>>3359203Tipp:
lookup/calculate your monitors ppi and the recommended viewing distance for that (the larger the monitor the better for this), move back said distance. Every image you see on your monitor should be sharp to your eyes now.
Open a 24mp in 100%. See how large it is, how many times you could move this viewable area left and righ/up and down?
Eg.: My 32" 1080p TV looks sharp ~80cm away (stands on my desk right in front of me). If I open a photo in 100% it has the total width of over 200cm. Thats pretty large considering how close I am. If i wanted to see it as a whole i would have to move back, which means you can print even larger and can print 24mp in quite a serious size.
More MP allows more cropping and yes, even larger prints. But the more MP, the better the resolution of the lens has to be to take advantage of it.
Btw, 42mp doesnt mean double the size of the picture in width and height but only area. With growing MP the outer "growing pixel ring" becomes larger and needs more pixel to fill in.
10 main differences between a7rIII and a7III
https://mirrorlesscomparison.com/preview/sony-a7iii-vs-a7riii/ 
