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enter image description hereI’m getting “ghost deer” on my trail cam. They only show up on the night pictures (black and white) and hit the paint palette which turns them into color.

Is it possible that a previous image of deer is showing up in my trail cam images, or getting "double exposures", if it’s a used SD card?

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    \$\begingroup\$ while much is unclear, I can guarantee that the SD card is not combining two picture files in a way that they still open up and have elements of both pictures. \$\endgroup\$
    – dandavis
    Sep 29, 2023 at 20:35
  • \$\begingroup\$ I think I added a picture of the ghost deer. The paint palette icon is also in the picture. Hope this helps. If it can’t be double exposure can anyone explain? This is just one example. We have more and the deer are in different places and different positions. Some are even super bright and super clear but most kinda look like this one. \$\endgroup\$
    – Lee Hicks
    Sep 29, 2023 at 23:30
  • \$\begingroup\$ I can see it. Interesting. Can you please add the black and white version of the same image? I have a theory that it uses an infrared LED as a flash that animals can't see, but it's also taking the image as a long exposure to get the color of the scene at night. If the deer misses the flash but walks into the frame while that long exposure happens, or vice-versa, you could see that effect. I made ghost pictures in photo class that way. I need the black and white version to be sure though. Lemme ask you this: Are the ghost animals always mid-stride, or do they ever stand straight up? \$\endgroup\$
    – dandavis
    Sep 30, 2023 at 1:44
  • \$\begingroup\$ I think I was able to load the black and white image but for some reason it wouldn’t let me crop it. \$\endgroup\$
    – Lee Hicks
    Sep 30, 2023 at 23:03
  • \$\begingroup\$ Does your game camera have a flash that is visible to your eyes when it fires? Does it have any infrared illuminators? Either longer durations, such as the visible light LED lights on phone cameras that are called "flashes" but are really continuous lights that light up longer than the shutter is open? Or one that emits a very short burst of IR light in the middle of a longer overall exposure like an actual flash? If you're not sure, you could tell us the exact model name/number of your game camera. \$\endgroup\$
    – Michael C
    Oct 1, 2023 at 7:10

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No. The SD card is just a medium for data storage. It behave completely different than a light sensitive surface, where an effect like this would be possible.

The allocation of images also is not using the exact same locations on the card. For this the SD card controller uses wear leveling and keeps track which storage cells have been used how often. This ensures even aging of the storage cells. So an image would usually not occupy the exactly same space in storage as before, making this effect near impossible.

Additionally if there was data from an old image present in your new image, there is a good chance that parity/error checking on the controller would detect that. Otherwise this would result in a corrupted image. In compressed images like JPG this would lead to large detectable areas of visual glitches.

What is possible, is that the sensor itself was not thoroughly resetted and carried over some residual values form a former image, although I would not know why.

Or, and that would be my guess - the illumination was way shorter than the shutter speed and you had the deer in there, but it was away before the illumination caught it. You can have these effects in a dark environment while using multiple flashes in common photography - either by accident or on purpose. This would result in multiple exposure.

A possible scenario would be that the camera uses something to detect the animals. This is enough to cause a very faint image, the animals was spooked, then the main illumination (IR light?) fired and you got the main image.

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  • \$\begingroup\$ That made sense until I came across a picture that has a ghost tree. I’ll try to add that picture \$\endgroup\$
    – Lee Hicks
    Oct 5, 2023 at 18:36
  • \$\begingroup\$ If you have unmovable objects as ghost image, then it is some residual image on the sensor or really, really crappy data flow in the imaging algorithm. \$\endgroup\$ Oct 9, 2023 at 8:43
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What seems to be happening is that the camera's shutter is open for much longer than the duration of the flash. If there is something in the frame when the shutter is open before or after the flash, but is not in the frame when the flash goes off, it will appear as a ghost. This is because almost all of the light collected at night will be from the flash, not from the very dim ambient light that exists before and after the flash.

Even during daylight hours one can take very long exposures that can make a busy street look empty of vehicles or pedestrians as they move through the scene. This is because they move so quickly that they're only in any one spot for a very short percentage of the total exposure time. The light from the same direction that shines on the film or sensor for most of the exposure time is so much more powerful than the light from the fleeting object in motion moving through the scene that the light from the stationary background totally overpowers the light reflected by the transitory objects for much shorter periods of time.

In the case of night shots with flashes, though, the light from the flash that happens in a very short period of time is the overwhelming majority of the total light collected by the film or sensor, with the dimmer ambient light that is collected for a much longer time period is only a very small percentage of the total light collected.

Digital storage media do not interpose the data from two different images in the same file in a way that would be readable at all. Instead you would have a corrupted file that either could not be displayed at all or would display a bunch of nonsense that isn't even remotely recognizable as part of any scene either image contained.

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  • \$\begingroup\$ I'm thinking there might be more than one flash per exposure as well, which would let them save power or uses smaller IR LEDs... \$\endgroup\$
    – dandavis
    Oct 1, 2023 at 23:15
  • \$\begingroup\$ @dandavis Could be. \$\endgroup\$
    – Michael C
    Oct 5, 2023 at 4:03

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