Photographing Edge Lit Carved Glass with a Digital Camera
Author: Jim Yount
Revised: August 03, 2005
Folks who have visited my site at http://www.graydog.org have asked how I've done the photographs. If you haven't already done so, visit David Paterson's excellent article on this subject for general background. Photographing edge lit bases is a special case, and I've thrown in using a digital camera, just for variety.
All this is done with one objective: to make the photograph look as close to the glass art as possible.
There are many ways to photograph edge lit carved glass; the methods described below work for me. If you have other methods that work, please send them to me, so that they can be posted and shared with other carvers.
Producing photos that realistically represent the way carved glass looks when edge lit requires that you tweak just about every aspect of taking a photograph:
I photograph in complete darkness, to avoid reflections of the camera or the room in the glass. I wrap the tripod with a black cloth.
Light meters (especially the ones in consumer level digital cameras) assume a scene with "average" lighting. That means that the scene averages to a medium gray, the so-called 18% gray of a photographer's gray card. With edge lighting, the scene is mostly black with a few very bright lights/lines. The light meter in your camera thinks "this scene is really dark, so I better open up the lens a bit", and generally overexposes by one to two stops. You'll need to compensate by selecting -1.5 to -2 underexposure on your digital camera. Experiment here; digital film is cheap.
Digital cameras are unforgiving when it comes to overexposure. All the tweaking in the world in Photoshop won't restore detail to a washed out highlight if the camera sensor has saturated. High end consumer cameras will indicate part of the photo that is beyond the range of the sensor. If you have one of these, use it. If not, experiment with exposure for your "standard setup", so that the image is within range of the camera.
So, how do you focus up close in the dark with a digital camera? Many times the auto focus will be confused, and you'll have to do this manually. Trying to see if the image is in focus on the tiny screen just isn't practical. My Canon has a video out connection, and I have a small TV in the room, so I plug the camera in to the TV, and it works fine.
The other half of focus is providing enough depth of field. You do this by stopping down the lens. Usually, this isn't a concern with digital cameras with their really large depth of field, but it can be a problem, especially with curved glass. My Canon goes to f8; many digital cameras don't even go that high. By comparison, if I was using a 35mm camera, I would shoot at f16 or f22; with a technical camera at f32 or f64, if it was available. Take a look at your camera owner's manual, and see how small an opening (how LARGE a number) is available on your lens.
Be sure the "digital zoom" is turned OFF for this and all serious work you do with your digital camera.
So, you've done all the good stuff in David's article, and your pictures still don't look right. Photoshop or image editing software is the next step:
Your eyes perceive the lighting color differently than either conventional film or a digital sensor. If you must use color for your photograph, use the desaturation/hue controls to make the image look like the glass does in real life.
"It looks too grainy"
Many digital cameras have built in software for adding sharpness to the image. This extra sharpness can make a smooth carving look coarse and grainy. First step: turn off the sharpness setting in your camera. If that doesn't remove the coarseness, then use unsharp mask/Gaussian Blur tools in Photoshop.
Outside on a sunlit day, your eyes can clearly see detail in the brightest highlights, and in most shadows, a range of maybe 12 to 14 stops. Long scale color film (such as the Portra 160NC that Tom and I use) is good for at least 8-9 stops (it's designed for wedding photographers, to photograph a man in a black tuxedo, standing next to a woman in a white dress, outside on a sunny day, and get all that within the range of the film). Digital sensors are closer to slide film in range, maybe 4-5 stops, depending on how you measure it. So, this evenly lit masterpiece you've just carved looks very UNEVENLY lit on your computer screen. Solution: use Photoshop's gradient tool to even out the exposure.
Sound like a lot of work? Yes, it is. It gets much easier and faster with practice, and the result is that your photos will look very much like the real thing. That has to really help your sales, and the pride you can take in your good work.
©2005 Graydog Services • webmaster: jim(at)graydog(dot)org