I saw this post and thought I would give it a try! It made for an interesting drive to work...
Camera: 550d; Canon Firmware: 1.0.9; 16GB SanDisk Extreme SD HCI 30MB/s; Canon 50mm f1.8 lens; Ambient Temp 32c
In this test I wanted to see how dialing down the FPS in movie mode, using FPS Override, worked. Shot was done in a covered porch, each shot starting immediately after the previous ended. All camera controls set to Manual. Shoots were done to create approx. 10 seconds of finished video for each test.
Tests #1-#4: Aperture, Shutter speed and ISO all same (f18; 1250; 100)
FPS Override as follows:
Test #1: 3 FPS, 100 second shoot
Test #2: 2 FPS, 150 second shoot
Test #3: 1 FPS, 300 second shoot
Test #4: 0.5 FPS, 600 second shoot
During the test shoots, it is obvious that exposure becomes more and more over exposed as fps rate drops.
Test #5 changed exposure parameters from #4, but almost to a reverse view as it seemed that where it should have gotten darker, the shot got even lighter.
Test #5 : Aperture f22, Shutter 4000, ISO 100
Camera overheated at about 4 minutes shooting time (4 seconds movie time) and required shut down. This may be only due to high outside temp, even though shooting in shade.
Main concern is that when using slow fps, trying to focus, set exposures are very difficult due to view delay in Live View. Not certain why over-exposed.
So I mounted the 60D to my hood and the result was my first attempt at using FPS override:
I will definitely practice some more with this feature!