With more and more of the general public using smartphones to capture their daily life events, just how far can these devices replace conventional compact digital cameras? This page will examines some of the images possible with just a smartphone.

Huawei P20 Pro DNG Heavy Vignette Problem

The Pro Pro has the ability to record in RAW (DNG) format which would be a big bonus for those photographers wanting to use this as another great imaging tool in their portfolio.

However if you look at the output from the camera you will notice a heavy blue vignette and overall slightly dark appearance to the file.

As there are no presets yet for this in Camera Raw I thought that I would build a Photoshop action to automatically normalise the image and remove the vignette.

So why does this happen?

Most digital cameras generally have an array of micro-lenses in front of the cmos sensor. Think of them as light guides for photons. These photons are directed to the individual photosites below through a "Bayer filter", which essentially splits light into components of red, green and blue.

On larger sensors, the micro-lenses are angled towards the centre of the sensor, and thus are more angled the further towards the edges of the sensor you go; this is more extreme on full frame sensors. The problem arises when light is altered in some fashion before it reaches the photosites, causing one or more colour components (RGB) to not register correctly. 

Using a physically short wide angle (as opposed to longer lenses and focal lengths) causes light hitting the micro-lenses in the border region to hit at a rather oblique angle to the micro-lenses. This leads to the "cyan-blue edge" 

Additionally because CMOS sensors are very sensitive to infrared wavelengths, the lens assembly includes an IR filter. These filters are quite effective, but they’re not perfect. For interference type filters, the cutoff wavelength is dependent upon the angle of the incoming light rays. Mobile cameras, whose lenses are extremely close to the image sensor, are especially susceptible to this aberration because of the larger CRA values (chief ray angle, which is the angle a light ray passing along the lens optical axis)  they encounter. Colour shading results in anomalous colour variation across the image. This issue may be more noticeable using different light sources, particular those that do not have a continuous spectrum such as LED or fluorescent lights.

As mobile devices continue to get thinner and mobile cameras try to compensate for smaller CMOS pixels by gathering more light with larger apertures, optical aberrations will become increasingly difficult to avoid and it is now down to the image processing system to make corrections for these problems. In the case of the Huawei P20 Pro it appears that the JPEG processing has this colour shading under good control but it would seem that no attempt has been made to "normalise" the RAW file from the camera. In my opinion this is a great shame as the use of teh RAW file is one of the considerations that might be made bu potential purchasers who are photographers. I hope Huawei do something about this in future update of the firmware.

So its the peripheral rays (off axis) which cause the vignetting because the light does not fall perpendicular and into the photosite (pixel).

This is the reason why the outer parts of the image are darker than the centre and additional colour changes can be made by the light as it passes through the IR filter at ray angles that are wider than the CRA.

The Photoshop actions script is here.

Following more research on this there is also a public domain program which will create a profile for the DNG file however it is a standalone program. It does have the capability to "batch process" a whole group of DNG files prior to your final editing in your favourite image editing program.

The program is called corner fix and is available for mac and pc. The file and instruction are found here

The Huawei P20 Pro Review (Camera only)

The Huawei P20 Pro has have some aggressive advertising and some glowing user reviews. How factual are these statements and just how good is the camera for general photography?

Unfortunately, the Huawei P20 Pro only supports RAW capture in one camera software mode (the Pro mode) and only on one camera sensor (the 40Mp sensor).

That means you can’t get RAW data from the 87mm telephoto 8Mp camera/lens combo, the B&W 20Mp camera, or the 24Mp front facing camera/lens combo.

You can’t even get alpha channel depth map data from the multi-camera artificial intelligence processes.

The RAW fie is in the DNG format 7280 × 5456 pixels and an average file size of 85MB.

At 1/1.78″, the main camera’s sensor is approximately twice the size of the Samsung Galaxy S9’s 1/2.55″ chip. Despite a slightly slower f/1.8-aperture lens, the RGB main camera sensor of the P20 Pro captures approximately 20 percent more light than the smaller sensors used in most competing models.

As with previous high-end Huawei smartphones, the main sensor is supported by a secondary monochrome sensor which helps further increase photon capture.

The main camera sensor uses a Quad Bayer structure with a total pixel count of 40Mp. It outputs data pixel binned in 2 × 2 units, resulting in 10Mp image output.

With an equivalent focal length of 80mm, the P20 Pro’s optically-stabilised tele-camera offers a significantly longer reach than the 2x tele-modules in the latest iPhone or Samsung Galaxy devices.

This is possible because the main camera in combination with the 20Mp monochrome secondary sensor is already capable of delivering decent zoom detail at a 2x zoom factor.

As a consequence, the engineers have been able to focus on squeezing a longer reach out of the P20 Pro’s tele-lens. The Tele also outputs 10Mp image.

