VR/VC/OS - How shutter speed and other factors “may” affect IQ.

Started May 12, 2013 | Discussions thread
jsr4522
Regular MemberPosts: 104
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Re: Nyquist - I had to google that one.
In reply to dwa1, May 15, 2013

I don't know enough about the guts of any manufacturer's VR system to make an informed comment, but if they rely on some form of algorithmic signal processing  -  this will be an inherent limitation that will make the VR ineffective or compromised above nyquist. Empirical evidence and a review of these postings would indicate that VR above 1/500 reaches a point of diminishing returns and/or smearing or the introduction of some VR related artifact.  There is also the issue of VR in Normal vs Tripod mode - which implies there is some algorithmic variation which introduces another variable.  Also given that each manufacturer uses a different system(s) (or they would be infringing on each others patents), there is going to be variation across the board.

My personal experience with Nikon VRII on 300 f/2.8, 200-400 f/4, 500 f/4, 600 f/4 and the new 80-400 AFS is that VR helps below 1/500 - no question.  The 600, which I shoot on a tripod, exhibits the greatest variation in image quality above 1/1000ss but I am shooting rapidly moving birds at this setting.  So it is tough to say whether the source of the problem is me / operator error, (most likely) atmospheric issues (another confounding variable) or some subtlety related to VR.  As a rule of thumb I usually keep VR on "normal mode" when shooting handheld.  If I am on a tripod I will us tripod for everything except BIF.  It is worth further experimentation to see if off vs on actually makes a difference  - which means I need a consistent subject.  Looks like I will be shooting pigeons in the park at some point.

dwa1 wrote:

jsr4522 wrote:

My memory of physics is rusty to say the least, but in reference to your example two below, VR may be less effective at 1/500 and faster shutter speeds because at that point you are trying to process a signal above nyquist.

dwa1 wrote:

Example 2…

With lens "XYZ" on my "Dnnn" body, when shooting a bird that is feeding on the ground (but not staying in one spot very long) in good light with shutter speeds of 1/500 sec and below, at a focal length of 300mm, with AF-S mode, CL (continuous low speed release mode), I find that I get more AF hits and a higher keeper rate with VR On.

Thanks for the post jsr4522. Nyquist? I had to google that one.

Does this wiki look to be a good place to understand this?

http://en.wikipedia.org/wiki/Nyquist_frequency

Do you think that this is applicable to all 3 versions of Nikon's VR as well as the 3rd party lens image stabilzation systems?

Wayne

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