I am a photographer and recently switched to a full iPad Pro 2020 setup, so I can edit my pictures on the go. Since SD cards tend to fail, I would also like to use my iPad Pro to backup the cards to an external SSD drive. A simple copy/paste from one drive (SD) to another (SSD) via the iPad.
However, I noticed that after importing RAW and JPEG files from the SD card to the iPad internal memory, some of the files seemed corrupted: RAW files couldn't be read by Lightroom, and JPEG files were half black or grey.
A couple of days ago, the same thing happened in the other way round. I processed RAW files in Lightroom for iPad, and when copying the processed JPEG to the external SSD, and viewing them on my PC, about 10% of them were completely trashed:
So I made a test, that I hope can be reproduced by someone. I'd love to have some feedback or even a solution to this issue. It's really disappointing that the iPad can't handle a copy/paste without corrupting the files...
First, I took a sample picture and made 500 copies on the external SSD. To be sure they're all exact copies, I used PowerShell on Windows to check the file hash. As expected, they're all the same:
Then, I transferred the 500 copies to the iPad's internal storage, using the "Copy" and "Paste" function in the app Files.
I renamed the folder in which the pictures are, copied it and pasted it back to the external SSD.
Finally, with the SSD plugged to my PC, I checked the file hash of the 500 files copied from the iPad, and indeed, some of them are corrupted, as you can see below (take Test (613).png for instance):
I am using an iPad Pro 2020 12.9", with the latest iPadOS 14, and the native app Files to do the transfer. My external SSD is formatted in exFat. My PC is the latest Windows 10.
I also tried with other kinds of devices: SD cards, cameras, USB thumb sticks, external SSD, SD card readers, USB-C hubs, even changed the cables, that all work perfectly with my PC, and never failed me. It's really coming from the iPad.
After some research, I saw a lot of complaints (slow transfer speed, mainly) that seem to be linked to the format of the external drive, and the fact that iPadOS seems to prefer APFS file format. But APFS isn't an option for people like me, who are using a desktop PC. Plus, the format of my SD cards are set by my camera, in that case, exFAT.
Finally, though I can understand speed may vary depending on the format of the drive -- corrupting the files is something that shouldn't happen, no matter what format I'm using. Especially for something as basic as importing photographs from an SD card...
At this point I don't know what to do, every time I try to copy/paste something, some files get corrupted. I would be grateful if somebody could give me some pointers, perhaps a solution, or simply confirm the issue by reproducing my test somehow.