Q: Iphone 6Plus camera low res

Hi AndrewMTM,

Thanks for checking out the Apple Support Communities and for the details about what's happening with your photos. Photos are such an important part of our everyday lives so I can certainly understand wanting to make sure you're able to see your full resolution photos. 

Something that can cause the photos on your iPhone to appear at a lower resolution is having iCloud Photo Library with Optimized Storage turned on. Here's some important information regarding that feature:

If you turn on Optimize [device] Storage, iCloud Photo Library will automatically manage the size of your library on your device, so you can make the most of your device's storage and access more photos than ever. All of your original, full-resolution photos and videos are stored in iCloud while device-size versions are kept on your device. You can download the original photos and videos over Wi-Fi or cellular when you need them. 

If you turn on Download Originals, iCloud Photo Library will keep your original, full-resolution photos and videos in iCloud and on your device.

You can see all of the info regarding iCloud Photo Library here: iCloud Photo Library FAQ - Apple Support

If you're not using iCloud Photo Library with Optimized Storage but are still having issues with the resolution of the photos from your camera, then I suggest to take a look at the section labeled 'Your photos are blurry or out of focus' in the article below. It includes some great steps to help troubleshoot issues with your camera. 

Get help with the camera on your iPhone, iPad, or iPod touch - Apple Support

Cheers! 

Hey AndrewMTM,

Thanks for the clarification on whether or not you're using iCloud.

Since you're still having trouble, the next best step is to try to isolate this to a hardware or software issue. I recommend backing up your iPhone first using either iTunes or iCloud. You can find the steps here:

How to back up your iPhone, iPad, and iPod touch - Apple Support

You may also want to import your photos to the computer if you're not already doing so with these steps:

Import photos and videos from your iPhone, iPad, or iPod touch - Apple Support

Once your data is safely backed up, I recommend to restore your iPhone using iTunes. This will erase the iPhone and reinstall the current version of iOS for you. Once you've restored it, you'll want to choose to set it up as a new device (temporarily). Then, test out the camera before restoring your backup. If your camera resolution is working normally without your backup being on the device, then you can go ahead and restore your backup and test it out again. If it stops working after restoring the backup, that means there's an issue with your saved data from your backup causing the issue. In that instance, you would want to restore it one more time, set it up as new, and sync data individually instead of restoring your full backup. 

You can follow the steps here to restore your iPhone using iTunes:

Use iTunes on your Mac or PC to restore your iPhone, iPad, or iPod to factory settings - Apple Support

You can find the steps for restoring your backup here:

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

If you find that the issue is with your iPhone and restoring as new and testing it doesn't help, then I would recommend bringing the iPhone into an Apple Store or an Apple Authorized Service Provider to have the camera inspected. You can find the nearest store locations here:

Apple - Find Locations - Country Selector 

You can also arrange for mail-in service depending on where you're located. You can start that support request here:

Apple - Support - Product Selection

Cheers!