I will be teaching Photography for Accident Reconstruction, Product Liability, and Testing – C1729 in Irvine, CA, on December 5-7, 2023. Please check out this link for more information or to register: https://www.sae.org/learn/content/c1729/.
Night photo of intersection with traffic light. (Made with ZEISS Milvus 50 mm f/2 macro lens on Nikon D850, at f/6.3, 1/60 second, ISO 1600.)
[Click on photo to enlarge, then click on back arrow to return to this post.]
In addition to the class presentations and materials, I will be bringing various tripods, tripod heads, and accessories, along with a lot of Godox flashes that we’ll use to practice multi-flash and off-camera flash techniques.
Please contact me if you have any questions about the class.
SAE International has just added another of my photography classes (Photography for Accident Reconstruction, Product Liability, and Testing – C1729) at their excellent training center in Troy, MI, for October 17-19, 2023. Please check out this link for more information or to register: https://www.sae.org/learn/content/c1729/.
Melted aluminum on lug stud. (Nikon D850 with ZEISS Milvus 100 mm f/2 macro lens.)
[Click on photo to enlarge, then click on back arrow to return to this post.]
In addition to the class presentations and materials, I will be bringing various tripods, tripod heads, and accessories, along with a lot of Godox flashes that we’ll use to practice multi-flash and off-camera flash techniques.
Mid-October is still a great time to be in Troy, with daytime highs about 60° and lows about 42°. The SAE Troy facility is just off I-75 at W Big Beaver and is surrounded by hotels and restaurants, so is quite convenient.
Please contact me if you have any questions at all.
SAE International has scheduled my next Photography for Accident Reconstruction, Product Liability, and Testing (C1729) class at their excellent Troy, MI facility from April 4-6, 2023: https://www.sae.org/learn/content/c1729/
It’s a great facility and is quite easy to access on W Big Beaver Rd just off I-75. It’s about 45 minutes from the Detroit airport. There are plenty of hotels and a lot of great restaurants in every price range.
The link above provides a detailed course outline. We’ll also get hands-on time to practice with exposure, flash, polarizers, tripod use, and more.
If you have any questions or would like more details, please feel free to email or call.
I needed to document the bolt holes on a wheel that came off the front of a pickup to show whether or not the wheel had been loose on its studs.
After making overall photos of the wheel and tire assembly, I made close-ups of the mounting surface and bolt holes from the back of the wheel. But on the outside of the wheel, the bolt holes were too deeply recessed to use a standard macro lens.
It was important to photograph the lug nut mating surface at the bottom of each recess, but it was nearly impossible both to get light down each recess and to fill the image frame with each hole. I wanted to get sharp, detailed, full frame images of the mating surface—not images cropped from a larger view.
The solution was the unique Laowa Probe lens. (I have previously discussed another unique Laowa super macro lens. I’ve found Laowa lenses to be well made and optically excellent.)
As the photo below shows, the Probe is a 16-inch long tube with a small diameter 24 mm lens surrounded by tiny LED lights at its end. You use a small USB power brick to power those LED lights. Laowa supplies a USB cable with a built-in dimmer switch, but you must supply the power brick. [Click on photo to enlarge, then click on back arrow to return to this post.]
Nikon D850 with Laowa 24mm f/14 2X Macro Probe macro lens made with Nikon Z 7II with Nikon Z 24-70 mm f/2.8 lens and two Profoto B1x studio flashes. f/16, 1/200 sec, ISO 200.
Laowa offers the Probe with several different mounts for many popular DSLR and mirrorless cameras. I used the Nikon F-mount version of the Probe lens on my Nikon D850. Note that all versions of the Probe require manual focusing and exposure; there are no electronic connections between the Probe and any camera.
Fortunately, the lens barrel fit perfectly into the recessed bolt hole, allowing me to get a full frame image of the mounting surface at the bottom. All I had to do was to adjust the intensity of the LEDs, adjust the exposure, and click the shutter. [Click on photo to enlarge, then click on back arrow to return to this post.]
Nikon D850 with Laowa 24mm f/14 2X Macro Probe macro lens made with Nikon Z 7II with Nikon Z 24-70 mm f/2.8 lens and two Profoto B1x studio flashes. f/16, 1/200 sec, ISO 200.
To steady the lens, manually focus, and keep the lens perpendicular to the bottom of the recess, I had the camera mounted on my rolling studio camera stand, which acted like an easily-adjusted tripod on wheels.
