webcam quality built-in iMac 21.5-inch: 3.06GHz

vip77,

Welcome to Apple Discussions.

I would recommend contacting Apple to ask, you are correct they don't publish the iSight camera's specifications.

I know you are new and probably haven't had a chance to read the Terms of Use please look to your right. One of the terms is:



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Regards,

Roger

Likely either 0.3 or 1.3 MP.

How to tell here: http://discussions.apple.com/thread.jspa?messageID=10690773&#10690773




Mac Pro Quad Core (Early 2009) 2.93Ghz w/Mac OS X (10.6.3)  MacBook Pro (13 inch, Mid 2009) 2.26GHz (10.6.3)
LED Cinema Display  G4 PowerBook 1.67GHz (10.4.11)  iBookSE 366MHz (10.3.9)  External iSight

vip77 wrote:
Does anybody know what the quality of the webcam built-in iMac 21.5-inch: 3.06GHz is?

That is a more complicated question than you might imagine. There is much more to it than the 'raw' resolution (megapixel rating) of the image sensor. For instance, it won't matter much if a camera has a sensor with a lot of pixels if it attached to a low grade optics system -- you just get lots of blurry pixels. Likewise, if the electronics or sensor are cheap, low grade components, you get noise (static, 'sparklies', etc.) in the images, especially in low light conditions, or weird color shifts.

These are especially important characteristics for live video. If the image is blurry, noisy, or the color cast changes frequently with subject motion, the transmission faithfully tries to preserve as much of that 'detail' as possible. The result is much harder to compress & decompress for transmission, resulting in more demands on the computers, higher bandwidth required for the same frame rate, & quite frequently very noticeable & annoying visual defects like dropped frames, freezes, blockiness, trails behind moving objects, or other artifacts.

IOW, quality is a measure of how well all these characteristics interact to produce a useable result. Bumping up the megapixel rating without improving the optics & electronics to match is pointless for anything other than looking good in marketing materials.

As such things go, I would rate the iMac's built-in camera as good as any other camera built into a computer, & probably better than most. But if that isn't enough for your needs, you will need an external camera, preferably one with a much larger lens & built-in, high performance optical autofocus & auto-color correction. You won't find detailed specs for these things on most data sheets (which are also compiled for marketing reasons), so as always independent reviews & price are better indicators. For price, higher cost per feature/spec is often a reasonable indicator of quality since it can mean that the design cut no corners to look better in marketing materials.

vip77 wrote:
Thank you for the link.

You're most welcome, vip77

Can anybody make a photo with this cam so I can compare the difference between webcam in iMac and the other one?

Yes, anybody can make a photo. However, I don't know how that could help you compare anything.

The only meaningful way I know for you to "compare" is to physically go to the Mac you are considering and view the image that its camera makes.

Nobody is having a webcam in his iMac 🙂 I suppose

You keep asking, so here is a snapshot made with with the higher res (1.3 MP) camera. If it helps you in any way, please help me understand how you used it to "compare the difference":

 

Thanks, and I hope this helps you.
EZ Jim



MacPro QuadCore(Early 2009) 2.93Ghz w/MacOSX (10.6.3) 
MacBookPro(13inch,Mid2009) 2.26GHz(10.6.3)
LED Cinema Display  G4PowerBook 1.67GHz(10.4.11) 
iBookSE366MHz(10.3.9)  External iSight

EZ Jim wrote:
You keep asking, so here is a snapshot made with with the higher res (1.3 MP) camera. If it helps you in any way, please help me understand how you used it to "compare the difference":

Vip77: note that the image EZ Jim furnished is not the original high res version. It is a version uploaded to a web site (actual link: http://2.bp.blogspot.com/_Eoo9IvneWRc/S9w41IZnQZI/AAAAAAAABBY/EOplJfqI2zU/s1600/ newsight.jpeg) & there stored as a 719 X 540 pixel jpeg format image with a jpeg compression ratio of about 2.5:1.

