mawyatt wrote:Peter,
Thanks, you have good intuition
Yes, the subjects in liquid as Lou mentioned are probably better isolated from the camera/lens.
Here's some MIT lecture notes on 2nd Order Mechanical Systems. The camera induced vibration from mirror flop and/or shutter curtains can be reasonably approximated as an impulse function excited 2nd order system.
As such note equation 1.67 and figures 1.25 & 1.26. These illustrate the vibration induced behavior well and aren't too complex. Note that the system stiffness causes the natural frequency to increase, and nicely illustrated in figure 1.25.
Here's a quote from the notes.
"Thus, the mass with initial velocity 1 “runs into” a stiffer system, and is returned to rest more rapidly"
https://ocw.mit.edu/courses/mechanical- ... lment2.pdf
Best,
Thanks for all the notes Mike.
Now that all said I carried out a quick real world test.
I shot 5 images at 1.3x and 1.5 second shutter speed, all focus bracketed, all with the subject and stand on a single base, release delay and Q mode. I did not bother to dig out a remote release.
1. Ambient only No EFCS / electronic shutter.
2. Full electronic shutter
3. EFCS only
4. Flash and EFCS
5. Flash only
The test was a waste of time, a total 100% failure.
They were all sharp at 100% view in PS
I don't think I would have seen these results on the D800/D800E/D810 from my experience.
Also went to a faster shutter speed of 1/4 sec and these were all too sharp to show anything useful.
I prefer to use flash over ambient for more consistent sharpness in my experience but this test was a surprise for me, I expected to see at least some sharpness loss with the mechanical shutter. I don't normally put too much faith in a marketing companies' new product brochure but this might have something to do with the sharp looking images in my test. From the Nikon D850 brochure, my highlighting: