This photo is very strange

OK, yeah, slightly dark, I'm not really done with manipulating it. I discovered something while editing it that has me truly boggled: the file size is wrong. And that requires some explanation.

I shot this with my Lumix LX-7. I almost always shoot in programmed exposure mode and record both RAW and JPEG images. The camera does a pretty darn good job of grabbing the exposure, and I knew I'd have enough pixels in the RAW file to adjust to get what I was seeing. The RAW side captures exactly what the camera's chip sees with pretty much zero alteration. It then applies a JPEG process which includes some curves adjustment, sharpening, and most importantly (and destructively!): compression. Then it writes a JPEG file. And JPEGs are fine for most people, but not for me. I want the raw pixels to fiddle with because if you know what you're doing, you can extract more detail/information from a RAW than the automated JPEG processing, assuming you're willing to spend the time.

So like any other RAW file, I open it up in Bridge, do some fiddling, tell it to open in Photoshop, and I notice the image is kinda small. I don't think much of it, I figure for whatever reason that PS decided to open at a smaller zoom level. No big deal. I do some fiddling, the last step before saving it as a Photoshop file and again as a JPEG is to sharpen it. This requires zooming it to 100% so that you can best see what effect the sharpening tool has on the overall image. And this is when I discovered that the image was already at 100% magnification.

I have a 2015 iMac 27" with a 5K display, so hi-res images look pretty awesome on it. A RAW image produced by this camera normally has the dimensions of 3968 x 2232 pixels when shot in 16:9 aspect ratio, which is my normal shooting mode. If you multiply that out, you get the number 8,856,576, or you can round it to 9 megapixels. At 16:9 resolution, that's an image that's 22"x12.4" when printed at 180 ppi output.

The JPEG file is also going to have the same pixel dimensions as the RAW. The compression is going to reduce the graphic quality, but it's not visible if you don't look at it under high magnification or on a big screen. You end up with a smaller file size. For example, this image was taken on September 3rd at 7:23pm, allowing for a little clock drift. The previous image, with a slightly different zoom setting, was taken eight seconds earlier. The previous image RAW file was 10.7 megabytes, the JPEG was 3.78 meg. Same dimension, less information. And this is typical: the JPEG will always be smaller than the RAW. Well, usually.

So now we get in to why the above image is strange.

This image's JPEG counterpart is the proper 3968x2232 pixels.

The RAW is 1984x1116, or 2.2 megapixels. Exactly a quarter the size it should be (half of both the horizontal and vertical dimensions). Which explains why it opened small in Photoshop. The JPEG file size was 3.25 meg, the RAW was 3.12 meg.

Of the images on this card and recently shot by this camera, this happened twice, and both times were while shooting this sunset. I only took four images. I didn't change any modes, I didn't change the aspect ratio of the camera (one of the things that I love the most about it, second only to the Zeiss glass!).

Frankly, I'm baffled. The battery is regularly charged. The memory card wasn't full. The memory card is speed rated fast enough, and I certainly wasn't shooting rapidly enough to stuff the buffer. I don't think it can be a file corruption problem because it happened twice in less than two minutes and the file is readable. There may be a OS update available for the camera available, I'll look in to that tomorrow. I'll also reformat the card, both on my Mac and in the camera, then when I'm feeling better do a little photo safari. It looks like the days of 80 degree highs are behind us, but maybe going down to White Sands will be OK. And I'll look in to my directory for more recent shoots, but I actually haven't been shooting too much recently, so that won't help.