External isight vs. internal

Question

How different exactly are the built in isight on a macbook and the external isight sold by apple a while back? i have both because i needed a camera for my stopmotions. Like resolution, color. Also, how does the external hold up to todays standards?

Answer 1

Hello Snipereye64
Such a well stated and brief question that requires a big answer!
Technically, I suppose the answer to your question depends on which built-in iSight is in your MacBook. 
Early MacBooks had a 640x480 (VGA) resolution USB iSight that is the same resolution as the external (Firewire) iSight is use. Given normal webcam distance from the lens and adequate light (video takes more light that normal room lighting), I think the image quality of that built-in iSight is approximately equal to, but different from, my external iSight's.
External iSight has auto-focus so it can offer better images at widely different distances to the subject. It is also easier to attach filters and accessory lenses, but this difference is not really an image quality difference.
If your only use for iSight is video chat, your image quality question can best be answered by your video chat partner, who is the one who sees the image your iSight sends. Here is a comparison video test I made some time back with a chat partner who has both internal and external iSights.
My chat buddy changed NOTHING between the two pictures except which iSight he was using.  I do not see any significant difference in actual image quality between the two. I do see differences in the amount of software image sharpening, contrast, and color balance. These parameters are software-controlled, so different apps might give different results.
If you want to compare the quality of snapshot still images for email or posting on the web, the best way to critically examine image quality is to make a print of the same subject made with both cameras. I have not done this kind of test using my iSight because, although I occasionally make an iSight snapshot to email, I almost always use my 5 and 10MP digital still cameras for images I want to have enough quality to print or post. No webcam offers sufficient image quality for me for prints beyond about 3x4 inches.
You can do your own comparison and judge for yourself with your iSights. Capture an image of your face with both of your iSights. It is best if you do this as near as possible to the same time, same size, and in the same light. Then print both images and look for image quality differences that are important to you Even though you may not use your iSights to make printed images, the prints will more readily reveal any faults in the test images you make.
Current iNtel Macs (other than MacBook Air) that I have checked have a 1280x1024 resolution. This 1.3MP camera has more than 4.25 times as many pixels as the 0.3MP (640x480) cameras. How this additonal resolution is used depends on the software application that is running the camera. When using iChat, I do not notice the resolution difference, but a printed image or one an image made with some other application might give a different answer. iChat's software image sharpening, contrast, and color balance of the 1.3MP iSights seem to be about the same as they were for the earlier built-ins.
Depending on your intended use for your images, you can use "The Test App" from this article to test which built-in iSight you have. However, the best test will likely be how the images made with the software you use looks to you for the purposes you intend.
My old "Rev A" external iSight still works as well as it did new for video chat and an occasional quick video clip for emailing. It is good enough for me.
Please let me know if I missed anything. ;-)
EZ Jim
PowerBook 1.67 GHz w/Mac OS X (10.4.11) G5 DP 1.8 w/Mac OS X (10.5.2)  External iSight