I have a D7100 & the 18 -140mm kit lens. When I try to auto focus on a low light or low dynamic range scene, using single point focusing, nothing is in focus. Is this a lens issue, or a camera issue? This image was taken yesterday. It and the other 2 from this location have this problem. All the other shots are beautiful.
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question about what drives auto focusauto focus
Posted 20 November 2016 - 01:41 AM
The D7100 focuses using contrast and sharpness. That scene - with all the twigs and sticks - could be difficult for that camera to focus. FWIW: the posted photo looks like plenty of light to focus. I'd be curious if you had stabilization on and if you had a bit of shake.
If you question the fine focus. Try running through Dot Tune. https://youtu.be/7zE50jCUPhM
Posted 22 November 2016 - 03:38 PM
You mentioned it was taken in low light which might mean a slow shutter speed was used with a wide aperture. Test again with an aperture in the lenses mid-range like f8. Mid-range values are usually sharper than wide open or completely stopped down. It might also be possible the image is not sharp due to slight camera movement during the exposure. To rule out camera movement use a tripod or place the camera on a stable surface then make the exposure with the self timer. Using the self timer will eliminate the possibility of jiggling the camera a bit when the shutter button is pressed. Its also possible wind might have caused some movement in the branches. Lots of reasons an image might not be sharp with no fault to the equipment. As mentioned knowing the exif data would help.
- TBonz likes this