A few days ago, I was taking some photos at dusk. I found myself with an annoying message “Subject is too dark” and my camera refused to shoot a photo. Sound familiar?
You can override the subject is too dark message on your Nikon camera by switching your focus mode from autofocus to manual focus. Your camera is set to autofocus by default and it’s difficult for your camera to autofocus while in a dark environment.
Why does this happen?
The subject is too dark message occurs when the subject your camera is trying to focus in a low light environment. It is generally too dark for your camera to properly autofocus. Your camera will then refuse to shoot the photo because the autofocus is not completed. Unfortunately for you, autofocus will never complete because it is still too dark. Instead, you will continue getting the message and you may hear a low pitched beep when you press the shutter release button. This may occur on any Nikon Camera.
It really depends on the lens your using.
How to change your focus mode
As I mentioned earlier, the easiest solution to the subject too dark problem is to switch from autofocus to manual focus. You can do this by first opening the control strip by clicking the i button in the bottom left. From there, move your selector to Focus Mode, press OK. You will now be presented with a few options including AF, MF, and some others. AF standing for Auto Focus and MF standing Manual Focus. Move your selector over to MF on the right and press OK. You are now in manual focus mode. If you don’t see an MF option it means your camera’s lens does not support autofocus. If your camera doesn’t support autofocus scroll down for some alternative methods.
Using manual focus mode
When photographing dark subjects we must use manual focus mode. Using manual focus is mode is far more complicated than using autofocus. With autofocus, the camera focuses by itself when you half click the shutter release button. But with manual focus, you are required to focus by yourself. Its a bit like focusing binoculars or a telescope. Look through the viewfinder and turn the focus ring on your lens until what you see becomes sharp. If you don’t turn far enough your image will be blurry, if you turn the ring too far you’ll image will also be blurry. You have to find the perfect point in which the image is focused.
You also might be attempting to focus on the night sky, in which case you must focus to infinity. Usually, there’s an infinity indicator on the focus ring on your lens. But if not you’ll have to use trial and error to find where your infinite focus point is. Change your focus and take a picture. Repeat until the night sky is in focus.
Focus assist light and flash
Another solution to the subject is too dark message is by preventing it in the first place. By using the focus assist light and your flash you can allow your camera to focus in the dark by making it bright. The first thing you can do is use the focus assist light which automatically turns on while pressing down on the shutter release button. Make sure the focus assist light is on in settings, it’s under the Shooting Menu.
Sometimes, the focus assist light is not enough and you need to use the flash. On Nikon Cameras, the flash pops out of the top when it needs to. If the flash does not pop out, change the flash mode to on by clicking the info button and selecting a flash mode. Make sure the flash is on by clicking the info button and moving your selector to flash mode and turning it on.
Using the flash and the focus assist light it makes it easier for your camera to autofocus in a dark environment thereby preventing the subject is to dark message.
Changing the center of focus
Something else you can try is simply changing where you’re focusing on. When your camera has trouble focusing because its too dark, something people often fail to think of is simply focusing on a brighter part of the picture. For instance, when focusing on the night sky, try focusing on the moon instead of the stars. The moon is far brighter than the stars and is therefore easier from your camera to focus on.
If there’s nothing brighter in your frame, you can try focusing on something bright outside your frame that has a similar distance to your darker subject. This is because autofocus works by distance, so focusing on a different bright object the same distance away as your darker subject will focus on your subject.
You can also try using external lights such as a flashlight or the light on your smartphone. This will illuminate the subject making it bright enough and easier to focus on. You can use the focus lock like in the changing your focus method then turn the light back off if you want your photo to be dark.
Changing your settings
Or if you want to do things the old fashioned way you can fiddle with your settings in manual mode until the subject is in the correct amount of light. The first thing I would do is to set the aperture on your camera to the max. The aperture is how much light your lens takes in which will most definitely help our dark subject issue. Increasing ISO is another solution although it may add noise to your photo. Finally, you can increase the shutter speed, which is how long your camera takes in light. But doing so may cause blur as the shutter is open for longer leaving more time for your hands to shake or move.
Sometimes your camera will refuse to shoot on a perfectly exposed subject. Not too bright, not too dark, but why won’t it shoot. There are other reasons besides a lack of light that will prevent your camera from autofocusing. Sometimes, the issue is with contrast. Low contrast situations are just as bad as low light situations because its hard to differentiate what is what. You’ll have to manually focus, but it may be hard for even you to do so in a low contrast environment.
Another cause of this problem could happen during macro photography. (close up photography) Many times, your lens simply isn’t designed for close up shots and it will be impossible to autofocus. Manual focus won’t help you much either but it will work out better than autofocus. The only thing you can really do if you don’t have a macro lens is to take a few steps back.
The final reason your camera refuses to shoot/focus is because of high-speed movement. It’s incredibly difficult to manually focus on something moving at high speeds and its just as difficult for autofocus to do so as well. This is because movement means the distance from you to your subject is rapidly changing and focus is based on distance as we mentioned earlier. My best advice is autofocus on a still subject in the position your moving subject will be in the near future. Then use the autofocus lock, and shoot the photo when your subject reaches the still object you focused on.