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Sony NXCAM / AVCHD Camcorders
Sony HXR-NX100, HXR-NX70, NX30, NX5, NX3/1, HXR-MC2500, HDR-AX2000, etc.


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Old December 14th, 2010, 10:43 AM   #1
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How is the AF on AX2000?

I keep looking for a suitable replacement for my aging VX-2100. I mainly shoot figure skating performances for which I must rely on auto-focus.The VX-2100 does a very good job of staying locked on the skater and not getting fooled by the advertising in the background on the ice rink walls. I keep wondering if the AF of the AX2000 is adaquate for this type of work?

I ran into a new problem this past weekend when the venue decided to "spot light" the performances. Normally they simply light the rink and I use manual exposure. However, manual exposure did not work for the spotlight because there was about a 3-stop difference between the spotlight and ambient and if the spotlight operator would slip off of the skater the scene would go almost black and the camera AF would lose the subject. Worse, they turned the spotlights off after each skater and didn't light the next performer until the music actually started. So I was forced to use auto-exposure and the "spot light" setting on the VX-2100. This worked ok, but still resulted in the subjected being just a tad hot for my taste but it was acceptable. I see the newer cameras have exposure compensation which would have helped as I could have dialed in -1/2 or -1 or so to help with the highlights.

This whole AF thing is driving me crazy though. I cannot aford to spend $4000-5000 for a camera only to take it to the rink and discover it wants to ignore the skater and lock on the wall advertisements. Or worse, continually hunt in and out of focus as the skater travels around the ice. There's really no place around here that I can rent something so I'm kind of stuck with a blind purchase.

I appreciate any words of wisdom anyone can offer.

Thanks.
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Old December 14th, 2010, 12:18 PM   #2
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I transitioned from the VX's to the AX's and to me the auto focus systems are relatively equal. I shoot a lot of stage shows and have not had any problems with auto focus. It seems lighting will trick the auto focus more than motion, so as long as your background is not brighter than your subject, auto focus is acceptable.

Ben
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Old December 14th, 2010, 12:25 PM   #3
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John:

Judging by my experience, in well-lit situations the autofocusing performance of the AX2000 is mediocre. Besides, it tends to depend on the distance from the object recoded: the shorter this distance the worse the AF.
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Old December 14th, 2010, 03:54 PM   #4
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I have a NX5U essentially the same camera and I think the autofocus is poor compared to the consumer Sony XR500 that I also have to shoot family stuff. NX5U is on a par with the FX1 both poor in my mind. I tend to focus manually most of the time now.

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Old December 14th, 2010, 04:59 PM   #5
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I tend to look at it less as a problem with the AF and more as problem with the camera's psychic powers: It has none.

Spot-focus would be nice, though!

Best,
Aaron
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Old December 14th, 2010, 05:28 PM   #6
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Yes I would like the spot focus that is on the SR11 and XR500. Really annoying when I just press the spot on the LCD on the XR500 and it locks into focus as I use the one shot focus button and the focus assist on the NX5 and it still isn't as sharp as the XR500 !!!! My hands and eyes are just not as good. Crazy since it has the same touch screen as the XR500 !!!

A more sophisticated camera with the consumer features priced between the consumer models and the NX5U would definitely be on my list of things to get!!!

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Old December 15th, 2010, 09:03 AM   #7
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Quote:
Originally Posted by Aaron Holmes View Post
I tend to look at it less as a problem with the AF and more as problem with the camera's psychic powers: It has none.
I am not sure what you are trying to say. Why are psychic powers required to focus properly? My VX-2100 (and my VX-2000 before that) has no problems maintaining focus lock on a fast moving ice skater or ice hockey player.
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Old December 15th, 2010, 10:29 AM   #8
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Psychic powers are needed because it is hard to tell were the camera is focusing. I do not know why the auto focus on the nx5 and the Ax200 is as bad as it is. My sxr11 runs ring around the auto focus on the nx5 and it is two times cheaper.
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Old December 15th, 2010, 02:16 PM   #9
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Quote:
Originally Posted by John Gayman View Post
I am not sure what you are trying to say. Why are psychic powers required to focus properly? My VX-2100 (and my VX-2000 before that) has no problems maintaining focus lock on a fast moving ice skater or ice hockey player.
If you're used to the AF on other pro Sonys, then I expect you won't be surprised by the NX5's AF. My comment was more directed at the comparison of consumer and pro camcorder AFs, which is not particularly valid, IMO.

Quote:
Originally Posted by Steve Kass View Post
Psychic powers are needed because it is hard to tell were the camera is focusing. I do not know why the auto focus on the nx5 and the Ax200 is as bad as it is. My sxr11 runs ring around the auto focus on the nx5 and it is two times cheaper.
Guessing you mean "SR11." It's hard to compare the AF on small consumer cams with pro cams. I have a CX12 also. I suppose it's tempting to call it's AF "better" than the NX5, sure. On the other hand, the CX12 has a very deep DoF, so AF only needs to be close. On a camera with a much shallower DoF, like the NX5, focus is a much more selective thing. You'd better want that, because you're paying big $$ for it! Consequently, the AF does kind of need psychic powers to do what you want, because its chances of simply looking for high contrast and finding what you wanted it to find are drastically reduced.

I think a lot of people simply assume that, except for price and portability, pro camcorders are universally better than consumer camcorders for any given purpose. That simply isn't true at all, and if you're not prepared for that then you *will* be frustrated.

