Stefan Mileschin

Yesterday, HTC updated their HTC Camera application for devices with HTC Sense. Normally, this isn't worth discussing, but the changelog had an entry for RAW photography mode on the One M9.

For those that are unfamiliar with what a RAW photo is, in essence it's exactly what would come to mind when it comes to something that is "raw". The file effectively encodes the sensor's data at each pixel, without any loss or significant processing. Normally, this file is completely hidden from the user, and once it enters the image signal processor (ISP) it is only used to produce the final JPEG and is presumably deleted once the JPEG file is saved to internal storage. As a result, we end up with a file that can be easily read by any computer, but is effectively impossible to change in a meaningful way. A RAW/digital negative can be easily changed to look almost nothing like the original image, but is impossible for most applications to view properly.

Fundamentally, a RAW photo is an unprocessed image, and if you could see the RAW image without demosaicing to handle the camera's pixel layout, it would look almost nothing like the final image. However, it's this relatively unprocessed state that allows for potential gains in image quality. After all, the ISP must determine how to process an image without human intervention in an effective manner, and it also must process and save the image within about a third of a second or less. Comparatively speaking, if I process it myself I might spend a solid 5-10 minutes playing with sliders to get a good balance between noise, detail, contrast, and dynamic range, and each image requires a second or two of maximum CPU load on a modern Core i7 4702HQ.

http://www.anandtech.com/show/9211/a...-m9-raw-photos