Wesley's Tool-Box

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.

For nearly a month, I've been using my iPhone 6 Plus every day. As one of the first users of such device in Korea, I decided to take an in-depth look at its improvements and functions whenever I can, to show what the Korean users are going to get soon. Now all the hard work is done, and I present to you the summary of all the reviews I wrote about it.

iPhone 6 series will finally launch in Korea officially on October 31, 2014, according to Apple's official announcement, and carriers are preparing to accept pre-orders about a week before that. I hope these reviews will help you decide if iPhone 6 Plus is right for you.

Preview	Summary
	0. One of the first iPhone 6 Plus in Korea (2014-09-19)
	Wesley gets his iPhone 6 Plus on the first launch day in Japan and brings it to Korea.
	1. iPhone 6 Plus - Unboxing & First Look (2014-09-22)
	The box containing the iPhone 6 Plus is opened up, and the phone is taken an all-around look. The bump caused by the camera lens is also examined.
	2. Protecting my iPhone 6 Plus (2014-09-23)
	Front and back side protection films are applied to the iPhone 6 Plus. Then, it is put inside a belt case intended for Galaxy Note series. Apple's own leather case is also tried out.
	3. Sizing up the shape & size of iPhone 6 Plus (2014-09-23)
	The size, thickness, and shape of the iPhone 6 Plus gets compared to other devices. It is first compared to other iPhones and iPads, then to a comparatively-sized Android smartphone.
	4. iPhone 6 Plus - LTE Compatibility & Speed (2014-09-24)
	Unlocked iPhone 6 Plus bought overseas is found to have LTE working on Korea's SKT & KT networks automatically. Also, real life LTE speed comparison is made between the 6 Plus and the 5S.
	5. iPhone 6 Plus - VoLTE Compatibility (2014-09-25)
	Initially, all calls were made in 3G mode despite changing the settings to allow VoLTE. To have the VoLTE actually working, a visit to an SKT branch office and a device registration process was needed.
	6. Testing iPhone 6 Plus battery w/o bending (2014-09-29)
	Real-life battery discharging and charging tests are performed simultaneously on iPhone 6 Plus and iPhone 5S to see the difference. Belt cases made sure the phones didn't bend.
	7. iPhone 6 Plus - General Performance (2014-10-01)
	Performance comparison across multiple apps are made between iPhone 6 Plus and iPhone 5S. This included 3DMark, Geekbench, and various JavaScript tests.
	8. iPhone 6 Plus - Camera's Quality (2014-10-01)
	Compared to iPhone 5S, the camera on the iPhone 6 Plus has improved dynamic range and enhanced night time photography performance. Image stabilization works well, too.
	9. iPhone 6 Plus - Camera's Speed (2014-10-04)
	The focusing performance of the iPhone 6 Plus is noticeably more advanced than iPhone 5S. Burst mode shooting and slow-motion video recording also saw improvements.
	10. iPhone 6 Plus - M8 Motion Co-processor (2014-10-08)
	The M8 motion co-processor and its new barometer are tested out by walking up the stairs and seeing how many floors are registered. Other uses are also taken a look at.
	11. How far does iPhone 6+ & SKT's VoLTE go? (2014-10-13)
	How the SK Telecom's network treats the attempts to make a VoLTE call from iPhone 6 Plus varies by how the person at the other end is connecting. All the possibilities are tested.
	12. Thoughts on a month of iPhone 6 Plus use (2014-10-14)
	Using the iPhone 6 Plus one-handed is not as convenient as Apple would hope. However, the big screen that caused this also offers many benefits that maybe considered as worthy trade-offs.

As I mentioned in the previous VoLTE post, all three major mobile carriers in Korea have been supporting VoLTE for quite some time now. One glaring problem, though, is that cross-carrier VoLTE still hasn't been realized, despite years of negotiations. This seem to have introduced some confusion. The truth is that a device can always request a VoLTE call, but it's up to the network to decide to go with it, and if so, fully or just on the surface.

In the case of LGU+, the carrier's aging "2G" CDMA network had been a weak point, so it worked hard to have everything done on LTE, even voice. That's why it'll accept a phone that can do VoLTE even if it doesn't support the needed CDMA frequency band - namely, the iPhone 6 series. ( One caveat is that they are not accepted for registration on the network yet until official Korean debut. This is largely a decision of policy, not technicality. ) If you have such a phone, all calls will be connected as VoLTE no matter what.

But in case of SK Telecom (SKT) or KT, their "3G" WCDMA networks are still widely used. So they don't have the urge to go fully LTE. A call could still be made on either 3G or LTE, depending on the situation. No handsets on these networks get to make all of its calls on VoLTE.

Since I'm on SKT, I made calls to various phone numbers on my VoLTE phone, iPhone 6 Plus, to see how they end up connecting, and what quality they were.

Case	Caller 1	Caller 2	Connect 1	Connect 2	Quality
1	SKT VoLTE	SKT VoLTE	LTE	LTE	HD Voice
2	SKT VoLTE	SKT 3G (AMR-WB)	LTE	3G	HD Voice
3	SKT VoLTE	SKT 2G/3G	LTE	2G/3G	Normal
4	SKT VoLTE	KT / LGU+ VoLTE	LTE	LTE	Normal
5	SKT VoLTE	KT / LGU+ 2G/3G	LTE	2G/3G	Normal
6	SKT VoLTE	Landline (02 ~ 064)	LTE	Landline	Normal
7	SKT VoLTE	Toll Free (080)	LTE	Landline	Normal
8	SKT VoLTE	Special (15xx, 3-digit)	3G	Landline	Normal
9	SKT VoLTE	VoIP (070)	3G	Internet	Normal

As of this writing, two types of phones on the SKT network, the VoLTE-enabled phones (case 1) and the AMR-WB supported phones without VoLTE (case 2), can make end-to-end HD Voice-quality calls to and from iPhone 6 Plus. AMR-WB codec is the same codec used by VoLTE, but some phones support this only on 3G at a lower bitrate, e.g. iPhone 5 and Xperia Ray.

As mentioned earlier, cross-carrier VoLTE agreements are not yet in place, so calling VoLTE phones on other networks (case 4) ends up degrading quality. I'm hoping this clears up soon because there's no technical reason to be like this.

Meanwhile, most calls connect via LTE, with the exception of special numbers such as the three-digit numbers (including emergency) and the 15xx, 16xx numbers that companies use (case 8), as well as the VoIP numbers with the 070 area code (case 9). I understand that these numbers don't connect with high-quality codecs so LTE connection isn't necessary, but it doesn't explain why regular landline connections do connect via LTE.