One of the most well-regarded series of digital cameras has just received an upgrade. Richard Sibley finds out whether the performance of the Canon PowerShot G15 befits its lineage. Read the Canon PowerShot G15 review...
Canon PowerShot G15 at a glance:
- 12.1-million-pixel, 1/1.7in CMOS sensor
- 5x 28-140mm lens
- ISO 80-12,800
- Optical viewfinder
- 3in, 920,000-dot LCD
- Street price around £549
Canon PowerShot G15 review – Introduction
Canon’s PowerShot G series began in 2000 with the launch of the 3.3-million-pixel G1 and for years it was considered vastly superior to most of its competitors in terms of quality, engineering and specification. Indeed, for a long time, this series of advanced compact cameras sat firmly at the top of the wish list of many enthusiast photographers who wanted the full complement of controls they had on their DSLRs.
Despite its moniker, the new PowerShot G15 is in fact the 12th camera in the line, and like its predecessors it has a larger than standard imaging sensor. The PowerShot G series is also the last range of compact cameras to feature an optical viewfinder.
During its lifetime, the G series has seen certain features come and go, and even sometimes reintroduced. For example, in the G7 raw image capture was lost, only to be brought back with the G9. Vari-angle screens have come and gone from model to model, and the 14-million-pixel resolution of the G10 was reduced to 10 million pixels in the G11, after photographers demanded fewer pixels in exchange for better image quality. Perhaps the most significant change was the introduction of the PowerShot G1 X earlier this year. This model uses a significantly larger 14.3-million-pixel sensor, which is basically a 4:3 cropped version of the 18-million-pixel CMOS sensor used in Canon DSLRs.
However, these days the latest PowerShot G series is beset by competition from all sides: compact system cameras have become smaller; bridge cameras are more advanced; and almost every manufacturer produces a high-end compact that shoots raw images. The new Canon PowerShot G15 may therefore find it much more difficult to gain a foothold in the market. That said, this latest G-series model is more than just a cosmetic makeover and offers a number of new features, notably a new image sensor and improvements to the lens, as well as a slight redesign of the camera’s body.
The most important change made to the PowerShot G15 is the inclusion of a 12.1-million-pixel CMOS sensor, although it measures 1/1.7in (around 7.6×5.70mm), which is the same as that on the preceding PowerShot G12. In addition to the extra 2 million pixels of resolution compared to the G12, the sensor has also shifted from CCD to CMOS technology in the G15. This switch to CMOS should help reduce power consumption and provide the quicker processing speeds required for faster frame rates and HD video. This is because some of the basic processing required for these tasks is done within the CMOS sensor architecture, whereas on a CCD sensor it is carried out by the camera’s processing system.
Handling the camera’s data is Canon’s Digic 5 processing system. This isn’t the first time we have seen a Canon PowerShot model with this combination of sensor and processor, as it was also used in the PowerShot S100 (see AP 3 December 2011). In fact, the G series is the last PowerShot line to receive the new 12.1-million-pixel sensor; both the S compacts and SX bridge cameras now have second-generation cameras that use this very combination.
The sensor is also one of Canon’s HS units, which are backlit, meaning that much of the circuitry lies at the back of the sensor, allowing more of the sensor’s surface to receive light. This is designed to ensure that more light photons reach the photodiodes, which should result in reduced levels of noise and increased dynamic range due to more detail appearing in shadow areas. All this, in turn, means the sensitivity range of the sensor is increased from ISO 80-3200 in the G12 to ISO 80-12,800 in the G15. Of course, this isn’t all down to the new CMOS sensor – improvements in noise reduction algorithms also have a part to play.
Optically, there have also been changes. The focal length of the G15’s built-in zoom lens is still the same 6.1-30.5mm (28-140mm full-frame equivalent) range as its predecessor, but the maximum aperture has increased from f/2.8-4.5 to f/1.8-2.8. The number of elements remains the same as in the previous lens, with 11 elements in nine groups, but it now contains one single-sided aspherical lens, one ultra-low dispersion lens and two double-sided aspherical lenses.
The larger aperture should help low-light performance and allow for a faster shutter speed when using the maximum zoom, as well as creating a slightly shallower depth of field for portraits or close-up work. As before, the lens is optically stabilised, with Canon claiming a 4EV reduction in usable shutter speed.
Helping to make sure that your images are perfectly straight, there is also a new dual axis level that displays both side-to-side, and front-to-back tilt – so no more excuses for wonky horizons.
There are a number of other changes, including significant improvements to video capture, a fixed screen, faster AF and a redesigned body, but more on these later.
