[Leica] OT: Help! How many Megapixels needed?

[lrzeitlin at aol.com]

 	Here is a question discussed at a recent photo show. I had no good answer.
	
	When I first got involved in digital photography almost two decades ago I was advised by engineers at the Kodak research lab that all of the information on a 35mm Kodachrome slide could be contained in 13.5 megapixels. They felt that it would take almost a century to reach that point. (Most of those engineers are now looking for other jobs.) Remember that the first antediluvian digital cameras had only .3 megapixels of resolution. Film, they said, would be safe for many years. That 13.5 megapixel estimate seemed to take on a life of its own. The 4/3s format as finally released was 14 megapixels (now 16 Mp.) and the Leica M8 and first DSLRs were content with less. My first digital Leica had a 1.3 megapixel sensor. I have owned cameras with 3,5 Mp, 5 Mp, 10 and 12 Mp, and 16 Mp. All produced very good results to the naked eye. Admittedly I didn’t use a magnifying glass to explore the details of the image. But then who does?
	Now cameras are marketed with 24, 32, and 64 megapixel sensors. Even the iPhone has 8 megapixels. Does it make any difference or is it simply a marketing tool. Theoretically visual quality should improve as the square root of the megapixel count but the electrical complexity of the computation and the display requirements are directly proportional to the pixel count of the sensor. Even Apple, a company that never backed away from complex systems, needs only 5.5 megapixels to drive a 27” Thunderbolt display. I view most of the LUG output on a 13” Mac Pro laptop screen and the work appears perfectly adequate.
	For people that want to produce 11” x 14” to 16” x 20” prints or publish their work in most consumer magazines, not display gigantic Colorama sized prints from minuscule portions of the frame area, does the number of pixels really matter? Inquiring minds want to know.
	Larry Z