As you’ll see, the next two images made with the Probe lens required 0.5 and 0.3 second exposure times, respectively. That range of shutter speeds required that the camera be secured on a tripod to eliminate camera shake. Raising ISO to get handholdable shutter speeds would introduce noise, reduce detail, and reduce dynamic range. That would defeat the whole purpose of using the Probe to get sharp, detailed full frame images.
The first image I made for each paired hole (the wheel was drilled for two bolt patterns) was to show the bolt hole pair, while concentrating on the appropriate bolt hole. [Click on photo to enlarge, then click on back arrow to return to this post.]
Nikon D850 with Laowa 24mm f/14 2X Macro Probe. f/unrecorded, 0.5 sec, ISO 64.
I then slid the end of the Probe deeper into the recess to fill the frame with details of the mounting surface. [Click on photo to enlarge, then click on back arrow to return to this post.]
Nikon D850 with Laowa 24mm f/14 2X Macro Probe. f/unrecorded, 0.3 sec, ISO 64.
I know of no other way to have attained this image without significant cropping and the inherent loss of detail and resolution.
Although it’s not a lens I use all that often, I’ve found the Probe unmatched for photographing inaccessible labels, fasteners, or other components, too. The built-in LED lights around the lens make it a really useful tool.
-1- The Laowa Probe (along with the more recent Peri-Probe) lens is a unique, specialized macro lens that can allow you to photograph areas that are otherwise inaccessible.
-2- The Laowa Probe lens allows you to capture all the resolution and detail of full frame images that would be lost with a significant crop.
-3- If you are stymied about how to photograph a challenging subject, you might be able to find a commercially available specialized solution.
-4- While it is preferable to have specialized lenses at your disposal, you can always rent lenses (or other photography gear) for infrequently encountered situations. Of course, you might find yourself using even seemingly specialized lenses more often if you own them and have them readily available.
Often, evidence is stored in plastic bags or containers with shiny surfaces that result in reflective glare when photographed. This glare can obscure both the content and any markings on the bag or container.
As an example, a small piece of the bead toe from a tire was placed in a plastic bag, which was labeled with a black magic marker. (The writing on the bags in the images below has been intentionally altered to preserve anonymity.)
This first image was made in my Studio Lab using just the overhead LED lights. [Click on image to enlarge, then click on left arrow to return to this post.]
Plastic Evidence Bag without Flashes (Made with ZEISS Milvus 50 mm f/2 Macro lens on Nikon D850 at f/16, 1 sec, ISO 64.)
Even though the image is properly exposed, the overhead LED lights resulted in so much glare that it is difficult to make out the tiny tire piece inside or the writing on the outside of the bag.
To show both the contents and the writing, I kept the overhead LED lights on, but added a Profoto B1x studio flash on the right and on the left side of the bag. (Note: any remote flashes or speedlights can be used for the same effect.) [Click on image to enlarge, then click on left arrow to return to this post.]
Plastic Evidence Bag with Flashes (Made with ZEISS Milvus 50 mm f/2 Macro lens on Nikon D850 at f/16, 1/200 sec, ISO 64. One Profoto B1x strobe to each side triggered by a Godox TT685N II flash in the camera’s hot shoe.)
Wait, how did adding even more light eliminate the glare? Two things combined to make that work.
First, the added light from the flashes allowed me to significantly reduce the overall exposure. In this case, for both images I kept the aperture at f/16 for depth of field, and the ISO at 64 for lowest noise/highest dynamic range.
In the original image using the overhead LED lights only, the shutter speed was 1 second. When I added the flashes, I reduced the shutter speed down to 1/200 second. This faster shutter speed prevented the overhead LED lights—and their reflections—from recording at all. If I turned off the flashes, the image would have been black, even though the overhead LED lights were on.
Second, the light that reflected from each flash bounced away from its respective flash, and not into the camera lens. Hence, their reflections were not recorded by the camera.
Takeaways:
-1- To reduce or eliminate glare from overhead lights, reduce the exposure enough to cause the image to go black, or nearly so.
-2- Add one or more flashes positioned (usually to the sides) such that any reflections bounce away from the lens, not into it.
-3- Adjust the power of the flash(es) to properly light the subject at the new exposure.
-4- Note: With curved or irregularly shaped objects (like plastic bags), some localized reflections may remain. These may or may not be moved or eliminated by changing the positions of the camera or the flash(es).
When your subject has multiple similar features, you’ll need to mark each of them to distinguish among them in your photographs. These markings must be repeated on the other side of your subject, too, if applicable.
Since you are dealing with evidence, you should never make permanent marks unless agreed to by all parties involved beforehand. Instead, it’s best to use removable stickers or labels.
