[Mobile Education] Basic introduction to raw files on the Axon 7 as well as raw processing.

razor512razor512 United StatesPosts: 2,633 ✭✭✭✭✭✭✭✭
edited September 22, 2017 6:38PM in Mobile Education

Many smartphones including the Axon 7 allow you to capture raw images from within the camera app. For those new to working with raw files, this post should give you a basic understanding of the capabilities of the raw files from the Axon 7 as well as from other smartphones.

What is a raw file?

A raw file contains the unprocessed sensor data, as well as some metadata relating to the camera information and basic settings used. Almost all aspects relating to how the image in interpreted and processed can be adjusted.

Raw files from the Axon 7:

In the case of the Axon 7, when raw capture is enabled within manual mode, the camera will save the raw images as a DNG file with a size of 43.9MB.
The resolution of the file is: 5952x3348
The bit depth of the file is: 10 bits per channel (jpegs are 8 bits per channel; each additional bit doubles the amount of information).

The metadata stored in the file and immediately present to the user are as follows:
• File name
• Application name (based on your camera app)
• Date created
• Date modified
• Dimensions
• Color mode
• Color profile
• GPS info if available (please turn off Geo-tagging if you are uploading images for public view and don't want people to see exactly where you took the photo.
• Lens data (Focal length, aperture)
• Shutter speed
• ISO
• White balance
• Tint

With the DNG container, a wide range of additional metadata can be added via your image editor or any other application which can edit EXIF data, or if you really want, you can also make edits to it through a hex editor.

Enabling raw capture:

Step 1: Launch the camera app.
Step 2: Switch to manual mode .
Step 3: Click on the gear icon.

Step 4: Toggle on "Save as RAW picture"


Once you have enabled the raw capture, photos taken in manual mode will be captured as Raw + jpeg.
Raw files will only be saved to the internal storage and NOT your micro SD card, even if you have it selected as your save location, thus you will be heading to the DCIM folder on the internal storage for your raw files. I believe this was done for performance reasons since the raw files are large. The jpegs will still save to whichever location you specify.


After you have captured a raw file, you can then proceed to edit it in a 3rd party image editor. I personally use photoshop CC, but a free alternative is GIMP.

To copy your raw files from the phone, to your PC, simply connect it via USB, and select "Media device MTP" from the menu that appears on the smartphone's screen. You can then browse to the DCIM folder on the internal storage, and then copy your raw files to your PC.

Processing your images:

Once you have the images on your PC, you can then begin processing your photos to look the way you want them to look.
If using photoshop, when you first open a raw file, you will be presented with the Adobe Camera Raw window which will allow you to alter a wide range of aspects of your image as seen in the animated gif below.

Benefits of raw files:
When you capture a raw file, since none of the settings outside of the exposure triangle are baked into the image, you have a wide range of adjustments that can be made to the image. Raw files also have significantly better dynamic range and color depth than the compressed jpegs that the camera will normally make, thus it is possible to easily correct for a moderate amount of under exposure or over exposure. Furthermore, if the camera jpeg automatic settings mistakenly picks the wrong white balance, or if you are dealing with situation within a single scene, you have multiple different color temperature light sources, you can correct for all of them. With a raw file, the white balance is not baked in, thus with local adjustments it is possible to correct for normally undesirably lighting conditions such as a camera flash that is 6500K color temperature while the background in the scene is lit by 2700K color temperature lights. Since you can selectively adjust the white balance for different parts of an image, it becomes possible to account for multiple white balances though that process can become tedious if there are a large number of different color temperature light sources.
For basic adjustments such as fixing an over or underexposed image, the process can be done rather quickly, and as long as the bulk of the scene falls within the dynamic range of the raw image (typically about 2 stops over or under exposed), you can recover it in post, though a large amount of recovery will always increase the visible noise in the image, thus increasing the need for noise reduction filters.

Below is a short animation showing the highlight recovery capabilities of a raw file from the Axon 7.


I also recorded a video showing my workflow of recovering an overexposed image that had additional contrast issues due to me shooting the image from behind a car windshield. Due to the issues with the image, the workflow is far longer than it would normally be for a properly exposed image, but I chose it because it provided an excuse to multiple levels of post processing using multiple strategies for a single image.

**Before: **

After:

Comments

  • saeedtedsaeedted United StatesPosts: 1,183 ✭✭✭✭✭✭✭✭

    **Snapseed **and Adobe LR are two apps that I use to edit RAW files on my Axon 7.

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