Having braved the upgrade queue – a decision driven mainly by my current iPhone 3GS and its pitifully depleted battery (lasting around an hour into the day) – by 9.30am Friday I was a proud new owners of the iPhone 4S.

There are myriad features on the new iPhone that I love; after 24 hours of testing Siri to its limits, playing with notifications, the integrated Twitter features, the location-based reminders, and more, I’m in no doubt the ‘phone will enrich my life albeit in some small way.

Rather than focusing on these features, however, here I’m reviewing the iPhone 4S camera from the perspective of a professional photographer.

Summary of improvements

Here’s a list of improvements you’ll see in the iPhone 4S camera, whether they are down to the iOS5 upgrade (which can be installed on older models) or to the iPhone 4S itself.

This review expands upon all of these improvements.

• Ease of access
• Quick access from the lock screen (iOS5)
• No access to existing photos if iPhone was locked with passcode
• Ease of control
• Quicker camera-ready time (especially compared with iPhone 3GS and older)
• Vastly reduced shutter lag (un-noticeable delay in taking shot after pressing button)
• Increased ergonomics: use side button to shoot (applies to iPhone 4 and iPhone 4S under iOS5)
• Optional grid for rule of thirds
• Flash (improved on 4S) – photographers: keep that flash off at all times!
• Quick Edit after taking photo
• Crop / free-form rotate
• Separate 90 degree rotate function
• Manual red-eye removal
• “Auto Enhance” – photographers: avoid!
• Vastly improved focus and exposure seek time
• Pinch to zoom – photographers: avoid!
• Photo Stream (iCloud)
• Redesigned sensor
• Increased resolution (7.99MP: 3264 x 2448)
• Lower noise despite increased resolution
• Increased sensitivity: especially great for low-light photography
• Redesigned lens system
• 5 elements: sharper images
• Wider aperture: f/2.4 – brighter and more impressive images. Reduced DoF for more ‘artsy’ photos

Some background – a personal disclaimer

As a professional photographer, there is a small part of me that despises the concept of a cameraphone. This ubiquitous device has landed in the hands of The Many, which has led to an explosion in the number of photographs taken across the world in any given second (which should be good), yet a proportionally huge reduction in the average quality of a photograph.

If this sounds a bit abstract, just consider what you see on Facebook. Every minute detail of our lives is now captured on our mobile phones in poor light, at low definition, and with little thought. Every moment, including the seminal moments – a child’s fifth birthday party, a graduation, the first dance at a wedding. These seminal moments are being lost in the sea of photos that we take, their significance diminished in our memories.

However this problem is not because of the technology itself; we can’t blame technology. It’s how we have adopted the technology. But then, neither can we blame lack of expertise; it’s not only the average Joe who doesn’t realise that ‘less is more’ when it comes to curating our lives’ photos, I have seen professional photographers who take the easy line and offer clients quantity over quality.

No, let’s not focus on the effect that ubiquity is having on the social function of photography. Let’s focus instead on the camera itself.

I wish I could attribute the following quotation to someone like Henri Cartier-Bresson, alas it’s a modern idea;

“The best camera is the one that’s with you”

The History

As a cameraphone, the iPhone has long been behind the competition. Users of the original iPhone, the 3G, and to a lesser extent the 3GS, have bemoaned the poor camera.

The iPhone 4 brought the ‘phone’s camera up to modern expectations.

The iPhone 4S, released yesterday, greatly exceeds expectations of a camera phone, and many are saying it’s the best camera on a ‘phone to date.

What makes a good cameraphone?

From the perspective of a photographer, here’s what I believe makes a good cameraphone.

Ease of access: capturing ‘the moment’ is difficult if you have to navigate through menus and buttons before the shutter is even ready

With iOS5, it is now possible to access the camera from the lock screen. This may be done by double-clicking the home button, either when the lock screen is already showing, or when the phone display is off altogether.

And for those who protect their iPhone with a passcode, there’s no need to worry that this could be used to circumvent entering the passcode to view existing photos:

 

Controllability: how responsive is the shutter release? To what extent can focus and exposure be controlled? Is it quick to change the settings? What about other tools like composition guides or in-app post-processing?

One of the main issues with the iPhone 3GS was a delay when entering the camera app. The shutter animation would hang for a second or more, which really affects your ability to point and shoot. The iPhone 4S has an upgraded processor, and there’s no more waiting.