This is common for such sites, but as he implied it makes it a poor standard for comparison to a "native" format image from the camera. Not only is it at reduced pixel resolution (about 0.4 MP vs 1.3 MP of the original) the "lossy" jpeg compression reduces quality & magnifies artifacts significantly, like the color noise (blotchiness) you can see on the fingers & along the bottom edge of the object they hold.

Also, the profile of this image indicates it is from the camera in an Apple LED display, not an iMac, but presumably they are similar. FWIW, the cameras in each of the 2 iMacs listed in my profile have 1.3 MP cameras & produce very similar looking results, although the higher end 24" one seems to have a slight edge in overall quality. Whether this is due to the camera, the faster CPU, the NVIDIA GeForce 8800 GS graphics processor, or maybe just more light coming off the larger screen is hard to say.

The point is judging camera quality is tricky, & much more so for live video transmitted over an Internet connection vs. even a high resolution, uncompressed still image.

Hello R C-R

You provide excellent comments and expansion on the points we have both offered. However, some additional information may be useful to OP vip77 when deciding how to "compare."

R C-R wrote:
... the image EZ Jim furnished is ...actual link: ht tp://2....AAAAAAAABBY/EOplJfqI2zU/s1600/newsight.jpeg) ...

Hovering the mouse pointer on the image above for approximately a second should give notification that the larger size (the same as the link you give) is available by a single mouse click there.
 
I think we agree that neither image serves any useful purpose beyond proving our points. With a clear look at them, I believe OP will agree, too. However, if OP can find a meaningful use for either of them, I remain eager to understand.

... stored as a 719 X 540 pixel jpeg format image ... common for such sites...

The size and type of image may be common at such sites, but *the site is not the cause of the size and format*.
 
As explained in the link that I included in my initial post here, software controls iSight. The resolution and format of the image made with any iSight depends on the software used to capture the image. A bit more about file format and size follows:

The file format of the image I linked was jpeg because it was captured using iChat's Video > Take Snapshot menu command. Had I used a different app, I could have saved the file in a different format.
 
Similarly, the file's size in pixels is also a result of my software and settings choices. My iChat Video > Video Preview window dimensions happened to be 719x540 when I captured the image. Changing the Preview window size before issuing iChat's Video > Take Snapshot command would have yielded different saved file dimensions. Although the image I saved was 719x540, note that iChat uses a maximum of 640x480 camera pixels (less for slower processors and lower internet bandwidth.) The iChat software calculates and displays a resized (in this case, enlarged) image whenever the Video Preview window is resized, but that calculation does not change the actual iSight hardware pixel resolution. Likewise, the pixel dimensions of any saved file are the same as those of the displayed image.

Cheers,
EZ Jim



MacPro QuadCore(Early 2009) 2.93Ghz w/MacOSX (10.6.3) 
MacBookPro(13inch,Mid2009) 2.26GHz(10.6.3)
LED Cinema Display  G4PowerBook 1.67GHz(10.4.11) 
iBookSE366MHz(10.3.9)  External iSight

Thanks for the clarification about the image. The software does indeed determine its characteristics, & for video that would normally be much different from a still image. IOW, we would not expect IChat or Skype to use jpeg compression or a non-standard video pixel resolution for a video feed.

So that Vip77 understands why this is important, consider that video is basically a stream of still images, so it is characterized not only by pixel resolution but also by how many images per second there are in the stream. Even a stream of 1.5 MP resolution images would be unsatisfactory if only one or two of them were transmitted per second.

I'm not sure what Skype's "HD" characteristics are, but it is a safe bet that it is not sending anything near 1.5 MP images, regardless of the display resolution. The only thing I could find on the Skype site about this was that it was easily adequate for sign language, implying the image rate is high enough not to miss signs flashed by a fast signer. This leads me to believe the HD version is optimized to preserve a higher frame rate than the original version, not for HD pixel resolution.

Anyone know anything about that?