warren_edney

<p>I have had that error code with a 7d and had a variety of fixes. Errors tend to revolve around communictaion issues between camera and lens. One version was resolved with a thorough clean, another was a problem with the focus drive in the lens itself whihc had to be replaced.<br>

It is often possible to clear the error by removing the battery and then replacing it after a few seconds.<br>

I have also had a version where the camera freezes with no error codes - canon tell me that this may be a fault with the miror box and costs $600. It hasnt happened in the last 800 photos so I haven't worried about fixing it yet.<br>

Hope this helps, good luck</p>

<p>I have a 100-400, the flexibility of the zoom on my 7d is really useful. I use it mostly for sports photography with subjects at varying distances. I must admit I really don't miss not having anything less than f5.6 but as the others have pointed out it does depend on what you want to photograph.</p>