I'll agree with you that few need 24MP, but that's only because few people print large. If you do print large, and want to show off your well exposed, well processed image shot with the best glass, give your printer some resolution to work with.
Graham
Hi Graham,
If you read the work at the DXO site, they say that for an 8 x 10 print, all that is needed is an 8MP sensor. They claim that will yield a retina sharp image for an 8 x 10 print at a normal reading distance of 14 inches. What distance from the print did you employ in your examinatins of the prints and did you use a magnfiying aid?
If you look for the resolution of a healthy eye with 20/20 vision and able to adapt to the 14 inch normal reading distance (alas I used to be able to do that) - you will note that 6-7 line pairs per millimeter is all that a healthy eye can do. That translates into 150 to 175 line pairs per inch on a print - and so I would assume that at 300 to 350 DPI the maximum viewable resolution might have been reached. Therefore the 8 MP value used by DXO (10inches x 300~350 DPI) times (8 inches x 300~350DPI) is reasonable. But of course you might want some extra room for cropping without loosing the highest visible quality. So is 24 MP really necessary?
Some say - what if you wanted to print a mural. The answer there is simple as people don't go around viewing murals from a 14 inch viewing distance - they are on the highway or far from the image and it will still appear retina sharp. So DXO is almost right - with the only difference is that you need to account for some cropping.
But some people are like me. I like to get into a photo - like explore it at full glorious size. That can easily be done on your computer screen. That permits enjoyment of this hobby without the added expense and time consumtion by printers, programs, and papers etc.
For instance, some of the DRreview posted images for test cameras are done in a recreational area where many people are in the image. Looking at the full size image (remember here that no pixels are seen at this size) you can find many stories at once. There are the lovers, there are people arguing, there is the mother scolding her child, and there are some elderly couples that hold hands which speaks of a true love that has persisted and flourished over a period of fifty or more years. There are children, teens, middle aged and the elderly. There is a story in each of those faces - if you look. But you cannot see that in an 8 by 10 unless you use a magnifying glass and perhaps printed at 600 DPI or more.
If you were at the scene in person and live - there is a movement of everyone's emotion and disposition. Expressions change in an instant and are as fleeting as a quick smile or wink of an eye. People seeing you looking at them and studing them would be alarmed. But in the photo you can look it all over without and change. The movement is frozen in the image you can look at the relationships that might be there.
Try that even with a lower MP camera and you will see what I am talking about. And do that in images that are from foreign lands to get a flavor of the people.
), but that's comparing a 14MP FF with a 24MP FF image, not APS.
