Live preview
The first interchangeable-lens DSLR to use a live preview for framing was the Fujifilm FinePix S3 Pro, which was launched in October 2004.
The first general-use interchangeable-lens DSLR with live view for framing preview only like most fixed lens digicams was the Olympus E-330 of 2006.
Bridge cameras in general are higher-end, that is they contain more advanced features, better build quality, larger size, and are more expensive than compacts, but retain a small digital sensor.
Mirrorless cameras feature a larger sensor and interchangeable lenses, like DSLRs, but sacrifice the SLR mirror mechanism and viewfinder to save size and cost, and hence only offer live preview.
New Zealand-based British photographer Gordon Laing describes the technology:"[A] fixed semi-reflective mirror allows around 70% of the light to pass through to the sensor for full-time live view composition, but reflects the remaining 30% or so to the phase change AF system, allowing quick and continuous autofocusing in Live View and movie modes.
Later, Canon extended its more sophisticated DSLR ExpSim LV all shooting light conditions like its Powershot digicams.
For ES-LV digicam users and ExpSim LV DSLR users, this advanced method of "Adjustable/Selectable Live Previewable Exposure Evaluation/Determination" shooting in Full Manual / M ISO mode completely eliminated light meter sensor reading TTL common from the film era, making optimally desired exposure selection with live preview rear monitor screens virtually "instant at a glance", and time was saved doing any spot/area evaluative light metering TTL, which non-ES-LV and totally non-LV DSLR users doing the TTL "light meter reading" routine, same as their film SLR counterparts.
This mode replaces the shortcomings of traditional estimation involved in the through-the-lens (TTL) metering techniques of the older framing type live view DSLRs with autogain/framing only, DSLRs without live view, as well as the shortcomings of optical viewfinders when ambient lighting becomes too low.
Some manufacturers of compact cameras, including prosumer models, still lack this exposure simulation live view feature, instead relying on the more rudimentary autogain/framing only live view, where slow focus and slow exposure estimation via TTL metering techniques are relied upon.
Additionally, 100% coverage optical viewfinders have recently become more common and affordable with the appearance of the Canon EOS 7D, Nikon D300, Olympus E-3 and the Pentax K-7.
[7] Still more recently, the (upper) mid-range Nikon D7000 has brought the feature to a somewhat lower price point.
Live preview can show additional information, such as an image histogram, focal ratio, camera settings, battery charge, and remaining storage space.
Many professional photographers and advanced amateurs prefer DSLR cameras that have a true optical through-the-lens viewfinder (OVF).
