Whether you’re a professional photographer or a regular phone user who likes to take pictures, there is no denying the iPhone’s significance to photography in general. It is undeniably the most used camera in the world after all. In fact, a majority of professional photographers I know use the iPhone as a phone, and do use the camera more than most would expect. Why? Because it has the most natural looking pictures with minimal digital artefacts compared to other camera phones available in the market.
Enter the iPhone 6 and 6 PLUS. These have been out a week now and for many, the decision of which one to buy has come down to one deciding factor – which one has better image quality? The iPhone 6, or the 6 Plus, with the additional Image Stabilisation (IS) feature? Both use the same sensor, but do they perform and operate in the same way?
During my own decision making process, I decided on the 6 Plus due to the following:
- Longer battery life
- Landscape formatting
- Image Stabilised camera
- Higher resolution screen due to higher pixels per inch (PPI)
Apple says it's the best camera they've made yet so I was very excited to see 'how' much better these cameras are, and in my initial testing I noted that they are better than any previous generation iPhone camera all-round. Most cameras perform well in bright light and considering the only difference between the two cameras was IS, I had to test these in low light. The only doubt in my mind was how good the Image Stabilisation is, and would it equate to providing better image quality compared to the smaller, more pocketable iPhone 6? I quickly compared them in my house and found out some very interesting facts just by running some low light tests on objects. So I decided to go out and do a quick shoot in the field to see if my findings would be the case in real world shooting.
Here is what I found - files have been reduced in size and have not been edited or altered.
Brief Field Test
iPhone 6 | ISO 125 | 1/15sec | f/2.2
iPhone 6 Plus | ISO 250 | 1/30sec | f/2.2
Immediately we see that the iPhone 6 is giving an extra stop of ISO, which is providing 1 stop extra in speed of 1/30sec to 1/15sec. Both images came out nice and sharp but we can already see that the iPhone 6 Plus is being a little sneaky and using its IS to get away with a lower ISO and shutter speed - well it worked!
iPhone 6 | ISO 250 | 1/30sec | f/2.2
iPhone 6 Plius | ISO 200 | 1/30sec | f/2.2
For this shot, I wanted to keep the exposure down as both cameras were overexposing when I positioned the focus/exposure point on the face, so I used the new exposure control to push it down and make them darker. Just by looking at the LCD's I managed to keep the exposures almost the same. Both are sharp but the 6 Plus is a tad sharper due to the IS system.
iPhone 6 | ISO 320 | 1/15sec | f/2.2
iPhone 6 Plus | ISO 100 | 1/4sec | f/2.2
100% zoom
200% zoom
This was the most extreme difference I encountered. A difference of nearly 3 stops in ISO and even at that you can see how well the IS is doing to keep things sharp. Looking at 100% and then 200%, the difference becomes more obvious.
iPhone 6 | ISO 320 | 1/15sec | f/2.2
iPhone 6 Plus | ISO 80 | 1/4sec | f/2.2
I think by now you are probably seeing what I'm seeing, in the EXIF information - the 6 Plus is forcing ISO and shutter down to very very slow levels. Ironically, as long as you keep the camera still enough, the image stabilisation is doing a great job of keeping things sharp. Of course it is also up to the operator to keep the phone/camera still. Ensuring you 'touch the shutter icon and release', compared to 'tapping' the icon will guarantee you a much higher hit rate.
Basic Analysis
As you can see, the iPhone’s exposure system has been programmed with algorithms that force the camera to keep ISO and subsequently, shutters speeds down very low, even in low light. This results in pictures that are very clean in low light, where most cameras would potentially be a little noisier. Most auto-exposure systems recognise that when light is low, the ISO needs to increase to where shutter speeds can be fast enough to handhold. This is extremely important with phone cameras because most people don’t carry around tripods.
I was quite shocked to see these iPhones selecting ISO’s as low as 64, and shutter speeds at ¼ second which is way too low for shooting in such low light. The differences between the iPhone 6 and 6 Plus is evident in the EXIF data, where you can see the iPhone 6 Plus is consistently selecting an ISO 1 to 2 stops lower than the iPhone 6. I can only assume that it is doing this because, the Image Stabilising system kicks in, and counter balances for potential camera shake.
Both cameras turned in sharp results as the lens is actually very good, and even when ISO’s did hit 400 to 640 (which was the highest I recorded), the pictures were still quite good. The IS in the 6 Plus worked very well and as long as my subject was still and I kept my hands and phone still while pressing the shutter, the results were sharper and a little cleaner than those shot with the regular 6.
In some ways you could say that the iPhone is cheating to keep the pictures clean, albeit at the risk of motion blur and camera shake. They're putting a lot of faith in their IS system and for good reason it works. Though they're probably putting a little too much faith in their users, who may not be able to hold the camera still enough, especially when taking selfies. Most cameras would be prioritising high ISO and shutter speeds in equivalent low light, so this does give Apple a 'clarity' advantage, as long as the pictures come out sharp. So it this a good thing? Only time will tell......
Conclusion
So what does this mean for potential buyers? The iPhone 6 will often select shutter speeds 1 to 2 stops faster, meaning you’re a little more capable of getting faster shutter speeds and freezing any motion that may be occurring in your picture, BUT, because the ISO is still so low, barely exceeding ISO 400, the speeds are barely fast enough to freeze someone walking at a slow pace. Therefor, the Plus with it’s Image Stabilisation is probably going to return better image quality more often compared to the 6, which just doesn’t do enough to keep images sharp in low light. There’s no point going to ISO 200 in low light when the shutter speed is still around 1/30 second.
So, with all other deciding factors aside, I give the 1st place trophy to the iPhone 6 Plus. In most situations, you’ll never see the difference side by side, but in low light, that is when the advantages of the IS will kick in and provide better images.....having said that, if you're after a phone/camera that can replace your serious compact camera, the iPhone is NOT it. Prioritising low ISO and slow shutter speeds in low light is not how a good camera should be operating and I'm a little surprised at Apple's decision to do this - though at the end of the day, what do they really know about making cameras? They make smartphones and computers after all ;-)