To Flash or Not To Flash

That is the question you’ll have to answer before making each vehicle, product, or component photograph.

To minimize noise and maximize dynamic range for any image, use the camera’s minimum ISO (it’s ISO 64 on my Nikon D850). For most tire, product, and vehicle component photos, you’ll also want to optimize depth of field (DOF). That requires stopping down the aperture to somewhere between f/11 and f/16. (Stopping down to f/22 or smaller will give you more DOF, but may result in softening due to diffraction.)

Exposure consists of aperture, shutter speed, and ISO. With minimum ISO and a small aperture already chosen, that leaves only shutter speed. The shutter speed will depend on how much light is available. To get enough light for a proper exposure, you can use all ambient light, flash only, or a combination of ambient and flash (often called fill flash).

Flash allows you to add the light you need to get a proper exposure, while maintaining a reasonable shutter speed. This is particularly important if you are handholding the camera. Way too many photographs are blurry because the shutter speed was too low. This can be true even with the image stabilization built into many cameras or lenses. Image stabilization helps some, but many times, component or even vehicle photos have to be made where light is insufficient for handholding.

For tires and other vehicle components, getting enough light to handhold a camera usually requires the use of flash. The alternative is putting the camera on a tripod to keep it steady during a long shutter speed.

You can get the same overall exposure using a long shutter speed with ambient light only, using a combination of ambient light and flash, or using 100 percent flash. But the resulting image will look different. (Click on image to enlarge, then click on back arrow to return.)

Valve Stem Ambient Light (No Flash). Exposure: f/16, 2.5 sec, ISO 64. (ZEISS 100 mm f/2 macro lens on Nikon D850.)
Valve Stem with Flash. Exposure: f/16, 1/60 sec, ISO 64. (ZEISS 100 mm f/2 macro lens on Nikon D850.)
In my studio lab, I have so many bright white LED shop lights some have said it looks like an operating room. Even with all that apparent light, I still either have to use flash or a very long shutter speed to properly expose an image.

Above are two images of a rubber valve stem. They were both made using my incredibly sharp ZEISS Milvus 100mm macro lens mounted on my Nikon D850, which was mounted on my rolling studio stand. I focused the ZEISS manual focus lens using Live View at 100 percent.

Both images were made at ISO 64 at an aperture of f/16. The image without the flash required a shutter speed of 2.5 seconds, which was obviously not handholdable. With an image completely illuminated by flash, the shutter speed doesn’t contribute to the exposure. (Shutter speed does contribute if the image is a combination of ambient and flash.) In the flash image below, the shutter speed was 1/60 second.

Both images are properly exposed, but they look very different. The image with flash has more contrast, which gives more of a three-dimensional appearance, where the ambient (no flash) image has more even light. When sharp and properly exposed, there’s no right or wrong to flash versus ambient light, but be aware there can be a profound difference between them.