How many Megapixels

falconeye · 02-25-2012, 04:17 PM

Originally posted by Laurentiu Cristofor

I expect most photographers think of diffraction limit in relation to the maximum f-stop they can use and few have heard of the Raleigh criterion.

But it is the same really. Divide a pixel size (like K-5's 4.9μm) by my .33μm above and you obtain the diffraction limit expressed as an f-stop for a given pixel size (4.9/.33 = F15). It's still the Raleigh criterion.

The only difference here was that the question was for the smallest pixel size whatever be the lens.

stevebrot · 02-25-2012, 05:28 PM

Originally posted by falconeye

But it is the same really. Divide a pixel size (like K-5's 4.9μm) by my .33μm above and you obtain the diffraction limit expressed as an f-stop for a given pixel size (4.9/.33 = F15). It's still the Raleigh criterion.

The only difference here was that the question was for the smallest pixel size whatever be the lens.

Falconeye...unfortunately there was some loss in translation for your text. What is .33μm above should have rendered:

.33μm (0.33 micrometers)

It usually works best to simply paste the required character directly into the editing box rather than attempt to insert the HTML character entity.

Steve

falconeye · 02-25-2012, 07:37 PM

Originally posted by stevebrot

rather than attempt to insert the HTML character entity.

Steve, it's a bug in the Tapatalk software or Adam's forum software. I entered the keyboard character. So, I can't do anything about it ...

olenl · 02-29-2012, 02:10 AM

imho it's already the limiting factor.

Most lenses look soft nowadays - they have best resolution in the center but as you move away, it goes way down and there are all sorts of defects like chromatic aberrations which would not be visible if the pixels were larger.

IMO they just can't make good enough lenses for current APS/C sensors, so the industry should refocus to increase lenses quality (for reasonable price) instead of cramping up the megapixels.

The reason FF and MF is good is exactly this - they got huge sensors with small pixel density, and their lenses, even with current level of technology, can deliver resolution enough to make images look sharp on pixel level. Cropped format however is doomed to be soft and chromatically aberrated because all it has is useless pixels and cheap lenses that can't use them.

02-25-2012, 05:28 PM	#17
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by falconeye But it is the same really. Divide a pixel size (like K-5's 4.9μm) by my .33μm above and you obtain the diffraction limit expressed as an f-stop for a given pixel size (4.9/.33 = F15). It's still the Raleigh criterion. The only difference here was that the question was for the smallest pixel size whatever be the lens. Falconeye...unfortunately there was some loss in translation for your text. What is .33μm above should have rendered: .33μm (0.33 micrometers) It usually works best to simply paste the required character directly into the editing box rather than attempt to insert the HTML character entity. Steve

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02-25-2012, 04:17 PM	#16
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by Laurentiu Cristofor I expect most photographers think of diffraction limit in relation to the maximum f-stop they can use and few have heard of the Raleigh criterion. But it is the same really. Divide a pixel size (like K-5's 4.9μm) by my .33μm above and you obtain the diffraction limit expressed as an f-stop for a given pixel size (4.9/.33 = F15). It's still the Raleigh criterion. The only difference here was that the question was for the smallest pixel size whatever be the lens.

02-25-2012, 07:37 PM	#18
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by stevebrot rather than attempt to insert the HTML character entity. Steve, it's a bug in the Tapatalk software or Adam's forum software. I entered the keyboard character. So, I can't do anything about it ...

02-29-2012, 02:10 AM	#19
olenl Senior Member Join Date: May 2010 Posts: 113	imho it's already the limiting factor. Most lenses look soft nowadays - they have best resolution in the center but as you move away, it goes way down and there are all sorts of defects like chromatic aberrations which would not be visible if the pixels were larger. IMO they just can't make good enough lenses for current APS/C sensors, so the industry should refocus to increase lenses quality (for reasonable price) instead of cramping up the megapixels. The reason FF and MF is good is exactly this - they got huge sensors with small pixel density, and their lenses, even with current level of technology, can deliver resolution enough to make images look sharp on pixel level. Cropped format however is doomed to be soft and chromatically aberrated because all it has is useless pixels and cheap lenses that can't use them.