Comparing Sony's 42mp and 24mp sensors

Started 7 months ago | Discussions thread
aSevenArr Contributing Member • Posts: 644
Re: Comparing Sony's 42mp and 24mp sensors

Horacecoker wrote:

I'm still undecided about which Sony FF camera to go for. I was seriously thinking about the A7Riii but then the A7iii appeared on the scene and now I'm not so sure. I'm pretty well clued up on the feature side of each camera and either will suit my needs so it really boils down to image quality. If I'm splashing out for FF (mirrorless) I want the best quality I can get. I know I will get more detail with the bigger sensor of the A7Riii but it costs a lot more than than the new A7iii. So like lots of other folk on here I then decided 24mp will be enough and I'd probably be downsizing the 42mp sensor images to 24mp or less anyway. Yes I know I will have much more scope for cropping with the 42mp sensor but I'm now not planning to use a FF camera for birding so any cropping of landscapes or grandkids pictures will be fairly minimal.

That's a bit of a preamble to what I'm getting round to saying. On comparing the A7iii to the A7Riii on DPReview's studio scene comparison tool, I expected to see more detail in the A7Riii image when clicking on the FULL view and this is exactly what I saw - quite a bit more detail as is right and proper with the fairly large difference in resolution between sensors. What I didn't expect is to see is more detail with the A7Riii when I switched to COMP. In this view the 42mp is downsized to match the 24mp sensor of the A7iii. So now all the objects in the studio scene appear the same size. Not only is the A7Riii image sharper it appears cleaner than the A7iii image. The difference is quite obvious to my eyes. The A7iii image looks either slightly blurred or slightly out of focus in comparison. I checked the lens used for each camera and they are identical. Then I thought surely DPR have made sure the lens was focussed correctly on the A7iii?

Apparently they did make sure because I then brought the A7ii and A9 into the tool and they are both more or less exactly the same as the A7iii. The image quality of the A7Riii trumps all three and it does so my some margin. This is with the A7Riii in 'Normal' mode, if you change it to 'Pixel Shift' mode, wow. the difference is even more pronounced.

This has made me lean more towards the A7Riii again but perhaps you guys don't see these image quality differences I'm on about? Or perhaps most folk haven't looked into it like I have. It seems to me that the majority of people only use the tool for noise comparisons with other camera models at high ISOs and not as a tool for checking image quality between cameras from the same manufacturer when deciding on what model of camera to buy.

Here's a screen grab of the text section of the studio scene for all four cameras. Text is good for highlighting any image quality differences but wherever I dragged the box i could still see differences. It just looks like the A7Riii was shot with a superior lens imho but this is not the case.

David

Here's a good link for you... all about megapixels and the BS surrounding them...

https://www.nytimes.com/2007/02/08/technology/08pogue.html

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