So we've done a few comparisons of the Nexus 5's camera to the Galaxy Note 3 and the Nexus 4. Sure the camera isn't the top of the line camera, but it is a pretty good one, especially considering it's only a $350 phone. I'm actually quite impressed with how much it's been improved over the Nexus 4. However, there are many out there that still think it's a pretty bad camera, which they are entitled to their opinions. But luckily, we have a ton of developers out there, especially over on XDA.
XDA forums, user Jishnu Sur, has released a flashable.zip that will replace the stock camera app with a camera app that enables all sorts of tweaks and potentially improves the camera dramatically. According to Sur, this new camera app turns on Stereo sound recording with the secondary mic, speeds up focusing and much more.
Now this part should go without saying, but you will need to be rooted to be able to flash this zip. Which isn't too hard to do. You'll just need to copy the zip onto your phone, then hop into recovery and install it. Your bootloader will also need to be unlocked. Here's the changelog from this modification:
1) Sound Recording now in Stereo with the secondary Mic.
2) Faster Focusing for the camera.
3) Front Camera also records 720P [email protected] 20 Mb/s.
4) Front camera Audio [email protected] 192000 Kb/s.
5) AntiBanding default set to 50Hz
6) Focus Range Adjusted.
7) Enhanced Smooth Zoom .
8) Turned Edge Enhancement ON.
I have not yet checked it out, but I think I may have too and then show some before and after pictures with the mod on my Nexus 5. Hopefully it really does dramatically improve the camera. I'm also hoping that The Verge was right, and that Google will be sending out an OTA for the camera soon. Hopefully in Android 4.4.1, which is rumored to be heading out real soon.
You can find out more information from this thread over on XDA's forums.