You can use any third party lens with your Canon camera, it just needs to have the Canon Mount This information will be visible somewhere on the packaging, you can also usually filter for this when shopping online.

Can a Canon T3 DSLR be used with my TAMRON AF TELE-MACRO 90-300mm lens?
I am creating a application, rails3 with ruby 1.9.2. I have a left menu with some blog posts. This is displaying in every page in my application, so I am using cache concept in views. That blog posts update in database every day using rake task. 

In rake task database update everyday first hour, after update database I want to clear that cache part from rake task. Any one help how to write rake task for expiring cache.
