Bridge camera

The Panasonic Lumix DMC-FZ50 bridge digital camera

The Fujifilm FinePix S9000 bridge camera

The Konica Minolta DIMAGE A200 (2005), the most sophisticated digital camera made by Konica Minolta before its fusion with Sony

The Sony DSC-R1

Bridge cameras are cameras which fill the niche between the single-lens reflex cameras (SLRs) and the point-and-shoot camera.^[1][2] They are often comparable in size and weight to the smallest digital SLRs (DSLR), but almost all digital bridge cameras lack an optical viewfinder system (film bridges generally had a lighter version of a reflex finder). In addition, SLRs normally feature interchangeable lenses, while current bridge cameras do not.^{[3][not in citation given]} They are prominent in the prosumer market segment. The phrase has been in use at least since the 1980s,^[1] and continues to be used with digital cameras.^[2] The term "bridge camera" was originally used to refer to film cameras which "bridged the gap" between point-and-shoot cameras and SLRs.^[4][5]

Like other cameras, most current bridge cameras are digital. These cameras typically feature full manual controls over shutter speed, aperture, ISO sensitivity, color balance and metering. Generally, their feature sets are similar to consumer DSLRs, except for a smaller range of ISO sensitivity because of their typically smaller image sensor (a DSLR has a 35mm, APS, or 4/3 size CCD or CMOS sensor). Many bridge cameras have long zoom lenses, so the term "bridge camera" is often used interchangeably with "megazoom", "superzoom", or "ultrazoom."^[6] However, some bridge cameras have only moderate or short zooms (such as the Canon Powershot G9^[7]), while many compact cameras have superzoom lenses but lack the advanced functions of a bridge camera.

With zoom ranges and sales rapidly increasing in the early 21st century, every major camera manufacturer has at least one 'super zoom' in their lineup.^[8]

One fixed but versatile lens [edit]

Bridge cameras typically have small image sensors, allowing their lenses also to be smaller than a 35mm or APS-C SLR lens covering the same zoom range. As a result, very large zoom ranges (from wide-angle to telephoto, including macro) are feasible with one lens. The typical bridge camera has a telephoto zoom limit of over 400mm (35mm equivalent), although some 21st-century cameras reach up to 1000mm like the Nikon Coolpix P510 For this reason, bridge cameras typically fall into the category of superzoom cameras.^[9]

A typical example is the 24× Zoom Nikkor ED 4.6-110.4mm f2.8-5.0 on the Nikon Coolpix P90, which in 35 mm equivalent focal length terms is a 26-624mm.^[10] To reduce aberration in a lens with such ambitious specifications, these have quite complex constructions, using multiple aspheric elements and often anomalous-dispersion glass. In this example pincushion- and barrel distortion can be corrected in the camera firmware as well. The ability to fit such a wide zoom range in one single small-diameter lens makes lens interchangeability redundant for most photographers. However, most bridge cameras allow the use of secondary lenses to improve wide-angle, telephoto or macro capabilities. These secondary lenses typically screw onto the front of the primary lens either directly or by use of an adapter tube.

Superzooms typically have a large f-number (aperture) especially at the long end. The resulting depth of field prevents using shallow field methods.

LCDs and EVFs as principal viewfinders [edit]

Bridge cameras employ two types of electronic screens as viewfinders: The LCD and the electronic viewfinder (EVF). All bridge cameras have an LCD with live-preview and usually in addition either an EVF or an optical viewfinder (OVF) (non-parallax-free, as opposed to the OVF of DSLRs, which is parallax-free). A high-quality EVF is one of the advanced features that distinguish bridge cameras from consumer compact cameras.

All DSLRs, by definition, have a through-the-lens OVF. Newer DSLR models typically also allow 'live view' on the LCD screen as an alternative to the OVF.

Electronic viewfinder (EVF) vs DSLR optical viewfinder (OVF) comparison [edit]

Live-preview EVF advantages [edit]

The EVF of bridge cameras, and the LCD of bridge cameras and DSLRs in 'live view' mode; continuously show the image generated by the sensor. The continuous digitally-generated live view has some advantages and disadvantages compared to the optically-generated view through the OVF of DSLRs. One advantage is that the digital preview is affected by all shooting settings and thus the image is seen as it will be recorded (in terms of things like exposure, white balance, grain-noise, etc.) which the OVF of DSLRs is incapable of showing.^[11] Another advantage is facilitating the framing from difficult angles by making the LCD movable (vari-angle). The LCD and EVF normally show 100% of the image while previewing (WYSIWYG). The OVF of professional DSLRs normally shows 100% of the image, but the OVF of consumer DSLRs may show slightly less than 100%.

Live-preview EVF disadvantages [edit]

The electronic screens of bridge cameras do not work as well as the OVF of DSLRs in situations of low light, or in bright daylight where the LCD screen might be difficult to see and use for framing. Also the screen has low resolution and refresh rate compared to the very high resolution and instantaneous refresh provided by an optical path in the OVF of DSLRs. Low resolution impedes manual focusing, but most modern bridge cameras implement a method that automatically magnifies a central frame within the screen (manual focus point) to allow easier manual focusing. A slow refresh rate means that the image seen on the screen will have a fraction of a second lag or delay from the real scene being photographed. The electronic screens used in modern bridge cameras are gradually improving in their size, resolution, visibility, magnification and refresh rate.

Continuous operation of the sensor shortens battery life and raises temperature. A DSLR's sensor (when not in live view mode) only operates when the shutter is open, and the electronic screen is typically off more, causing less battery drain. In bright conditions the light impinging constantly on the sensor of a non-SLR so it can show the image can heat the sensor, increasing image noise; in a DSLR, the sensor is exposed to light only during the fraction of a second that the shutter is open.

Examples of bridge cameras [edit]

DxOMark [edit]

DxOMark by DxO Labs tests the image quality based on RAW (not JPEG).

Market [edit]

In late of 2012 Techradar says that when the general compact camera market is on a downturn, the DSLR-like bridge camera market is continuing well.^[14] As of early 2013, Canon, Fuji, Nikon and Sony are producing DSLR-like bridge cameras with larger and larger zooms which most DSLR users maybe only dream to use or perhaps look to achieve at huge expense.

A recent category is the mirrorless interchangeable lens camera, which features a large sensor and an interchangeable lens, but no mirror. These occupy a niche at the top end of the bridge camera range, and in many aspects (such as live view or electronic viewfinder only) are similar to smaller ones. They differ in that the larger sensor provides advantages (as noted above), but makes super-zoom lenses more difficult.

References [edit]