How Aperture Controls Sun Stars—and Exposure and DOF

(Note: This post incorporates several important fundamentals along with the discussion of controlling sun stars. As always, it’s all summarized in the Takeaways at the end.)

A previous post illustrated how the number of aperture blades affected the number of rays produced in a sun star. As discussed, sun stars are created from bright spots of light in an image when the lens aperture is stopped down. While prominent sun stars might be desirable for landscape or creative photographs, they are usually unwanted in forensic photos. In fact, there have been instances where photographs with distinctive sun stars have been limited or disallowed. Here’s how to control—or even eliminate—their prominence.

There were three small, distinct bright light sources in the following night scene. A series of images was made at every whole aperture from f/16 through f/2. (As a reminder, there are six stops up from f/16: f/11, f/8, f/5.6, f/4, f/2.8, f/2.) Only four of the seven total images—each two stops apart—will be shown below. The other three intermittent images fit in the progression as you’d expect from what you’ll see below.

This first image was made with the aperture stopped down to f/16. As expected, the sun star rays were most distinct at this aperture. [Click on image to enlarge, then click on back arrow to return to this post.]

Sun Stars at f/16 made with Nikon Z 8 with Nikkor Z 50 mm f/1.2 S lens at f/16, 2.5 sec, ISO 64.

Opening up two stops to f/8 noticeably reduced the sun star effect. [Click on image to enlarge, then click on back arrow to return to this post.]

Sun Stars at f/8 made with Nikon Z 8 with Nikkor Z 50 mm f/1.2 S lens at f/8, 0.6 sec, ISO 64.

Opening up two more stops to f/4 almost completely eliminated the sun star effect. This should be acceptable for any foreseeable use. [Click on image to enlarge, then click on back arrow to return to this post.]

Sun Stars at f/4 made with Nikon Z 8 with Nikkor Z 50 mm f/1.2 S lens at f/4, 1/6 sec, ISO 64.

Finally, opening up yet two more stops to f/2 eliminated any trace of sun star rays. [Click on image to enlarge, then click on back arrow to return to this post.]

Sun Stars at f/2 made with Nikon Z 8 with Nikkor Z 50 mm f/1.2 S lens at f/2, 1/25 sec, ISO 64.

As you can see, the wider open the aperture (which means the lower the f-number), the less pronounced are the sun stars. But you can’t just adjust your aperture to either intensify or to eliminate sun stars. Whether it is daytime or nighttime photography, changing your aperture affects your image in two main ways: exposure and depth of field (DOF). 

Recall that the smaller the f-number, the larger the lens opening. Just like 1/2 of a pie is twice as large as a 1/4 of a pie, a lens aperture of f/2 is twice the diameter of f/4. Here’s how changing aperture changes exposure and DOF:

Exposure: Opening the lens aperture lets in more light, which brightens the exposure. To keep the overall exposure the same, you must compensate by the same number of stops by using a faster shutter speed, lowering your ISO, or using a combination of both. Since all the above images were already at my Nikon Z 8’s lowest ISO of 64, my only option was to select a correspondingly faster shutter speed every time I opened up the aperture.

This means that for this series of four images, every time I opened up the lens aperture by two stops, I had to use a shutter speed that was two stops faster. As you can see from the captions under the images, at a constant ISO 64, the f/16 image required a 2.5 second exposure. Opening the aperture two stops to f/8 required a shutter speed of 0.6 seconds, which is two stops faster. Likewise, f/4 required 1/6 second and f/2 needed 1/25 second to keep the same overall exposure. Each were two stop increments of aperture and shutter speed.

As a side note, since the camera remained on a tripod throughout all the photographs, the shutter speed had no effect on the sharpness of the images. But changing shutter speeds will definitely affect the appearance of any moving elements in the image frame.

Depth of Field (DOF): DOF is how much of the scene—from near to far—is in acceptable focus for a given focus point. DOF is controlled by aperture. The more open the aperture, the less DOF. Conversely, stopping down the lens aperture increases DOF.

A deeper DOF is more critical in daytime photographs where almost everything is visible and, in most forensic photography, should be acceptably sharp. At night, a more shallow DOF can be perfectly acceptable, especially if the background and foreground are mostly black, as in the photos above.

