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(MPG4) Sanyo Xacti (all models)
A compact 720p MPEG4 digital media camera recording to SD Card.


 
 
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Old April 14th, 2006, 01:20 AM   #16
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Ouch !! thats pretty bad !!! How bad does it do this to Video ? (does video use the whole sensor or just the center portion of the sensor ? the distortion might not be so bad with video if the latter

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Old April 14th, 2006, 08:42 AM   #17
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A slight difference might be noted when the video is HD, because of the upper and lower crops. For the most part however, barrel and pincushion effects on videos should match those on photos. The HD1 compresses the content from the entire width of the sensor, not the center.

I have read a theory on this board that the camera simply captures a 720X1080 frame from the sensor, but this wouldn't work for what we see. I expect what the HD1 does is pixel aggregation, combining four pixels into a single higher sensitivity pixel. It explains the quadrupling of ISO sensitivity in video mode, as well as the dramatic falloff in dark areas. This, by the way, is a digicam technology.

If my theory on how the HD1 produces video is accurate, there will be little difference between photo and video with respect to optical distortion.
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Old April 14th, 2006, 08:49 AM   #18
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Pitty. I really want the wide angle but that kind of distortion is too high a price to pay.

Hopefully it will get popular for a third party better quality lens to be made

Anyone tried the telephoto 1.4x adaptor ? thats the one I am REALLY interested in !

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Old April 14th, 2006, 09:39 AM   #19
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"The HD1 compresses the content from the entire width of the sensor, not the center."

Yes, that was my original assumption too.

But how do we account for the semi-transparent areas visible outside the 16:9 frame when shooting HD?

From where do they get their picture, if not from some of the sensor?
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Last edited by Graham Jones; April 14th, 2006 at 11:29 AM.
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Old April 14th, 2006, 05:01 PM   #20
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The sensor shape isn't appropriate for the 720p format, so while it grabs from the entire width, it only grabs the vertical resolution necessary to produce the correct aspect. When capturing 640X480, more of the vertical resolution is used, resulting in the necessary 4:3 ratio.
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Old April 15th, 2006, 03:44 AM   #21
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Once again, I am indebted to Joseph. Seeing his results with the WA adapter, I am even more content with my old Crystal Vision Titanium High Definition Wide Angle 0.45x adapter (reported on earlier under Tweaks and Options). It is at least as sharp as the Sanyo, offers a much wider angle, and zoomed in to the same angle as the Sanyo, seems to have less distortion (at the full width, equivalent to 17mm, it looks pretty much like a Fisheye lens). It is also a lot smaller and less obstructive of the flash.
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Old April 15th, 2006, 07:58 AM   #22
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"The sensor shape isn't appropriate for the 720p format, so while it grabs from the entire width, it only grabs the vertical resolution necessary to produce the correct aspect. When capturing 640X480, more of the vertical resolution is used, resulting in the necessary 4:3 ratio."

Gotcha..
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Old May 1st, 2006, 05:28 PM   #23
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I got a WA adapter and went online to buy filters as described by Daniel, but there is a big difference in price between cheap filters (Sunpak) and the B+Ws.
Are B+W filters worth the 5x difference?
Any bad experiences with Sunpak Filters?

Thanks for any advice.


Quote:
Originally Posted by Daniel Kissel
An afterthought would be to buy a normal 49mm UV filter for protection and a 49mm slim CPL so one does not get vignetting and can leave the UV filter on all times.

Unless you are planning on buying a lens cap, the original Sanyo lens cover is too loose over the OD of standard screw-on filters, so you may want to add this to your list.

A slim filter will most likely come with a PVC cover already (B+W usually do).
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Old May 1st, 2006, 06:45 PM   #24
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Generally speaking expensive filters have higher quality.. however this is a truth with a lot of variation to it. (smile)

I shoot high-rez images for print and feel that expensive filters is worth my money. However for the HD1 which even though it is a video camera, practically speaking is a 1 megapix camera.. you are not going to be able to detect a whole lot of difference. particularly if you are sticking the filter on there as a protective layer... by all means pick up whatever you can find at a good price.

But something like a tiffen high-contrast filter is still going to run you 3 digits, and will be worth it.. probably the same with a polarizer. a soft-filter on the otherhand.. well its entire purpose in life is to render the image softer.. so hey.


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Old May 15th, 2006, 08:37 AM   #25
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According to the specs, it has a 5.36 Megapixel sensor, and the HD should use something like 821,600 pixels for native 1280X720, and I've shot HD with "less expensive" filters, and there is a huge difference.
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Old May 15th, 2006, 08:50 AM   #26
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Quote:
Originally Posted by Robert Rock
According to the specs, it has a 5.36 Megapixel sensor, and the HD should use something like 821,600 pixels for native 1280X720, and I've shot HD with "less expensive" filters, and there is a huge difference.
You are right, I did get it wrong, its not 1 megapix - its 0.8 megapix files being shot for the individual frames in the 720P mode. compared to 14 megapix for the still camera. Reality is that "even" in 720P mode, a HD camera can not resolve a lot of the imperfections in a mid-range filter. (even though for video HD is like a largeformat camera to photographers - its still a pretty low resolution) (smile)

The 5 megapix rating applies to still images, naturally it will be helpfull to have good fiters for shooting stills with the camera.

That said, I do not mean to argue with you, You are right about the better filter, people should always purchase the most filter they can. After all, the light we want to record have to pass through these filters. (smile) Without a doubt, the more we can baby the light entering the camera, the more quality in the form of sharp details, contrast and smooth graduations will there be to record.

Personally I was most excited about sticking a graduated ND on the HD1 last week.

Bo
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Old May 16th, 2006, 05:15 AM   #27
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The HD1 does use pixel aggregation to achieve the higher ISO for video. The frame is not based on the entire width of the sensor as I had thought. Crops are found on the right, left, top, and bottom. You will see them if you go into HD mode to shoot video and watch the screen as you depress to take a picuture. The image will recalibrate and you will note you are using more sensor on all sides for the picture.
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Old May 16th, 2006, 05:33 AM   #28
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Yeah, I was worried about that before:

http://www.dvinfo.net/conf/showthread.php?t=63230
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Old June 27th, 2006, 06:03 AM   #29
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Quote:
Originally Posted by Chris Wells
The HD1 does use pixel aggregation to achieve the higher ISO for video. The frame is not based on the entire width of the sensor as I had thought. Crops are found on the right, left, top, and bottom. You will see them if you go into HD mode to shoot video and watch the screen as you depress to take a picuture. The image will recalibrate and you will note you are using more sensor on all sides for the picture.
I think this only happens if you leave "Stabilization" on.
When you turn it off the image remains the same for video and stills.
But then what's the trick here?

1st case: video captured with "stabilization" comes from a smaller area of the CCD and when you turn it off the whole CCD width is used (optimal pixel count)

2nd case: video captured with "stabilization" comes from a smaller area of the CCD and when you turn it off the same part of the CCD width is used (some pixels around are missed)

If it's so, then let's hope it's the first.
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Old June 27th, 2006, 06:04 AM   #30
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By the way, hello to everybody. I'm new here.
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