HDR imagery has grown in popularity over the past few years, and we are increasingly seeing cameras released that can shoot and create HDR images. The G15 also includes this facility.
In HDR shooting mode, the camera takes three images: one for highlights, one for shadows and the third a normal, evaluative exposure image. The shots are taken sequentially with one press of the shutter button. Afterwards, the G15 takes a few seconds to combine the three exposures into one single HDR image. Sadly, the individual images are not saved, only the final HDR JPEG file.
The results are good, and more importantly they are realistic. There is no sign of the intense local contrast-halo effect typically seen when HDR images are pushed too far. Instead, there is a nice overall contrast, with just a little more detail in the highlight and shadow areas, rather than creating an image that is almost a complete midtone.
However, there are some restrictions. Unlike some other consumer cameras, the G15 doesn’t automatically align the images, so a tripod must be used. If not, there is bound to be some slight movement between shots, which will cause a ghosting effect on the image. Similarly, any movement in the scene will cause ghosting, the most obvious example of which is when someone moves across the scene. It is also important when taking landscape images to make sure the wind is not blowing strongly, as trees and plants may move between each image.
However, for most landscapes, night-time cityscapes or interior shots, the G15’s HDR option is a useful feature to have.
Build and handling
Despite carrying all those DSLR controls, Canon PowerShot G cameras always managed to be pocketable. However, the arrival of compact system cameras, as well as smaller competing cameras from rival manufacturers, has meant that G-series models now look decidedly bulky. Canon has realised this, and has shaved a few millimetres off the G15. Most notably, it is 8.2mm slimmer, although this seems to have come at the expense of an articulated LCD screen.
The magnesium-alloy metal body of the PowerShot G15 is sturdy, with no creaks, loose parts or points of weakness. Even the small pop-up flash is solid. One thing I really like about the G15 is its texture, which is so rough it feels almost like sandpaper or an emery board, and gives the camera a secure hold.
There is a slight grip on the front of the G15, with the body just a few millimetres thicker and a slight rubber leather-effect panel. Although not substantial, it is just enough on which to rest a middle finger to help hold the camera. On the rear there is a rubber thumb rest on the top right, with a new direct video record button set into it.
The button arrangement and layout of the G15 are largely the same as those on its predecessors. The dials on the top of the camera have been given a tweak and are now in an overlapping formation, presumably to make them clearer and to save space. As before, one dial is for the exposure mode, while the other is a very useful exposure compensation dial, making quick adjustments to the exposure values possible. There is also a dial on the front of the camera for adjusting the aperture value in aperture priority or manual mode, while the rear dial, around the directional control buttons, changes the shutter speed.
A customisable function button on the rear of the camera allows the user to select one function to be quickly and directly accessed, and the ISO, focusing, flash and metering settings can also all be changed via direct buttons. Other features and more advanced settings must be accessed via the camera’s on-screen menu, which has remained largely unchanged for years, and is the same as that found on nearly all Canon compact cameras. It is intuitive and works well.
Although there have been changes to the body of the G15, and slight tweaks to the handling, Canon hasn’t given this aspect of the G15 a major overhaul as it simply wasn’t needed.
White balance and colour
Image: A good amount of detail can be recovered from shadow detail in raw files, although some noise is visible
The colours produced by the Canon PowerShot G15 are almost perfect, even in the AWB and default colour style. For the most part they are well saturated, with a fairly neutral colour balance, and it was only in extreme situations, such as shooting in woodland, where I found that the white balance could actually do with being manually set. In this situation the camera removed some of the green from the image, causing it to be slightly more neutral than it should have been. Switching to the daylight white balance setting helped to correct this.
There is a good selection of image styles to suit most people’s tastes, with the usual vivid, neutral, sepia and black & white modes, as well as positive film, light skin tone, dark skin tone and vivid red, blue and green options. Should none of these be appropriate there is a custom colour setting, which allows the main colour and contrast parameters to be adjusted. Sadly, there is no option to alter the settings of the black & white mode. While I found this monochrome image style produced nice images, I would have liked the option to increase the contrast on occasion.
Noise, resolution and sensitivity
These images show 72ppi (100% on a computer screen) sections of images of a resolution chart, captured with the camera’s lens set to around 105mm. We show the section of the resolution chart where the camera starts to fail to reproduce the lines separately. The higher the number visible in these images, the better the camera’s detail resolution is at the specified sensitivity setting.
Our resolution chart test shows that in good light, the Canon PowerShot G15 is capable of resolving about as much detail as a 12-million-pixel DSLR, even when shooting JPEG files. At ISO 80-200, the camera can resolve up to 24 on our chart, and the fall-off in detail as the sensitivity increases is fairly slight. It is only when ISO 3200 is reached that there is a noticeable loss in the quality of JPEG images. At this point the luminance and colour noise reduction starts to have a real effect in textured areas, causing softening and loss of detail.
