While we all think the Nokia Lumia 920's camera is a quality camera, we also note that image quality from the Windows Phone camera can be slightly on the soft side. The softness isn't something to send you running from the room in a panic but evident.
Until Nokia updates the firmware on the Lumia 920 to bump the in-camera sharpening you can easily fix things with Nokia's Creative Studio or even the auto-fix in Windows Phone 8 can help.
There also may be another fix available. WPCentral Reader Atif sent in a tip where he's found changing the aspect ratio on the Lumia 920 from 16:9 to 4:3 produces sharper images from the get go.
The aspect ratio is simply the proportional relationship between an image's width and height. The 4:3 ratio is more square like while the 16:9 has more of a wider, landscape feel to it. Here's what Atif discovered in the sample shots he submitted. The 4:3 samples are posted above the 16:9 samples. Images have been resized for publication purposes.
While the 4:3 image does appear sharper in the above samples, we tried to replicate Atif's results but couldn't. Here's our sample.
So to answer the original question: Does changing the aspect ratio improve sharpness? We don't think so. Rather, we surmise users are getting different, sometimes better results due to the camera re-focusing (and how you focus comes into play to e.g. tap-to-focus versus shutter button). In conferring with other Windows Phone Central staff writers who own the Lumia 920, none were able to verify that switching to 4:3 yielded better results.
We still believe the solution is a simple firmware update to boost the in-camera sharpening. As is, the images the Lumia 920 produce are quality images and the slight softness may not be an issue to most. We aren't being picky about things, we just would like to see a great camera reach its full potential.
Thanks, Atif, for the tip and sample photos!