Did you or anyone near you have a cell phone with them? Just because you're in a "dead zone" doesn't mean that someone doesn't have a phone with them anyhow
When you're far from a cell site, the phones transmit at full power when "searching for service", which they do automatically and intermittently.
You'll notice that your cell phone's battery dies far more rapidly when you're in an area with no service or very weak service than when you're in an area with good coverage. So if you know there's no service, it makes sense to just switch the phone off.
Anyhow, the phones adjust their transmit power in an intelligent way to save battery power. They use the least power when they have the best RF path between them and a cell site.
So when you are in a remote area with bad or zero cell service, or in an area that's shielded so that you have a bad signal (no "bars"), that's when the phone really cranks up the transmitter power to compensate for the poor signal path.
I've got no idea if that's what's actually causing these diagonal lines or not. It's just one thought.
Some lenses were known for their ability to cause that type of problems in photos when shooting in burst mode with AI-Servo focusing because the AF motor would be running at the same time as the sensor was being "read out".
I'm not sure if that problem has been fixed by adding some power supply filtering or regulation in newer bodies or if it's still an issue.
What was the state of charge of the camera battery when this happened? Were you using burst mode? AI-Servo focusing? What lens? So many variables
There are a lot of things that come to mind, but it'd be neat to know what the real answer is so that we can all take steps to avoid it.
It's an odd and annoying artifact in the photos to be sure!
One other observation:
In many of these photos, it seems as though this artifact is only visible in the out of focus background areas and not on the main subject. Now this might be simply because the sharply focused areas have detail that hides the subtle lines while the smooth OOF areas allow that pattern to show. Or it might be that the main subjects are brighter and it only shows well in darker areas.
But if it really IS only in the OOF areas, and that's not just a perceptual thing, then that means that it just about has to be an optical issue and not an electronic or interference-related problem.
Does anyone have any shots with this problem where it shows up in the in-focus areas?
--
Jim H.
