tonybrown

<p>One more comment on the difference between autofocus on the Live View and on the regular view. On one occasion I did find it autofocus on the regular view with the 500mm F4 and 2X multiplier. I suspect the real difference may be related to the difficulty of actuating the shutter at 1000mm equivalent without shaking the camera, since the Live View has less camera shake. In anycase I think the firmware has been programmed to exclude the 10oomm equivalent from regular autofocus and automatically displays the message M Focus when it detects the lens. This way Canon have avoided customer complaints?</p>

<p>Avinash,<br> Thank you for your response. What you say about the design limits of autofocus on the EOS 70D makes sense. However according to the specification listed on the DPREVIEW website, the autofocus is designed to work with lenses down to F11: here is the quote:<br> According the Canon the EOS 70D's Dual Pixel CMOS AF system has the following key characteristics:</p> <ul> <li>Usable phase detection AF area covers 80% of the frame horizontally and vertically</li> <li>AF works at apertures down to F11</li> <li>AF works in light levels as low as 0 EV</li> <li>Can work with face detection to keep moving subjects in focus</li> </ul> <p>See: <a href="http://www.dpreview.com/reviews/canon-eos-70d/3">http://www.dpreview.com/reviews/canon-eos-70d/3</a><br> In the light of my experience I'm inclined to believe you are correct and DPREVIEW got it wrong. Also, I have found the autofocus works with the EF 500mm F4 L and the 1.4X multiplier, that is equivalent to F5.6.<br> Thanks again.<br> Tony</p>

<p>I'm wondering if anyone has any insight on the following limitations of the EOS 70D. The autofocus is superb, but when used with an EF 500mm and 2X multiplier the camera reverts to Manual Focus for normal still photography. However with this lens combination, autofocus is achieved in Live View and in Movie mode, and it is very good. Another limitation is when using wifi with an iPad for remote control. This works great in Live View, but is not available in Movie mode. And finally, continuous recording is limited to 30 minutes, and requires restarting to continue. I am not aware of any physical limitation to the length of recording.</p>