Quote:
Originally Posted by musicguy 
There are ways to check to see if the jacket is canvassed or not. First, try to gently pull apart the fabric above the breast pocket. If it feels like there is an independent layer in between, it's at least half-canvassed. To determine full canvassing, try the pinch test below the bottom buttonhole. If there's a third layer there, it's full canvas. But, it's not cut and dry. Source and more info: http://www.styleforum.net/showthread.php?t=65638
But I think it is not a 100% sure method to determine real canvassing. Feel an independant layer in between is not a proof : just a sign that it can be canvassed. You must know that the "fabric" used for canvas can be more expensive than the wool fabric used for the suit itself. And the tailoring is generally quite harder and time consuming than cut & dry (even if it is said that some machines can do it). So in a $300 suit... Would be easier for me to explain it in french but i must admit that do it in english is an impossible mission for me 
I let english fluent experts trying to explain it. IMO the definitive test would be organizing a collective purshase for one suit and give the jacket to a good tailor to dismantle it. 
Anyway, to give you my feedback, what I can say for my MT suit : above the breast pocket : I can feel a third layer. below the bottom buttonhole : I can feel a third layer too. Is it full or half canvassed ? I don't know. 