Best,
Aaron
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Old December 15th, 2010, 03:43 PM   #10
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I have a NX5U, XR500, SR11 and FX-1. The NX5U is not as good at auto focusing as the FX1 neither of them are as quick or as good as the XR500 or SR11. Unfortunately the video noise level of the NX5U is also not as good as the XR500. It does have some advantages it will hold close to its poor focusing through most of the zoom range whereas the consumer cameras will not hold focus through any zoom changes if left in manual. They need auto focus to zoom.

In full auto the consumer cameras are clearly superior in almost all respects. They just lack the creative control offered by full manual operation.

I shoot theatre and it is sometimes annoying to find a similar focal length shot from my wife using the SR11 that is sharper than my NX5U. We are both shooting from 150 feet from the stage so depth of field from both cameras is quite large and I have the NX5U at F4 to F5.6to get the maximum when I know the SR11 is probably wide open at 6db of gain. Both cameras are 1/3" sensors though lenses are very different of course.

I am pleased with the NX5U over the FX1 for a number of reasons that make the purchase worthwhile. The NX5U has XLR's for audio, it has a longer zoom than the FX1 and the tapeless worklow is great especially in a theatre environment not having to worry about tape changes. The picture from the AVCHD output of the NX5U is also a big improvement over the HDV from the FX1. However the differences from the XR500 are marginal at best and most of the time the XR500 video is better due mainly to the better video noise performance and the difference between my focusing ability and the spot focus of the XR500 !!!

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Old December 16th, 2010, 11:16 AM   #11
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Ron, do you have some real-world examples that you can post here?
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Old December 16th, 2010, 12:27 PM   #12
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What are you interested in seeing? I can't post my project video and clearly I do not want to post family stuff either. In focus, in good light, still images from the NX5U, XR500 and SR11 are indistinguishable. Video in good light the 24mbps NX5U shows more detail on things like leaves, grass etc when viewed on a good TV. A marginal TV has more issues with deinterlacing than the difference between the detail in the XR500 or NX5U higher bit rate video. In low light when all cameras need some gain then the XR500 has a visually cleaner picture than the NX5U, grain can be seen on solid dark colours etc whereas there is nothing on the XR500 image. To a lesser extent grain is also seen on the EX3 image compared to the XR500.

I think you may have to take mine and others word about auto focus as this is so specific to content and situation. My projects are theatre so are somewhat different in requirements to lots of outdoor video. The XR500 and SR11 spot focus will lock very quickly in focus visually sharp on the LCD, the NX5U seems to focus reasonably quickly but is not in focus most of the time. Pushing the focus aid button to expand the image confirms every time that the focus is not correct and a slight adjustment is needed. This is similar to the FX1 which unfortunately did not have the focusing aids like the NX5U of expanding the image as well as using peaking.


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Old December 16th, 2010, 05:34 PM   #13
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I'm just curious about some practical differences in quality on NX5 vs other consumer camcorders that you own. If you can post any example it would be good. I'm surprised to read that a consumer camcorder can actually do better than a much expensive one.
Did you use any picture profiles on NX5 in your projects? Do the other cameras have picture profiles option?
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Old December 17th, 2010, 09:23 AM   #14
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I will try and find the time over the next few days to put something together but this is a busy time of the year. I use PP3 on the NX5U which is a 709 preset gives a little more detail in the shadows and makes it closer to the XR500 or SR11. There are no presets on the XR500 or SR11 that are used. All are set on indoor WB preset fixed for theatre and most of the time would be outdoor fixed or auto depending on situation for family video. I prefer to use fixed presets for WB as I can always correct in editingrather than have the WB shift during filming .

I have found for years that the main difference between good consumer cameras and the more pro models is in the ability to control the image. In auto the consumer models usually win !!!!! In manual the pro models win. In good even light there is sometimes little to choose between similar technology cameras. In difficult light the consumer camera can sometimes still win. For instance many of the consumer AVCHD cameras can vary response within the frame to give detail in the shadows and correct exposure to retain detail in the white areas. The pro cameras can do this but need to be stopped, change the gamma and knee curves before shooting again. Then change all these parameters back again to carry on normal shooting. The NX5U can speed this up using presets. The consumer cameras, like the CX550 with auto scene detection will just adjust for the scene, look for faces and individually correct for exposure, WB and focus realtime. Swing around to shoot the mountains and the CX550 will adjust again for landscape mode realtime.

Is it possible to make the pro model give a better picture. Of course, all the time if the situation allows the time for set up and checking etc. Which is why I have the NX5U and not a set of consumer models. But I certainly would not use an NX5U as an unattended camera like I use the XR500. The output would not be usable as I would not have the time to keep adjusting controls. The XR500 with AE shift at -3 or -4 works just fine since it maintains its ability to manage shadows and highlights while in auto at the same time keeping level down. Controls that are not available on the NX5U. AE shift is available but NOT with the convenience of a knob as on the consumer XR500. That's Sony for you !!!! The opportunity is there on the NX5U but not implemented. It would be nice to be able to fix shutter speed give a range for gain and iris then let the camera manage. The NX5U is close in that limits can be set for gain and iris but not ranges.

A few things I would like from the consumer models on the NX5U are as above, set ranges for shutter speed, iris, gain or have one of these fixed and use AE shift on a realtime knob/thumb wheel, spot focus on the touch screen.
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Old December 19th, 2010, 11:13 AM   #15
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John - to get back to your exposure question - have you tried the spotlight mode? I've found this mode to be highly intelligent (verses the stupidity of the backlight mode) and it's saved the day on many a shoot where I've had to make use of footage from an unmanned camera.

Have a play. You'll be impressed with Sony's 5 stop correction when there's a hi-light that needs correct exposure. And when the scene's evenly lit the spotlight mode turns completely off. All automatically, all faultlessly.

tom.
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