The front of the phone is dominated by the 18.7:9  6.1-inch notched display. The display notch contains the 24MP front-facing camera, a circular-shaped earpiece that doubles as a speaker, the proximity and ambient sensors.

Despite the presence of the notch, there is a sizeable chin on the bottom of the front. This is because Huawei has placed the fingerprint sensor on the front this time around. The placement of the sensor may seem strange, but I did not experience any problems with it.

The advantage of a front fingerprint sensor means that you can use EMUI’s fingerprint gestures to navigate the phone without using the on-screen navigation bar. This ensures that display estate isn’t wasted, and essentially cancels the drawbacks of the fingerprint sensor placement.

Despite having 40MP resolution, the P20 Pro takes 10MP photos in 4:3 ratio by default. You can still take 40MP photos, but the recommended choice is to use the 10MP default option. Why? It’s because the 10MP option uses  2 x 2pixel binning to enhance clarity and remove noise.

The camera Pro mode is a fully featured implementation of a manual mode, with options for ISO, shutter speed, exposure compensation, white balance, and metering. The P20 Pro can go up to an ISO of 102,400 in auto mode. In Pro mode, the maximum ISO which can be chosen is ISO 6400.

The camera app also includes different Aperture and Portrait modes. Aperture mode is a general wide-aperture mode that lets you simulate apertures between f/0.95 all the way to f/16. The aperture and focus point can be changed after the photo has been taken. Portrait mode, on the other hand, is intended for taking photos of people. It allows users to enable or disable the background blur effect, and it also has simulated lighting effects to compete with Apple’s 2017 iPhones.

The Huawei P20 Pro can record 4K video at 30fps, and 1080p video at 30fps and 60fps. Huawei provides an option to record videos with the standard H264 encoder or the new HEVC (H265) encoder, but there is minor difference in file sizes between the two encoders. Using the standard H264 encoder, 1080p@30fps videos have a variable bitrate between 8-14Mbps, while 4K@30fps videos have a bitrate of 38-40Mbps and 1080p@60fps videos have a bit rate of just 19Mbps.

Unfortunately, electronic image stabilisation is only present in 1080p@30fps videos.

4K videos and 1080p@60fps videos don’t have any stabilisation. This means that camera shake is highly visible in both 4K@30fps and 1080p@60fps videos.

Night Mode is one of the most important modes in the camera app. It performs stacking of photos with long exposures of up to 5 seconds, and it manages to mostly avoid camera shake thanks to AI-assisted stabilisation. 

For the most part, the P20 Pro uses its 4D autofocus to focus quickly and take photos in quick succession. However, in many cases, when a photo is taken, the camera app displays the message “Sharpening the photo… Please steady your device.” This adds to the shot-to-shot time of taking photos, as there is a noticeable delay after taking such a photo. This message is predominantly displayed in low lighting conditions, but strangely, it’s displayed sometimes in daylight as well.

Master AI is headlined as one of the P20 Pro’s main camera experience. It can identify some 500+ scenes and dynamically switches to different scenes without the need for user intervention. This means that in low light, the camera automatically switches from Photo mode to Night Mode to improve photo quality.

However, the implementation of Master AI isn’t flawless and it can sometimes misidentify a scene.

It can take its time switching between scenes. There is a delay of around two seconds between Master AI deciding a scene and actually switching to it.

This means that you may inadvertently take photos in the “incorrect” scene as photos are taken before the camera app switches to the mode decided by Master AI.

The 24MP front-facing camera has a f/2.0 aperture and a fixed focal length and focus.

It can take video clips at up to 720p resolution.

Sample image from the Huawei P20 Pro (click for larger images)

Iphone X Sample Images

I recently upgraded my iPhone 8 plus to the iPhone X because of the fact that this new device has dual optically stabilised lenses.

I found the normal x 1 lens on the iPhone 8, which had stabilisation, was a great benefit for video so the fact that the x2 lens was also stabilised was a big bonus to me.

Image quality is excellent. Colours may be a bit vibrant but they can be tamed in post editing if needed.

Here a re a few images taken with the iPhone X just to show how far smartphones have really developed.

Click for larger images.

Bluetooth Remote Shutter Release

For images without camera shake and smoother starts and stops for video recording it is preferable to use some form of remote shutter release on the camera. Some phones allow the use of the call button, or the volume buttons on the headset to fire the shutter or are implemented through a simple bluetooth push button. The pushbutton acts as a one key keyboard in effect sending the right command to the phone or app to release the shutter.

I found this neat device on Amazon which has a circular, removable, clamp which allows you to fit it to a number of handle options.

Here you can see the button mounted on my handle that I use to hold my phone in a camera grip. With a simple thumb press I can start and stop video recording or take a picture/

Review of the OlloClip Core Lens Kit for iPhone7/7plus-8/8plus

The 29mm EFL lens of the 7/8 series iPhone may be too large in some situations where a wider field of view is necessary.

