I am fairly new to Live View, as I had been shooting with the K200D for 4 years which did not feature it. My mother has that camera now, and I have a K-r.
I am having a few issues with live view .
1) AF in Live view mode.
With the K-r, I have noticed that the AF is extremely slow in live view. With my 50mm/1.7, starting with the focus ring on infinity, I have seen it turn the focus ring 3 times, and take 3 seconds to focus at a distance of about 12ft.
In low light, it's not just slow. Not only does it turn 3 times, it ends focusing completely wrong - at 45cm
. It just never achieves proper focus no matter how I try.
I had to read the manual to figure out that the AF method can be changed to Phase Difference for Liveview. But then Liveview is interrupted. However, it works far better. The Face Detection and Contrast Difference methods for Liveview AF are just too slow and inaccurate. What's even more confusing is that in Auto mode, it defaults to Face detection and cannot be changed ! And that performs really poorly in low light. A few weeks ago when I first got the camera, I decided to use Liveview in a dark restaurant. Every single picture was out of focus
Even the few that I tried to take with flash, before the restaurant owner told us to stop. And my partner was extremely upset at the green AF assist lamp light in his face for so long, too ! All for naught - I never got him in focus at all !.
This seems to be an algorithm issue with the Face Detection and Contract Difference.
I am surprised that the problem happened even with my fastest AF lens, the Pentax-F 50mm/1.7.
I just tried to raise the ISO, thinking it might help the AF Liveview, but the accuracy did not improve - still wrong focus. My default auto ISO is up to 1600. But even at ISO 25600 it still couldn't AF correctly.
Once I turned all the lights on, then Liveview finally did AF correctly, though slowly. But improving the lighting before focusing is not an option in most situations.
I must now remember never to use Liveview with green mode indoors. My favorite mode is actually "no flash" auto mode, and for that it's possible to switch Liveview AF to Phase difference. It's still very disconcerting to see the Live view "die" once the camera switches to Phase difference. The screen goes completely black. I wish it retained the last (frozen) picture while the camera focused, instead.
If it makes anyone feel better, my Canon T3i with 18-55 IS II lens at 55mm isn't any better in the same test. Liveview AF is even slower, and also inaccurate. The AF makes a different mistake, it's not as much off. I can't tell how much exactly since the lens doesn't have any indication of distance on the focus ring. But the focus is still wrong. AF is achieved correctly at 18mm, though.
The Canon does let you switch to AF "quick mode" even for auto (green), though.
2) Manual focus in Live View mode.
I want to use Live view for manually focusing. This is especially the case when using my 800mm mirror lens which is manual only.
On the Canon T3i, there is a very useful feature which allows magnifying part of the Liveview picture. Magnification can be set to x1, x5 or x10. This helps tremendously with focusing distant objects.
Is there a way to do this with the Pentax K-r ?
So far, the only magnification of focus point that I see with the K-r is in AF Liveview mode.
3) Remote AF with Live View .
When using Liveview, the camera does not honor custom setting 14, "Autofocus when using remote control".
That might seem silly, but I like to use Liveview to compose the shot with the camera on a tripod, and then use the remote to actually focus and take the shot. As it is, I have to remember to turn off Liveview first before I use the remote to take the shot.
I guess this is documented on p148 on the manual. But still a bit annoying.