Photographs Through Tinted Automobile Windows
When I watched the testimony at the trial of Steven Avery for the murder of Teresa Halbach, I heard state’s witnesses testify about their inability to see the inside of the Halbach vehicle.
John Ertl of the State Crime Lab was dispatched to the scene. He testified that he used a flashlight to look inside, but could not see much due to the tinting on the windows.(1)
State witnesses testified that at that time in the investigation, the case was considered a missing person search. It would have been reasonable to open the vehicle to determine the whereabouts of Halbach in case she was still alive, but for some reason, this was not done. Prosecution witnesses were vehement that no one opened a door to check for evidence.(2)
Given the reluctance for law enforcement people to open a vehicle to look inside, is there a technique that will allow a reasonable view inside an SUV with even heavily tinted windows and in darkness? Of course there is.
I took some photographs through the tinted windows of a 1997 Dodge Grand Caravan. There was nothing special or exotic with my gear. This experiment was more of a proof of concept rather than a detailed procedure, but the results are sufficient to show that this is a viable and useful method to show what’s inside the vehicle. Making use of a digital camera can provide instantaneous results.
I took photographs at 7:00 P.M when it was still daylight at and at 9:55 P.M. when it was dark with no outside lighting except a camera flash. The dates and times are part of the file name of the photograph.
My gear was a Nikon CP5400 and a Sunpak Flash type NE. The trick is to hold the camera and flash either on the window or very close to it so the flash is not reflected. Here are some photos demonstrating results.
The first two photos were taken with plenty of ambient light. Photo A is a view through the rear window and photo B is a view through the rear passenger side. Items inside the cargo area and the passenger seating area are visible.
Photo A: Afternoon photo – cargo area.
Photo B: Afternoon photo – middle passenger area.
Photo C was taken at night and is not a good picture. This was taken with full zoom. The aperture is stopped down. Noise is evident. The shot is dark and difficult to use. CA is this same photo with some rudimentary contrast enhancement. No information was added to the photograph. There is a catsup spill showing the door threshold on the opposite side of the SUV.
Photo C: Zoom to passenger door threshold on opposite side. Unretouched.
Photo CA: Zoom to passenger door threshold with contrast enhancement.
Finally, this is a photo taken at night in an enclosed garage. The aperture is fully open. The result is useable.
Photo E: Nighttime in enclosed garage.
None of these tests were an attempt to determine when blood spatter is indicated. The limit of detection will depend on the gear used and the experience of the photographer. It is also a possibility that add on filters can be used to assist in bringing out detail.
For investigative and information gathering, this is a useful tool. Protocols can be developed with standards for minimum noise and best exposures. With a digital camera, there will be instant feedback. Cameras that read focus information from the flash unit infrared beam will give clear photographs.
Some post work is acceptable such as contrast enhancement and moderate sharpening. However, too much is a problem. A creative technician can inject information (often unwittingly) at the prodding of a field investigator who has preconceived notions of what they want.
To ensure that the original information on the memory card is accurate, a requirement for the use of digital cameras by law enforcement must be write once memory cards.
With proper protocols, field investigators can gain valuable information, and direction before having the vehicle arbitrarily removed from the scene. And with proper restraints on post processing, the photos can provide additional information.
The photographs in this article can be freely downloaded and used by others with attribution to http://www.convolutedbrian.com. Of course, linking to this page is permissible.
in category Steven Avery,Technical Stuff
