10 April 2012
The iPhone 4S is one of the most popular smartphones on the market and comes packed with an 8 megapixel camera as one of its main features. The iPhone's glass and metal construction makes the phone feel very solid in the hand but a little less gripy than some other smartphones. This is a phone that cries to be used with a case for better grip and protection.
The camera lens lays flush with the back of phone and so does not protrude like on some ohter smartphones. Next to the lens is an LED flash that can double as a video light whilst shooting movies. In terms of movies the iPhone 4S can shoot at a resolution of 1080p with mono sound.
There are no physical camera controls provide on the phone but one of the volume buttons can serve as a shutter release. With the latest iOS 5.1 firmware the camera can be quickly enabled by just swiping up the standby screen (even if the phone is locked).
Of interest here is the iPhone 4s camera. The iPhone packs an 8mp camera with improved optics compared to the previous model. The feature set can be considered as follows:
- 8 megapixel backside illumination sensor
- Full HD video
- 3.5 Touch Screen
- HDR mode
- Face detection
- LED Flash
- Image Stabilisation (video mode only)
- High resolution screen
- Quick activation from standby screen
- Digital zoom
The iPhone 4S has a simple user interface compared to many other smartphones. On starting up the camera the autofocus is immediately engaged. There is no audio or visual confirmation of correct focus but only an indication of the area where autofocusing is taking place. If faces are detected then each face will be highlighted momentarily with one face uses as the main AF point.
The autofocus is started immediately the camera is activated and will focus on anything in the central area of the screen. Refocusing will take place automatically if the subject moves. Touch focus permits autofocus anywhere else on the phone's screen.
There is no image stabilisation for stills photography. Image stabilisation has been provided for movie capture.
Using the iPhone as a camera is fast and straightforward with the latest iOS 5.1 installed. It’s just a matter of pressing the home button to wake up the screen and then swiping upwards to activate the camera from standby. This works even of the phone is locked (and will return to the locked screen once the camera is closed). The iPhone seemed to determine exposure from across the whole image area when first activated or after a shot had been taken in preparation of the next. Autofocus was carried out in the central area denoted by for focus area initially displayed. The iPhone 4S has a form of continuous autofocus but could not follow focus a moving subject across its screen.
Photos were rendered with plenty of detail and without excessively boosted colours. The colours came across as quite neutral overall although this depended in part on how well the white balance was adjusting to the lighting conditions. The shutter speed can can drop as slow as 1/15 seconds. The fixed f2.4 aperture with the variable ISO of between 64 to 800 provided versatility to the lighting conditions that the iPhone shoot in and return acceptable results.
Although it was possbile to take decent photos under low lighting conditions it was a challenge to ensure that camera shake did not spoil the end result. The best results seemed to have been obtained using the volume button as the shutter rather than the on screen shutter button. The only downside to using the volume button was that fingers could easily partialy obscure the lens. Usually the lens should be on well away from the hand that grips that phone. This can be solved by rotating the camera and having the shutter button facing downwards but this felt unnatural.
An example of a typical daylight shot is shown below. The white balance has worked well here maintaining the slightly warm colour temperature given by the sunlight.
f/2.4 @ 1/2000s - ISO 64
100% Crop A
100% Crop B
The evening shot below was illuminated by street lights. The result looks more than acceptable and the image noise was kept under control. Despite to slow shutter speed and low lighting conditions the photo maintains a good level of detail as well as sharpness.
f/2.4 @ 1/15s - ISO 800
100% Crop A
100% Crop B
Generally the autofocus performed consistently well in a variety of lighting conditions but the best performance was obtained by tapping on the phone's screen to select the required point of focus. Not only was this spot focusing but spot metering too. This worked well but there were times spot metering from the point of focus did not give the require results. It was not possible to separate to the two features. Tapping and holding the screen cause the focus and exposure to be locked so a shot could be recomposed if necessary. The face detection worked reasonably well and detected faces quickly. Faces in profile were more difficult to detect.
The built in flash light proved effective at providing illumination on subjects no more than a meter away. It can be set to automatically provide illumination when light levels dropped, force on to provide illumination under any ambient light conditions or kept off. Preference was to shoot with it forced off and just rely on ambient light. The LED flash acted as a focus aid light when it was enabled but unfortunately this feature is lost when the lfash was disabled. There were times it would of been helpful for the LED flash to aid focusing in low ambient lighting but not to fire during the actual exposure. This is one of the features that tends to separate the compact camera from the smartphone.
Full HD Movie
The movie mode delivered decent quality 1080p videos but it will quickly eat into the phones available memory. There was no facility to reduce the resolution to say 720p or 640 and so this mode needs to be used with care especially if shooting with the iPhone 4s with only 16GB of memory. Just like when shooting stills the exposure and autofocus are locked together and there and the white balance is not adjustable.
The Image stabilisation became activate in the movie mode (and it cannot be turned off). It did not provide a great deal of stabilisation to the video so walking whilst recording always returned shakey results. However, it was good enough to sensor movies looked more presentable than the typical results seen from smartphones that provided no image stabilisation at all.
The phones integration with iCloud means that photos taken can be automatically transferred to any computer with iCloud enabled. This is really just a convenience feature but it worked well. The images can always be transferred in the usually way by connecting the phone directly to a computer.
- Straightforward user interface
- Good quality optics
- 8 megapixel sensor
- Reasonable AF operation
- Neutral type colour balance
- HDR feature is useful (although not totally effective at times)
- iCloud integration
- Full HD 1080p video capability.
- Tap to refocus during movie capture
- High quality screen viewable in bright conditions
The Not so Good
- Using the volume button as the shutter may result in a finger getting in the way of the lens
- No selectable white balance
- Autofocus and exposure cannot be separated (requires third party apps)
- Stills and video size non selectable
- Using the volume control as a shutter can result in fingers obstructing the lens
- No panorama mode
- Movie resolution not selectable
The iPhone 4S camera app was simple to use and on the whole got the job done. It's well suited for taking photos for use on social media sites or for general display on computer monitors. Prints should look good printed up to A4 in size and even stretch to A3 under optimal conditions. The 8 megapixel images are sharp with a good level of detail. The auto white balance worked well in general but could change from shot to shot, for the same scene, which made results a little inconsistent. The iPhone's Retina (high resolution) screen made it easy to check for focusing errors.
It would have been better if the iPhone 4S had a dedicated shutter button than using the volume control. Having the lens placed under the shutter just made the lens too prone to being obscured by fingers. It is worth noting that some phone cases make using the volume shutter control awkward.
If more control is required over the camera then it is necessary to use one of the third party camera applications. These apps allow the focus area and exposure metering area to be selected separately. Some allow the metering, white balance, and focus to be locked independantly. Some can even show a level gauge to help avoid any sloping horizons. Unfortunately none of the apps (as far as has been determined) provide features such as exposure compensation and while balance presets which as generally standard on most smartphones. Such features may be appreciated by those wanting to create the best possible photographic or movie content directly out of their phone. Third party apps such as Camera+, Camera Awesome, Pro Camera and Filmic Pro are worth consideration to get that extra bit of operational quality out of the iPhone's camera. Given the shortcomings, it is hard to compain about the camera as delivers where it counts the most in terms of the general image quality. The iPhone 4s delivers where it counts in terms of image quality. It may not totally replace the compact camera for many but it has the advantage that any photos taken can be quickly adjusted and circulated as required. EA