Gear – Page 4 – Vadnais Engineering

April 21, 2018January 20, 2019

Accurately Photographing Scales

Including a scale in a photograph is an excellent way to document dimensions. But it’s essential to properly position the camera to record an accurate measurement.

One of the most common mistakes made when photographing scales or rulers is making the photo from an angle. The camera lens must be perpendicular to the scale, both vertically and horizontally. A camera positioned too low or too high, and correspondingly tilted up or down, will result in parallax distortion. Worse is a horizontal offset that results in misleading measurements due to the angle of the camera to the scale markings.

Take this example made to show how far a mirror protruded from the side of a van. The first photo was taken at the proper scale height, but was at an angle to the scale. Note how different the reading appears in the second image with the camera perpendicular to the scale. The latter accurately showed the measurement. (Click on image to enlarge, then click on back arrow to return.)

Photographed at angle to scale. (Made with ZEISS 50mm f/2 macro lens on Nikon D850 with fill flash.)

Photographed perpendicular to scale. (Made with ZEISS 50mm f/2 macro lens on Nikon D850 with fill flash.)

Making an accurate photograph requires several steps:
-1- Make sure the pocket rod is parallel with the ground. Use something like a Wimberley Plamp clamped onto the upper mirror support arm to hold it at the proper height. Place the other end of the pocket rod firmly against the ground with enough pressure to hold the rod in proper position and angle.
-2- With the camera on a tripod, make sure the center of the lens is vertically level with the pocket rod.
-3- Move the tripod until the center of the lens is centered on pocket rod horizontally.
-4- Use a hot shoe bubble level or the in-camera level to make sure camera is level.
-5- Manually focus, or make sure your autofocus point is directly on the scale.
-6- Use a normal (50mm) or longer focal length to eliminate wide angle lens distortion. Macro lenses are ideal because of their flat field and edge-to-edge sharpness.
-7- Use fill flash to balance image, despite abundant sunshine.

Use scales, but take care to get the camera in position to show them accurately. Fortunately, you can check the results on your camera’s LCD (zoom the view if necessary) to make sure the dimension in the photograph matches the measurement you made. Fairly close isn’t accurate, and is misleading. A deceptive photo is worse than no photo at all.

February 23, 2018September 16, 2018

Nite Ize Gear Ties

How do you hold loose items in place long enough to photograph them, especially when you’re by yourself? I encounter this with almost every tire failure and vehicle I analyze. I have tried every Velcro strap, bungee cord, string, wire, rope, and tape I can find. Each worked—a little. But I kept searching for a clean, simple, and reusable solution for years. I finally found it at The Home Depot! It’s a reusable rubber tie called Gear Tie by Nite Ize. You can get them at The Home Depot, Amazon, or directly from Nite Ize: Nite Ize Gear Ties (Click on image to enlarge, then click on back arrow to return.)

Nite Ize Gear Tie Packaging. (ZEISS 50mm f/2 on Nikon D850.)

Gear Ties are available from 3″ through 64″. I’ve found the 32″ and 64″ most useful for securing passenger/light truck and medium/heavy truck tire pieces, respectively.

Nite Ize Gear Ties: 32″ Top; 64″ Bottom. (ZEISS 50mm f/2 on Nikon D850.)

You can also use them to hold sprung doors, loose bumper covers, and loose pipes or wires in place while you photograph them. Conversely, Gear Ties are also handy for holding wires, trim, etc., out of your photographs.

Here’s an example where two 32″ Gear Ties are holding two separated pieces from a passenger tire in place so I can photograph them.

Using 32-inch Gear Ties on Tire Pieces .(ZEISS 50mm f/2 on Nikon D850.)

I carry sizes from 12″ through 64″ with me. You won’t find more useful “third hands”. Highly recommended.

October 31, 2017November 12, 2018

A Dark Cover-up

When I travel for a work or a personal photography trip, I either drive my Toyota 4Runner TRD Pro or rent an SUV so I can easily access my gear in the field. Years ago, my friend and mentor Bruce Dale suggested a cheap, easy way to keep prying eyes from cargo and luggage in the back. It’s a black flat bed sheet. I bought two of them at Walmart; one for my 4Runner and one to keep packed in my travel bag. They’ve become the black sheets of my family. (Sorry, couldn’t resist.) (Click to enlarge, then back arrow to return.)

If I’m going to be parking any distance from the inspection site, I try not to keep valuables in my vehicle, if possible. But I’ll still cover even extra jackets, water, snacks, or empty camera bags or luggage. I find the black sheet most useful when going to and from my shooting or working location, at airports, restaurants, and hotels, and when stopping at any store or gas station. It’s cheap, simple deterrence. I even use it day-to-day when I’m at home.