[One (M8) Original Android Development] CutGlass:
LineageOS / google play store camera vs HTC play store camera

Just a basic test this morning, already we have a general result that the HTC camera is better for the average normal person. I'll try and explain why. Below are two images, the first is taken by the google camera, the second by the HTC camera app in the play store. Both cameras are set up previously to be fully automatic with white balance, all program and no exposure compensation.

I'll make no bones about it, the HTC is slightly slower but that is because of what it is doing. Without touching the picture to be taken and just pressing the camera button with the bottle of laundry detergent in the centre of the frame, the HTC wins entirely. The Google camera exposes for the average of the frame by default, the HTC continually adjusts for the centre of the frame which is where most amateurs place their primary point of interest.

Well lit green grass in monochrome is with 33% of an exposure value for 18% grey which is what the manufacturers calibrate to (1/3 stop, 18% Kodak grey scale card). Because the google camera appears to take an average reading from the entire frame until the screen is touched, the white bottle has blown the whites entirely and there is nothing there. The HTC appears to be centre weighted metering (possibly even spot metering based on the circle that appears later) based around the centre of the frame if the screen is not touched so it gives an exposure for the middle of the frame, which makes the grass darker and darkens the white of the bottle too, (which leads me to believe it is more like spot metering). Basically the HTC has a usable image of the primary object from pulling out of a pocket and pressing the shutter, the google camera does not.

Interestingly both cameras are set to Hard sharpen the image from the EXIF data, the google also records the direction being faced even though GPS location was turned off (I wanted to minimise variable to start with). The HTC is maybe 1/2 slower but when it beeps and a message that AE and AF are locked is on the screen, then it will give the better result. Both cameras appear to be saving at 92% quality using identical subsampling as jpegs, but the darker HTC image is significantly smaller due to the blackened grass and the way jpegs still undergo some compression and discarding of duplicate information.

Next two photos. Now this is where the camera is moved so the bottle is at the top right and the screen tapped to focus and get an exposure reading so the little circle is over the bottle, (corners are always softer and I was asked if there was a difference in sharpness between the two apps). This could be a point of contention the HTC had gone too dark again but there is therefore a lot more details in the text on the bottle as there is less creep from the highlights of the bottle being too light. But just hitting auto levels in any photo editing package is going to retain a lot more detail and adjusting the midtones and contrast is going to bring the grass back up, the Google camera doesn't have the information to bring back the details.

The contention would be that the metering on the google has in this case given a better initial picture after having touched the glass, this is true but it comes at the expense of fine detail and if any section of the image needed enlargement, the goole just doesn't have it. I would prefer a slightly incorrect darker image with detail that if I'm going to print, I'm going to open some software and hitting auto-levels and moving the slider in the middle and contrast is not excessively time consuming. I believe "everybody" if they were going to print a snap would probably do the same and in that case the HTC app wins because of it's retention of detail. The only case I can think of was if you were bluetoothing a picture to a print booth, but the HTC gallery app has image adjustments (as does google photos) in it and they are probably worth using, or if it was a selfie to be sent out immediately without editing.

More tests will follow for real world situations rather than an example chosen to push the metering through it's paces. An unedited more average image will be next to see if there is any difference in the apps or whether the HTC compensates for how the lens is constructed.