- Live preview
In
digital photography , live preview is the feature that allows adigital camera 's electronic display to be used as aviewfinder , that is, as a means of framing and previewing before taking the photograph. In most such cameras, the preview is generated by means of continuously and directly projecting the image formed by the objective lens onto the mainimage sensor , which in turn feeds the electronic screen with the live preview image. The electronic screen can be either aliquid crystal display (LCD ) or anelectronic viewfinder (EVF).Historical background
While some types of digital cameras trace back their origin to a corresponding type of film still cameras (for example
digital single-lens reflex camera s "DSLRs" to filmsingle-lens reflex camera s "SLRs"; digital rangefinders to film rangefinders, etc.), cameras with live preview also derive from electronic (video ) TV cameras.Most early digital cameras through 1995 did not have a live preview; most
digital single-lens reflex camera s still do not have this feature, as it is fundamentally incompatible with thesingle-lens reflex mechanism. The first digital still cameras with anLCD display and live preview were theCasio QV-10 andRicoh RDC-1 in 1995. [cite web | url = http://www.digitalcamerainfo.com/content/Evolution-of-the-Live-Preview-in-Digital-Photography-.htm | title = Evolution of the Live Preview in Digital Photography | author = K. J. Kabza | work = DigitalCameraInfo.com ] TheOlympus E-330 was the first SLR to use that feature in 2006.Compacts & bridges, the low- and high-end cameras with live preview
Live-preview cameras include two different but not so distinct categories:
Bridge digital camera s and Compact digital cameras. Bridge cameras in general are higher-end and more advanced (feature-packed), expensive (higher build quality) and sizable than the compacts.DSLRs, cameras usually without live preview
When considering the advantages and disadvantages of DSLRs, the comparison is usually made between the best bridge cameras, and the smallest and cheapest DSLRs, so most of what can be said in this respect is treated in the bridge camera article. Check in particular the following sections in that article:
* One single fixed but versatile lens
* LCDs and EVFs as principal viewfindersA comparison between compacts and DSLRs would be really a very contrasted one in terms of size, weight, price, capabilities and image quality.
Almost all modern bridges and compact cameras have a movie mode, while no DSLR offered this option until the
Nikon D90 released in August 2008. DSLRs have faster performance than other cameras in many areas (for example, start-up time, shutter lag, continuous mode,autofocus ). This means that DSLRs are more reliable in certain situations, such as sport or action photography, where being late for a fraction of a second may result in missing the right moment of taking the picture. The idea that DSLRs perform better than other cameras in high ISO settings has to do primarily with the sensor size of the camera, not whether it has live preview. DSLRs always have large sensors while a great majority of other cameras have a small sensor (notable exceptions being the Sony R1 and theSigma DP1 ).Digital SLRs with live preview
Live-preview functionality is becoming more and more common on digital SLR cameras, and as of mid 2008 almost all new DSLRs have the feature. The following is a partial list of DSLRs with live preview:
*
Canon EOS 40D
*Canon EOS 50D
*Canon EOS 450D
*Canon EOS 1000D
*Canon EOS 1D Mark III
*Canon EOS 1Ds Mark III
*Canon EOS 5D Mark II
*Leica Digilux 3
*Nikon D90
*Nikon D300
*Nikon D700
*Nikon D3
*Olympus E-330
*Olympus E-410
*Olympus E-420
*Olympus E-510
*Olympus E-520
*Olympus E-3
*Panasonic Lumix DMC-L1
*Panasonic Lumix DMC-L10
*Sony Alpha A300 and A350
*Pentax K20D
*Samsung GX20 Live preview in some or all of these cameras is not conventionally generated (the image formed by the lens is either not directly or not continuously projected over the main sensor). Also the live preview in these DSLRs does not typically serve as their principal means of framing and previewing before taking a photograph. (As DSLRs, they have an optical view reflected in the OVF (Optical
Viewfinder ) for that purpose and the live preview is an additional feature).While live-preview technology has been advancing, as for March 2008, there are no DSLRs which show a live preview as seamlessly as a fixed-lens camera. The main issues are with slow focus and lack of exposure-priority display. [ [http://blog.neocamera.com/?p=90 Digital Camera and Photography: Tips, Information and News | Neocamera Blog » Blog Archive » Live-View Advancement ] ] Among the DSLRs that do manage to focus using the standard phase-detection sensor used by DSLRs, none has managed to show 100% frame coverage like conventional digital cameras, thereby removing the key advantage of live preview over optical viewfinders. Additionally, 100% coverage optical viewfinders have recently become more common and affordable with the appearance of the Nikon D300 and Olympus E-3. [ [http://blog.neocamera.com/?p=94 Digital Camera and Photography: Tips, Information and News | Neocamera Blog » Blog Archive » Olympus E-3 - Another 100% Coverage Viewfinder ] ]
Digital camera backs with live preview
Phase One
*P20+
*P21+
*P25+
*P30+
*P45+
*P21
*P30
*P45 See also
*
Digital single-lens reflex camera
*Photography
*Digital photography
*Still camera
*Digital back References
External links
* [http://www.digitalcamerainfo.com/content/Evolution-of-the-Live-Preview-in-Digital-Photography-.htm Evolution of Live Preview in Digital Photography.]
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