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losing focus

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Ted Strickler
losing focus
on Jan 13, 2012 at 5:45:58 pm

Sorry, if this is the wrong forum but I could not find anywhere else to ask. I am using a sony ax2000 for shooting high school football and hockey. As I do a pan to follow the ball/puck the camera goes out of focus sometimes for a second or more. Manual focus, of course, prevents that but also creates it own problems when the action get close to me or during a zoom.

Is there a good solution?

Ted


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Bob Mark
Re: losing focus
on Jan 15, 2012 at 3:19:00 pm

Not really. Auto focus is always going to "hunt", especially in motion scenes.

Bob


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Ted Strickler
Re: losing focus
on Jan 15, 2012 at 7:02:25 pm

Thank you for your answer Bob, even though I don't like it. I guess the reason I was hoping for a more positive answer is that my pd-170 camera did not lose focus nearly as bad as my ax2000. And they are used in the exact same situations. The ax2000 is much worse!
Ok, enough crying. Thanks again for your response.

Ted


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Bob Mark
Re: losing focus
on Jan 16, 2012 at 12:37:30 am

Hello Ted. Don gave you a much better explanation about auto focus.
Since you are shooting sports, the situation is compounded because you will more than likely be zoomed in at certain points and that will reduce depth of field and make focus more critical. I will use auto focus once in blue moon when I have to pan, zoom, ride iris and focus at the same time. That is when I might use auto iris too, but I try not to use either "auto." Good luck!

Bob


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Ted Strickler
Re: losing focus
on Jan 16, 2012 at 4:02:39 pm

Bob, you're right, thank you Don. Sorry about that. I'm even worse in with names in person.
As far as Sony verses Canon focus, both my cameras are sony and I would think the focus would be very similar. Maybe because the ax2000 is high def I can see the "out of focus" more clearly than with the pd170. Is that a play on words?
Anyway thank you for your input. I will just have to find the happy medium here. One last thought. When I am fully manual, my iris will change by itself anyway. I Continually have to readjust the iris ring to brighten up the picture. Keep in mind though that I am still learning this camera.


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Don Greening
Re: losing focus
on Jan 17, 2012 at 12:09:54 am

[Ted Strickler] "One last thought. When I am fully manual, my iris will change by itself anyway. I Continually have to readjust the iris ring to brighten up the picture."

The operating manual for your HDR-AX2000 states that you can adjust iris, zoom and focus manually and independently from each other. The camera wouldn't be much use if this wasn't the case. Better consult your PDF version or the paper manual. The PDF version addresses this starting on page 30.

[Ted Strickler] "both my cameras are sony and I would think the focus would be very similar."

Perhaps, but there's at least a 10 year difference in technology between the PD170 and the DHR-AX2000 so I doubt that they would react quite the same. There's nothing stopping you from carrying out a little test, however. I do know that the OIS (optical image stabilization) used to be superior on the Sonys compared to the Canons. At least that was the case between my PD170 and my Canon XL2.

- Don

Don Greening
A Vancouver Video Production Company
Reeltime Videoworks
http://www.reeltimevideoworks.com


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Bob Mark
Re: losing focus
on Jan 17, 2012 at 2:18:29 pm

You are right Ted. Hi Def will show more focus issues than SD. I am not at all familiar with your camcorder. Why would the iris change, if you are in full manual mode? Some camcorders will let you set how quickly the auto iris responds. That can be quite helpful.

Bob


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Don Greening
Re: losing focus
on Jan 15, 2012 at 10:03:24 pm

Not all auto focus features are created equal. Traditionally, Sonys take longer to achieve A/F but they also take longer to lose it. This means that if someone or something momentarily moves in front or behind what you have in focus you won't lose that focus because the A/F has jumped to something else. That's good.

Canon cameras take less time to achieve A/F but also lose it more quickly. Canons are "hunters" meaning it's easy to confuse the A/F with something else moving in the frame. In those cases the auto focus will pulse back and forth, shifting focus on more than one object in the span of a half second. That's bad.

These are the only 2 types of cameras I've had experience with. Since cameras with A/F generally work on differences in contrast, the bigger the contrast difference between what you're focusing on and what you don't want in focus the better. No camera's A/F works well unless your subject is in the middle of your viewfinder, and no A/F works well in low light because of the low contrast.

The moral of the story is, don't use A/F at all unless it's unavoidable. If you do use it then be aware of the pitfalls I've described above.

If you want a deeper depth of field on manual focus then use a camera with small imagers. Close down the iris (if lighting permits) go to the lowest safe shutter speed to get more light on the imagers. Zoom out to the farthest point you think your action will be, set focus and the pull back to what you want in focus now. Everything from that furthest point back to you should stay in focus (as long as you don't change anything else such as your iris). A test for this is to zoom out, set focus, pull back full wide then zoom back in again to that same point. if it's still in focus then you're golden. Go for coffee.

- Don

Don Greening
A Vancouver Video Production Company
Reeltime Videoworks
http://www.reeltimevideoworks.com


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