Wesley's Tool-Box

Ever since Apple integrated a fingerprint sensor into the iPhone's home button with 5S, unlocking the phone had been quick and painless for me. The success rate is really high, and it's basically a touch-and-go experience that is faster than even sliding to unlock. Still, Apple must have thought that this could be improved further, so now there is a 3rd generation Touch ID on my iPhone 6S Plus. How does it perform?

As the video illustrates, the speed has gotten to the point where the fingerprint recognition is virtually instantaneous. Even if my finger was resting on the home button very briefly, the lock screen would disappear. Analyzing the video, this is how long each device's Touch ID sensor took to unlock.


iPhone 6S Plus is nearly twice as fast as 6 Plus, taking only 0.23 seconds. 5S's performance was measured to be 0.70 seconds here, but it sometimes does get close to (but not surpass) 6 Plus's time of 0.40 seconds.

If 5S and 6 Plus's speed were "good enough", 6S Plus is bordering on "too fast". Unless you intentionally take your finger off the home button as quick as possible after you press or just use the power button, you'll miss the chance to see or interact with the lock screen most of the time. This includes loading the camera app via sliding up the lower right corner of the lock screen. It took a lot of time of getting used to.

Meanwhile, shooting burst photos is a completely different story.

I take a lot of casual photos every day. I fill the storage space of a 128GB iPhone in a year just with photos. The habit goes way back before using iPhones. I used to have a digital camera tucked into a waist holster along with a GPS tracker so I can take geotagged photos all the time. Smartphones these days can do that automatically, but back when iPhones weren't around and "PDA phones" were niche curiosity this was so out of ordinary I was on a TV show for that.

So I'm rather grateful that the iPhones have made my habit easier to manage. But the high cost of the device (I buy the highest storage option, off contract) means that I'm sort of putting the digital camera purchase budget into it as well. In fact, I never bought an ordinary P&S camera after iPhone 3GS. I had effectively bet on Apple to improve the camera module every year so that investing in another camera was unnecessary. So did it pay off? I took the photos in the default camera app with no adjustments whatsoever to find out.



Well, it was initially a huge downgrade. I already had a compact 10-megapixel, 10x optical zoom camera before iPhone 3GS, so I carried both the 3GS and this camera around. The 3-megapixel module was doing alright, but only just so for quick snaps. It was only with iPhone 4 that I could wean off from a separate camera.

Let's look at the colour reproduction. The output from the 3GS camera looks quite alright by itself, but in reality the colours are exaggerated. It looks more colourful than it should be. This is evident when you compare with the results from the subsequent generations. Gradually, it gets toned down to get closer to being more natural. The low point is 6 Plus. 6S Plus picks up a little again.



With the landscape photos, 3GS falls rather short again. The automatic exposure setting comes out tad low, making the scene flat. Meanwhile, the introduction of the 8-megapixel sensor in the 4S set the basic standard of daytime photo quality that people have come to expect from iPhones. 6S Plus carried this tradition well to the 12-megapixel era.

In both of these well-lit photo examples, the 6 Plus and the 6S Plus are contending for the best quality, as expected. The 6S Plus doesn't feel like a clear winner, though. It seems to be trying to keep the 6 Plus quality intact while boosting the number of pixels. But what about going more extreme?

One of the things I've noticed about the iPhone's camera is that its field of view seemed to change with each generation, especially in the early days. This meant that the focal length was different. While the EXIF data does show the 35mm equivalent focal length, I wondered if this was really accurate. I wanted to check this out before doing deeper comparison.


By taking photos of a tape measure from a set distance and calculating the focal length with a formula, this is what I got. The last three generations have been stable - they all report 29mm, and the actual measurements are nearly the same at around 30mm. For the three generations before that, the measured values are around 32 to 33mm, although the reported values exceed this by a mm or two.

Interestingly, 3GS has the longest focal length of all at about 37mm. It isn't particularly good for selfies or group photos, and since it didn't have a front-facing camera, this was doubly unfortunate. As the selfies and wide-angle lenses became popular, perhaps Apple saw this as a problem and kept reducing the focal length until iPhone 5S in addition to adding the front-facing camera.