Another major gripe was that you had to use the software button on the screen to take a photo. The iPhone 4S now has a physical button for shutter release: the up-volume button on the side. This is a lovely button which provides a good level of physical feedback without jogging the ‘phone in the slightest when pressed. Great for macro shots, where the tiniest movement can throw the focus off.

Most importantly, something that angers most photographers about cameraphones – and indeed small point-and-shoot cameras – is the shutter release delay. These inferior cameras usually use autofocus; even if you have pressed the button, that shot isn’t taken until the camera thinks the image is in focus. This can lead to a delay of a second or sometimes more, and we professionals (or anyone with an SLR camera!) absolutely hate that!

The iPhone 4S has an instantaneous shutter release – like an SLR.

The result is that inexperienced users may end up with photos that are out of focus – but let’s face it, in many cases if you leave the camera to choose your focus point then you won’t be getting the best results anyway. At least this gives power back to the real photographer.

Combine this with the new face recognition feature, and the new super-fast focusing, and it’s actually very difficult to end up with photos that are out of focus.

The new iPhone 4S sports a grid for composing a shot according to the rule of thirds. Of course, this grid may be turned off, but it’s great for shooting landscapes. Here it is with the options screen:

Naturally, of course, we have the ability to turn the flash on or off, or set to auto. For a professional photographer, this switch is set to the ‘off’ position 95% of the time. If there isn’t enough light, the last thing we want is a horrible harsh flash lighting the scene. There are some occasions it is nice to switch the  flash on, such as … wait for it … when the sun is shining. Why? This is called fill flash, and if the subject is close enough to the iPhone, the bright LED light is just enough to take the harsh edges off the shadows that are cast on the subject’s face. Similarly the flash is useful for more ‘functional’ photographs, e.g. if you are trying to read a number from the rear of a box and you can’t quite reach it otherwise.

Other than that: turn that horrid flash off, and leave it off!

From the above screencap, you can also see the switch camera icon (top right). This allows you to use the front-facing camera on the iPhone instead. Whilst this might be great for that narcissistic shot of yourself, it most certainly won’t do your photography any good. The front-facing camera on the iPhone 4S is still pretty horrid, and should be avoided for anything except its primary intended use which is video.

Another brilliant boon to iPhone photographers in the release of the iPhone 4S is the quick edit function. This is where, after taking a shot, you can quickly crop, rotate, or fix red-eye. There is also an option to ‘Auto Enhance’, however this should be avoided if you are serious about the photo. Apple have mercifully avoided any other ‘artistic’ editing functions, as well as manual post-processing control over exposure or contrast, and stuck to the basics: crop, free-form rotate, and red-eye. This is a good thing.

  

The focus and exposure control offer a similar interface to previous generations – tap anywhere on the screen to focus on that point – however they are noticeably faster and more accurate. iPhone 4S now also has a face recognition feature which assists when focusing on a single subject or taking a group shot. The focus can of course be overridden by tapping the screen to focus on another point.

Unfortunately, there is no separation of exposure and focus control, which means the point you focus is also the point which you choose for correct exposure level. Personally I think that separating these two controls would indeed have been one step too far for the average user. If you require this kind of functionality… there’s an app for that.

The zoom control now uses multi-touch pinch rather than the slightly fiddlesome zoom scroll-bar on previous generations. However, as this is digital zoom as opposed to optical zoom, the result is that you are cropping the image rather than actually zooming-in. Therefore, never use digital zoom; it’s a bad idea because it reduces your options. If you need to see something close-up, you should crop the image afterwards using the new iOS5 in-app editing (mentioned above) or using other software e.g. on your computer. (The same applies for any camera with digital zoom!)

One final point of interest about the improvements to photo handling in iOS5 worth noting is the integration of photos into iCloud. A new folder appears within the pictures app when you upgrade to iOS5 (or by default on the iPhone 4S) called photo stream:

If you have upgraded to iOS5 (whether you restored a backup of your older phone to a new iPhone 4S, or just upgraded your non-4s to iOS5), you have the option of using the photo stream function. If you switch this on, all photos you take from that point onwards will be uploaded / backed-up to iCloud, and will appear in both the camera roll and the photo stream folders.

