Strange, it certainly can do sub 5s on some bodies. But I don't have a 5d2 to test with.

Could this be a conflict with long exposures? Conceivably AF, too. The intervalometer will attempt to trigger capture every 5s wall time. If the combined time to AF seek, expose, and finish saving to card (etc) is >5s, you will skip a shot.

When the time comes, compare the price of a used 5d3 vs a shutter replacement on the 5d2, maybe you'll get a "free" upgrade :) Thanks for the kind words!

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dylan604 6 days ago | parent [-]

> Could this be a conflict with long exposures?

I've done lots of 1/2 second exposures with 3s interval, and it shoots some at much shorter interval than 3 and some 3+??? At one point, the docs said 5s was a barrier. Maybe it was the 5dmkii specifically. All of my cards are rated higher than the 5D can write (but makes DIT much faster) so I doubt it is write speed interfering. What makes me think it is not the camera is that using a cheap external timer works without skipping a beat.

	▲	names_r_hard 6 days ago \| parent [-]
		Yeah, the external timer behaviour is fairly strong evidence. Curious though. These cams all seem to have a milli- and micro-second hw clock, and can both schedule and sleep against either. But it's also true that every cam has some weird quirks. And I don't know the 5d2 internals well. From what I've seen, the image capture process is state machine based and tries to avoid sleeps and delays. Which makes sense for RTOS and professional photography. If you care enough to debug it, pop into the discord and I can make you some tests to run.