My D90 lens (18- 105) makes the photo even more blurred. I see how others magnified it, and it is still so clear that even the hairs can be seen clearly.

1, it may be that your photo file settings are relatively small, that is, the pixel settings are low, which naturally looks rough after enlargement. The solution is that you set the image size to the maximum in the menu, or set the image quality to RAW, so that you can reach the highest pixel.

2. It may be that your photo has been blurred, and shaking hands or not focusing properly may cause blurring. But the problem was covered up after enlargement, and it was exposed after enlargement. This problem can be improved by using faster shutter speed, improving hand stability, using tripod and other brackets and improving photography technology.