Decrepit Old Fool

On a recent field trip to the Creation Museum in Kentucky, the Pharyngula crowd (about 300 of them) – experienced a common problem with photographing glass-covered exhibits: flash glare.  It didn’t happen on very many of the pictures but in some cases it obscured important details of the displays.

There are several approaches to flash glare, and if you are a professional hired by the owner of the display, you can set up 45-degree slave flash units on either side, to get a perfect, glare-free shot.

But suppose you are just passing through the “museum” (the Creation Museum really does deserve the disqualifying quotes) and you’re trying not to bother other visitors?  Your only tool is a small digital camera.  You stand in front of the display, and snap the shot with a result something like this:

The flash comes from your camera, which is shooting at right angles to the glass.  Angle of incidence equals angle of reflection, so the light bounces right back at you.  You’re seeing the reflection of the flash. This is predictable in that you were able to see the reflection of the camera itself in the camera’s preview screen before even snapping the picture.

The flash glare may even cause underexposure of the subject, by shutting down the flash before full exposure duration is reached.  In any case, you lose some of the display in the glare, and the TV show “Numb3rs” notwithstanding, no amount of “Photoshopping” will repair pixels that contain no information.

Step to one side even with the frame, and shoot towards the center of the display, and the flash reflection will be exactly even with your position at right angles to the glass.  This gives you a clue how to proceed:

Step a little further to the side, just past the edge of the frame, and aim the camera to the center of the display.  

Now the reflection, such as it is, comes from the wall beside the display.  There are two disadvantages to this technique: distortion and light fall-off.  Both can be mitigated in Photoshop if the picture is important enough.  The advantage is that it’s very easy to do, it’s quick, it’s reliable, and the only equipment required is the camera itself.

One way of thinking about this is; if you threw a tennis ball at the display from wherever you’re standing, where would it bounce?  If it would bounce right back to you, so will the flash.  In the example where you’re standing even with the edge of the frame, and you threw the ball at the edge of the frame, you could catch it when it bounced back.  I recommend not trying the tennis ball trick in an actual museum, by the way.  It’s more of a thought experiment, really.

One more technique is to shut off the flash, brace your elbows against your chest, steady yourself, and smoothly squeeze off the shot. 

Depending on lighting conditions and how steady you are, this might work very well. The disadvantages are that it’s difficult to get a sharp picture due to camera movement, and ambient reflections (as visible here) are more of a problem.  Try moving from side to side to see if you can catch a “reflection” of a dark are somewhere in the vicinity. The advantage is that it works in places where flash photography is undesirable.

Practice with both of these techniques to find your favorite. Digital cameras are great for experimentation because they give instant feedback.

Note to museum curators – an easy way to fix this problem would be for you, the curator, to angle the glass outward from the wall.  That is, farther from the wall at the top than at the bottom, so the flash reflection is diverted even when shooting straight at the display.  If your museum allows flash photography.