C11 review - A Blog to Read

Documentation and CW-related information
User avatar
28800bph
"Asylum Knight of the Diver"
Posts: 907
Joined: Sun Oct 05, 2008 7:48 am
CW-watches: 1
Location: USA

Re: C11 review - A Blog to Read

Post by 28800bph » Sat Oct 22, 2011 2:58 am

Nice review and photos. That's the kind of review that will make people go buy a watch!

But one point of contention: It can't be single layer MgF2 for the AR coating. That is very low cost and doesn't look very impressive. I think the C11 has multilayer AR or people would not think it was anything special. And there are multilayer ARs that are harder and more durable than MgF2, like Econorm ARdur. According to CW (via Kip), the "museum grade" AR coating on the C11 added more than $65 to the price of the watch.

phubbard
Newbie
Newbie
Posts: 13
Joined: Mon Sep 18, 2006 7:47 pm
CW-watches: 1
Location: San Diego, CA
Contact:

Re: C11 review - A Blog to Read

Post by phubbard » Sat Oct 22, 2011 3:40 am

28800bph wrote:Nice review and photos. That's the kind of review that will make people go buy a watch!

But one point of contention: It can't be single layer MgF2 for the AR coating. That is very low cost and doesn't look very impressive. I think the C11 has multilayer AR or people would not think it was anything special. And there are multilayer ARs that are harder and more durable than MgF2, like Econorm ARdur. According to CW (via Kip), the "museum grade" AR coating on the C11 added more than $65 to the price of the watch.
You could be right, and I have no way of knowing. I can do reflectivity testing, but I don't have wavelength selectivity so I can't quantify it. I've got multilayer watches (my IWC referenced in the review) and the C11 is bluer and slightly less effective; thus my assumption.

I wish this were better disclosed. I found your Econorm post earlier, well done there sir. I've been looking high and low for A/R suppliers and sources.

Regardless, I'm delighted CW went this route, it's a big improvement on the watch. Any suggestions as to how to photograph/measure/document the effects for reviews?

User avatar
28800bph
"Asylum Knight of the Diver"
Posts: 907
Joined: Sun Oct 05, 2008 7:48 am
CW-watches: 1
Location: USA

Re: C11 review - A Blog to Read

Post by 28800bph » Sat Oct 22, 2011 1:30 pm

Hi Paul,

I had the same question and asked a friend who works at NIST in optical metrology. He looked at how Econorm quantifies their coatings as they show on a datasheet here:
http://econorm.ch/Portals/0/docs/MCSC.pdf

He said they are probably using this measurement system from Olympus, or something very similar:
http://www.olympus-ims.com/en/metrology ... /uspm-ru3/

It reports reflectivity vs. wavelength from 380 to 780 nm. The angle of reflectivity can also be varied. And it reports colorimetry determined from the prismatic reflectivity. A bluish tint of an AR coating would be quantified, like the one shown on the Econorm datasheet link above.

Here are screenshots of the Olympus software:

Image

Image

Of course, this rig would be too expensive for watch reviews. He suggested what you had in mind: photographing watches side by side in the same lighting for relative (qualitative) comparisons.

JP

Post Reply