Telecompressor: Difference between revisions

Revision as of 20:35, 31 May 2018

Revision as of 20:38, 31 May 2018

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A '''telecompressor''' or '''focal reducer''' is an optical element used to reduce [[focal length]], increase [[lens speed]], and in some instances improve [[optical transfer function]] (OTF) performance. Popular applications include [[photography]], [[videography]], and [[astrophotography]]. In astrophotography, these qualities are most desirable when taking pictures of nearby large objects, such as [[nebula]]e. The effects and uses of the telecompressor are largely opposite to those of the [[teleconverter]] or [[Barlow lens]]. A combined system of a lens and a focal reducer has smaller [[Flange focal distance|back focus]] than the lens alone; this places restrictions on lenses and cameras that focal reducer might be used with.

[[Lens adapter]]s that include telecompressors are useful with digital [[MILC|mirrorless]] cameras.<ref>{{Cite news|url=http://www.mirrorlessjourney.com/blog/2014/9/focal-reducer|title=Focal Reducer|work=Mirrorless Journey|access-date=2018-05-31|language=en-CA}}</ref> By combining a telecompressor within a lens adapter, mirrorless cameras can use the lenses of both [[digital single-lens reflex camera]]s (DSLRs) and film-based SLR ([[Single-lens reflex camera]]s). and canAbout gain aone stop in light collection ability can be achieved due to the concentration of light on a smaller sensor. Well-known brands include '''metabones'''<ref>{{cite web|url=http://blog.uniquephoto.com/metabones-speedbooster-tele-compressor-speeds-up-mirrorless-cameras/|title=Metabones Speedbooster Tele-Compressor Speeds Up Mirrorless Cameras - Unique Photo Blog Unique Photo Blog|author=|date=|publisher=|access-date=22 September 2016}}</ref> and '''KIPON'''.<ref>http://www.adorama.com/brands/kipon</ref><ref>{{cite web|url=http://www.adorama.com/g/kipon-main|title=Kipon Adapter Finder|author=|date=|publisher=|access-date=22 September 2016}}</ref>

<gallery caption="Digital telecompressor (0,64x) for [[Canon EF]] lenses with [[Micro Four Thirds]] camera bodies" mode="packed">