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@Timpetus and
@antiprotest mentioned above, from the two examples you posted, this is the natural
bokeh effect of your newer phone having a larger sensor and a brighter lens than your previous one.
Bokeh is the blurry look of things in the foreground and background that are not the subject the lens is focused on. For example, a portrait where the subject is sharp but there is a soft and blurry background.
The bokeh blur is most noticeable under a few conditions:
- A larger sensor tends to show more blur of out-of-focus items than a smaller sensor under the same conditions. You have gone to a phone with a larger sensor.
- A larger aperture (the opening in the lens that lets the light through) will provide a more shallow area of sharpness, with the point of focus being sharp and a more dramatic fall off of sharpness of foreground and background elements, than a smaller aperture. The variety of lenses you could be using on these two different cameras have different apertures, so without a (sorry) apples-to-apples comparison of photos shot the same way with the two phones, it's hard for me to tell which aperture is being used. But even the same aperture being used in both cameras under the same conditions will result in a shallower depth of field (d.o.f. is items that are acceptably sharp in front of and behind the point of focus) with the new, larger sensor camera. In other words, if you were to put the 13 Pro Max and 16 Pro Max next to each other and shoot the same thing the same way, it's likely that the 16 would have a more shallow depth of field, with more of the blurriness of the things that aren't the point of focus.
- Distance from camera to subject. You are shooting closeups, and the falloff from sharp to out of focus is more exaggerated when your camera is closer to your subject. That's why some replies above have suggested you take pictures from slightly further away if you want everything sharp.
- Telephoto lenses tend to show more exaggerated bokeh than the same subject, same settings, as photos shot with a wider lens. So try using a wider lens for closeups.
The 16 Pro Max has a macro setting. Make sure you are using that when you take closeup photos. Here's a quick video that has several tips for macro photography on your new iPhone. I hope this helps!