When Apple released the iPhone 4, praise for the phone’s redesigned rear camera system was universal: the company had made the wise choice to focus on pixel quality rather than quantity, including improved low-light capabilities and color rendition, resulting in nearly point-and-shoot camera-quality pictures and videos. It seemed like a foregone conclusion that the rear camera on the fourth-generation iPod touch would be similarly powerful, potentially replacing the need to carry both a pocket camera and the iPod at once.

But as we learned yesterday, that didn’t happen. Instead, Apple went with an iPod touch camera that has lower resolution than any iPhone—including the original model—at 0.69 Megapixels (960×720) for still images, and 0.92 Megapixels (1280×720) for video. The first-generation iPhone had a 2-Megapixel still camera, and the most recent one has a 5-Megapixel still camera. It’s unclear whether Apple is using a 1280×720 sensor in the iPod touch and cropping off the left and right sides of the video image for still images, the most likely scenario by a wide margin, or whether it is using a 960×720 sensor and upscaling it on the sides for video, which would be quite unlike Apple, but not inconceivable.

 

This matters because the sensor inside will critically affect the quality of both the still images and videos that the iPod touch captures relative to the iPhone 3GS and iPhone 4. Our screenshots show how Apple significantly crops the iPhone 4’s 5-Megapixel still camera when it switches the device into 720p video mode, losing not only the top and bottom of the still frame, but also some of the left and right. Consequently, when you hold an iPhone 4 steady and flip between modes, you need to step backwards a little when shooting a video to capture the same left and right details that the still camera would have grabbed. Apple may be doing this to get the highest-quality pixels from the best part of the iPhone 4’s lens and sensor during video shooting, or there may be other reasons.

 

On the iPod touch, this appears to be different. If the sensor has only 1280×720 pixels, literally every pixel is being used when it records video, and rather than still pictures looking better than videos as they do on the iPhone 4, they’ll look like chopped-off versions of video recordings, missing 160 pixels on each side. To get a sense of what that would be like, take a look at the last of the pictures here from the iPhone 4. (By default, Apple fills the iPhone 4 screen with a cropped version of what the video camera is actually recording, rather than the full wide frame. Underpublicized is the fact that you can tap twice on the video to see everything that’s really being grabbed at once, complete with letterboxing on the top and bottom of the screen, shown two shots above.) For the iPod touch 4G, what you’re likely to get as a still image will be closer what you see on this last shot—the same image as two shots above, minus the left and right sides. Unlike the iPhone 4’s camera, the still image won’t look much better on a computer than it does on the device’s screen. This is probably the reason Apple hasn’t shown off galleries of iPod touch photos as it did with the iPhone 4.

According to Apple, the iPod touch is using a backlit sensor, so the color rendition and low light performance will hopefully be closer to the iPhone 4 than earlier iPhones, which took comparatively grainier and muted photos. There’s a tap-to-adjust exposure feature, but seemingly no tap-to-focus, which suggests that colors will look fine but depth of field won’t be possible. Apple’s new high dynamic range (HDR) feature in iOS 4.1 may enable patient users to make lemonade from otherwise lemony iPod touch shots, too. Since the sensors aren’t the same between devices, it’s even possible that the videos may look way better on the iPod touch than on the iPhone 4; a sample on Apple’s site shows a beautiful (but slow-moving) scene from nature, cropped to the touch’s screen. Hopefully it’ll actually be that impressive in real-world use.

On a related note, we’re also really wondering how the new iPod touch is going to handle FaceTime, given that it appears to lack the dual microphone system of the iPhone 4—there’s a tiny microphone hole located on its back, by the rear camera. Given the way that sound waves travel, it wouldn’t be shocking for audio to sound a little muffled when using the front camera, but then, perhaps Apple has come up with a smart way to process sound. We’ll let you know what we discover during testing.