Before applying any labels, photograph the subject as you received it. This will ensure no part of the evidence is masked. As an example, here is a photograph of the mounting surface of an eight-bolt wheel with sixteen holes so it can be used with more than one bolt circle. (Click on image to enlarge, then click on the back arrow to return to this post.)
Nikon D850 with ZEISS Milvus 50 mm macro lens and Nikon R1C1 macro flashes. f/16, 1/200 sec, ISO 64.
Using a Brother P-touch labeler, I made one long label with two strings of numbers from 1 through 8, then cut between each number to create small labels of each individual number. The goal was to make the labels as small—yet as legible—as possible so they would mask the least amount of the evidence.
Choose a font with legible numbers, and set the font style to bold. Depending on the color of evidence, I usually use either white on black or black on white labels. On rare occasions, I have used black on clear labels. It’s advantageous to have all three label tapes available.
A label maker creates labels that are more legible and more professional looking than writing numbers by hand on torn pieces of tape.
For this wheel, I numbered the holes in pairs. Note that the numbers are counterclockwise on the inside so they will correspond with the same numbers on the outside of the wheel, which were clockwise. (Click on image to enlarge, then click on the back arrow to return to this post.)
Nikon D850 with ZEISS Milvus 50 mm macro lens and Nikon R1C1 macro flashes. f/16, 1/200 sec, ISO 64.
Here is the outside of the wheel showing the clockwise bolt hole pair labels. (Click on image to enlarge, then click on the back arrow to return to this post.)
Nikon D850 with ZEISS Milvus 50 mm macro lens with two Profoto B1x in diffused silver umbrellas. f/16, 1/200 sec, ISO 64.
Now close-ups of every hole will be easily identified whether on the inside…
Nikon D850 with ZEISS Milvus 100 mm macro lens and Nikon R1C1 macro flashes. f/16, 1/200 sec, ISO 64.
…or the outside of the wheel. Note that the labels are a good size in the close-ups without overwhelming the subject. Also note that the label is still effective even if it is out of the depth of field of the subject and is slightly out of focus.
Nikon D850 with Laowa 24mm f/14 2X Macro Probe. f/unrecorded, 0.5 sec, ISO 64.
Takeaways:
-1- After photographing evidence as found or received, mark repetitive features on any sides that will be photographed.
-2- Do not make permanent marks on evidence.
-3- Mark evidence with small, legible, and removable labels instead of handwritten numbers on torn pieces of tape.
-4- While labels should be included in close-ups, they do not have to be within the depth of field of the subject as long as they are still discernible.
-5- After making each close-up image with its label, you may want to remove the label and take another photograph without it. Having your camera on a tripod will allow you to made identical shots both with and without the label.
Perspective is the relationship between the elements in your photograph. The only way to change perspective is to move the camera. In fact, any time you move the camera, your perspective automatically changes. Conversely, staying in one place and zooming in or out doesn’t change perspective; it only crops the image differently.
This series of photographs demonstrates perspective change by using a 24-70 mm zoom lens and changing the camera position while using four increasingly long focal lengths: 24, 35, 50, and 70 mm . All were made from my standing eye height. The goal was to keep the subject car the same size in each image by moving the camera further away at each longer focal length.
When the resulting images are viewed at the same distance, you’ll note two effects from increasing camera distances while using longer focal lengths: -1- the car appears to change shape and compress, and -2- the background and other vehicles seem to be getting closer to the subject car.
This spectacular 1937 Cord Model 812 Beverly Sedan was photographed at the Savoy Automobile Museum in Cartersville, GA. Like most car museums, neither tripods nor flash are allowed. This requires using high ISO and slow shutter speeds to obtain your images. Fortunately, almost all full frame and some cropped sensor mirrorless cameras have amazingly effective in-body stabilization, which allows handholding the camera at low (slow) shutter speeds that were almost impossible before.
While these examples were made at a car museum, the principles apply exactly the same for any vehicle—or any subject—anywhere.
For this first image—made with a 24 mm focal length—I was quite close to the car. Note how long the hood looks and how far away the DeLorean and the background appear. [Click on image to enlarge, then click back arrow to return to post.]
Made at Savoy Automobile Museum, Cartersville, GA, using handheld Nikon Z 7II with 24-70 mm f/2.8 lens at 24 mm. Exposure: f/9, 1/30 sec, ISO 1600.
Stepping backward with a 35 mm focal length, the Cord looks less distorted, and the background vehicles seem closer. Of course, no vehicles were moved between any of these images. [Click on image to enlarge, then click back arrow to return to post.]