As you can see on the enlargements by clicking on the photos above, f/4 would likely produce acceptable DOF. Depending on your case, even f/2 (or an aperture between f/2 and f/4) might give you all the DOF you need. As the photographer, you need to (and you get to!) decide on the tradeoff between DOF and sun star prominence.

Takeaways:

-1- You can control the prominence of sun stars from small, bright light sources (day or night)  by your choice of aperture. The more stopped down your aperture, the longer and more prominent the rays. Opening up the aperture will shrink the rays until they essentially disappear at the most open apertures.

-2- Opening up or stopping down your aperture will also affect the DOF in your image. You must decide how much DOF you will need. That amount would likely be different for daylight versus night photos—even of the exact same scene.

-3- Just like with any other photography, opening up or stopping down the aperture will require that you correspondingly adjust your shutter speed, ISO, or a combination of both, to maintain the same overall exposure. Make sure your shutter speed is sufficient for your image, especially if there are moving objects in your frame. Also, setting your ISO as low as possible minimizes noise and maximizes dynamic range, both of which are even more important in night photography.

SAE C1729 Automotive Forensic Photography Class – May 2024 in Orlando!

It’s been a few years since my SAE automotive forensic photography class has been offered in the Southeast—or even in the East, for that matter! Now it will be offered May 14-16, 2024 in Orlando, FL.

Anyone working in accident reconstruction, product liability cases, vehicle testing, or other forensic, evaluation, or testing investigations knows the importance of creating consistent, quality, and useful photographs. You’ll be glad to know that you can (probably) do that with the camera you already have! Just think of how much money you’ve already saved! You just need to understand and use that camera and just a few essentials such as a tripod, flash(es), and a polarizer.

In the classroom, we will learn the fundamentals of making good, consistent photographs with lots and lots of good and bad examples. We will do hands-on sessions—both indoors and out—with tripods, polarizers, night scenes, and the big one—using one or more flashes. While it will be most useful to bring your own camera gear—including flash(es) and tripod—I will bring various tripods, tripod heads, flashes, polarizers, and neutral density (ND) filters for you to evaluate during the hands-on sessions. Those will help you determine if your gear is what will serve you best, or if you need to upgrade a piece or two.

Here’s a link to the class description and registration: https://www.sae.org/learn/content/c1729/

Please contact me if you have any questions or would like more information about what to expect from the class.

Hope to see you in Orlando!

Sun Stars with Even or Odd Number Aperture Blades

Many lenses have an odd number of aperture blades, but several have an even number. For most photography, there is little to no noticeable effect.

There is, however, a noticeable difference if you have a “sun star” in your image. A “sun star” is the name given to noticeable rays—day or night—emanating from the sun or from an artificial light source.  A sun star is created when the lens is stopped down. The more the lens is stopped down, the larger the rays of the sun star.

An even number of aperture blades results in the same number of sun star rays. As the image below shows, a lens with ten blades (the TTArtisan 50 mm f/2 lens), stopped down to f/16, resulted in ten pronounced rays from a street light at night. [Click on image to enlarge, then click back arrow to return to this post.]

Made with Nikon Z 8 with TTArtisan 50 mm lens at f/16, 3.0 sec, ISO 64.

An odd number of blades results in twice the number of rays. Using the same camera as above, but switching to a lens with nine aperture blades (the Nikkor Z 50 mm f/1.2 S lens), also stopped down to f/16, resulted in eighteen sun star rays. [Click on image to enlarge, then click back arrow to return to this post.]

Made with Nikon Z 8 with Nikkor Z 50 mm f/1.2 S lens at f/16, 2.5 sec, ISO 64.

Takeaways:

-1- Day or night, “sun stars” are often created from small, bright light sources in a photograph when lenses are stopped down.

-2- An even number of lens aperture blades creates the same number of sun star rays. An odd number of blades results in double the number of rays.

-3- An even number of blades creates more pronounced rays than does an odd number of blades.

-4- Sun stars are usually undesirable in forensic photographs. A future post will describe how to control the prominence of those rays. But if you must stop down for depth of field, an odd number of lens aperture blades will create more rays, but they will be less obtrusive.

Why Full Auto Exposure Mode Creates Inaccurate Night Photographs

One kind of forensic night photography requires you to accurately capture the appearance of a scene as closely as possible under lighting conditions similar to what they were at the time of an incident. Of course that results in an overall image that appears dark since, after all, it is a night scene.

