Questio about image size and focus - Sony A7iii

[wm17959]

I recently got the camera and there is still a lot to learn. I always shoot RAW files and when I open them on a screen  I'm surprised at how small they  appear when viewed at 100%. I thought a 24MP image would appear huge, but it isn't.

Also, I have done some tests with the camera on a tripod and I find the focus should be sharper. I use a 2 second timer so I'm not touching the camera and when viewed at 100% it just seems to me it should be sharper. For a full-frame camera and a Sony lens (28-70mm, 3.5 - 5.6) I was expecting more. Any suggestions?

[Chrissie]

5 hours ago, wm17959 said:

I thought a 24MP image would appear huge, but it isn't.

Your A7iii has a 24MP sensor, and raw images are 6000 Pixels wide by 4000 pixels high. How much screen space those occupy when viewing at 100% depends on the resolution [Pixel] of the screen you use. If, for instance, you have a screen that has a horizontal resolution of 6000 pixels and and a vertical resolution of 4000 pixels, a 6000 by 4000 pixel image would cover the full screen if viewed at 100%. If a very hypothetical screen had 12000 pixels horizontally and 8000 pixels vertically, your 6000x4000 image would cover only 1/4th of the available screen space. (1/2 its width by 1/2 its height =  1/4 screen). And so on.

To further dig into this, I would do the following, in the sequence as given. And please excuse if I propose something obvious:

• verify that the camera is indeed shooting raw. Raw images are always 6000by 4000, whereas jpeg can be configured in terms of size and quality.
• verify that you are indeed opening a raw file. These have the '.arw' filename extension. (At least on my a9).
• Look up the technical specifications of the screen you use. Particularly its maximum screen resolution in [pixel].
• verify, that your viewing program (which one are you using?) has its zoom settings indeed at 100%.

If all this doesn't help, please report back the details of your findings. Would be helpfull if you could post a raw image on flickr, also for your second question re. sharpness.

Good luck. 

[wm17959]

Thank you Chrissie, this is actually very helpful! My computer is also new and the screen resolution is 5120 X 2880 on a 27" screen, so it makes sense that the image does not appear vey large. My other camera is a Canon with a crop sensor, and for a long time I was shooting jpeg files, which would explain why the images appeared much larger. I guess with jpeg files it's just a matter of changing the screen resolution of the image to make it bigger. I know a lot of these things must be common knowledge for most people who are into photography, but I'm still wrapping my head around it. I appreciate your information.
I'm going to do some more tests regarding focus at various apertures, but it could be that shooting with a zoom lens is part of the problem. At this point I don't have the budget to invest in several prime lenses, and zoom lenses are very convenient.

[LiveShots]

What software are you using to view the raw files ? If I open a Sony raw file using just the Finder/Preview on my Mac the image is very small. When using CaptureOne I set the image preview size the same as my monitor and the image almost fills the entire screen.

Edited December 16, 2018 by LiveShots

[Chrissie]

6 hours ago, wm17959 said:

this is actually very helpful! My computer is also new and the screen resolution is 5120 X 2880 on a 27" screen, so it makes sense that the image does not appear vey large.

On the one hand I'm glad you feel helped, but on the other hand it looks like my explanation still wasn't thorough enough:

Indeed, 5120 x 2880 is a really nice resolution, but this is still less than your raw images at 6000 X 4000 require. So viewing a full size picture at 100% would still make this image "overlap" the available screen space in both width and height, and you would have to pan around a little bit to view it all.

You didn't mention which OS and which application you are using. 27" iMacs aren't the only ones using that resolution.