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Extended Optical Zoom?


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Extended Optical Zoom?
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MBHockey
skates=grafs
 
Join Date: May 2005
Location: New York
 
2008-07-24, 13:33

Hey guys,

I just recieved a new camera that I purchased off of Circuit City's web site (Panasonic Lumix DMC-TZ5). I am by no means a photographer, but I do enjoy taking pictures and video of friends and family whenever I can (who doesn't?)...just a casual point and shooter.

Anyway -- this camera had everything I was looking for. It is compact (camera next to mouse), can take nice wide screen 16:9 pictures (along with 4:3 and 3:2), can shoot 720p HD video, and packs in an amazing 10x optical zoom for its size.

However, I'm curious about this feature called "Extended Optical Zoom". The manual says that with extended optical zoom I can hit up to 16.9x and it seems it lowers the resolution of the picture to 2MP in order to get the 16.9x zoom...my question is -- is this a "fake" zoom? How does it differ from traditional digital zoom (which it also has, but is off by default...I don't usually use digital zoom when taking pictures)?

Here are some pictures of my driveway with the various zoom: Sample Pics. There are four shots which represent 1x, 5x, 10x, and 16.9x respectively. The 16.9x shot looks good (to my untrained eyes, mind you) so I'm not really sure what's going on here.

Last edited by MBHockey : 2008-07-24 at 14:04.
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Dorian Gray
Veteran Member
 
Join Date: May 2005
Location: Paris, France
 
2008-07-24, 14:36

Digital zooms and Extended Optical Zooms or anything of the sort are "fake" in the sense that they don't reveal more detail. In other words, they don't do anything that you can't do equally well or better in post-processing.

Digital zooms work by cropping the central portion of the image, then resampling it to create an image with a higher pixel count. The result is a large, soft image.

The Extended Optical Zoom on your camera also crops the centre of the image, but unlike the digital zoom, doesn't resample at a higher pixel count. The result is a small, sharp image with the same amount of detail that the digital zoom would have provided, in a smaller file.

Digital zooms aren't totally without value for novices because:
  • they give you an image that's ready to print if you absolutely refuse to even crop your images before sending them to the printer
  • they improve the camera's metering performance for the area that you're interested in
  • they may make framing and focusing easier for similar reasons
Personally I'd never use either a digital zoom or an Extended Optical Zoom, because you never know what you might see later in the portion of the frame that the camera cropped away, and memory is cheap and abundant these days.

If you view your 10x and 16.9x sample images at 100% on-screen, you'll notice they both contain the same detail: the 16.9x version is merely a cropped version of the former (which of course you could do on your computer). You'll also note though that the camera did a better job of metering the bright road at the end of the drive in the 16.9x version, simply because it forms a larger part of the frame. The file is 1.5 MB versus 4.3 MB. So those shots are a perfect example of the pluses and minuses of the feature.
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MBHockey
skates=grafs
 
Join Date: May 2005
Location: New York
 
2008-07-24, 14:53

Thank you very much for that explanation...really helpful!

I talked with a guy at Circuit City about it and he was less knowledgable than I was. He claimed that the extended zoom was truly 16.9x optical zoom, so I asked him why they don't advertise it as a 16.9x optical zoom digital camera instead of 10x...he didn't have an answer. It's shocking the amount of misinformation they give out...I know very little about cameras but knew enough to realize it wasn't a real optical zoom and that he was full of it.

It would have been cool if you were there to put him in his place
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Mugge
Thunderbolt, fuck yeah!
 
Join Date: Jan 2005
Location: Denmark
 
2008-07-24, 15:07

What's the frame rate on that 720p video?

My new Powershot G9 does 1024*768 video, but it drops to 15 fps compared to the usual 30 fps at 640*480.
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ezkcdude
Veteran Member
 
Join Date: Jan 2005
 
2008-07-24, 15:33

Quote:
Originally Posted by Dorian Gray View Post


The Extended Optical Zoom on your camera also crops the centre of the image, but unlike the digital zoom, doesn't resample at a higher pixel count. The result is a small, sharp image with the same amount of detail that the digital zoom would have provided, in a smaller file.
Am I the only one who thinks this is completely bogus marketing? What they should call it is "In-Camera Crop to Make Smaller File Sizes"! Extended Optical Zoom my ass.
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Dorian Gray
Veteran Member
 
Join Date: May 2005
Location: Paris, France
 
2008-07-24, 15:40

Quite, ezkcdude. Then everyone including the seller and the consumer would also know exactly what it does. But I think that's somewhat the point: to confuse the heck out of the public so that they keep upgrading.

Anyway, congrats on your new camera, MBHockey. I'm also trying to decide what new camera to get at the moment.
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MBHockey
skates=grafs
 
Join Date: May 2005
Location: New York
 
2008-07-24, 21:10

Quote:
Originally Posted by Mugge View Post
What's the frame rate on that 720p video?

My new Powershot G9 does 1024*768 video, but it drops to 15 fps compared to the usual 30 fps at 640*480.
It does 720p @ 30 fps -- Looks very good (better outside with a lot of light otherwise it comes out a tad grainy)


Quote:
Originally Posted by Dorian Gray View Post
Quite, ezkcdude. Then everyone including the seller and the consumer would also know exactly what it does. But I think that's somewhat the point: to confuse the heck out of the public so that they keep upgrading.

Anyway, congrats on your new camera, MBHockey. I'm also trying to decide what new camera to get at the moment.
Thanks!
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