主要是覺得7D拍出來的感覺100％檢視都覺得顆粒比較大...所以就感覺比較糊...
所以看了一下照片內容，7D的照片只有 72 DPI，
NIKON D300S的 也都有300DPI....
所以在網路上找到一篇文章就是探討72DPI與300DPI的差異....
無奈小弟英文不好，且專有名詞太多....
用GOOGLE翻譯也只能看懂一點點....
不知道是否有好心的前輩能幫忙解釋呢？
原文來源：http://www.foto-biz.com/Lightroom/300dpi-vs-72dpi
內容：
DPI stands for "Dots Per Inch". DPI only applies to output devices, that\'s for monitors and printers… PPI stands for "Pixels Per Inch". PPI only applies to input sensors, that\'s for camera sensors… If somebody talks about PPI when talking about screens or printers, they don\'t know what they are talking about! Many printers do not deal in DPI but in LPI "Lines Per Inch", those are mostly CMYK commercial printers, printing presses, magazines, newspapers… What\'s the difference between a 300 DPI and a 72 DPI? None, zero, zilch! Almost… It\'s only a double flag that is stored at location: 0Ah for the horizontal resolution and at 0Ch for the vertical resolution. If you have an original photo that\'s 5184 pixels by 3456 pixels, the full size of a Canon 7D - 18 megapixels sensor, that you export as a jpeg of 518 pixels by 345 pixels at 100%, meaning no compression, with a DPI of 300, the file size will be 1.8 megabytes. If you have an original photo that\'s 5184 pixels by 3456 pixels that you export as a jpeg of 518 pixels by 345 pixels at 100% with a DPI of 72, the file size will be 1.8 megabytes. Oops! What happened? Why are they both 1.8 Megabytes? One photo is set to be 300 DPI and the other is set to be 72 DPI. If you use a program like bsdiff to extract the differences, it\'s only 4 bytes. The DPI, that\'s it! No other difference, otherwise both jpegs are identical. The DPI and the LPI are only indicators of what density you should output the photo. The important word is should. Most printers will obey the DPI suggestion, but on many printer drivers you can override the DPI/LPI settings. Also you can use an “hex editor” to change the DPI from 72 to 300 and save the file. Back to what\'s the difference between the 72 DPI and the 300 DPI photos? The output of the 72 DPI jpeg image will be 4.166 wider and taller than the 300 DPI jpeg image. But the 72 DPI will look much spottier, and if you are close enough you will see the individual pixels. |
