Sunday, September 16, 2012
New iPhone 4s -- it’s just a click away
The recent announcement of the new Apple iPhone 4s held excitement and some disappointment to various Apple fans. One comment I read in response to the disappointment people that said, “outside had not changed” is a comparison to the Porsche 911. It’s outside hasn’t changed much over the years either, but -- as they say -- it’s what’s under the hood (or, if you’re English, the bonnet) that matters.
Let’s talk about under the hood, specifically the new camera in the iPhone 4s. I’ve been a camera buff, a shutter bug, a photography want-to-be since about the sixth grade. I recently purchased a replica of my first two cameras on eBay, and I’m working on a historical reference article about all the cameras I’ve ever owned. Expect to be bored out of your seats when that movie hits the theaters, but, for now, let’s talk about the iPhone camera.
I’m a big believer that the best camera is the one in your hand, yet I personally own and carry a flotilla of cameras, each tuned to a particular use. I’ve got a big (and heavy and clunky) DSLR with more glass than a picture window, plus a nice little camera that is probably the most advanced “point and shot” every made by Canon. I supplement that with a Nikon super zoom camera, a tiny Canon that I’ve hacked the software on, and a small “viewfinder” digital camera with interchangeable lenses from Olympus. I also own a plethora of video cameras from a Flip to a Sony, to a Canon handicam to a large JVC and a Professional Canon XL2.
I do use my current iPhone camera on occasion, but mostly to take pictures of wireless router labels to capture the SSID and Passcode. My brother-in-law, Chuck, on the other hand, takes tons of excellent pictures with just his little old iPhone. He usually gets up close and personal, since the phone lacks a zoom lens, and it is really quite a good camera in the iPhone 4, but still -- it is a phone after all, and typically phone cameras lack many of the basic functions and features found even in the cheapest point and shoot cameras. All that said, Chuck takes really excellent pictures in all kinds of light with his iPhone 4. How much better can it get?
Well, let’s look in detail at the new camera under the hood of the iPhone 4s.
The 4s camera gives you 8 megapixels -- that’s 60 percent more pixels than the camera on iPhone 4, and the older iPhone was quite good in the pixel department. The advantage of the increase is self-explanatory, but really the least important part of the upgrade. In general, the pixel race is really over and even somewhat self destructive. Other phones and small cameras have high megapixel counts, and, really, you don’t want or need that many. The thing is all those tiny pixel have to be packed into such a small place that you end up with image quality problems. (Sure, the top of the line DSLR cameras are up in the 12 - 18 - 24 megapixels range, but those are on much, much larger sensors.)
In the case of the iPhone incremental pixel increase, I expect your best photos will look better and it probably won’t affect any shots negatively. But I think it is just the icing on the cake. Wait until you hear about the cake!
As an aside, the primary advantage of high pixels is that you can enlarge the picture to a bigger format without becoming grainy or “pixelated.” Maybe more important is that lots of pixels means you can crop the photo and frame on a small section. That is sometimes called “digital zoom.” That is important since no phone camera has optical zoom. There just isn’t room for a complicated, motor driven zoom lens. Eight megapixels is nice and catches up to some of the competition smart phones, but, as I said, cramming more pixels into a small sensor can actually reduce photo quality due to increased noise and loss of individual sensor sensitivity. Along with the higher bit resolution, the iPhone 4s has gone to 1080p video resolution. That’s nice, but all the earlier caveats still apply.
Now, the cake: what really excites me is the changes in the lens and the camera light sensitivity. The biggest achievement has to be with the lens, which is said to let in 73 percent more light. Moonlight and candles may now be enough! And that is good since camera phones don’t really shine in the flash department either. (Get it? Shine!!)
Action shots should be less blurry too, since higher sensitivity means faster shutter speeds, but we will not know how much truth there is in that statement until we get our hands on one --and that must wait until pre-order delivery day.
How was this done? Well, let’s get technical for a moment. In any camera, phone, video, still, film -- any camera with a lens, the key is the amount of light gathered. The more light the lens lets in, the better the performance under lower light conditions. This “size” of the lens is measured in a technical specification called F-stop. This is a ratio between the diameter of the aperture in the lens and the focal length of the lens. If the ratio is 1, then that is one big and “fast” lens. (I won’t explain the fast part here. You’ll have to wait for the movie.) Basically, the bigger around the lens for a given sensor size, the more light that is let in. Kind of like the bigger the bucket, the more water you can carry.
