Small Sensor Cameras Make the Grade

By Lloyd Chambers Back to

chambersMA13a

Introduction

The fast-paced digital photography market kicked into high gear beginning with cropped-frame sensors (Nikon D1, 1999), and then quickly moved to full frame (Nikon and Canon). But disruption is in full progress, and if Canon and Nikon aren’t careful, companies like Sony and Olympus could eat their lunch.

Hugely improved sensor quality coupled with market demand for smaller, lighter and more convenience now drives a move back to smaller sensors, accompanied by an impressive assortment of lenses, including support from stalwarts such as Zeiss and Schneider. No longer are smaller sensor cameras mediocre solutions for amateurs; professional photographers are using them for serious still and video work.

While the full-frame DSLR remains important for peak image quality and resolution, cropped-frame DSLRs (Nikon DX, Canon EF-S) now reveal themselves as awkward compromises straddling the image quality and usability/ergonomics fence: bettered by full-frame DSLRs on image quality, and bettered by smaller cameras on friendly ergonomics and usability (size, weight, EVF, etc.). The cropped-frame DSLR might not survive the brutal competition now emerging unless some non-inertial thinking is applied to the traditional DSLR design. And as full-frame DSLRs

surpass Nikon’s 36-megapixel mark, the medium for- mat market will face pressure too. Increasingly I see digital trifurcating into these distinct areas:

• High-megapixel and ultra high quality full-frame DSLRs
• Compact and lightweight cameras with breakthrough image quality.
• Camera phones and iPads and the like, which surely will someday deliver advanced image quality and usability.

Absent from the above is the cropped-frame DSLR, a shopworn compromised design running on inertia without the image quality and ergonomic benefits of full-frame; an un-fun user experience offering image quality only marginally better than the best compact cameras. The market is asking for the best combinations of high image quality + best ergonomics + ease of use.

Camera Size & Format

No longer does a small camera mean a small sensor— the existence proof being the Sony RX1 which utilizes a full-frame state of the art 24-megapixel sensor. The RX1 is not as small as its RX100 sibling, but it is much smaller than even a cropped-frame DLR. Expect this trend to continue. The compact camera market breaks down into these common sizes:

• Full-frame compact: Sony RX1
• APS-C: Sony NEX , Sigma DP1/DP2/DP3 Merrill, Fuji X, Canon M
• Micro Four Thirds: Olympus E-M5, Panasonic GH3
• Not-so-small sensor cameras: Sony RX100

With proper exposure, use of raw format and proper conversion, any of these cameras can print exhibition- quality prints up to 16×24″.

An all around DSLR replacement and my “go to” camera for video. Interchangeable lenses make it the most versatile of the three, and its EVF make adverse lighting a non-problem. Hangs around the neck when cycling (stabilized with strap over shoulder); too large with lens for a jersey pocket. It has superb image stabilization.

Field Use with Smaller Sensors: ETTR

Over a period of months, I shot the Olympus E-M5, the Sigma DP1 Merrill, the Fuji X-Pro1 and the Sony RX1 extensively under highly varied conditions. I discovered that image quality varies substantially under different lighting conditions, especially in the mountains at dusk, and especially with the smaller sensors (even at the base ISO using “correct” exposure as per the camera meter).

For example, using the Olympus E-M5 I obtained various disappointing results with detail-destroying noise even at the base ISO. Or at the least, noise that made my usual sharpening quite difficult because of artifacting. This was frustrating, and it did not seem consistent with the higher quality results I had also obtained from the E-M5.

The key factor turned out to be optimal exposure. Almost every camera’s metered “correct” exposure is usually at least a full stop too dark (for raw capture). A stop less of exposure means 1.4X as much noise; two stops means twice the noise. But it’s worse to the eye; the “channel chunkies” can make an image look gritty and speckled. One more stop of exposure reduces that particularly ugly noise; this is particularly important for black and white conversions.

The noise vs. exposure behavior piqued my serious interest. My research on exposure with a variety of cameras has proven beyond any doubt that image quality rewards from optimal exposure accrue not only with smaller sensor cameras, but with full-frame DSLRs. Camera exposure algorithms almost always underutilize 1⁄2 or even 3⁄4 of the sensor dynamic range. The cause appears to be outdated thinking about exposure that is geared towards avoiding highlight loss for JPEG shooting. RAW data format images are required to realize the gains from increased exposure, but the improvements are substantial.