Now I decided to figure out the optical resolutions of the iPhone cameras. This is done by using the ISO 12233:2000 chart and looking at the test lines to see how far each of the lines remain distinguishable. I've done this test five years ago with 3GS, and I had promised to revisit it with newer iPhones. It's rather long overdue, but it's definitely worth it.

Considering the processing done to the output photos, conventional sensors would be alright with Lines per Picture Height (LPH) being 65% or greater of the sensor resolution. Let's see how the iPhones have progressed throughout the years. The photos were taken in a sufficiently well-lit room so that the lowest ISO setting would automatically be chosen by the default camera app.


Sharpening applied to the image processing during the iPhone 4 to 5 eras have apparently enhanced the percentage slightly, while the more recent ones have toned this down and still maintained the numbers in the high 60s. So it seems that the optical resolution has been kept up with the increase in the sensor's pixel count more or less. It does seem that, to go beyond 12 megapixels used in 6S Plus, Apple may need to opt for a sensor size increase to avoid degradation in quality.

When you upgrade to the latest high-end device, you would expect it to perform faster than the last one. Thanks to the ever-progressing technology this has always been the case with the flagship iPhones, but the performance jump was not always consistent. Let's see how the seven generations of the iPhones stack up.

One thing to note is that I'm probably not missing much by not having the original iPhone or iPhone 3G here. Many of the tests are already flaky with iPhone 3GS or 4, largely due to not getting a newer OS. 3GS at least is barely holding on with an OS that got its last security patch in February 2014. iPhone 3G is considerably worse, with its last update in November 2010, nearly five years ago.

First up is the GeekBench 3, as shown in the video. 3GS was able to run the 3.1.1 version of the benchmark on iOS 6.1.6, while the 4 ran the 3.2.0 version on iOS 7.1.2. All the others were running the latest version at the time of the writing, 3.4.0, which supports iOS 9.0.2 installed on the devices.


Links to Results
[iPhone 3GS iPhone 4 iPhone 4S iPhone 5 iPhone 5S iPhone 6+ iPhone 6S+]

The results provide some interesting observations. There are two instances where the performance upgrade wasn't quite as significant as the other times: 3GS to 4, and 5S to 6 Plus. These were the times when the screen resolutions saw a significant jump from the predecessor - 360x480 to 640x960 and 640x1136 to 1242x2208 (downscaled to 1080x1920 on the display), respectively, which is about 4 times the pixel count. Much of the enhancements seemed to have sunk into supporting the higher display resolution.

In the other times, the performance increases approximately twofold each generation. At the transition from 4 to 4S, this was achieved purely by going dual-core. Since then the per-core performance was boosted. In the end, you can see an 11-fold improvement for going from the first dual-core iPhone (4S) to the latest (6S Plus).

I've been using an iPhone ever since it started going on sale in Korea back in December 2009, with iPhone 3GS. The original iPhone was not compatible with Korean mobile networks and at the time of the release of iPhone 3G, laws effectively prevented anyone from using foreign cellphones on the domestic networks other than in the form of roaming. People seeking to use the latest phones from abroad eventually succeeded in persuading the lawmakers to change the rules and paved the way for an official domestic launch of the iPhone as well.

I sought to get the latest iPhone as they were up for pre-order on the domestic carrier's website. So I was able to get mine usually on the first day of the Korean release day. This continued all the way up to iPhone 5, when I was invited to the carrier's launch event, as evidenced by a certain media photo. But wanting to get my hands on even quicker, I sought out the first-wave releases from overseas starting with 5S. And with that I started doing some in-depth reviews, too.

In this way, I went through seven generations of iPhone for the past six years. The only ones I skipped were either the lower-cost version (5C) or the smaller version (6 and 6S).


Since I never sold the iPhones, they always circulated within the family. And with the most recent upgrade cycle, all the older phones not in use were returned to me for a big reunion. Yes, I now had seven iPhones in my hands.

Luckily, all of the phones were in good working conditions in general, needing just a recharge or a change of battery to return it back to life. This prompted me to do a big comparison that let me see how far iPhones have come during all these years.