What triggered this change to "File save format"?

[ColinM]

I've just come back from a trip where, a few images in, I see that instead of just saving each file as a .NEF, it started saving a .JPG too. This is on a D300.

Sure enough the Image Quality menu saws RAW + JPG, but it's in a place I hardly ever visit (and I didn't knowingly go into the menus at all on this trip).

I'm wondering if you've ever come across this when a CF card is near to failing? I'd cleared old images off the card before going away and also seen strange behaviour I'd never come across when importing the images to HD using Lightroom. I found a duplicate of each image on the destination drive (see below).

Because I'd been in a hurry, I wondered if I'd interrupted LR before it had finished and that these extra files were something it did part way through the import process, before finally clearing them down? But does this indicate a problem brewing somewhere else?

[ColinM]

Mmmm
I'm still interested in your view on the Image Quality switch that happened.

But a quick Google on the LR issue reveals it's affected other people:
https://forums.adobe.com/thread/1331362

[Merco_61]

It is easy to inadvertently switch to RAW+jpg as you only have to accidentally press the QUAL button instead of the ISO or WB button. The setting is just one click on the thumb wheel away in that case.

When it comes to your LR problem I am clueless.

[Akira]

Glad that the "Quality" was switched to NEF + JPEG, not JPEG only!

This may not be likely, but didn't you accidentally pushed the Quality button instead of ISO button when you changed the ISO setting?  I realize that they are located next to each other on the left side of the top cover.

[Akira]

Ooops, Peter beat me to it!

[Merco_61]

If you turn the wheel the other way, Tiff is the first click, so getting to jpg needs lots of bad luck.

[ColinM]

Thanks Peter & Akira.

This is obviously a pitfall that others have slipped into. Still a little strange as I didn't change ISO or WB either during the trip. However (my) human error has to be the most likely cause!

[the solitaire]

I had that happen on a D300 as well. I'm quite glad my current camera moved these settings to another area where accidental operation is less likely. Still, I recently revisited a few files I made with the d300 about 2 years ago and these files are really good at ISO speeds up to about 800. I still know now why I liked my D300 that much

[Akira]

The "accidental changed of the image quality setting while trying to change ISO value" might be the genetic problem of Nikon cameras, as ISO and QUAL buttons tend to be placed side by side on many of Nikon bodies, either on the top or on the back.

To avoid the problem, I assign the video recording button on my D750 to ISO select function.

[David H. Hartman]

I only change the ISO on my D800 in the "ISO sensitivity settings" from the Shootings menu which I place in My Menu. This has kept me from accidentally changing the quality settings on my D800 and D300s. I don't recall ever having that problem. I'd really hate to end up with only JPG(s) or even TIF(s).

Dave

[elsa hoffmann]

Happened to me before too - nice bunch of Jpegs.... 
Accidentally managed to change it