See this thread from a couple years ago.
https://www.uglyhedgehog.com/t-337412-1.html

Check the condition of the battery in the Menu. You might have one that’s on its last legs. The AF doesn’t just stop working when the power gets low. The camera just shuts off. It sounds like the camera may not be accurately displaying battery level, resulting in the battery being much closer to drained than you realize. The other suggestion would be to check for firmware updates, but I’d look into the possibility of a battery problem first. A Firmware update would likely only be needed if you were shooting a lens released after your D7100’s firmware date.

The manual goes into how to update it, but I’m always a little wary and if the battery could be in question, you Absolutely Cannot lose power while updating firmware. It will brick the camera.

The freeze up only happened once to me. Good luck!

Same thing happened to me a few months ago. I was shooting in low light with ISO High 2.0 and my D7100 froze up. I powered down, removed the battery, and fired it back up. That worked for me, but the next stop would be to hold down the two green dot buttons and reset the camera to factory settings.

Yes, the batteries are compatible. The 15a is supposed to perform better in cold weather as well as last slightly longer. I was looking to pick up another battery for my D7100 and discovered the 15a is now the only thing on offer as far as official Nikon. Also, the old 15 had a manufacturing lot that was recalled. My 15 battery was fine, but they fixed the manufacturing problem and issued the updated design as the 15a to avoid confusion. You can buy the 15a and it will work in your D7100 or a D850.

Thanks Rich! I’ll do my best.

Thank you!

Thank you!

The D7100 displays the JPEG version of the image on the LCD. Similarly, the thumbnails are JPEG as well. This type of image corruption is usually a problem with storing the full size image on the card. The card may be too slow. This causes the beginning of file marker and encoding information to be written correctly, but the end of file marker and compression encoding gets corrupted. Basically, at whatever point before the end of file marker the card can’t keep up and records whatever it can result in a half written image.

If you’re shooting “RAW + JPEG Fine” in Ch (continuous high) mode, it tends to happen when shooting a ton of frames in rapid succession. If you edit RAW, then reduce the “Shooting Menu->Image Quality” setting down to “RAW + Basic”. Then adjust the “Shooting Menu->JPEG Compression” setting down to “Size Priority”. That will shrink the JPEG size of what has to be written to the card. If you’re using a two card setup, have card 1 write RAW and card 2 write JPEG.

If all else fails, perform a “two button” reset by holding down the two buttons with green dots by them “Zoom Out/ISO” on the back and the +/- EV button on top. That will reset everything back to the factory defaults.

Side commentary, I work in IT and if you had a bad card, it would likely not write a good file header and then screw up the end of file marker. It would just all be garbage. I used to see a lot of these images 20 years ago, when tech wasn’t as good. The issue appears to be a buffering problem. The card appears to be too slow.

I found this thread because I enjoy your other work and we share the same D7100 body. ;-) Happy hunting and I hope this fixes the issue for you.

You may have already googled jpeg image corruption. It might provide some additional insight.

Thank you Pat!

Thank you!

Grew up in an Architects house and he had a photography hobby. Learned composition early on, and finally learning how to use my Nikon D7100. I have been reading the topics daily, and finally decided to take the plunge. Pic is part of my first attempts to take a long exposure.

30” exposure, mirror up, remote trigger