Rumors cropped up last week that Apple had put down a big order for LED flashes, something useful for one thing, and one thing only: a digital camera. It doesn't take much to figure that the next iteration of the iPhone is likely to be packing one of these, since many of the latest cell phones--including HTC's recently released Nexus One, now have them included.

That got me thinking: how does the Nexus One's 5-megapixel camera and its eye-searing flash stack up against the 3-megapixel, flashless camera module of the now-aging iPhone 3GS? Is the ability to take bigger, and better-lit photos worth touting as the end-all, be-all feature among smartphone cameras? The easiest way to figure that out is to run a few tests.

Full disclosure here: I'm not a camera-testing expert. I am an avid photographer with a handful of pro gear, as well as a few high school and college photography courses under my belt. I'm not even going to try to get into things like testing dynamic range, color sensitivity, signal-to-noise ratio, etc. So instead, I've set up the two cameras to take essentially the same photo in various situations, to see how the two stack up.

All photos in this comparison were taken within the same minute of each other, while balanced from a leveled tripod to maintain the same height and distance. Images were then transferred directly from the devices for analysis. All comparison shots are presented side by size, at full quality, without any recompression or conversion. Any timings were done with a stopwatch.

Basic lens specifications

(Credit: Josh Lowensohn/CNET)

Apple iPhone 3GS

• 3-megapixel camera (resolution: 2048x1536 pixels)
• autofocus (can also be set by touching the screen to select focal point)
• aperture: f2.8
• focal length: 3.85mm

HTC Nexus One

• 5-megapixel camera (resolution: 2592x1944 pixels)
• autofocus
• LED flash (optional)
• aperture: unknown
• focal length: unknown

It's worth noting that Apple is a little more liberal with the camera metadata, something the Nexus One could gain in a future software update. Right now, any photos snapped on it come without things like ISO, exposure time, aperture, and the lens' fixed focal length. However, both come with embedded GPS metadata, which makes for easy geotagging. It's just surprising that Google would have location, but not some of the more rudimentary camera info, within its metadata.

Camera speed

Time to boot built-in camera app:

• iPhone 3GS: about 2.5 seconds
• Nexus One: About a second

Lag between pressing the button, getting the shot, then returning to on-screen preview for next shot:

• iPhone 3GS: A little less than 2 seconds
• Nexus One: A little less than 2 seconds

Macro focus

Macro photo testing was done with a tape measure and a shipping box.

(Credit: Josh Lowensohn/CNET)

A camera's macro-focusing capabilities are no minor benchmark. This is how good your camera is at focusing as close to a subject as possible. This is most useful for taking shots of business cards, bar codes, and QR codes.

Between the two, the 3GS gives users a bit more control over what area they want to focus on, allowing users to simply touch the phone's screen to select the part of the photo they'd like in focus. The Nexus One, on the other hand, does the thinking for users, putting things into focus as it sees fit. In other words, users don't really know what the camera will focus on until after it takes the picture.

For our testing, we set a tape measure out across a table, and moved a labeled box closer and closer to the phone's camera, until it reached an optimal focus. For the iPhone, that length was 2.5 inches on the dot. A centimeter closer, and it lost a noticeable amount of sharpness. The Nexus One was able to pull in just a tad (and we do mean a tad) closer than the iPhone, coming in at 2.4 inches. To take it a step further, you can pull in both phones to about an inch of a subject and still have details such as text be legible. It's just not anywhere near as sharp as it is from 2.5 inches and beyond.

Both cameras' close-focusing capabilities are to be commended, but between the two, we'd happily put the 3GS out as the victor. Despite it's 0.1-inch disability, it lets you see what will be in focus before you take the shot. It also refocuses as you get closer or farther away from your subject, which the Nexus One does not.

Low-light sensitivity

Low-light performance is one of the big differentiators between these two cameras. Any camera nerd will likely scoff at the low-light capabilities of a camera phone and its tiny sensor, but in real-world use, this ends up being important. Having a camera you can use with less-than-ideal lighting can be incredibly valuable.

The first part of the low-light test has both cameras taking photos in a darkened room, with very little available lighting. And the second test compares the iPhone to the Nexus One in an even darker room, with the Nexus One's flash on.