For the longest time, comparing image quality between point-and-shoot cameras and full-frame cameras, or even APS-C format cameras, was a conversation you could have start to finish during the course of an elevator ride. Point-and-shoot cameras were convenient, but the detail and dynamic range of their smaller sensors never measured up to the detail and dynamic range you get from larger sensors. And then one day Sony introduced a new 1" format CMOS sensor, and BOOM! People started having second thoughts about slinging heavy camera bags over their shoulders.
Not Too Big, Not Too Small—The Perfect Sensor Size
The size of Sony’s 20.1MP 1" BSI CMOS sensor, which has since been licensed for use in cameras produced by other camera manufacturers, is situated in a sweet spot among sensor sizes. Compared to a full-frame sensor, 1" sensors have a 2.7x crop factor, which is smaller than MFT (2x) and APS-C (1.5x or 1.6x) camera sensors. Conversely, 1" sensors are larger than the tiny 1/1.7" (4.6x) and 1/2.5" (6x) sensors found in conventional point-and-shoot cameras.
The physical size of the 1" sensor is large enough to suppress much of the noise that traditionally plagues photographs taken with point-and-shoot cameras. The dynamic range of 1" sensors is also notably greater than smaller point-and-shoot sensors, which results in greater detail in the highlights and shadows. In the world of point-and-shoot cameras, this has long been an issue. Sony’s 20.1MP 1" BSI CMOS sensor puts much of this to rest.
Weight and Size Factors
For some shooters, weight and size are major factors when choosing camera systems—and this is the target audience for cameras like the Sony Cyber-shot DSC-RX10 IV, which in addition to featuring a 20.1 1” BSI CMOS sensor, sports a 25x ZEISS Vario-Sonnar T* 24-600mm f/2.4-4 equivalent zoom lens. (The actual focal length is 8.8-220mm) The camera and lens weighs in at 2.41lb and measures 5.2 x 3.7 x 5.7", which, on paper, makes Sony’s RX10 the ultimate travel camera of all time.
While there aren’t any full-frame equivalents of the 24-600mm zoom range of Sony’s RX10 cameras, a Sony A7-series camera with a Sigma 150-600mm f/5-6.3 DG OS HSM Contemporary lens comes close for capturing distant wildlife subjects, albeit with a notably smaller maximum aperture. This camera/lens combination is also notably larger and heavier than Sony’s RX10 IV. Sigma’s 150-600mm f/5-6.3 DG OS HSM measures 4.13 x 10.24" and weighs 4 lb, which is already larger and heavier than the Sony RX10 IV. Add to this a Sony a7R III mirrorless camera, which weighs 1.45 lb and measures 5 x 3.76 x 2.9".
Photographs © Allan Weitz 2021
In all, the Sony a7R III and Sigma 150-600mm zoom combo is about twice the weight and size of the Sony RX10. As a bonus, Sony’s RX10 also enables the option of shooting at wide-angle, normal, and midrange telephoto focal lengths, whereas the Sigma zoom first starts at the 150mm mark.
It's also worth noting if a 24-600mm f/2.8-4 existed for full-frame cameras, you’d need a team of Sherpas to haul it around. And forget about squeezing it into an overhead bin—that’s simply not happening.
Are there compromises being made to create such an inviting camera and lens combo? You bet, but for many, these compromises are worth the price of admission.
Large Sensors vs. Smaller Sensors
Nobody will deny the fact modern point-and-shoot cameras take impressively fine photographs. Generally speaking, smaller sensors, which typically contain smaller pixels with smaller light-gathering photons, have narrower dynamic ranges than larger imaging sensors. As a result, highlights tend to blow out and shadows get crushed into inky darkness when shooting in bright, contrasty situations. More often than not, you must choose between highlights or shadows. Sony’s 1" CMOS sensor is large enough to handle these extremes far better than the smaller sensors we typically associate with point-and-shoot cameras.
Just as large-format film captures a wider range of tone (dynamic range) compared to medium-format film, larger imaging sensors invariably have greater light-gathering abilities than their physically smaller counterparts. When it comes to photographic tonality, bigger sensors are always better.
However, with the above-mentioned parameters in mind, Sony’s RX10 IV and other cameras containing Sony’s 20.1MP 1" BSI CMOS sensor are capable of capturing high levels of both detail and dynamic range under a wide variety of shooting conditions.
Close Focusing—A Deal Breaker If There Ever Was One
When comparing Sony’s RX10 IV and the Sony a7R III with Sigma’s 150-600mm f/5-6.3 3 DG OS HSM, focal range aside, one of the most jarring differences between the two camera systems was the difference in close-focusing distances. At 600mm, Sigma’s 150-600mm f/5-6.3 DG OS HSM zoom lens can focus down to 9.19' (0.2x). At the 600mm mark, Sony’s RX10 IV focuses down to 11.81"! Any questions?
To illustrate the differences in close-focusing abilities between Sony’s RX10 IV and a full-frame camera with a Sigma 150-600mm f/5-6.3 DG OS HSM zoom lens, I photographed a crop of newly emerging spring crocuses. (I chose crocuses because they don’t scare easily).
It may not always be possible to get within minimum focusing distance to your subject with either of the two camera systems described in this article, but in the case of the Sony RX10 IV and similar cameras containing Sony’s 20.1MP 1" BSI CMOS sensor, it’s reassuring to have a camera that can get you in as tight as need be to your subject.
