Wesley's Tool-Box

Battery life is something most smartphone users take a big interest in, sometimes more than the raw performance. What good is a fast phone if you can't use it long enough without recharging? For iPhones, this is especially important because you can't swap out the battery without disassembling. So I decided to test this as the time allowed.

Now, each of my iPhones had been used for wildly different lengths of time, so the level of remaining battery capacity would be different as a result. This would obviously affect the tests, so I checked the capacity using iBackupBot, as you can see here.


Fortunately, batteries were mostly in good condition, having 90% or more capacity left. The brand new iPhone 6S Plus actually had slightly more than it should. Still, the difference is non-negligible. So the results of my battery tests would be normalized to the design capacity to make the comparisons fair. The 6S Plus results would be lowered a bit while the others would be boosted, all according to their respective ratios.

For a heavy-load scenario like playing a game, I used the battery test included with GeekBench 3. This is available for version 3.3 and higher, so iPhone 4 and 3GS, which can only run lower versions, had to be left out. With this test, airplane mode was turned on and the low power mode was turned off. To see how much effect the display backlight has, the test was run with both lowest and highest brightness settings.



With the screen brightness lowered, iPhone 6S Plus pulls ahead of all other previous generations. It's an impressive feat, beating the 6 Plus at the second place by about two and a half hours. The gap significantly narrows with full brightness, but it still manages to stick around slightly more. Considering that this is done with 5% less design capacity, it's certain that the 6S Plus is quite efficient despite all the enhanced performance.

Meanwhile, the battery capacity of the Plus series is so large that it has enough power left over even after driving a bigger backlight and much more screen pixels. Overall, the Plus series lasts noticeably longer than the predecessors. Curiously, the 5 and 5S don't show much difference in regards to the screen brightness compared to the other models. It seems the characteristics of the screen used for these devices were different.

LTE is the 4th generation (4G) wireless data communication standard that supersedes WCDMA and other 3rd generation (3G) ones. Unfortunately, the far more diverse range of frequencies that the carriers around the world uses for this standard is a big headache, especially for Apple.

This is because a single model of iPhone tries to support as much of the entire world as possible in order to simplify the lineup. iPhone 4S, the last model before LTE support, indeed came in a single model for the entire world. In contrast, iPhone 5 and 5S had to be split up into multiple models that each had differing LTE band support. This was largely because the chipset couldn't support all the needed bands at once.

This meant that an iPhone bought in one country may not support LTE in another country. With iPhone 5, you needed model A1429 (for Sprint and Verizon in US) if you wanted it to use LTE in Korea. A1428 (for AT&T and T-Mobile in US) wouldn't do. That may have been a factor in the Korean carriers not automatically enabling LTE for foreign phones until 2014.


If you wanted to use LTE, you had to take your phone to a carrier branch or a certified store to have the device manually registered as being LTE capable. My AT&T iPhone 5S was put in as an "OMD Apple LTE Handset" on the SK Telecom network. Come 2014, though, this situation was largely resolved. Not only would your iPhone from overseas work with the LTE network, iPhone 6 and 6 Plus had worldwide LTE band support regardless of the specific model.

Situation is similar with iPhone 6S and 6S Plus, which adds a few more obscure or upcoming LTE bands on an already extensive array of support. There are still three specific models for each type, but one is for adding an upcoming AT&T-specific band 30 (A1633, A1634) and the other is for Chinese release (A1700, A1699). They are identical to the general model (A1688, A1687) otherwise.


However, not everything is in the clear. VoLTE (LTE-based voice calls) support is still not a universally supported feature among phones and carriers are still enabling this on a manual basis as of this writing. Owners of internationally bought iPhone 6, 6 Plus, 6S, and 6S Plus still need a visit to the carrier branch or store.

I had two iPhone 6S Plus that came from overseas - one is a "SIM-Free" version from Japan that you saw in my earlier post and the other is from United States intended for T-Mobile network. Both are model A1687 and the same version expected to be sold in Korea in a few days' time (October 23, 2015). The former was registered at an SK Telecom branch office as "OMD Apple VoLTE", the same title my iPhone 6 Plus received last year. The latter was registered at a local certified SK Telecom store as "OMD Apple VoLTE_6S" as shown here. Only after doing this, and waiting for a while to let the network know of the change, did the VoLTE function start to work.

The interesting (or cumbersome) part of doing the registration at a certified store was that it required me to have a separate, pre-registered device that was not in use to help with the registration. According to the store, once I inserted the SIM card into my iPhone 6S Plus, the network automatically registered it under "OMD Default Handset" because it wasn't recognized. In order to change that, the SIM card had to be put into another device so as to make the 6S Plus not be associated with any SIM card. Only then could the re-registration could proceed. Branch offices didn't have this requirement, so I have to assume that the system provided to the store is limited compared to the branch.

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.