Olloclip do a range of lenses and phone adaptors to enable wide angle, fish eye effect and macro shooting

Firstly the Olloclip Core lens set consists of three parts: the clip, the lenses and a stand.

The clip fits onto the iPhone body (versions for the iPhone 7/8 and 7 Plus/ 8 Plus are included), and two lenses click into place in a cavity in this clip, holding them in place in front of the phone cameras.

One neat trick here is that you can use both the front and back cameras, because the clip can hold one lens on either side of the camera body, over both the front and back cameras. The clip is reversible, too.

The Core Lens Set includes a fish-eye lens and a super-wide lens, both of which increase the viewing angle of the iPhone camera.

The fish-eye lens offers a clean, sharp fish-eye view that covers about 175 degrees.

If you unscrew the front of the fish-eye lens, it becomes a macro lens, offering a 15x magnification on the standard iPhone camera. This combination of camera and macro lens can focus on objects that are between 1 and 2 centimetres (about 0.4 to 0.8 inches) away from the front of the lens, so it can get very close to an object and capture a lot of detail.

Well we probably know that lenses have to be placed on the lens axis to be most efficient and provide least distortion. Getting this clip to sit exactly on the axis was a bit of a hot and miss affair.

The clip is so tight on the cameras that if you have a glass screen protector fitted which is over 0.5mm thick it is unlikely that you will get the clip to for or when you are sliding this into place you will crack the screen protector at the top slot.

The clip is of a hard plastic nature and the two lenses are fixed into the frame on two mounts which pivot in the frame - thus allowing them at align perfectly flat with the front and rear screens. I found it really difficult to get the clip down over the lens area without some fear of it scratching the diamond glass lens cover or the iPhone screen or back glass panel (on the iPhone 8 Plus). One pin is spring loaded and should be placed to the outside edge of the mount - if you fit it the other way round you will need a fine piece of rod (like a toothpick) to be able to reach the pin through the longer side of the clip - A very bad design point here.

There is absolutely no way to use the clip without the camera being removed from any protective case that you might have fitted.

So in summary the optical quality may be OK for Instagram/Facebook type images where image quality isn't necessarily the key important factor. For me the image quality loss, the very fiddly nature of fitting the clip and lenses to the clip itself renders the complete kit virtually useless and I will be returning the clip for refund.

iPhone 7/8 and iPhone 7/8 Plus New File Formats

Apple have implemented two new file formats for images and video clips recorded with these cameras, High Efficiency Image File Format (HEIF) and High Efficiency Video Coding (HEVC) are powerful new standards-based technologies for storing and delivering images and audio visual media.

The formats of HEIF and HEVC were developed by MPEG (Moving Pictures Experts Group), similar to JPEG that developed the JPG format.

Right now there is no way to export a .heic file from the Mac OS Photos app for photos that were uploaded to iCloud from the iOS 11 devices (only standard image formats are offered).

These use HEVC which cuts file size to roughly 50 % with no loss of detail. Standard encoding uses 16x16 macroblock techniques where HEVC can use up to 64x64 resulting in much better edge definition.

Follows on to H.264 and delivers significant compression improvement over H.264.

                              iOS                      macOS
Hardware Decode  A9 Chip              6th Generation Intel Core
Software Decode   All iOS Devices    All Macs

When the iPhone is connected to a Windows device the resulting file appears as a JPEG file and this is automatically encoded if the "automatic" feature is set in the Photos app settings.

Currently there is no Windows support for the .heif file type but a new add-in for Windows will allow the opening of the HEIF files.

CopyTrans HEIC for Windows 
Once you have installed the add in for windows explorer the HEIC files will show up if you BROWSE the DCIM folder of the USB connected iPhone if you have selected the Keep Originals in the iPhone Settings, Photos menu.

Programs which import the .heif and convert to a 16bit TIFF image that I have tested are

Photoshop CC2018, DXO Optics Pro9, Affinity Photo 1.6.6

The new format gives 50% smaller file sizes and 16 bit colour but currently Apple do not furnish any of the IOS devices with the facility to WRITE/SAVE to the file type from any of their applications.

HEIF has an added benefit too. It can store groups of images as a single file. This is especially handy for things like burst photos or keeping an edited image and the original in the same file. It's also a natural fit for Live Photos (including the new Live Photo options debuting in iOS 11), which act as one photo in your library, even though they contain multitudes.

iPhone 7 Plus sample images

A few sample images from the iPhone 7 Plus  12M image sensor F1.8, fixed aperture and 12M F2.8 fixed aperture

iPhone 6S images

Some sample images from the iPhone 6S with the 12M I-sight camera. Most images have been acquired using ISO 25-50 at f2.2

Sony Xperia Z3 Sample Images

A Gallery Of Images from the Sony Xperia Z3