The Faster the Lens, The Better Guarantee of Successful Wildlife Photographs
Creative and technical skills aside, the success of wildlife photographs often hinges on how well your camera can focus on the subject and nail a sharp, accurate exposure before the moment passes. If your lens spends too much time searching back and forth before nailing the focus on your subject's eyes, chances are you are going to miss the moment.
Lenses with slower maximum apertures also require longer exposure times once the light levels start dropping, and slower shutter speeds increase the likelihood of motion blur. Image stabilization (IS) can steady your camera, but if your subject decides to take off as you press the shutter button, no amount of image stabilization will freeze the moment a bird takes wing from a branch.
Closed System vs. Open System
Another consideration when choosing a camera system is whether you want an open or closed camera system. Sony’s RX10 IV is a closed system, meaning the camera and lens are permanently attached. DSLRs and mirrorless cameras are open systems because the camera and lens can be upgraded when newer/better options become available. This shouldn’t necessarily be a deterrent when choosing a camera system, but should be a consideration, nonetheless.
Apples and Oranges
In some ways, comparing results between the Sony RX10 IV and Sony a7R III is a rigged match. Sony’s RX10 IV contains a physically smaller 20.1MP sensor while Sony’s a7R III contains a much larger 42MP imaging sensor. And perhaps that’s the point. While it would be fairer to compare the RX10 to a camera with a camera with a comparable pixel count, an open camera system allows for upgrades and performance improvements that evolve with newer camera and lens technologies.
Though I did not have an opportunity to compare Sony’s RX10 IV to a camera more fairly against a 20 or 24MP DSLR or mirrorless camera, I know from past experience with a variety of cameras containing 1" CMOS sensors and larger-format DSLRs and mirrorless cameras, size matters—the larger the sensor, the better the overall image quality. This held true in the days of film cameras and holds equally true when it comes to modern digital technologies.
The Challenges of Wildlife Photography
Capturing close-up photographs of wildlife in its natural habitat is not a matter of driving to the local park and grabbing curbside photos of squirrels rummaging around the picnic tables in search of leftover fries. The best photographs occur when animals are hunting and feeding, which, depending on your choice of wildlife, are typically around dawn and dusk. And while many forms of wildlife hunt and graze in open fields and skies, some prefer the stealth enabled by shadows. These are also the times when one learns the limitations of lenses with smaller, slower maximum apertures.
A Tale of Two Juvenile Bald Eagles
The juvenile Bald Eagles illustrated below are the offspring of a pair of nesting eagles who set up housekeeping along the Raritan River near New Brunswick, NJ. After spotting them, I moved in as close as possible. The birds were backlit by late afternoon light and even at 600mm were small in the frame. Cropping in 66.7% enabled me to fill the frame better, but it also illustrated the shortcomings of the smaller imaging sensor.
Even after extensive post-processing to hold the detail in the shadows and highlights of an already high-key lighting situation, the photograph taken with the 42MP Sony a7R III clearly displays the advantages of the larger imaging sensor.
Convenience vs. Performance
The size, form factor, and image quality of cameras like Sony’s RX10 IV are dead-on. Where the camera stumbles is at start-up—the camera takes a few moments to come alive. Although power zoom enables smooth video sequences, for still images, zooming the lens can prove to be too slow when trying to zoom in or out quickly. This criticism applies to most if not all cameras in this category. Conversely, most DSLR and mirrorless zoom lenses are far quicker to compose with than their bridge camera counterparts.
Hair-trigger response times may not be critical when photographing landscapes, but when photographing quick-moving subjects you want a camera that can keep up with your instincts.
In the case of the two cameras compared in this review, the 1.3x speed advantage of the 24-600mm f/2.8-4 lens on the Sony RX10 IV counterweighs the operative speed and agility advantages of the Sigma 150-600mm f/5-6.3 3 DG OS HSM zoom lens. Depending on the lighting conditions, most shooters would be probably be able to zoom—and possibly but not necessarily focus the Sigma zoom quicker than the slower-zooming RX10 IV, but the wider maximum aperture on Sony’s RX10 IV will probably guarantee sharper results.
The Best: Full-frame, Super-Telephoto Zoom System or Compact Super-Tele Bridge Camera?
Choosing the so-called "best" of anything is not as straightforward as it often appears, and choosing between camera systems isn’t any different. What I consider important considerations when choosing a camera or lens may not be yours, at least not entirely. We all want quick response times and photos that are razor-sharp, but few of us share common weight and ergonomic preferences when it comes to camera gear.
There’s no shortage of cameras containing Sony 20.1MP 1" BSI CMOS sensors that are capable of capturing pro-quality photographs, many of which have appeared on magazine covers. Do the photographs these cameras capture equal the quality of photographs taken with cameras containing larger, MFT, APS-C, and full-frame sensors?
Under ideal circumstances, the photographs can be indistinguishable from one another, but when photographing under lower lighting conditions, photographs taken with cameras containing smaller imaging sensors often display noise and artifacts at notably lower thresholds than cameras with larger imaging sensors. Autofocusing also suffers accordingly with these cameras. How much? That depends on the camera and the circumstances you are shooting under, but as the photographs captured using Sony’s RX10 IV clearly indicate, the differences between photographs taken with Sony’s "point-and-shoot" camera closely rival the image quality of photographs captured with a larger and heavier pro-quality camera with a midrange super-telephoto lens.
Do you have any experience using comparable camera systems? If so, what are your thoughts? Please share them in the comments section, below.