Made at Savoy Automobile Museum, Cartersville, GA, using handheld Nikon Z 7II with 24-70 mm f/2.8 lens at 35 mm. Exposure: f/9, 1/30 sec, ISO 1600.
Moving further away using a 50 mm focal length appears to once again shorten the hood and wheelbase of the Cord, while bringing the background even closer. [Click on image to enlarge, then click back arrow to return to post.]
Made at Savoy Automobile Museum, Cartersville, GA, using handheld Nikon Z 7II with 24-70 mm f/2.8 lens at 50 mm. Exposure: f/9, 1/30 sec, ISO 1600.
Back even further with a 70 mm focal length apparently compresses the Cord even more and brings the DeLorean and background closest yet. [Click on image to enlarge, then click back arrow to return to post.]
Made at Savoy Automobile Museum, Cartersville, GA, using handheld Nikon Z 7II with 24-70 mm f/2.8 lens at 70 mm. Exposure: f/9, 1/30 sec, ISO 1600.
Takeaways:
-1- When you move your camera, the perspective of your resulting image changes.
-2- When viewing images from the same distance, moving your camera closer to your subject with a wider focal length makes your subject appear distorted and your background objects farther apart.
-3- Again, when viewing images from the same distance, moving your camera farther away from your subject with a longer focal length makes both your subject and background elements to appear more compressed.
Although the effect is usually unintentional, a single image may be deceptive!
In the photograph below, both the height and the angle of the camera seem to indicate that the subject SUV was a two-door model. But actually, there was no such vehicle as a two-door 2004 Chevrolet Trailblazer. In fact, the subject shown here was even the extended EXT version of the standard four-door. (Note the top of the chopped off B-pillar visible above the window frame, which is the clear giveaway that it is actually a four-door SUV.) [Click on image to enlarge, then click back arrow to return to post.]
2004 Chevrolet Trailblazer EXT LT 4WD 3/4 side view. (Nikon D850 with ZEISS Milvus 50 mm f/2 macro lens with polarizer, fill flash, and tripod. f/13, 1/40 sec, ISO 125.)
It is standard practice to make multiple photographs around every subject vehicle. It’s also often necessary to make images at different heights and angles. No one who sees all of our photographs will be deceived. The problem is when you get only one or maybe a couple photos of a subject you either haven’t or can’t inspect yourself.
Using the same prime ZEISS 50 mm lens at the same tripod height, the photo below clearly shows the vehicle was a four-door. [Click on image to enlarge, then click back arrow to return to post.]
2004 Chevrolet Trailblazer EXT LT 4WD side view. (Nikon D850 with ZEISS Milvus 50 mm f/2 macro lens with polarizer, fill flash, and tripod. f/13, 1/30 sec, ISO 125.)
This unintended deception isn’t an issue when you’re making your own photographs, but it can be a problem if you’re trying draw conclusions based on a limited number of photographs provided to you. This frequently happens when the vehicle has been destroyed or is otherwise unavailable, and only one or a couple photographs—often made with a cell phone—are all the evidence that remains.
Takeaways:
-1- Be careful making conclusions based on a single photograph.
-2- Make a series of images around the entire circumference of any vehicle or subject you are documenting.
Thanks to Matt Wasowski of SAE for putting together such an excellent digital accident reconstruction conference, and thanks, Matt, for allowing me to present. Thanks to all those who attended, too. Sorry about my abrupt exit; it was a technical glitch on my end.
As promised, here are the slides from my talk: Tom Vadnais Photography SAE Presentation_2022-03-30. Bonus: You’ll see there are some additional slides that I had to remove from the talk to get it to fit the alloted time. No additional charge for those extras! Ha, ha.
Please don’t hesitate to call or e-mail if you have any questions about what we covered or about my upcoming SAE class. I hope I get to meet you personally at my class July 12-14, 2022, at Mecanica Scientific Services in Oxnard, CA.
With live classes now returning to SAE, I’m excited to announce that my next Photography for Accident Reconstruction, Product Liability, and Testing class will be July 12-14, 2022 at Mecanica Scientific Services’s fantastic classroom facilities in Oxnard, CA. Special thanks to Mecanica’s John Steiner for hosting this class for the third time!
The class has ten major subject modules that build upon each other. We’ll explore in-depth about gear, light, camera fundamentals, settings, post-processing, and much, much more. You’ll come away not just knowing about, but actually understanding how to make better, more consistent, and more useful photographs during all your inspections and analyses, regardless of lighting conditions.
Please call or e-mail me directly if you have any questions or need more information.