At the highest ISO 12,800 sensitivity, colour and luminance noise, as well as areas of noise reduction, are clearly visible. As is often the case, this maximum setting should only really be used as a last resort. However, we should still remember that the fact a compact camera is capable of shooting at such a high sensitivity setting is impressive in itself.
I found the range between ISO 80 and ISO 400 gave very clean results. There is noise in shadow areas, which becomes more prominent if the images are adjusted in editing software, but on the whole they are crisp.
It is at ISO 800 when shadow noise really begins to creep in. Looking back on images taken with the G12, I would say there is a slight improvement, with shots taken at ISO 800 on the G15 looking more like those at ISO 400 on the G12.
As would be expected, more detail can be extracted from raw files, and the rather basic preset settings of the Canon DPP software can actually make significant improvements, particularly to sharpness. Colour noise can also be tackled more easily using the software.
Generally, the evaluative metering system performed well with a clear emphasis on making sure that the foreground subject of a scene is bright and well exposed. My only complaint is that the camera tends to create bright skies with little detail, as will be discussed in the Dynamic Range section. I found that when taking landscape images, I had to use spot or centreweighted metering and take a reading from close to the brightest point in the sky to make sure there was very little burnt-out detail. This did, of course, mean having to push the shadows, but there was enough detail to be able to do this, and by using lower sensitivities not too much noise was introduced.
At other times a quick turn of the exposure compensation dial was all that was needed to reduce the exposure, from between -0.3 and -1EV. In many ways, this ability to change the exposure using the compensation dial is one of the G15’s best features. After all, when the exposure is correct there is no problem, but when it needs adjusting, having the option to do it very quickly via a dedicated wheel, rather than fiddling around with buttons and dials on the rear of the cameras, is a real bonus.
Image: When shooting away from the sun, the G15 produces beautifully vivid blue skies
While the dynamic range of the Canon PowerShot G15 is good, it is nothing really to write home about. Although there is some detail that can be recovered from shadow areas, this can easily introduce noise, while the amount of highlight detail is perhaps only a fraction better than other compact cameras.
Highlight detail was most noticeable in landscapes, where some bright-blue skies were rendered almost completely white. Shooting away from the sun obviously produces images with rich blue skies, but clearly it isn’t always practical to do this.
On a number of occasions I adjusted the exposure to darken the image to make sure there would be minimal blown-out detail in the highlights. Although this did darken the shadows and midtones considerably, I was aware that the dynamic range of the camera was wide enough to ensure that detail in these dark areas could be recovered. I would have to shoot raw images and accept that a little luminance noise would be inevitable.
here are three different autofocus modes on the Canon PowerShot G15. The first is Face AiAF, an intelligent autofocus mode that automatically selects one or more from a choice of nine AF points and will prioritise any faces it detects in a scene. While the focusing is fast, the system obviously doesn’t know exactly what the intended subject is, so it doesn’t get it right every time. It is useful, however, in social situations for photographing people.
The next mode is tracking AF. Again, this works well, and is useful for choosing a subject and then recomposing the image. The AF target is placed in the centre of the frame and then the camera is moved so the target is over the subject. A half-press of the shutter button then locks the focus to this target, and the AF point will move and stay focused on this target if either the subject or the camera moves. Again, it is useful for portraiture where you may wish to focus on the subject’s eyes and make sure they remain in focus even when recomposing the image slightly. Similarly, it is handy for tracking a moving subject, such as a child or a pet. While tracking AF is fairly responsive when subjects are moving at moderate speed, don’t expect it to perform well with sports or fast-moving vehicles.
Finally, Flexi-Zone is the mode that will most commonly be used. This allows any one of up to 493 AF points to be selected on the rear LCD. Given the number of points available, switching between them is relatively fast, although the very edges of the image frame don’t contain any points.
As most images won’t have the subject that close to the edge of the frame, this shouldn’t be of any concern. Overall, the focusing is very snappy when the lens is at its widest focal length. It tends to slow at the 140mm equivalent setting, and I found that a few times it was hunting back and forth. However, for the camera’s intended market, the focusing is as comprehensive as it is fast.
Viewfinder, live view, LCD and video
Image: Shot in macro mode with an f/1.8 aperture, this image was trickier to take than it would have been on the G12, due to the G15’s lack of an articulated LCD screen
By including a fixed rear LCD screen, Canon seems to have given with one hand and taken with the other. The screen is now bigger than on previous models, measuring 3in compared to the 2.8in screen on the G12. Likewise, the resolution has also increased from 461,000 dots to an impressive 922,000. This makes a definite difference when reviewing images on screen, and is a good addition to the camera.