Using fully automatic exposure modes will result in the scene being significantly (and obviously) overexposed. This is because the camera is trying to record the scene as a mid-tone (frequently referred to as “middle gray” even when the subject isn’t gray). This automatic brightening of night scenes usually results in noisy, overexposed images that don’t resemble the actual scene at all.

Almost all consumer and prosumer cameras have a fully automatic exposure mode denoted by a green camera icon with or without the word “Auto”. The image below shows the full Auto mode icon on a Nikon D5600 and Canon T7i. (Professional cameras like my Nikon Z 8’s often do not have this mode.) [Click on the image to enlarge. Then click on back arrow to return to this post.]

Made with Nikon D850 and ZEISS Milvus 100 mm macro lens.

In Auto mode, the camera sets the aperture, shutter speed, and ISO, and you cannot change or override any of them! Because the photographer cannot affect exposure in any way in full Auto mode, when teaching I refer to it as the “Green Mode of Shame” to drive home the point that you as the photographer are left without any ability to control your exposure (or a number of other important settings). While this mode might work for ideal lighting during the day, it just doesn’t—and can’t—work for ambient light night photographs. (Note: Semi-automatic exposure modes Program, Aperture Priority, and Shutter Priority will be addressed in a future post.)

I made the following two images in a lighted parking lot that had a white, a black, and a silver vehicle in the scene. (Note: both images were captured in the camera’s raw NEF format.)

For this first image, I used a Nikon Z 5 in Auto mode (its Green Mode of Shame). As discussed above, the camera tried to create a mid-tone image, and I couldn’t do anything about it. [Click on the image to enlarge. Then click on back arrow to return to this post.]

Auto exposure mode with Auto ISO. Made with Nikon Z 5 with Nikkor Z 24-70 mm f/4 lens at 49 mm in raw mode. f/4, 1/50 sec, ISO 25,600.

Note the camera chose a wide open aperture to let in as much light as possible (f4 on that lens), and an ISO of 25,600(!), while setting the shutter speed to 1/50 of a second. (A shutter speed of 1/50 of a second is considered handholdable with a near 50 mm focal length. The thinking is that if someone is going to use a camera in Auto mode, the camera will most likely be handheld. Consequently, the camera will open the aperture and boost the ISO to keep the shutter speed handholdable. But as usual, I had this camera on a tripod, like I almost always do in any light. )

Even though the original image is quite noisy (the great reduction in size and the JPEG compression of this posted image reduced the appearance of noise from the original raw), that’s not the biggest issue with it. The real problem is the scene was nowhere near this bright; it didn’t look anything like this at the time I made this image.

For the image below, I switched to manual exposure mode (the only exposure mode I ever use). I kept the aperture at f/4, but then set the ISO to the camera’s minimum of 100 to minimize the image noise. Because the camera was on a tripod, I wasn’t too concerned about shutter speed as long as it stayed within reason. [Click on the image to enlarge. Then click on back arrow to return to this post.]

Manual exposure mode with ISO set at 100. Made with Nikon Z 5 with Nikkor Z 24-70 mm f/4 lens at 49 mm in raw mode. f/4, 1/3 sec, ISO 100.

With the aperture and ISO set, I adjusted the shutter speed until the image on the back of the LCD looked like what I was seeing with my naked eye. As it turns out, the Auto image was four stops lighter than this more accurate one.

Note 1: By default, I have the camera’s Picture Control set to Neutral with reduced contrast and saturation so the LCD closely matches my computer monitor.

Note 2: For an actual night photograph case, I start by tethering my camera to a laptop that is calibrated to match my desktop monitor. There’s much more to the actual process than I did for this demo, but it’s close enough to illustrate the point that you need to take manual control of the camera.

While this second image is close to showing the scene as I saw it, to view it properly, you would need to view it with a black surround in a darkened room with your monitor brightness set to 140 cd/m² to match what I see. Regardless of these technicalities, comparing the two images—in whatever light you’re in or computer you’re on—it is obvious that the upper Auto exposure image doesn’t look anything like the more accurate lower manual exposure mode image.

In a number of cases where I’ve done both the night photography and explained why photographs submitted by other experts or photographers were improper and misleading, all of those inaccurate photographs have been stricken and disallowed by the judge.

While it’s a little bit off-topic, being able to explain how and why photographs were made and why they accurately represent what they purport to show—and why other ones don’t—is critical in almost all ambient light night photography cases.

