Dp3 Merrill Macro Focus Issues: Am I a dingus?

Started 3 months ago | Questions thread
xpatUSA Forum Pro • Posts: 20,719
Re: This is not a good test image

brendanpaxton wrote:

xpatUSA wrote:

brendanpaxton wrote:

DavidWright2010 wrote:

brendanpaxton wrote:

DavidWright2010 wrote:

exposure of 0.6 seconds? Anything could go wrong. And it looks blurred all over.


Nothing wrong with 0.6 sec, We were told the camera is on a tripod (and there is clearly no motion blur in the image).

Here's a 400% crop from the center .It certainly looks blurry to me:


Anything will look blurry at 400% crop.

I disagree.

David's zoom above is not smoothed; therefore the blur is in the capture and was not caused by the 400% zoom.

Creating pixels out of thin air where there were none (zooming to 4x the data's resolution, i.e. upscaling by 4x) requires extrapolation of data.

David's zoom was not smoothed. It was upscaled Nearest Neighbor.

The result will always appear blurred.


Blurring (i.e. averaging of neighboring points) is inherent to any interpolation or extrapolation process.

When up-scaling Nearest Neighbor by integer values 1x, 2x, 3x ... etc, there is no interpolation. At 400%, each original pixel just becomes a 4x4 pixel.

For example, a one-pixel cross-hatch (see middle):

Becomes a pure cross-hatch even at very high zoom:

No blur at all ... agreed?

The OP's image is sharp in the bottom of the frame. And there is no >>motion<< blur in the image.

I did not comment about the OP's image, only David's blur due to zooming 400%, i.e. none.

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Just interested in the technology.

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