Nikon d3100 autofocus not working -Causes and How to fix

A Nikon D3100 camera is a great camera to have. Despite its age, the camera is still strong and can meet most of an average user’s needs.

The autofocus system on a camera is a very crucial part as it automatically adjusts the camera focus. The system uses a motor, sensor, and a control system to focus on a subject that has been manually or automatically been selected. You see, cameras usually have a 2-stage shutter-release button where when lightly pressed, you achieve the first stage and for the second, you need to press the button all the way down. The Nikon D3100 operates this way and like any other electronic device, it’s not perfect despite its consistent service. One of its most common issues is its autofocus not working.

What are the causes of the autofocus not working?

A problem with the autofocus means that it cannot adjust correctly. There are various probable causes of a Nikon D3100 camera not working. This makes it hard to pinpoint the exact issue. The only way to tell the issue and solve it, is by checking off the probable areas and eliminating the one after another. Firstly, try rotating the lens a little by forcing it as it sometimes works. The next step is to try and switch a single auto focus point, if they are all ok, then go ahead and update the firmware.


The Nikon D3100 kit lens has a manual autofocus. It’s important to check its lens and the camera ensuring that they both point towards Autofocus. On the lens, there’s a switch that you can move from M to A. THis means that you are switching the lens from manual focus to autofocus. Also, check and make sure that the camera too is switched to AF (Autofocus) and then test the camera to see if the issue is still there.

Back dial and AEL/AFL

Digital cameras like the Nikon D3100 support different modes that can be selected using a dial or from a menu and these cameras come with a dial used for changing the camera’s mode. If this back dial is locked, your autofocus won’t work. Check to make sure that the Nikon D3100’s back dial is pointing towards the camera icon instead of the L (Lock). Also, check the AEL or AFL (Focus and Exposure) button and ensure that it too hasn’t locked the focus. Note that by clicking this button once, it locks focus. To unlock focus, click it again one more time.


If your focus is unlocked and the issue still persists, then the lens could be another cause. To check if the lens is the issue, remove it and then inspect the rear and front lens looking for dirt or scratches. The filters should be clean and have no physical issues. Using a clean cloth, clean the lens but do not blow on to the lens. This is because your breath can have harmful acids that will further damage the lens. If it’s necessary, then use a brush and a lens bulb blower to blow. When reattaching the lens, make sure that you hear a click sound. In addition, you can also check the DSLR viewfinder for dirt, oil, or scratches. If you find any of the above issues, then clean the viewfinder using a piece of cloth instead of a solvent.

If you have attempted all the above troubleshoots but the issue still persists, then switch off the Nikon camera for at least some seconds and remove the battery. After a few seconds, insert the battery and then switch the camera on. Check and see if the autofocus has improved. As a last resort, reset the camera back to factory default.


Though the camera is old, it’s still worth fixing its issues and then using it. This is because the Nikon D3100 has the capability to meet your needs.


How old is the Nikon D3100?

The Nikon D3100 camera was announced in August 2010 to replace the D3000. It has since undergone various advancements.

Why does my camera have trouble focusing?

Your camera and its lens have metal contacts that have to keep constant communication in order for the camera to function properly. If the lens is not properly attached, then the focus will experience issues.

Philip Taylor believes in helping people achieve their dreams and has, therefore, gone to the lengths to make the subject of photography and cameras more digestible to individuals who are passionate about this line of career. He believes with the right mentorship and experience, novice photographers can turn into professional photographers, the excerpts on beginner cameras at Photo MD are, therefore, the perfect guide for individuals who are into photography, want to get their first cameras but have no idea what to look for. Philip is a father to two lovely boys, and when not working he loves to research and will, therefore, be found in the library.

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