Today we consider and discuss surprising fact about Sync for DJI. Strange as it may seem, iOS DJI Go 4 provides lower quality of 'Share photos' than the actual file stored on SD card. 'Sync for DJI' allows you to share files without any compression and get the original quality of your pictures.
So let's look at some examples. Here is our demoscene — two ancient scrolls with a picture of a tiger, beautiful Asian beast; and dragon - mystical, powerful creature. We made pictures with DJI Mavic Air with best settings and 4K dimension, JPEG output. A lot of details and colors should help us find quality problems.
We shared this image to our iPhone X with 'Sync for DJI' and DJI Go 4 and downloaded original jpeg file from SD card. Below you can find the results. All files have 4056x3040 dimensions, but file shared with DJI Go 4 was compressed to 3022 KB. Whereas file, shared with 'Sync for DJI,' has its size 4947 KB (*1). Original jpeg on SD card — 5065 KB.
Full resolution comparison you can find here. As I see, the difference is subtle and mainly affects details on the edges of different colors. Also, I can pay attention to the slightly poor gradation of the same color(look to tiger's eye).
Again, this happens only if you share the file from DJI Go 4 directly. SD card has the full quality 5.1mb image on board. However, what if you do not have Mac or PC? Why do we buy better and better drones with improved matrices and lenses(almost not visible to the human eye) and we lose quality on the road to social posts and sharing? Right! This case is exactly why we created Sync for DJI.
P.S. This is true for iOS and at the moment of writing the article(May, 29). With further updates of 'DJI Go 4', Share logic may be changed without notice.
P.P.S. For comments and feedback you can find same post on Facebook.
(*1) The photo was shared with watermark in the corner. That's why the size of it is slightly different from the file on SD card. If you have PRO mode - Share delivers exactly same file without compression.