Thanks Digital! You're always getting me to double check my work and learn more lol
You are right the Ariy disk does begin to overlap pixels around f/6.3 but it isn't really noticeable until f/8 so most people consider that diffraction limited.
Unfortunately I think with "line skipping" to down-res the image to 2.1MPs we do not benefit from an increased diffraction limit like we did with Photo mode's pixel binding method which physically makes each pixel sensor larger rather then in the line-skipping method we still have the same sized (4.3micron in this case) pixel sensors :/
You're welcome. Most people refer to f/8 since it's the closest full stop measurement near the diffraction limit
. I don't currently have the facilities to test where we start loosing detail between the 18 MP sensor and the resulting 1080p video. However, this is what I've looked at so far...
Ok, so I've done some testing myself. The only consistent scene I've been able to record (partially overcast day) is a patch of grass. Detail here is similar to leaves, but with a lot less movement. Using the all I-frame firmware, I acheived a max average bitrate of ~281 Mbps using CBR @ 20x and the flush rate at 4 frames. I had ML stop recording at 60 seconds and the buffer started out at 28% and then leveled off at 22-23%.
All recording was done with a VAF-7D installed as well and sharpness set to 1. I have screens showing a significant increase in perceptable detail, but I don't have a quick enough of a connection to upload them at this time as they are ~5 MB png files. The artifacting that I previously saw in my test scene with leaves showed scaling artifacts when in-camera sharpening was set to 0. With the VAF-7D, I saw none of these artifacts, even on the grass blades.
I noticed it was a bit hard to get the bitrate above ~230 Mbps for the scene. I had only 1 issue with my CF card not writing out all of the frames and throwing an Error 70 message, but I only had ~70 MB left on the card so I'm assuming it was due to fragmented freespace. When I did this scene for testing the speed of the card w/ the bitrates, I adjusted the 12 points (not worth the words to explain why) on a logarithmic scale (e^(x*ln(20)/11)) from 1 to 20. The file sizes were as follows:
1x 333 MB
1.3x 408 MB
1.7x 531 MB
2.3x 744 MB
3x 975 MB
3.9x 1.2 GB
5.1x 1.62 GB
6.7x 1.73 GB
8.8x 1.63 GB
11.6x 1.66 GB
15.2x 1.72 GB
20x 1.62 GB (ended ~2 seconds early)
These were I-Frame btw... Based on these numbers and the ones others have produced with similar tests, it appears that the sweet spot of recording is 4x-7x. I'll see what I can do for some controlled tests in this area because it appears that the encoder is currently hitting a wall. No reason to give users options to go beyond 10x atm. When/if we establish a best-case upper limit, we could just set it there so we don't have people trying to figure out if they should push their hardware harder?