Samsung Galaxy S6 and DNG

[wolfnowl]

Hi Folks:

I just sent the following message to Samsung technical support. Was wondering if anyone else has had the same challenge?

Mike.

Hi There: About a month ago I upgraded my Samsung Galaxy S4 to the Galaxy S6 (Android 5.1.1). One of the primary reasons for this was to be able to shoot RAW (.DNG) images with my phone. Samsung has for some reason disabled the ability for the native camera app to shoot raw files (why they would disable THE most important feature for an experienced photographer is beyond me, but is also irrelevant for the moment). There are however third-party apps that will allow the phone to capture .DNG images. I have both Camera FV-5 and Shoot Advanced Mobile Camera on my phone.

There is a bug in the OS that records incorrect capture time for the .DNG files. Since the camera shoots RAW+JPG, the capture time of the two files should be within a second of each other. They are not. The capture time for the .JPG files is correct, but the capture time for the .DNG files is both inconsistent and several hours later. An image made today might be off by 4 hours and 32 minutes, and an image made tomorrow might be off by 6 hours and 18 minutes, for example. At first I thought the problem lay within the app itself, and so directed my concerns to the support staff of the Camera FV-5 app; today I downloaded and tried the second app and encountered the same challenge with it. Whether the bug lies within the base OS as provided by Google or in the Samsung adaptation is beyond my ability to know.

I have attached two screen captures showing the metadata for the same image (both DNG and JPG) obtained using the EXIFTool tab of XnViewMP. The capture times are clearly marked and you can see the problem. If you would like to see the complete EXIF information, I have compiled the .DNG, .JPG and the .XMP files into a .ZIP file and put it in a publicly accessible Dropbox folder:

https://www.dropbox.com/s/s7tbosckezxr0gk/DSC_0104.zip

I look forward to an updated version of the OS. While it is true that there are billions of people taking pictures of themselves or their cats for Facebook, there are a growing number of people using their cell phone cameras for serious work. This needs to be corrected.

Mike.

[wolfnowl]

BTW, in case anyone's wondering why bothering to shoot DNG on a phone, here's a 100% Compare view from Lr (all sliders zeroed) showing the DNG and the adjacent JPG. The DNG file is 30MB compared to the JPG file's 9MB and it's easy to see why. Using Snapseed on my phone, if I go to the Gallery app and click on the JPG then share to Snapseed, it opens the DNG file.

Mike.

[aduke]

It's interesting that the camera makes two different exposures, one for JPG and one for DNG.

I would assume that most cameras create the JPG from the raw data that then goes into the DNG.

Alan

[francois]

It would be interesting to check whether the JPEG file and the DNG do really have a different exposure or if this "correction" is made later, after the shot.

[wolfnowl]

Alan: I would have thought so too, but apparently not. Francois, I'm afraid I can't answer that question. I was surprised to see a shutter speed difference of 1/100th of a second of essentially the same image, taken a split-second apart. Still, it's the incorrect capture time for the DNG that has me puzzled. At first I thought it was Lr reading the metadata incorrectly somehow, then I thought it might be the Camera FV-5 app, but after downloading and trying a second app and running into the same problem I'm assuming it's in the OS. Whether it's in the Lollipop version provided by Google or the Samsung version of same I don't know. What puzzles me is that the time offset is inconsistent If I shoot a series of DNG+JPG images all of the time differences will be close but not exactly the same, but if I make more images later that day or the next day the offsets are completely different.  I dunno...

Android Marshmallow is supposed to be out in a couple of months. Maybe that will fix it. Lr can fix simple time zone offsets easily, but more specific corrections must be done file by file.

Mike.

[Atina]

... and it's easy to see why.

Why?

[Rory]

Why?

Compression.