kmilo wrote in post #18572547
My original image is 6000x4000 pixels.
6000 times 4000 equals 24,000,000 total pixels
A 50% crop would leave you with 12,000,000 total pixels .... roughly 4250x2867
Even if you resize that 4250x2867 crop to something like 600x400 ... you're still showing a 50% crop of the original.
... or someone needs to teach me this principle as well
edit to add: When someone says 100% crop, they mean the displayed 600x400 pixels is exactly equal to the crop of the original ... it's not resized.
It does not help that explanations are throwing in concepts that need not apply. Let us use a mythical example to help you understand:
Starting assumptions for this scenario
- Let us assume that your monitor of the future is 4800H pixels wide x 2700V pixels (16:9), it is 20.75" tall and 37" wide and is marketed as a 42" diagonal '12k monitor',
the current state of the art
- You wish to view a JPG file which is 6480H x 4320V pixels, a 28MPixel image
- When the JPG image was created by your best friend, he stored it with the JPG 'save for web' option, and so there is no EXIF data embedded within the file
...the computer does not know whether the image is to be displayed at 72dpi or 83dpi or 94 dpi or 101 dalmations per inch!
Now the analysis of the scenario...
Your monitor's native resolution displays 130 dots of image per inch (2700 pixels / 20.75" =130ppi)...no resolution characteristics buried within the image file alters that inherent 'ppi' of the monitor, it is inherent to the design characteristics of the monitor. Period. Nothing changes that, except buying a new monitor!
1. We display your image on your 42" monitor at 'full screen'
...it has to fit 6480H x 4320V pixels onto a monitor of 4800H pixels x 2700V pixels (16:9). The computer knows the screen resolution, so it computes that it needs to 'throw away' pixels from the image in order to fit the image on the monitor at 'full screen'.
- Your application shows that the image is at 63% (2700 / 4320)
- In terms of image display on the monitor, it is effectively fitting 4320 pixel tall image with thee 20.75" monitor height, or 208 ppi -- but your monitor only supports 130 ppi.
2. We display your image on your 42" monitor at 100%
...the monitor has 4800H pixels x 2700V pixels, so 'at 100%' the monitor shows a 4800H pixels x 2700V pixels section of the entire image, and 1620V pixels and 1680H pixels are 'off the edges' of monitor.
- Your application shows that the image is at 100% (2700 /2700)
- In terms of image display on the monitor, it is effectively fitting 2700 pixels of the 4320V pixel tall image with the 20.75" monitor height, or 130 ppi -- your monitor supports 130 ppi.
3. We display your image on your 42" monitor at 200%
...the monitor has 4800H pixels x 2700V pixels, so 'at 200%' the monitor shows a 2400H pixel x 1350V pixel section of the entire image, and 2970V pixels and 4080H pixels are 'off the edges' of monitor.
- Your application shows that the image is at 200% (2700 /1350)
- In terms of image display on the monitor, it is effectively fitting 1350V pixels of the 4320V pixel tall image with the 20.75" monitor height, or 65 ppi -- your monitor supports 130 ppi.
Now if your friend had output the JPG with full EXIF data embedded, and the EXIF said the image was '300 dpi', ALL THREE of the above apply with no changes to any of the description because the embedded EXIF data for 'dpi' simply does not matter to your computer display or to the 'fill page' output to your printer!!!