Longshadow Loc: Audubon, PA, United States

That's what I thought.
Then..... maybe the changed something and I didn't notice yet.
(Not like they haven't done that before...)

JimH123 Loc: Morgan Hill, CA

I just tried this on my Sony A6600. And there is a difference on if I delete images on the computer or in the camera.

For this experiment, started with a clean format and then shot 5 images. And then verified that I can see those 5 images. In fact, if I hit the forward button, it cycles thru the 5 images over and over when I press the forward (or reverse) button many times.

If I delete one image by using the camera, then I have 4 images left, and I can cycle through those 4 images in either direction.

Next, took the card out of the camera and deleted one image on the computer and placed the card back in the camera. Now when I cycle the images, there are only 3, but when I get to the spot where the deleted image on the computer was, I get the message "unable to display". Now I discovered that I can do a delete in camera on the spot I get that message and now it cycles through the 3 images with no more gaps.

Next, I put the card back into the computer and deleted all the remaining images. Back to the camera, and I get the message "unable to display" again, and as I cycle, I see this message endlessly as I move forward or backwards. If I now take a new image, and then display it, I see the new image. But as I hit the forward or backward buttons, I still get the "unable to display" message until I get to the new message, and then back to the message again.

Next, I formated the card in the camera and created 5 new images with the camera and displayed to see everything working.

Now I went back to the computer and copied another picture of the same type camera and same RAW format onto the card. Back to the camera with the card and I verify that I still have the 5 new images. But I do not see the additional image I copied to the card. Camera absolutely ignores it.

Now what does this mean:

The camera is keeping track of the pictures on that card. I can verify this by looking at the card with Windows Explorer where I see 3 sub-directories on the root of the card. The images are stored in DCIM. There is another called PRIVATE in which there are sub-directories with timestamps of the current time. And another sub-directory on the root named AVF_INFO which has 4 files, and they all have the current timestamp.

What this tells me is the camera is keeping track of the image files that are on the card. And when I add an image on the computer, this tracking is not updated. And when I delete the image on the computer, again the card is not updated as to what had been done and the camera is left with holes in the file structure where it expects to see a specific image, but that image is not found, and it displays the message.

Now, I am guilty of deleting images on the card, and I recall seeing that message, but the camera continues working and still displays the message when I forward or backward click through them and get to the end.

Now, I am not sure what the impact will be when done over a longer period of time? But this tells me there is a reason to format the card each time. Or to manually erase the images on the camera which also fixes the image structure on one image at a time.

Now this is with a Sony A6600. I assume all Sony's are similar. I also have Olympus and can try the same experiment. There may be cameras that this doesn't matter??? But for this Sony, it does matter.

JimH123 Loc: Morgan Hill, CA

Tried the same experiment with an Olympus EM5ii. The process is not very sophisticated like the Sony camera and it only keeps an ALBUM.BIN file which has the current timestamp.

And I can delete a file on the computer, and no holes develop back on the camera. And I can add another RAW file onto the card, and the camera does display it. So, this camera is not creating a library structure.

I am thinking the purpose of this ALBUM.BIN file is to be able to display multiple thumbnails of the image when you make them smaller. And the file I added did show up as a thumbnail which tells me it is updating this file as needed.

So, the answer with this Olympus camera seems to be that it doesn't seem to matter if I just erase the card on the computer.

Perhaps someone with other cameras can try this experiment also?

Longshadow Loc: Audubon, PA, United States

That proves that all camera software is not written the same. How about that! Amazing.
On my camera I don't get that message. My camera sees the card only having visible images. Or none if I deleted them all on the computer.

Silverman Loc: Michigan

When you say "Cut & Paste", is that after or before you have downloaded images on your SD CARD to your Computer? I am confused by some of the explanations I am reading here on UHH.

I would think you always download the SD CARD image to your computer before any other action is accomplished.

Am I NOT UNDERSTANDING something here?

After your download to your Computer then I would put the card back in the camera and clear the SD card of all those images.