Accuracy of Camera Clocks

[Mick West]

Modern phone camera generally set their time from GPS or the cellular network, and so the timestamps on those images are usually accurate to within a second.

Other cameras (not on phones) are increasing using this. However many cameras still don't have GPS, and there are lots of older cameras out there.

This issue cam up in the Twentynine Palms UFO case, where the times on photos of the flares shot with a Sony Alpha 9 DSLR were about 15 minutes slow. I was able to find the time correction using planes in the images and ADS-B data, but it's unfortunate that it gave people a nit to pick for a while.

How common is clock drift in cameras? I asked about it on Twitter.


Source: https://twitter.com/MickWest/status/1678626953073655810


And got some comments for people sharing their own experience.

• My Sony mirrorless cameras have this issue. I believe my A7R3 drifts a bit more than my A1. I'll have to test it out to confirm. I typically take a photo of my computer clock with each photo session/camera to sync them up after.
• My Canon 70D drifts but I usually shoot with a GPS on the flash shoe for geotagging photos and that corrects it
• Yes I've had that same problem with the 7D and the 5Diii.
• Mine goes off too 7D mark 2, but not sure if that effects the meta data of transfered photos as I thought that was supposed to stay accurate incase a serious investigation was needed etc.
• On my EOS R I have to remember to connect the phone app to the camera via bluetooth and it transfers the correct time (IIRC I still have to do it manually). I also connect the app for geotagging though so it's something I usually don't forget to do.
• My Canon R6 and R5 have kept time well for 2 years
• My clock on my A7rii also sux. Firmware update did nothing.
• Old Nikon D80 no issue at all, clock set over a year ago and difference is less than 1 min.
• Old Canon 20D, 36 mins slow.

So it seems like a relatively common occurance, at least on Sony and Canon DSLRs.

I have a mirrorless Sony A6400, and the clock was off on that too.

 

[Paladinhgwt]

Many cameras seem to have a time issue of losing or gaining time after being set if not synced with an ntp.

I've got several different ip surveillance (dahua / hikivision) cameras that needed to sync with an ntp server or they would lose a minute per day.

 

[tinkertailor]

Both of my cameras are older (Canon Rebel T2i and a Pentax Q) and I don't leave batteries in them between taking them out. Every time I put batteries back in them and get ready to shoot, I have to reset the time manually. If I'm in a rush I don't care too much about accuracy with the time, so I often make mistakes. It's very common for me to forget about military time, for example, and end up setting my camera 12 hours off. Not too much of a problem for a hobbyist, but a problem if I ever see a UFO!

 

[deirdre]

Not too much of a problem for a hobbyist, but a problem if I ever see a UFO!

not if you dont wait 5 years before writing the needed data down somewhere

 

[beakflip]

A quartz hand watch has great accuracy, as does any wall or table clock using quartz or other kinds of oscillators, whether analog or digital. I expect an oscillator used for time keeping in a camera to be just as accurate, but a poor design choice may use the "CPU" 's internal clock for timekeeping, rather than an "external" oscillator like the clocks do, which can result in dramatic drift of the timekeeping. This is just an electronics noob throwing stuff at the wall, hoping something sticks... For expert opinion, I would suggest r/askelectronics on Reddit, but last I checked(must have been months ago), they locked the sub after the 3rd party pricing fiasco, not sure if they restarted activity on Reddit.

Some more thinking later, even with an external oscillator, the "CPU" can still ignore it and end up lagging; there should be a dedicated realtime clock IC, which should remain reasonably accurate as long as the batteries aren't on their last breath. In PC's, there's a battery for timekeeping IC and BIOS settings. But if accurate timekeeping isn't a design requirement, then there are many ways that it can fail.