This is a real boon for those who use desktop or laptop computers (Mac or PC) as your iCloud photo stream can be synchronised with your computer. No more emailing yourself files, or uploading them to Dropbox! Windows users will need to download the iCloud control panel application (download link here) for Windows, and Mac users will need to upgrade to OS X Lion and switch on iCloud. The windows client allows you to set the location of your photo stream, if you choose to have this downloaded to your computer.

The Lens and Sensor: more important than megapixels

Everyone knows how futile the ‘megapixel race’ is; this is where camera manufacturers play on the general public’s lack of knowledge and get them to focus on meaningless specifications such as the megapixel count. Of course, it’s not an entirely meaningless specification, but in many cases over the last decade, cameras have been released with dog-awful lenses and a high megapixel count; all this does is to show you in even higher resolution how terrible the photograph is!

It’s like matching hi-fi speakers with an amp. No use spending a tonne on lovely speakers if the amplifier doesn’t do them justice.

As long as the megapixel count does justice to the lens and the quality of the sensor, that’s all the matters.

Apple upgraded the iPhone 4S camera’s megapixel count (this is a function of the new sensor itself, of course) to 8MP. This resolution definitely does justice to the upgraded lens and sensor. It’s worth noting at this point that the video function does not use the full resolution of the sensor, and as such the image is cropped. Therefore, it’s no longer possible to take such wide angle images in video mode. This is a great shame, and it would surely have been possible to use the full sensor frame but reduce the resolution on-the-fly.

So – onto the good stuff: the lens and the sensor.

Apple stated that, despite having a higher resolution, the new sensor is 73% more sensitive. This essentially means the lens performs better in low light, which means that there is less blur and less noise. Let’s take a look. This is actually a comparison of images from iPhone 3GS rather than the iPhone 4.

The image from the iPhone 4GS had its resolution reduced in Photoshop to match that of the 3GS, for comparison’s sake. The images were taken in the same light.

The brighter image is from the iPhone 4GS.

As well as poor response to light and higher noise, below we can also see the increased JPG artefacts from the iPhone 3GS, however this may be due to the fact the image was not reduced in size, whereas the 4GS image was reduced in size, for this comparison.

If you can look past the noise and the JPG artefacts, it’s also possible to see that the image has a greater clarity of edges and increased detail in the blacks. Compare the cat’s eyes and nose; on the 3GS version they are blacker and with less detail.

As well as this revised sensor, the iPhone 4S has a completely redesigned lens setup, with a wider aperture (f/2.4, as opposed to the iPhone 4’s lens aperture of f/2.8). This wider aperture allows more light in, and as you can see from the below test images, it reduces the depth of field; this is something many photographers will enjoy about the new lens, as it can slightly improve the feel of portraits.

Note that the aperture of f/2.4 is not equivalent to that of the photographer’s standard measurement based on the 35mm film. The equivalent aperture would be much higher, in the order of f/18-22, as is appropriate for a fixed-aperture and fixed-focal-length lens.

Of course, the focal length of the iPhone 4S has also changed, and it’s now 4.3mm as opposed to the iPhone 4 focal length of 3.85. Whilst it may seem at first the image should appear zoomed-in in comparison to the iPhone 4, remember that the crop factor may be slightly different if the sensor has been redesigned. Very little detail has been released on the dimensions of the sensor itself.

The below two images show the effect of DoF (depth of field) of the iPhone 4S as compared with the iPhone 3GS. The images are shown here uncropped; the iPhone 3GS image is taken at a slightly higher elevation to compensate for the different focal length. These images are not intended as technically accurate comparisons of DoF.

Observe the bottom horizontal stick (a thin bamboo skewer) in both photographs. The focal point of both images was the middle stick. The iPhone 4S version shows the bottom stick to be much more out of focus.

The reduction in DoF is not severe, however it will have a noticeable effect on portrait shots, where backgrounds will appear that little bit more blurry and out of focus, thus accentuating the subject. A lesser proportion of the iPhone 4S image is in focus, which results in a more artsy photo. Great in most cases.

For example, here’s a picture of an avocado in the foreground, with me in the background…

And Apple has proven the DoF point with a slightly less attractive model, and a pretty flower…

The new lens consists of 5 elements, one of which Apple has stated is a ‘hybrid infrared filter’. This is presumably due to the increased sensitivity of the sensor to incident infrared light.

Summary

Please do see the summary of improvements listed near the top of this review.

Hopefully I have covered the main improvements to the iPhone 4S camera. As always, I’d love to hear your comments. Thanks for reading!