GX7 image resolution

norman shearer wrote:

alcelc wrote:

No, dpi (dot pre inch) or better described in digital world, ppi (pixel per inch), is something you instruct your printer to or print a hard copy of image. So, if at a printing resolution of 300 ppi, a 3000 x 3000 (9Mp image) can print out a 10" x 10" hard copy without any enlargement. Of course if you print at 100 ppi, you can get a 30" x 30" printout. When a printout of 300 ppi can look good at certain distance, at the same distance a 100 ppi print out would look less well resolved. That is the only difference between different resolution of printing.

However, it has nothing to do with the output from you camera. Of course you can capture a lower resolution image out of the camera (e.g. 3:2 mode, or S size etc). However it will just limit the headroom of how you can use the image, e.g. print large, view on a higher resolution screen, to crop etc.

Sorry to jump in but on a similar note. If I elected to use a smaller size in camera would the camera still shoot full size and then reduce it afterwards to the selected size?

If shooting RAW, for the brand I used, it must be in full resolution.

If shooting in jpg, when a smaller than full resolution output be selected, the pixel data from a smaller section of the sensor would be recorded. Therefore, it is no difference from shooting an image in full resolution, and crop it by an editor later. IMHO its IQ including noise condition would remain the same as a full resolution output at the time of recording (providing the output will not be viewed >100%).

I shall not mix the idea of picture quality usually referring to the degree of compression of a jpg by the camera, that the actual file size could be reduced for the same amount of pixels recorded. The higher compression the lower IQ from the best quality of jpg output.

If not then a smaller jpeg size derived from the same size sensor may have less noise?

I'm just thinking this because I have Sony A7S and that is good for high ISO due to bigger pixels etc.

Pixel size is fixed when manufactured. Data from certain pixels not recorded (used) will not affect the physical size of the sensor. And the total amount of light received by the sensor will also remain unchanged. So use a <100% resolution will not give any benefit except for a narrower AoV only.

Some models might use a binding pixels method to avoid AoV cropping on video and it can benefit IQ. But generally on still shooting this binding method will not be applied.

I could test for myself but I'd probably draw the wrong conclusions! I usually shoot RAW btw.

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