Any of the new crop of smaller sensor cameras can approach image quality similar to full-frame digital on a per-pixel basis, but under many field conditions concessions must be granted to the sensor on exposure: make an optimal (brighter) noise-friendly exposure via ETTR (Expose To The Right).

The use of ETTR is an essential technical skill that must be mastered to extract full quality from any camera, at least until camera vendors get their act together on automating ETTR (see dgly.org/ETTR-call).

While high quality results can be obtained under many conditions without using ETTR, my research shows that nearly every exposure can be improved by using ETTR. This fact makes small sensor cameras viable as an alternative to a DSLR, but does demand attention to extracting full quality via optimal exposure.

Three Compacts, All Good, All Different

A gallon Ziploc in my storage drawer contains an assortment of small cameras that I’ve tried over the past few years. They all gather dust because all proved disappointing in multiple ways, with the exception of the Fuji X100, but even it didn’t quite satisfy. There was literally nothing on the market through mid-2012 that combined image quality + usability + form factor that was attractive to me−the synergy just was not there.

The small-camera landscape shifted in June–August 2012, starting with the Olympus OM-D E-M5, fol- lowed rapidly by the Sigma DP1 Merrill and the Sony RX100. I now have extensive field experience with all of them. For well-exposed images from these three cameras, noise is usually not an issue. Still, ISO 800 is the high end I would consider, and only then if the exposure is ample. Here’s a summary of what I found in practical use:

Olympus OM-D E-M5

The Olympus E-M5 is a Micro Four Thirds camera (17.3 x 13.0mm sensor) accepting Olympus and Panasonic and many other lenses via adapters. Its 16-megapixel sensor is capable of very high image quality with proper exposure, while its 5-axis image stabilization is a breakthrough for handheld video, and a boon for still shooting.

The E-M5 is just plain fun to shoot. Something about its controls, its response time, its size just works. The synergy of it working like a real camera is high; it induces creativity. The E-M5 contrast-detect auto-focus is exceptionally speedy and accurate under most conditions, and the EVF is a godsend when lighting conditions or presbyopia make the rear LCD trouble- some (especially favorable for older users).

Overall, the E-M5 controls are very good, though a few buttons are badly placed and too small. But the E-M5 menu system is a nightmarish labyrinth that needs a complete redo: I spent 15 minutes one day trying to figure out how to unset a feature that (somehow) had turned itself on! Considerable study and effort is required to set up the E-M5 as one wishes, but once done the menus can mostly be ignored.

My favorite lenses on the Olympus E-M5 are the Panasonic 8/3.5 fisheye (especially for cycling videos), the Panasonic Leica 25mm f/1.4 (gorgeous bokeh) and the Olympus 75mm f/1.8 ED. For those looking for world-class optics, the Olympus SHG (Super High Grade) lenses offer outstanding image quality, but note that the SHG lenses are huge, heavy and expensive.

The E-M5 is the first and only camera I’ve found that is suitable for video when the camera is moving; its 5-axis image stabilization and physical size makes my on-the-bike cycling videos feasible. (By comparison, the Sony RX100 elicits nausea when viewing video shot while in motion)!

The 28mm (equivalent) DP1 Merrill is a more versatile focal length than the DP2M 45mm, but I like to have both along when possible (e.g., in a hip pack), as they can share batteries and accessories. This is my favorite compact camera for no-compromise sharpness, and black and white conversion options. Can fit into a cycling jersey pocket, but somewhat tight, and an extra battery is mandatory.

Sigma DP1 / DP2 Merrill details

The Sigma DP1 Merrill has a fixed 28mm (equivalent) lens, the DP2 Merrill has a fixed 45m (equivalent) lens. Both the DP1 and DP2 Merrill contain an APS-C Foveon true-color sensor—15.0 x 3 megapixels, with each pixel location containing a red/green/blue photosite (stacked). Finished RGB images are 14.75 megapixels capable of stunning per-pixel sharpness like nothing you’ll see from any other technology short of the Leica M Monochrom. Speaking of monochrome, the DP1/DP2 Merrill files are exceptionally versatile for black and white shooters since there are three ultra-sharp true-color channels from which to choose, or which can be blended.