However, Canon has also reverted to a fixed screen, rather than the articulated vari-angle screens found on the G1 up to the G6, as well as the G11 and G12. The articulated screens are a popular feature, and one I have used a lot on previous G-series models, so it comes as a surprise that it has been removed. The advantage, of course, is that without the articulated mechanisms and extra housing required for the screen, the G15 can be made smaller than its predecessors while still incorporating a larger screen. It will be interesting to see what photographers make of this compromise, especially as the camera isnot significantly smaller than the G12.
Nikon has recently reduced the size of its latest G-series rival, the Coolpix P7700, by removing the optical viewfinder (OVF). This leaves Canon’s new G15 as the only high-end compact camera to include one. However, the viewfinder has continued unchanged for some time now, and while it is useful on occasions, particularly in bright weather or for helping avoid camera shake, it is far from ideal.
The viewfinder is small and is coupled with the zoom, but at wider focal lengths the lens barrel obscures the view; there are very visible chromatic aberrations from it, and there is no information on display, so the user cannot tell which AF point is in use. So while having an optical viewfinder is nice, I do wonder how long it will be before Canon incorporates an electronic version, which would be much more suitable in this type of camera.
One of the main advantages of switching to a CMOS sensor is that it allows the G15 to record full HD, 1920×1080-pixel video footage at 24fps. Unlike the G12 and other earlier models, the G15 can also focus and zoom while footage is recording, making it much more useful. Video is saved as a .MOV file with H.264 encoding, and audio is recorded in stereo. For watching recorded movies back on a television, there is an HDMI port on the side of the camera.
Image: Canon PowerShot G1 X
There are many options at the top end of the compact camera market, but there are two cameras that really stand out, mainly because they have altered expectations. The first is Canon’s own PowerShot G1 X. As mentioned in this test, the G1 X has a custom-sized 14-million-pixel CMOS sensor, based on the 18-million-pixel sensor used in Canon’s EOS DSLRs. As such, it provides a great compact camera with excellent image quality and a built-in 28-112mm equivalent lens.However, the G1 X is large for what is described as a compact model.
Image: Sony Cyber-shot DSC-RX100
Far smaller is Sony’s Cyber-shot DSC-RX100. This uses a 1in-sized sensor, which has more than twice the surface area of the G15’s sensor but is smaller than that of the G1 X. However, the RX100 sensor has an impressive 20 million pixels and a 28-100mm equivalent zoom lens. The RX100 has certainly been turning heads at this level.
With so many advanced compact cameras now available, the Canon PowerShot G15 may not hold the lofty position among enthusiast photographers that its predecessors did. That is not to say it isn’t an excellent compact camera, though, as it is certainly equal to, if not better than the competition.
The new 12.1-million-pixel CMOS sensor performs well, and the camera’s build and handling are as good as ever. However, the decision to remove the articulated mechanism on the screen is an odd one, despite the few millimetres it saves.
Increasing the maximum aperture of the lens is a worthy move for the G15, and it will be of real benefit in low light and to improve shallow-depth-of-field images. Overall, though, I’m just not sure there is enough that is new about the G15 to warrant G12 users upgrading, particularly if they are fans of the older model’s vari-angle screen.
Canon PowerShot G15 – Key features
The internal pop-up flash is activated via a sliding switch on the camera’s top-plate.
This button can be customised for quick access to a number of different settings, including ISO sensitivity.
The hotshoe is compatible with Canon’s full range of Speedlite flashguns.
As can be seen here, the rear 3in LCD screen is now fixed, with no hinge on the side to allow it to be flipped and rotated.
With the PowerShot G series now so well established, a wide range of accessories is available for it. Apart from all Canon’s Speedlite flashguns, there is the TC-DC58E 1.4x teleconverter, as well as a range of 58mm filters that must be used with the LA-DC58L conversion lens adapter.
On the side of the PowerShot G15 is an HDMI port, which allows an HDMI cable to be connected so that images can be viewed via a compatible television screen.
The Canon PowerShot G15 uses the same NB10L lithium-ion rechargeable battery as the G12. Canon quotes the battery life as up to 350 shots.
As usual, the G15 comes with Canon’s software suite, including DPP. To get the most out of raw images, I found it best to use minimal noise reduction and sharpening in DPP, and then export files as 16-bit TIFFs for further editing in Adobe Camera Raw and Lightroom.