Minolta AF Reflex 500mm f/8

Originally produced by Minolta, then by Sony, the AF Reflex 500mm f/8 was a catadioptric photographic lens compatible with cameras using the Minolta A-mount and Sony A-mount lens mounts.

Minolta Reflex 500mm f/8
MakerMinolta, Sony
Technical data
TypeSpecial Prime
Focal length500 mm
Aperture (max/min)f/8 fixed
Close focus distance4 m
Max. magnification1/7.7
Diaphragm bladesNo blades, circular
Construction7 elements in 5 groups
Features
Ultrasonic motorNo No
Macro capableNo No
Unique featuresAF capable Mirror Lens
ApplicationTelephoto
Physical
Max. length118 mm
Weight665 g
Filter diameterFront 82mm & Rear drop-in (Clear and NDx4)
Accessories
Lens hoodFront threaded
Angle of view
Horizontal4.9°
History
Introduction1989
Discontinuation2010
SuccessorMinolta version succeeded by Sony version in 2006
Retail info
MSRP699 USD (as of 2006)

The Minolta/Sony Reflex 500mm lens was the only production mirror lens designed to auto focus with an SLR camera. There are other mirror lenses that can mount onto current mounts such as Canon EF-mount and Nikon F-mount, but all of these mirror lenses are manual focus only. Only this lens can have its focus controlled by the camera's autofocus motor in conjunction with TTL autofocus sensing. In terms of the Minolta AF and subsequent Sony α SLR systems, this lens is an anomaly, being the only lens guaranteed to auto focus at f/8. Minolta also produced a V-mount 400 mm f/8 Reflex lens that can autofocus at f/8, but only the Minolta Vectis S-1, Minolta Vectis S-100 and Minolta Dimâge RD 3000 can use it.

The mirror design does not utilize aperture blades, and thus the aperture of the lens is fixed at f/8. Exposure may only be controlled by shutter speed, film or sensor sensitivity, or a rear-mounted neutral density filter.

By using a mirror design similar to that of a telescope, this lens uses very little glass compared to traditional telephoto lenses and is thus much smaller, lighter, and far less expensive than traditional lenses in the same focal length. However, like all mirror lenses, it can produce donut-shaped bokeh in images, due to the secondary mirror partially obstructing the front element.

Adapters for Sony E-Mount

Using this lens on a Sony E-mount camera requires an adapter such as one of the Sony LA-EA series, not all of which are compatible with all E-mount cameras[1] or A-mount lenses.[2] The LA-EA2, LA-EA4 and LA-EA5 adapters have the screw drive required to enable autofocus, which is however limited to select cameras for each adapter.[3] Otherwise, the lens will be manual focus only.

RF ROKKOR-X manual focus version

Minolta also made a manual focus, SR-mount version of this lens. That version was designated RF ROKKOR-X. Adapters are available for Sony E-mount cameras.

American Robin taken with the Minolta AF Reflex 500mm F8 showing the Donut Bokeh
American Robin taken with the Minolta AF Reflex 500mm F8 showing the 'donut bokeh' characteristic of mirror lenses

See also

References

Sources

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