On a per-pixel basis, the sharpness from the DP1/ DP2 Merrill is unequalled by any color camera on the market: there is no anti-aliasing filter and no Bayer- pattern demosaicing process because each pixel is derived from a red/green/blue photosite on the sensor−no color interpolation. Sharpness approaches that of a 20-24 megapixel full-frame DSLR with a conventional sensor. All this in a pocketable camera. But since the files are actually 45 megapixels (15 x 3), the files are huge, approaching 50-60MB each (for X3F raw format). The color rendition can be terrific under daylight conditions, but can suffer under some lighting conditions such as tungsten, and it is not up to the accuracy of the Sony RX100 or Olympus E-M5 (in general).

After some months of use, I’ve concluded that the Sigma DP1/DP2 Merrill cameras are an outstanding value with superb image quality. The menu system and controls are among the very best small-camera designs on the market by virtue of avoiding the clutter and confusion of other cameras. The DP1/DP2 Merrill lacks an EVF, which means holding the camera at arms length to shoot, as with any rear-LCD-only camera; this is the one thing I’d want to see changed. And its low-res video mode should have just been left out; it is a pity that it cannot produce 1080p video from its ultra-sharp sensor.

Sony RX100 Details

The Sony RX100 has a relatively smaller sensor; at 13.2 x 8.8mm it is only 52% of the size of Micro Four Thirds (Olympus E-M5) and 31% the size of APS-C (Sigma DP1/DP2 Merrill). One might assume from sensor size that noise would be high and color grad- ation dubious. But this is most definitely not the case− the sensor appears to be of the same superlative generation as the Nikon D600 (and presumably Sony RX1). This is not to say that noise is never an issue; the afore- mentioned ETTR techniques are useful, and using a raw conversion program like DxO Optics Pro can pro- duce much cleaner files than Adobe Camera RAW.

Its diminutive size makes the RX100 a take-anywhere camera— avoiding the “I didn’t want to carry a camera” excuse. When cycling it slips into a cycling jersey pocket with ease and weighs so little it can be ignored. It’s my “go to” camera for self-portraits out on the trail, or for spontaneous snapshots of people.

The Sony RX100 delivers gorgeous color rendition with lovely lens bokeh from its built-in retracting Zeiss zoom. However, the lens delivers peak sharpness only at the wide-angle end of the zoom range and especially at close distance. At long distance and zoomed, image sharpness tends to disappoint; consider it to deliver 8-10 megapixels worth of detail under many condi- tions. Still, the 20-megapixel oversampling remains valuable for image quality even though 20 megapixels of actual detail are rarely captured. Avoid stopping down past f/5.6 or image quality quickly degrades (from diffraction).

The built-in flash used for slow-sync fill flash produces the most natural and reliable results that I have ever obtained from any camera at any price— I was stunned at the near perfect success rate using fill-flash outdoors (slow sync with -1.3 or -1.7 stops). This is reason alone to buy the RX100 if you shoot people a lot, especially outdoors where the face is often shadowed.

Conclusions

It is an exciting time for compact cameras. It’s not just the image quality, but the combination of image quality + ergonomics and usability + size/weight that are all coming together in synergistic ways. Developments in 2013 are sure to further disrupt the digital camera market, forcing out weak entries and accelerating the pace of innovate-or-die. It is both a threat and an opportunity for camera companies, and ter- rific for photographers. The other exciting aspect of these new compact cameras is what the future holds in extending the breakthroughs in image quality to all size cameras. The Sony RX100 sensor scaled to a full-frame sensor would be 148 megapixels. While this exceeds the resolving power of most DSLR lenses, the oversampling eliminates the need for an anti- aliasing filter, as well as offering the potential for 72 megapixel downsampled RAW files all but free of digital artifacts.

Resources: Cameras: Olympus-olympusamerica.com; Sigma sigmaphoto. com; Sony-sony.com; Canon-usa.canon.com; Fuji-fujifilm. com; Nikon-Nikon.com; Panasonic-panasonic.com; Lenses: Schneider-schneideroptics.com; Zeiss-zeiss.com


About the Author

Lloyd Chambers
LChambers
Lloyd L. Chambers enjoys all-digital photography after shooting film for years in 35mm, 4 X5, 6 X7 and 617 formats. His web site diglloyd.com offers a wealth of material on advanced photographic techniques, and his Making Sharp Images is a reference work on sharpness and blur of all kinds.