of a performer in a solid wash of red, roughly 75% of the image data is discarded by the camera with a high likelyhood of the resulting image being blown out due to abundance of the red channel with little detail resolution due to lack of image data beyond the red channel or in variations of color within the red channel. This is were shooting in RAW and using the largest bit depth possible retains as much of the image data as possible.
Shooting subjects in a solid wash of red in practical terms and through practical experience, your eyes and your camera’s meter are going to be tricked into an overexposure and over saturation of the red channel. This is another example supporting manual as the best choice for exposure mode in concert photography. For my personal gear, I find the Nikon D700 to be a bit hot on the red channel at all times so as a default setting the red is dialed down a notch in-camera.
Understanding your camera’s meter and its normal exposure offset underexpose by 1-2 stops to compensate for the known confusion the meter will exhibit in such circumstances. If a fog effect is part of the mix, underexpose in the neighborhood of 2-3 stops as fog further confuses the meter into an overexposure. Of importance as well are where these stops come from. You can raise the shutter, decrease the aperture, or lower the ISO. Generally I favor a decrease in aperture and ISO to get the stops of light contributing to the underexposure per the camera’s meter. Increasing the aperture adds more fine detail to an otherwise flat image thus providing more data for the camera to work with. Decreasing ISO reduces the noise in the image to again bring more usuable data into the image capture. Working together, more graduations of color are visible with the single channel color space and thus a perfectly usable image can be captured as presented without the need of excessive post processing or deviation from original presentation.
As concert photographers we must constantly adapt to lighting designers presentations and artist preferences to get the shot. We seem to face an unlimited array of impediments to our success. Learn to get the shot no matter the circumstance and understand why and how to react to different lighting presentations. The next time Rob Zombie comes to town you’ll be ready for exposure challenges the likes of which you’ve never seen. Experience and instinct will see you through it.