Today’s Question: Is there any advantage between shooting black and white in camera versus converting in Lightroom Classic?
Tim’s Quick Answer: Assuming you’re capturing in raw (which I consider critically important for black and white images) the only advantage to setting your camera to black and white is to get a preview on the camera’s LCD of what the image will look like in general as a black and white image. The actual conversion from color should be done after the capture.
More Detail: While I recommend raw capture for all photography, I consider raw capture absolutely critical for photos that will be converted to black and white. If you capture in or convert to black and white for a JPEG capture, the image will have a maximum of 256 shades of gray. That results in a very high risk of a loss of smooth gradations (posterization) if relatively strong adjustments are applied to the image.
With raw capture you are recording at a higher bit depth, which for most cameras translates to a bit depth of 12-bits or 14-bits per channel (with a small number of cameras supporting 16-bit per channel capture). By comparison to a JPEG capture, that translates up to 4,096 shades of gray for a 12-bit capture, 16,384 shades for a 14-bit capture, and 65,536 shades at 16-bits.
Setting your camera to black and white will provide a grayscale preview of the raw capture, which can obviously be helpful. However, as soon as you import that raw capture into Lightroom Classic or open it with other raw processing software, the image will appear again in color. You can then convert to black and white and apply adjustments to optimize that image, confident that you’re taking full advantage of the additional tonal range represented by the raw capture compared to a JPEG capture.
If you set your camera to black and white when capturing JPEG images, there will not be any color information recorded and you’ll be left with a grayscale image with only a maximum of 256 shades of gray. That can lead to serious image quality problems if moderate adjustments are applied, which is why raw capture is so important when your intent is to convert the images to black and white.