Excellent post, Mike. I think the bottom line from lensrentals.com is
that there is a lot of variation between lenses and bodies but that most
of it doesn't matter very much. And, of course, the variation that's at
the heart of the discussion was accuracy of focus. Focus accuracy is
not an issue for a landscape taken at f/11. :-)
Chuck Norcutt
On 10/4/2011 2:01 PM, usher99@xxxxxxx wrote:
> Wondered for many moons how much QA differs in lens manufacturing. Mike
> Hatem noted significant performance differences in Zuiko 21/2's. Much
> grousing on several Canyon L lenses with many reports of bad apples.
> Whether the QA is bad or just the # sold and who they get sold to
> (pixel peepers) is an open question . The below analysis seems to raise
> as many questions as it answers.
> Where is the source of the variability?---cam is clearly one. On repeat
> with a top dog sample---less impressive results---regression to the
> mean? There is clearly even registration distance manufacturing
> tolerances as Zeiss often makes lenses that focus past infinity to
> allow for this. They say if it bothers the customer they will adjust it
> for your cam -no charge.
>
> It does confirm that 10X LV manual focusing is more precise than
> AF--for a target at least.
>
>
>
>
> http://www.lensrentals.com/blog/2011/10/notes-on-lens-and-camera-variation
>
>
> No none seems to put a lens on a scanning slit optical bench anymore
> but measure system performance. For fun looked into for a minute the
> fully automated Zeiss K8 system: Base price about 194K euro.
> There are a few options which are: Image height measuring option,
> 4,100,-; Azimuth measuring option, 4,100,-; Collimator option 150mm f=
> 1.2m, 7,800,-; Collimator option 150mm f= 2.25m; "on request". So in
> total US Dollars, figure about $280K. Hmmm, take a pass.
>
> Wonder what it would show for a similar test, however.
>
> Don't want any bad apples, Mike
>
--
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/
|