The (in)significance of resolution

Started Apr 15, 2013 | Discussions thread
DaSigmaGuy Forum Pro • Posts: 12,304
Re: You haven't increased the resolution....

Lin Evans wrote:

DaSigmaGuy wrote:

Lin Evans wrote:

Hi David,

You really haven't increased resolution at all with what you have described below. You simply have increased the field of view composing the scene.

Nonsense...Take two DSLR's with identical size sensors, one with 20mp and one with 10mp.  If you use a 40mm lens on the 20mp camera it will capture exactly the same resolution as the 10mp camera if its fitted with an 80mm lens.  But if you use a 80mm lens on the 20mp camera it will capture twice the resolution as the 10mp camera.  In other words for a given focal length, resolution is entirely dependant on the sensor or film frame you use.  Stitching shots increases resolution in exactly the same way that increasing the sensor or film frame size does.

No, for a given focal length resolution is both dependent on the sensor and the distance to the subject. The closer to the subject the more pixels per unit area of geography. We "measure" comparative resolution of sensors by normalizing "both" the focal length "and" the distance to the standardized resolution chart. If I shoot the horizontal and vertical only section of a standardized resolution chart with a macro lens attached to a 10 megapixel sensor from a distance of six inches and shoot the same entire resolution chart from the normal distance with a Nikon D800E and the same lens, the 10 megapixel camera will measure higher resolution than the Nikon D800E. If you shoot a subject with a 20mm lens from 20 feet, then shoot it again from the same distance but take three overlapping frames and stitch them you will have increased the pixel count of the file and the field of view, but you will "not" have changed the resolution one iota.

If by that you mean, a shot captured with a wide angle lens has less resolution than a several shot panorama of the same subject taken with a longer focal length lens and which when stitched has the same FOV as the wide angle shot, as long as the subject distance is the same and the sensors are the same?...If so, then we agree.

In Daves case, frame A + frame B + frame C = 3x the resolution of a single frame, minus the stitch area between frame A and frame B and between frame B and frame C, which is always required when you stitch several frames together in order to blend the shots seamlessly.  Say 3x res minus 10-20%...Its still a significant increase in resolution over using a single frame.

It's not "always required" Dave just said he used a tilt/shift lens. There is only a resolution increase if you are "A" closer to the subject or "B" use a great focal length lens.

Dave said: "So there you go. Unless you are printing much larger than a 13" wide desktop printer or cropping like crazy, a 10MP class camera (4.6MP) is every bit at good detail wise as a D800/Merrill."

No mention of the focal lens used or the distance to subject...

This is why so many people who only have low res cameras, take the trouble to stitch multiple shots into a multi row panoramas...Because it increases resolution!

The reason Dave didn't see any difference in his same size prints from various cameras is simply because his printer doesn't have a high enough print resolution to render the extra image resolution onto the print paper (Not enough DPI).  The solution is buy a higher res printer, but that would cost a lot of money.

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