It is an advantage of having a small sensor that you can then use a small lens and get good light. Bigger sensors require bigger lenses for the same F-stop and bigger is heavier, larger, and more expensive. But, again, the best cameras have large sensors and large individual pixel sensors and ... well, let’s leave that idea for now too. (Before we go on, I should explain that the bigger the lens aperture the lower the F-stop number ... that’s just to confuse you all ... so, is that working?)
The new iPhone camera has a five element lens, including a filter to block infra-red light from saturating the sensor, and the lens is F/2.4. That will let in about twice the light of the previous iPhone’s F/2.8 lens. More elements means better quality in terms of bending the light and focusing it on the sensor without color separation or blurriness of “spherical aberrations.” (Don’t you just love it when I talk that way?)
The most important part of a camera is… the photographer — but next in importance is the lens. And the lens of the iPhone 4 was already pretty solid for a camera phone: F/2.8 (apparently limited to F/3) at about 30mm equivalent focal length. The new one is F/2.4, about half a stop better, which doesn’t sound like much, but at this point of the aperture scale counts for a lot.
It’s a pretty big increase in the total amount of light hitting the sensor. The focal length wasn’t specified by Apple, but in its announcement they mentioned it was “super wide.” Which, if wider than 30mm equivalent, starts putting the iPhone into true wide-angle territory (starts around 24mm equivalent if you ask me) -- but that may have been referring to the aperture. At any rate the half-stop improvement is real enough.
(The advantage of limiting a lens to a slightly higher F-stop is that the outer portion of any lens has more aberrations or “blurriness” than the center portions. That is a reason that professional photographers often stop the lens down a step or two to improve the quality of the image. Starting with a lower number F-stop helps that too. Also, F-stop affects depth of field. But, again, we won’t get into that here either.)
There are other factors at play here too. One is the “shutter speed.” In DSLR and other high cost digital cameras and all film cameras there is an actual shutter. But in point and shoot and phone cameras the shutter is simulated by the time it takes to scan and read the digital sensor. The faster A5 processor gives that higher speed to the new iPhone 4s and should lead to less blurry photos. That also helps with the higher video resolution and progressive scanning.
Speaking of the new and faster A5 processor, it is part of the overall equation too. The new system was described by Apple as being “1/3rd faster” than the previous iPhone, which is a phenomenally vague description, but I’m guessing the onboard electronics are able to offload the image data 30% faster. But with these small sensors, what matters isn’t getting the image off the sensor, but getting it processed, encoded, and displayed to the user. The A5 processor has a major focus (“focus,” get it?) on graphics enhancement. Having a chunk of the CPU entirely dedicated to JPEG processing is a given. So the combination of a faster sensor and an expedited pipeline for that image data to go through makes the iPhone 4s camera twice as fast as the competition at making the shot happen. It also allows for more accurate white balancing and color tweaking, so your shots won’t look like they were taken with a red heat lamp or under a blue sun.
The new sensor even has another trick up its sleeve. In previous digital photo sensors, the actual light sensitive material was on the bottom and over the top were the interconnecting “wires” that hooked it all together. The “so-called” backside illumination sensor basically flips the sensor over so light strikes the light sensitive bits without having to navigate a forest of circuitry. This improves light sensitivity.
This iPhone has one of the new “next-generation backside illumination” sensors. An upgrade to the upgraded sensor that made the original iPhone 4 camera much better. I won’t know for sure who makes the camera until the teardown comes, but Omnivision did the last one and they have a newer version called the OV8812 with the exact resolution specified by Apple in this new phone. The improved sensitivity probably isn’t as impressive as the jump from 3GS to iPhone 4, but better low light performance is always welcome.
Why Apple even added real-time stabilization. This is a nice feature for small cameras, since, lacking heft, they tend to wiggle around a lot. Besides, I have shaky hands. (Me and Neil Young.) I’m assuming it’s not optical stabilization, since that would require more space than they’ve got, so it must be electronic stabilization based on live image analysis. Again this is the A5 at work. By designing the camera’s image processor around the hardware (and vice versa), Apple can do this kind of heavy graphical analysis without taxing the battery too much. (Another improvement is that you can now press the “volume” button to take a picture rather than the “shaky” press on the touch screen. Apple just puts it all together -- don’t you think?)
As usual from Apple, and what I’ve grown to expect, the balance of hardware and software is nearly optimum in the latest iPhone. The camera is so good that even I may start using it for more than just “honey did you bring the camera to take a picture tonight” response. After all, the most important part of all cameras is the person standing behind it and it is a poor workman who blames their tools, but I think Apple has really put a powerful photographic tool in this version of iPhone. It just keeps getting better. I can hardly wait for next year, but I’m not waiting ... “hello, Apple, just checking on the status of my pre-order."