Focus issues even when using Single-Point [duplicate]

Question

I have been noticing, even if I use AF-S with Single-Point focus and set the focus on the eye of the bird, still the final photo either comes out blurred or has less details.

Someone in a response to one of my previous question advised me to first half-press the shutter button and set the focus on the subject. Then move the center point slightly to either left or right and then take the shot.

I tried this as well. Still the exposure and focus both are not satisfactory.

In the below picture, I set the ISO sensitivity to Auto.

Other parameters are:

• Camera: Nikon D5600
• Lens: 300 mm
• Shutter Speed: 1/160 sec.
• Aperture: f/14
• ISO: 2800

I set the focus on the eyes, still it came out blurred.

Edited This question is not related to Auto-Focus. It is related to:

1. Manual Focus
2. Aperture Priority, and
3. Shutter Priority modes

Is the problem with the Lens or Camera is not equipped for such type of shots? I read D5600 does not have optical image stabilization.

Answer 1

Super crisp at f/14 and maximum zoom, then you're asking a bit much of a kit zoom lens. Any lens will start to show weaknesses as you move toward the extremes; a zoom to either limit, very large and very small apertures, the edges and corners of the frame, sometimes even noticeable at the ends of the focus range. All these weaknesses will in general be more pronounced with a cheaper lens. I don't know exactly what lens you have, but I found data on a budget Nikkor 70-300mm lens on DxOMark which illustrates my point. As you can see it gets softer at larger and smaller apertures, getting more pronounced at the far end of the zoom range. My guess is that this, together with some ISO noise, is what softens the image. I don't know much about Nikons, but the D5600 seems like a decent enough camera to me, I doubt it's holding you back. A better lens would likely make a bigger impact, but probably not a massive one, and would cost you a pretty penny.

The cheapest, and most significant improvement would be to open up the aperture a little, and in general get more familiar with the lens. Under controlled conditions, take a bunch of test images at different aperture and focal length values, peek at those pixels, and find out where your lens' sweet spots are.

Answer 2

Your issue probably has nothing to do with focus or how sharp your lens is at various focal length/aperture combinations.

You're using a 1/160 exposure time with 300mm focal length on an APS-C size sensor. Camera movement is almost certainly what is causing most of the blur you see.

If you use the same ISO and open up the aperture three stops to f/5, your exposure time would be reduced to 1/1,250 which would significantly reduce blur caused by camera movement. That would be a little overkill, though. I'd open up three stops to f/5, go two stops faster to 1/640, and reduce ISO one stop to ISO 1250¹. That should give you less detail lost to noise or the resulting noise reduction.

You haven't been able to tell us specifically which 70-300mm lens you are using. It could be one of a handful of different models from Nikon and several third party lens makers. The cheapest 70-300mm lenses, which are the ones typically sold in kits with a camera body, are usually softest at their longest focal length.

For more about how to diagnose the cause of blurry images, please see How do I diagnose the source of focus problem in a camera?

_{¹ You say the image was taken at ISO 2800, but that is not one of the standard full, 1/2, or 1/3 stop values that your camera allows you to select. I'm guessing you mistyped 2800 when the actual value was ISO 2500.}