Sun and Sunspots 24th March 2014

[ejwwest]

Taken with my 100-400mm zoom lens and 2x extender and Thousand Oaks Filter.  Is it me or is the Canon 70D able to achieve autofocus at f/11 with the 2x extender on via Liveview? The camera definitely did focus automatically, albeit very slowly.

Sun with Sunspots by ejwwest, on Flickr

[Steve Ward]

To be honest I don't think it did a great job with the focus , you'd be better monitoring the Liveview while tethered to EOSUtilities and using the focus control built therein ... 

[ejwwest]

To be honest I don't think it did a great job with the focus , you'd be better monitoring the Liveview while tethered to EOSUtilities and using the focus control built therein ... 

It's comparable with best attempts at manual focus through Liveview given it's very challenging in bright sunlight to adjust the focusing ring and keep the image steady enough to focus. I'm not sure the EOS utilities will work as I think the reason the Liveview auto focus works on the 70D is because of the builtin new technology. However, will give it a try next time I get the chance. 

[Steve Ward]

It should work in the 70D , it works on my 1000D's ... 

There's a focus control panel on the Liveview screen in Utilities , just set the lens to AF and you have coarse , medium and fine focus control available .

[ejwwest]

It should work in the 70D , it works on my 1000D's ... 

There's a focus control panel on the Liveview screen in Utilities , just set the lens to AF and you have coarse , medium and fine focus control available .

Capture.PNG

I think the problem is with the 2x extender - with my 40D I couldn't get the Canon Utilities to fine adjust the focus with the extender on the 100-400mm lens, but could without it. The 70D comes with a new technology "Dual Pixel CMOS AF" whereby in LIveview there's contrast detection between adjacent pixels which I think may allow it to focus with the extender on. As I was trying to manually focus this morning the camera started (slowly) focusing down to minimum then back to infinity and seemed to get a reasonable (but clearly not sharp) focus. I'll try the utilities to see if I can improve it next time. I did get a manual focus but at a longer exposure than desirable which I processed with PSE 12:

[Steve Ward]

Oh I see , I assumed the tele-extender would link up the electronics in the lens to the body .

[ejwwest]

Oh I see , I assumed the tele-extender would link up the electronics in the lens to the body .

Normally the telextender takes lenses like the 100-400mm beyond f5.6 (to f/11 at 400mm) which, for some reason, means the normal autofocus doesn't work. Manual focus has the problem of keeping the image steady enough at this high a magnification whilst adjusting the focus ring. However, I successfully managed to get EOS Utility to adjust focus on the 70D with the extender attached. I'll just have to wait for a sunny day to try this with the sun.