|One of the most popular of Minolta's RF series lenses is the 250mm f/5.6 model. This super-compact telephoto is nearly the same size and weight as a standard 50mm lens, but with five times greater magnification. Combined with quality construction and optics, Minolta produced one of the lightest (8-13/16 oz.), most compact telephoto lenses of its kind.|
|One of the little quirks with Minolta's original factory 62mm diameter lens shade is that lens flare would sometimes occur in certain shooting situations. You can easily purchase after-market lens shades such as the two pictured above. The lens shade depths from left to right are factory = 17mm; standard = 24mm; telephoto = 41mm. These measurements include thread depth.|
|Minolta made the first truly compact 500mm mirror lens. Coming in as a close second to the 250mm RF in popularity is the 500mm f/8 RF model. The focusing method like the 250mm is accomplished by rotating the front component (lens and mirror) forward and backward by helicoid. Slightly more bulk and weighing in at 1lb. 5-1/8oz. Roughly twice the weight of the 250mm RF model, but still amazingly compact for a 500mm telephoto. Don't let its compact size fool you. With a 5 degree angle of view I strongly recommend using a tripod with this lens. These generally sell in the range of $150 to $300 depending on condition and accessories. They command much higher prices in Europe and abroad.|
|I have two 500mm RF versions pictured above with a late model production copy on the right. You will notice that Minolta decided to extend the standard 77mm diameter lens shade depth from 21mm to 32mm. These measurements include thread depth. This design modification was done to address lens flare that was occurring in some shooting situations. The base element design remained essentially unchanged with some slight cosmetic changes.|
|Minolta's AC (anti-reflective achromatic coating) filters were slightly more expensive and as the above table indicates limited to certain sizes. General applications for achromatic coatings were used for reducing the glare and ghost images from secondary reflections which will result in a clearer and sharper image on any optical substrate, that are necessary for camera lenses, instrument panels, binoculars, cover glasses and telescopes. Most commonly available substrate are BK7, Fused silica, Magnesium Fluoride (MgF2) and Calcium Fluoride (CaF2). Minolta used BK7 glass in many of their common detachable filter applications.|
|The filter wrench pictured above is inserted into the integral filter's two opposing slots and is designed to safely remove or install the filter.|
Special thanks to Minolta user Andrea Apra` (from Italy) for his contribution to this article.
Article last updated 9/1/2017
|I will be adding more information in the future about digital photography applications along with Minolta's 800mm RF and 1600mm RF Mirror lenses.|
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