Takeaways:

-1- Fully automatic exposure modes (like Auto) are not designed to—and cannot—accurately capture ambient light night images.

-2- You need to shoot night photographs using manual exposure mode with a low ISO to minimize noise, with the appropriate aperture for the depth of field you need, and with the shutter speed set to match what the scene looks like to the naked eye. There’s much more to the whole process, but that’s the essence of it.

-3- While the lower photo looks much closer to what the parking lot looked like when I made the photographs, it was not made with the procedure I use for case work. It is close enough to make a quick demo comparison against a demonstrably incorrect Auto method that yielded a demonstrably incorrect image.

SAE Photography Class December 5-7, 2023, in Irvine, CA

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.

New SAE Photography Class Scheduled October 17-19, 2023!

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.

Truck Tire Revs/Mile in HVEDR Downloads

When inspecting a truck and downloading its HVEDR, it is important to document the actual tire parameters. This includes not only confirming tires sizes, but their load ranges. You must confirm that the tire sizes and load ranges match those on the safety certification label on the door jamb and in the values programmed into the HVEDR.

In its 2023 Truck Tire Data Book, Michelin summarizes the effects of different revs/mile in this Rule of Thumb: “When going from a lower Tire Revs./Mile [sic] to a higher Tire Revs./Mile, the actual vehicle speed is less than the speedometer reading. When going from a higher Tire Revs./Mile to a lower Tire Revs./Mile, the actual vehicle speed is greater than the speedometer reading.”

The revs/mile differences between load ranges in a given tire size might not be large, but they do exist—even in the same line of tires. For example, Michelin lists two 11R22.5 X Multi D tires: one load range G and the other load range H. For the load range G tire, Michelin lists the revs/mile as 496 while it lists 494 revs/mile for the load range H tire. Likewise, for the 11R22.5 Michelin X Line Energy Z tire line, the load range G revs/mile was 502 and the load range H was 503.

So just between two Michelin tire lines, there is a range of revs/mile from 494 to 503 for 11R22.5 tires. Not only that, but for one tire line, revs/mile were higher for the LRH tire than the LRG, while for the other tire line, the opposite was true.

At first it may seem that all tires of the same size would have the same revs/mile. But variations in tire construction, tread design, and tread depth can result in small variations in the actual revs/mile of a specific tire of the same size.

Tire companies determine the revs/mile from the test procedures set out in SAE Recommended Practice J1025. J1025 specifies speed (45 mph), load, inflation pressure, ambient temperature, configuration, break-in, warm up, surfaces, measurement devices, and test distances required for each test.

The four revs/mile values of the four 11R22.5 Michelin tires above weren’t far apart, but it is best to check and confirm. And even though a small difference in revs/mile may not end up being significant in your analysis, you want to confirm that the truck tires sizes and load ranges matched what was used when programming the HVEDR.

Many trucks have a variety of tire brands, sizes, load ranges, or a mixture of original and retreaded tires. In some cases, the truck may be gone or repaired, and all you have to work with is the HVEDR report itself. When you have tire variations or unknown tires, you might consider researching the ranges of any relevant tire property, like revs/mile, then running a sensitivity analysis to quantify the effect that range of values might have on any subsequent analysis involving data from the report.

Takeaways:

-1- During a truck inspection, don’t just document the tire manufacturer(s) and tire size(s), but be sure to include the tire load range(s). Compare their properties with the programmed values in the HVEDR report.

-2- If there are variations in the truck’s tires, check the various tire properties against the HVEDR programmed values.

-3- Using those tire property variations, it might be useful to perform a sensitivity analysis to quantify the effect of a range of revs/mile or other variable.

-4- To learn how to apply HVEDR data, I highly recommend SAE International class C1901 Advanced Applications of Heavy Vehicle EDR Data taught by Wes Grimes, Greg Wilcoxson, Dave Plant, and Brad Higgins:  https://www.sae.org/learn/content/c1901/

SAE Automotive Forensic Photography Class – April 2023

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 look forward to seeing you there!

Photographing into the Abyss with the Laowa Probe Lens

Well, maybe not the abyss, but into a recess….

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.

If you have (or anticipate) a singular need for it, you can rent one in just a day or two from someone like LensRentals.com at: https://www.lensrentals.com/catalog_search?q=laowa+probe.

Takeaways:

-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.

 

Perspective: The Effect of Focal Length on both Subject and Background

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.