I've had my Nikon D3100 camera for about 3 years. I recently accidentally reset my shooting options.

Since I've done that, I'm having a hard time getting the camera to focus and take photos in lower light. I can hear it (and see it) hunting to focus, but the bottom right flashes the image suggesting I use the flash and it won't let me take a picture.

I've ensured that it's set to AF-C, but I'm still not able to force the photo to be taken. This happens with multiple lenses, including my prime which is fairly decent in low light. Often the exposure information on the screen shows me that I am close to perfect exposure (and sometimes just a bit underexposed).

What's going on? Is there something wrong with the camera? What other settings can I check?

Some other tidbits, I have it set to Manual, and I'm able to take the photos if I manually focus--but that doesn't work for me since my eyesight isn't great.

  • 2
    I'd point you at some of our earlier questions about why cameras won't take pictures in low light, because that's a common situation, but it sounds like yours have a twist — is it very clearly acting differently from the way it was before you rest the options?
    – mattdm
    Jan 17, 2014 at 0:12
  • 1
    What exactly is "low light"? There IS a limit on how low light a camera can autofocus in. A low end model like the D3100 is limited to AF in EV 0 and above. Many modern cameras support EV -1 down to EV -3, which is twice to eight times less light than your D3100. If some of the lenses causing you problems are f/4 or f/3.5 maximum aperture, and low light is "really low light", that would definitely put a damper on things.
    – jrista
    Jan 17, 2014 at 3:39
  • I know that on a similar Canon camera it has quite a bit of trouble in very low light so it uses the popup flash to help achieve focus. Will the flash popup on it's own in any mode? It is possible the flash mechanics are broken.
    – dpollitt
    Jan 17, 2014 at 4:46
  • 4
    Focus assist light setting went Off in that reset? Jan 17, 2014 at 4:54
  • 1
    I'm voting to close this as unclear, since the questions above were never answered, and without those, we are just guessing.
    – mattdm
    Jul 15, 2015 at 15:13

4 Answers 4


In the User Manual, under AF-Assist, it says:

If Off is selected, the AF-assist illuminator will not light to assist the focus operation. The camera may not be able to focus using autofocus when lighting is poor.

Can this be the reason?

Also, see this thread on dpreview.com. Clearly, you cannot release shutter without focus unless being in Manual mode. And the User Manual says the same.

And one comment: could you make a try with Sports mode? I have read somewhere that Sports mode will release shutter even if you do not have perfect focus.


What I try to do in these cases is to shoot in Manual and with manual focus using Live-view to assist. Of course you can always use the flash, that should help.

Have you got the AF light turned on? In alternative, you can use a torchlight or a smartphone flashlight to lit the scene and autofocus before taking the shot.


In my experience shooting in any of the auto modes will require focus lock to take the picture. There may be a custom function to allow overriding of this but I am not familar with that model of camera. As you have said - by putting the lens into manual mode, it then works. Unfortunately this is what you will have to do to get the shot, or use a flashlight to light your subject so the camera can focus, then switch the lens to manual before taking the shot.


I had this problem in Low light with the AF Assist Light still coming on.

What I found was that using the Live View is completely different to focusing while keeping Live view off.

I just stopped using Live view and the problem was immediately solved. Of course the AF Assiste light was working in my case for both scenarios.

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