Holiday Buyers Guide 2011: Which Big Sensor Camera Should You Buy?

Remember when a small coffee was just a small coffee? Our choices have multiplied to include the impossibly complex tall triple nonfat, no foam latte. Camera shopping has likewise gained in complexity. If you're shopping for a big sensor camera, your options are many - mirrorless or traditional DSLR? Four Thirds or APS sensor? EVF or LCD only?

Whether you're shopping for yourself or someone else, searching for a camera is more confusing than ever. We're going to break down some of the advantages and disadvantages of each big sensor system to help you put the right camera in the right hands.

Big Sensor? Big Deal.
Is a bigger sensor better? In many ways, yes. For our purposes, we'll call a Four Thirds sensor, and anything larger, a ‘big sensor.' Compacts like the Canon PowerShot G12 and even the ILC Pentax Q offer sensors larger than that of a typical point-and-shoot, but for now, let's focus on Four Thirds and bigger. What advantages do they offer?

• Shallower depth of field: A larger imaging chip allows you greater ability to single out your subject and encompass the rest of the scene in beautiful out of focus bokeh. This is only if you're shooting wide open (at a wider aperture) of course.
• Better colors and dynamic range: Better colors will mean that your images will look much more pleasing. The dynamic range boost means that you'll be able to recover more details in the shadows or highlights while editing.
• Better high ISO settings: If you're not the type that likes to use a flash or that love to shoot sports, better high ISO settings will mean that you shoot images with less noise/grain and less color noise issues as well.

Combine all the advantages of a big sensor and put them into a camera approximately the size of a Point and Shoot and you'll get a powerful but compact package. That's the type of camera that professionals are asking for as a backup, or as their leisure camera.

So then why have a big camera in the first place?

Traditional DSLRs: Big Sensor, Big Camera
Big cameras, like the Canon 5D Mk II, Nikon D7000 and Sony A580 all have advantages over mirrorless cameras. For starters, the bigger cameras sometimes use larger full frame sensors: which are almost the size of an exposure of 35mm film. Besides being able to currently house larger sensors, they also have other advantages.

Cameras with mirrors and pentaprisms all use phase detection focusing. Phase detection is extremely quick and also very smart in focusing on a particular subject based on the user's composition of the scene. At the time of this writing, phase detection is the only system that can quickly focus the large and heavy f/2.8 zoom lenses. When they switch into contrast detection mode (Live View) they focus significantly slower. If you need faster focus with lenses that many professionals call their bread and butter, then DSLRs are for you.

The exceptions to this rule are the Sony line of cameras with a translucent sensor, such as the Alpha A77 we previewed this fall. They don't have a pentaprism, but do have a translucent mirror. Because of this, you get an electronic viewfinder. Depending on who you ask, this is either a good or bad feature. Indeed, many people prefer to see through the lens optically, and not electronically. For that reason, the pentaprism is preffered.

Big cameras like a DSLR are currently able to take more punishment in real life shooting environments and situations. For example, no mirrorless camera at the moment has weather sealing. In contrast, DSLRs with weather sealing can be used in inclement weather. Still though, most people would not take their camera out into the rain unless you are an Olympus or Pentax shooter. The high end cameras made by these two companies can endure punishment like no other. In fact, I buried an Olympus E-5 in the snow for 10 minutes and it still worked. I've also shot on assignment in the worst blizzard NYC has ever seen with one.

If you're talking about entry-level DSLRs like the Canon Rebels, their advantage still lies in the large line of lenses that they can use and still be able to autofocus.

Mirrorless ILCs: Big Sensor, Small Camera
Cameras with a smaller body but bigger sensor aren't necessarily geared for professionals, but they are designed to offer DSLR and professional image quality. Enthusaists, semi-professionals, and people that want to get their feet wet with interchangeable lens cameras might be best suited for this class.

The major design difference with these cameras is their lack of a pentaprism and mirror. Instead, what the lens sees directly hits the sensor. These cameras are often called:

• EVIL: Electronic Viewfinder Interchangeable Lens cameras
• CILC: Compact Interchangeable Lens Cameras
• MILC: Mirrorless Interchangeable Lens Cameras

These cameras use the Contrast Detection focusing system which, up until now, has been very slow. Olympus, Panasonic and Sony have made large strides in improving the system to the point where they say that the speed rivals and even bests those of top end phase detection cameras. They've even proven themselves to be steller performers in low light focusing situations.

One of the chief strengths of the cameras with interchangeable lenses is the fact that they can adapt nearly any lens due to the lack of a mirror. This has created a lust for vintage lenses that has spread like wildfire across eBay and Craigslist. It also meant that photographers with older cameras could finally use their lenses in the digital age.

Situations where we have seen these mirrorless cameras really take off is in street photography and videography: with cameras like the Fuji X100, Olympus EP3 and Panasonic GH2 pioneering the front. For more, consider reading this posting on how to use your CILC like a pro.