Problem with Autofocus in the EX1
 

I noted that the EX1 is very slow in focusing using the autofocus mode. Sometimes it does it with great diffficulties. Pushing the Push AF button doe snot help.
Have other users of the EX1 found the same problem ? What do do to solve it, apart from using manual focusing ?

If I'm in auto focus mode and it doesn't snap into focus right away when I change focal points, I simply manually focus to get it in the right zone. The auto focus on the EX1 is not one of its strong points. Sometimes it does pretty good, other times no. I don't do any serious shooting in auto focus.

Doe snot will NOT help. Now, buck snot....that's different. ;-)

Don't judge it so quickly - the whitetail doe snot has some peculiar properties that might prove beneficial.

You guys making fun of bucks and does is not fawny.

You don't know the hoof of it.

That's it, I'm tailing.

I'm laughing over my doe nots and coffee.

Oh deer!
(10 characters required!)

The auto focus on the EX1 is very poor. It is extremely slow to reach focus when subject distance changes and once focus has been achieved it hunts, rhythmically going slightly in an out of focus until AF is switched off. I feel it is pretty much unusable.

I am surprised Sony haven't sorted this out. I can't believe that the design brief was to create a useless auto focus function so maybe there is a deeper reason within the lens design that makes auto focus implementation difficult, but Sony felt that not having the button would impact sales. It is possible that it is something which may be fixed in a future firmware update, but it seems like something quite obviously wrong so if they haven't fixed it already...

I wonder what AF is like on the EX3? If that is bad too then I wouldn't hold your breath for a fix on the EX1.

M

I think the auto focus has a very different function in the EX compared to other cameras (particularly consumer prosumer). The Vortex training DVD implies it. The slow auto focus means you can track a subject that is moving both in front of and behind other objects without it loosing the tracked subject. This might be typical of a sporting event for example. On the above DVD they have people passing behind trees I believe as the example.

It would be nice if it had a auto focus speed control though.

That's a great observation. I noticed while doing a nude shoot, the subject (my dog) remained in focus while she walked behind the trunk of a maple tree.

My understanding is that the lens used on the EX1 was changed partway through the design process, so that may have thrown the autofocus engineers off course -- but that should still be resolved for those who appreciate the functioning autofocus on earlier Sony HD cameras.

Hmmm. Wonder if that is a bit of post rationalisation. If it were true I would expect the PUSH AF button to be really snappy, no reason for that to be tracking a moving subject, but it is just as sluggish. Also the manual specifically states that auto focus is activated each time it detects a change in the image. No mention of a delay for tracking subjects. I wonder if the Vortex DVD is just looking for a positive spin. There is no way I would use the EX1 auto focus for sporting events its way to slow.

In the manual it also says the adjustment is terminated when the subject comes into focus and stands by until the next change is detected. That isn't my experience. The AF seems to be constantly hunting so that even when it achieves focus on a well defined subject it doesn't stay there for long, it pulses slightly in and out of focus constantly. Not really useful for anything I can think of.

M

That would make a lot of sense Kevin. I wonder if the EX3 is any better.

M

On a related note, does anybody know where the autofocus detects these changes? I'm assuming that it is detecting changes inside the small center square but I'm not sure.

You can observe the behavior of the auto focus by leaving peaking on. Set the color to red, level mid or high.

It's pretty understandable what it keys on, tilt the camera up or down a few degrees on your subject and observe the change. If it's locked down and the subject doesn't move, neither does the focus.

It also helps immensely to have detail ON. You can adjust the parameters of the detail setting to eliminate most of the concerns with it, namely the ugly EE halos. For example, for 60i turn the detail level to +10, the frequency to +50, the black limit to +50, and the white limit to -50. You'll struggle to see any halo-ing at all. For 24/25p, that's way too much sharpening however, turn the level down to -13 or whatever suits your preference. The salient point, is that contrast within the details is what the auto focus keys on. If you want to use auto focus, your opportunities are reduced when you turn detail off.

Thats not what I get with mine. I get constant hunting once focus is achieved. Its as if the AF is constantly moving to focus slightly either side of the current focus point to assess the sharpest focus. I know I am not alone because there was a lot of discussion on the subject in the early days. Are you sure yours stays rock solid in focus if you leave the AF switched on Tom?

Again. Are you sure Tom, I haven't got my camera here to check but it would seem crazy to make AF effectiveness dependent upon the detail setting. Detail does affect the display of peaking however so if detail is off peaking is reduced and you don't see so much peaking when things are in focus, doesn't mean they aren't just as in focus though.

M

That's a good point Martin. It would seem crazy to make AF effectiveness dependent on the detail setting. But then why make peaking dependent on it?

What I am sure of, is that I see the focus hunting stops after 2-3 seconds, on clear targets in front, with non-confusing uncluttered backgrounds. I know this because the distance/depth of field display stops moving, and the distribution of the peaking dots.

When you get back to your camera, will you try turning the detail on for a test? Interested in your finding. Again, I'm getting decent auto-focus performance, with detail at the above settings, std3 gamma.

The video signal displayed on the LCD is post processing, which is a plus because it means you can see the effect when you change the level of detail or gamma etc, etc. Peaking, Zebra, and other operational information is applied to that processed video signal for the LCD so they are affected by the processing previously applied. So it isn't ideal if you are using peaking as a focus assist for manual focusing, but it is understandable why it is done in this way. In contrast, I can't see any advantage to using a post processed signal for AF feedback, it would seem to make more sense to take that pre-processing and add any function specifically appropriate to improving AF effectiveness. That doesn't mean I am right of course, just seems odd to me. I will have to check on my camera when I get a second.

Not for me. locked off camera, siemens star filling the entire frame and it still hunts. Not dramatically but very noticable if you are looking for it. It could be that some cameras are better than others. I hope that is that case, if it is I will get mine fixed.

M

Will do

M

I do agree with your logic Martin, except I don't understand why peaking should be displayed post processing. I do understand why Detail ON would be displayed post processing, but not peaking.

Peaking is a very functional focus aid, doesn't have any other purpose, and could be made even more functional if you didn't have to enable the Detail ON circuit to obtain the full benefit of the peaking. Why wouldn't the same level of peaking be displayed preprocessing?

It's that specific peculiarity that makes me question whether Detail ON is contributing to improved Autofocus behavior, or as you would say...not.