The (in)significance of resolution

Started Apr 15, 2013 | Discussions thread
Lin Evans
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Re: You haven't increased the resolution....
In reply to DMillier, Apr 15, 2013

DMillier wrote:

Stitch was done with a 65mm lens simulating a wider view.

Results are pretty much the same a comparing Dp2m to RX100. It takes a huge print to see a difference.

The reason presumably is that there is only so much detail you see in a given area.  The best the eye can resolve is 300 ppi and that only with perfect black and white dots side by side. Colour resolution is way lower.

You want more detail, you print bigger. And that is what resolution gives you: the ability to print bigger.

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Hi David,

The experiment you describe does not increase the resolution at all.

Here is one unalienable fact: The "only way" you can increase resolution by stitching over the base resolution of your sensor is by using a telephoto lens or moving closer to the subject.

The sensor can only produce "X" optical resolution. That "X" factor does not change magically with the number of images stitched. Each portion of that stitched image has precisely the same resolving capacity as the other portions. Stitching them together simply increases the field of view, it has zero bearing on optical resolution. Yes you have more "pixels" composing the image, but resolving power is unchanged.

Think of it like this. Use a three megapixel resolution camera with a 50mm lens and shoot an image of the wing of a butterfly from three feet away. Now mount the three megapixel camera on a microscope which has 50X magnification and shoot three hundred overlapping horizontal and vertical images of that butterfly wing which you move slightly between each frame until you have photographed every square mm of the wing. Now stitch these images together and you will have effectively increased the resolution over the original capture. "Only" by getting closer to the subject with multiple overlapping frames and stitching, or by doing it with magnification (telephoto) can you change the resolution.

Indeed, you can see a difference in even a 5x7 inch print between a high resolution sensor and a low resolution sensor if you use a magnifying glass to examine the prints. Depending on how good your eyesight is, you "may" not see a difference without doing this, but there "is" a difference assuming sufficient print resolution. For example, it's been said that the human eye can't discern much more than 300 dpi resolution. On the other hand, many can immediately discern the difference between a 300 dpi laserjet text print and a 1200 dpi laserjet text print. Why is this so if we can only discern 300 dpi?

I don''t have the answers, but I can say without hesitation that "I" can tell the difference in an 5x7 print from my 3 megapixel Canon D30 and my DP2 Merrill. I can also tell the difference between my 12 megapixel Nikon D300 and my DP2 Merrill. It's more difficult between my 16 megapixel D7000 and my DP2 Merrill, but by 8x10 I can definitely tell the difference.

Best regards,

Lin

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