I have an image, below, that seems "soft" and I'd like to know why. Possibly it was resized from something like 3000 x 3000 and not sharpened. Possibly it's a 500 x 500 image, expanded to 960 x 960. Maybe the camera was out of focus. Maybe it was taken with a mobile phone instead of a $1000 Canon. Is there a way to determine what's wrong with it? Thanks.
There are generally certain characteristics that can be attributed to certain factors... for instance a heavy crop will tend to have artifacts more apparent. Massive enlargement/low resolution similarly...
This is a low resolution image at 960x, but when viewed at full size I don't see characteristic artifacts of higher noise, pixelation, banding, moire, etc. etc. So I can't see anything I might attribute the issue to in those terms.
The image is almost certainly downsampled... but that doesn't typically cause an apparent lack of sharpness/detail, actually the opposite.
What is apparent is that the image is sharper towards the back (glass/wall) than it is towards the front (plate/table). So the main issue causing the softness you are concerned with is mis-focus.
Is there a way to determine what's wrong with it?
If you're asking whether there's any data in the image file that would tell you how the image was created, the answer is maybe. Digital photos generally include metadata in a format called EXIF. If there's EXIF data attached to your image, you can see it with many image viewers. However, that data may have been removed at some point if the image was edited or otherwise modified. If it's there, the EXIF data can tell you things like the camera and lens make and model, shutter speed, aperture, ISO setting, which focus point was selected, and so on. If it's not there, you're out of luck.
Your best bet is to talk to the person who took the photo. They might be able to provide the original image, which is more likely to have its EXIF data in tact, and they might remember for more than the EXIF data can tell you about how they took the photo.
Ultimately, the problem is that it's just not a great photo. The equipment used might have contributed to that, but it's not the cause. You can take a good shot with a smartphone or a compact camera, and you can take a bad shot with a top-of-the-line DSLR.
I see three things that need improvement:
It looks like some kind of glop hiding behind the two halved Brussels sprouts and the mac-'n-cheese glop in the black casserole on the black serviette. Where's the wine in the glass? Someone forgot to fill the glass with the… Where's the wine? Do I eat this with my hands?
The subject has no point of focus and the elements are far-flung around the composition. Do I eat this with my hands? Why is the goblet so far away that the top isn't even in the photo? Nice table dressing on that plywood-print Formica sheet table in front of that attractive background of plywood. Very appetizing layout.
The exposure is not optimal. The subject is badly flat lit. The focus is off. The white balance isn't and the yellow cast is off-putting.
I'd recommend against using these legacy resources in favour of stock photography. The royalties won't be wasted so much as trying to save these badly conceived attempts portraying inept hospitality.
You eat with your eyes. Food must be prepared properly for the camera. You cannot get a satisfactory result from photographing food prepared for eating with your mouth and nose. BTW, the same is true for supermarket flyers that show uncooked food. It must be prepared for the camera.
Soft is the least of the problems. It's unappetizing and unappealing.