Effects of Wide Angle Lens on Vehicle Photo

Often, a vehicle we need to photograph will be crammed in between other vehicles or in a small garage or storage area. I’ve encountered the same problem when trying to photograph a whole tire in a small conference room. A wide angle lens then becomes necessary to capture an overall photo in a single frame. But doing so will inevitably cause the vehicle or tire to appear distorted. (Click on image to enlarge, then click on back arrow to return.)

Van with Normal 50 mm Lens. (ZEISS 50 mm f/2 macro lens on Nikon D810.)
Van with Wide Angle Lens. (ZEISS 25 mm f/2 lens on Nikon D810.)
These two images show the same van, but the top one was made with a ZEISS 50 mm lens, while the bottom one was with a ZEISS 25 mm lens. To fill the frame with the van, I made the photo with the 25 mm lens much closer to the van than with the 50 mm lens. The photograph made with the 25 mm lens looks like the van was the long wheelbase version while the 50 mm photo looks like it had the short wheelbase. This closer distance to the subject caused the wide angle lens to stretch the appearance of the van.

The best solution is to try to capture as much of the subject as possible with a lens as close to a 50 mm “normal” lens as possible. This might entail getting a higher vantage point, or shooting between obstacles. When that’s not possible, take the wide angle shot, then normal lens shots of parts of your subject.

Other effects of using wide, telephoto, and normal focal lengths for vehicles, accident sites, and for tires will be discussed in future posts.

The Importance of Quality Photographs

How many times have you looked at a series of photographs but have been unable to find a single one that is clear enough to provide the evidence you need to address a specific issue? 

Unfortunately, regardless of the source, many of the photographs you encounter during the investigation of an accident or a product failure are likely mediocre at best, and completely useless at worst. Taking care to make decent photographs applies equally to consulting experts, police agencies, insurance adjusters, and law firm investigators. You don’t have to become a professional photographer (although many of you are getting paid for making photos during your work!), but there are fairly simple things you can do to make your photographs more useful.

At more than one inspection, the subject of making photographs has come up. Quite a few times I’ve heard, “Well, my photos aren’t great, but they’ll be good enough.” Do you treat your measurements, analysis, or reports the same way: “They’re not exactly right, but close enough”?

Some of the all-to-common problems are: blur from camera shake; poor focusing; inappropriate lens focal lengths; bad composition; bad camera menu settings; bad lighting; and incorrect exposure. Close-up photographs are often essential, but have their own additional potential issues.

Fortunately, almost every one of these photo faults is easy to correct with a little care and a little knowledge. Even used on automatic, most cameras and flashes today are incredibly accurate for 95% of the photographic situations you’re likely to face–if you are careful handling your camera. But even the most advanced technology can’t overcome carelessness.

Rather than making this into one giant post, I will be posting a number of separate articles addressing the problems I’ve mentioned above, plus some other photographic issues. In the meantime, remember it’s worth taking the time to make the best photos you can. After all, if you’re not going to try to take good, usable photographs, why bother taking them at all?

 

Don’t Move That Truck!

After a truck has been involved in a wreck, driving it even a couple feet at the crash scene without first disconnecting the vehicle speed sensor (VSS) will almost certainly destroy any last stop data recorded by the Heavy Vehicle Event Data Recorder (HVEDR), whether it is an Engine Control Module (ECM), an Electronic Control Unit (ECU), or some combination. This loss of digital evidence has often been cited as evidence spoliation, which can have serious repercussions.

This situation is easy to avoid by locating the speed sensor near the transmission output shaft, and disconnecting the electrical plug from the speed sensor. Let the plug hang free. The truck many then be driven or towed without danger of overwriting and losing important data.

It is important to make this common knowledge for truck drivers, wrecker drivers, investigating police officers, and truck service and maintenance personnel. This information can be disseminated through training classes and service bulletins. Labels on trucks near the VIN, near the toll-free number decal for the trucking or adjusting company, and on the accident packet can also help at the crash scene. Here’s a suggested label:

After a crash, do not drive or move vehicle at all without disconnecting vehicle speed sensor.

 

Out of Service (OOS) Brake Defects and Brake Force Calculations

Various CVSA (Commercial Vehicle Safety Alliance) Out of Service (OOS) violations may be found when inspecting heavy trucks. These can be maintenance or safety items that fail to meet the criteria in Appendix G of Subchapter B of the FMCSR (Federal Motor Carrier Safety Regulations) (40 CFR §396.17). This post will focus on brake issues only.

CVSA uses the term “defective” to denote a brake condition that does not meet specific criteria. CVSA declares a vehicle OOS if twenty percent of the brakes are defective. A common three axle tractor with a two axle semi-trailer will have ten brakes total. Twenty percent of ten brakes means the truck would be put OOS if two brake defects were found. (Click on image to enlarge, then click on back arrow to return.)


CVSA brake defects often result from inadequate maintenance. One important purpose of a CVSA inspection is to catch maintenance issues before they adversely affect the stopping ability of the truck. While it is essential to properly maintain vehicles for safe operation, the presence of one or more OOS brake defects does not necessarily mean the braking ability of the truck was compromised at the time of the accident. So there are two separate, but related issues: -1- Were there any problems with the truck? -2- Did any of those problems affect the truck’s ability to stop during this particular incident? Continue reading “Out of Service (OOS) Brake Defects and Brake Force Calculations”