introduction
mirror lenses on mirrorless cameras
mirror lenses
- 2000mm
- 1000mm or more
- 600-800mm
- 500mm
- <500mm
- cheaper designs
comparison of 500mm mirror lenses

super telephoto mirror lenses

introduction

mirror lenses are difficult to use and for most people are probably not the best option
they were popular in the 1970's and 80's as they mainly competed against manual focus big, heavy, f/5.6-6.3 telephoto lenses
in the 1990's, the advent of new high refractive index glass, computerised lens manufacture combined with a now mature autofocus technology and optical image stabiliser, meant that mirror lenses were generally only for those whose budget could not afford a “real” telephoto lens such as a 400mm f/4 IS
catadioptric mirror lenses share the following characteristics:
- manual focus (apart from the Sony / Minolta AF Reflex 500mm f/8.0 mirror lens)
- fixed aperture
- virtual elimination of chromatic aberration and lateral color fringes as uses mirrors rather than lenses
  - also means focus position for infrared photography is the same as for light photography
- central mirror:
  - allows much more compact lens length as the optic path is reflected internally twice
  - by necessity, blocks some of the light and thus causes:
    - decrease in image contrast
    - characteristic ugly “donut” shaped bokeh imagery in out of focus areas
- front filter thread if present, rotates with focus
- significant vignetting
- difficult to suppress stray light, ghost and flare
- shallow depth of field (DOF) with low contrast makes accurate manual focus difficult, further compounded on most lenses by the lack of micro-focus gearing so that only small incremental changes to focus can be made
apart from their telephoto reach for such a small size, these lenses were difficult to use for film photographers using SLR cameras as:
- they usually had slow apertures around f/8 and were thus dim in optical viewfinders making manual focus difficult and requiring bright sunny conditions for any action shots
- they were not image stabilised, and the light weight actually worked against getting sharp images without camera shake - even the camera's mirror was sufficient to cause camera shake

mirror lenses on mirrorless cameras

mirrorless camera systems cameras address many of the issues of mirror lenses by:
- using an electronic view finder with magnified, image stabilised manual focus +/- manual focus peaking
- no mirror to cause mirror-induced camera shake which is a big problem in SLRs and dSLRs at high magnification work such as when using these lenses
- image stabiliser built-in such as the Olympus Micro Four Thirds system
- Micro Four Thirds system have cropped sensors which give twice the telephoto effect as they are 2x crop sensors
- allow better image quality at high ISO levels to ISO 1600 which partly addresses the f/8 aperture issue
- post-processing of digital images can improve the lower contrast levels these lenses give
the Carl Zeiss Contax 500mm f/8 is said to be the sharpest with best contrast but these are also the most expensive and are quite rare
if small size, light weight and high image quality are your main requirements, then the Olympus OM 500mm f/8.0 mirror lens and the Minolta Rokkor RF 250mm f/5.6 mirror lens are the clear winners
However, on a Micro Four Thirds system camera, a 500mm f/8 mirror lens will be 1000mm f/8 and you should weigh this up against use of refractor style lenses such as:
- Olympus ZD 50-200mm f/2.8-3.5 lens with EC-20 2x teleconverter which gives 200-800mm f/5.6-7, is weathersealed and will autofocus when used with a Olympus Four Thirds dSLR system or a Micro Four Thirds system with phase detect AF such as the Olympus OM-D E-M1
  - this will give much more versatility and far better bokeh but will weigh much more, look much longer when at full telephoto, and cost much more
  - total length of this combo on Micro Four Thirds is 217mm but lens extends to almost double at maximum zoom
  - total weight ~1.1kg
  - filter thread 67mm

mirror lenses

2000mm

Nikon F Reflex-Nikkor 2000mm f/11 mirror lens - rare
Pentax SMC 2000mm f/13.5 mirror lens
see also Schmidt-Cassegrain telescopes eg. 8“ f/10 Meade or Celestron SCT telescopes

1000mm or more

600-800mm

500mm

<500mm

Vivitar Series 1 450mm f/4.5 Asph Solid Cat mirror lens
Tamron SP 350mm f/5.6 mirror lens
- not very sharp
Rubinar 300mm f/4.5 mirror lens - Russian
Minolta Rokkor RF 250mm f/5.6 mirror lens
- one of the few mirror lenses with focal length < 500mm that is worth buying, but they sell now for very high prices 2nd hand - eg. $1400!!

cheaper designs

older cheap brands include Hanimex, Makinon, Soligor
contemporary cheap models with generally lesser image quality and build quality, and often marketed as Albinar, Vivitar, Rokinon, Bower, Walimex, etc, include:

comparison of 500mm mirror lenses

model	aperture	diam	length	length incl. MFT adapter	weight	optics	close focus	front filter	Infinity on Canon EOS
Olympus OM	f/8	81mm	97mm	123mm	590g	v. good	4m	72mm	YES
Canon FD	f/8	90mm	148mm	170mm	705g	v.good	4m	none	NO
Nikkor N	f/8	89mm	116mm	143mm	823g	v. good	1.5m	82mm	YES
Nikkor C	f/8	93mm	142mm	169mm	1000g	good	4m	88mm	YES
Sony/Minolta	f/8	89mm	118mm	142mm	665g	v. good	4m	82mm	NO
Tamron SP f/8	f/8	84mm	92mm	mm	595g	good?	1.7m	82mm	YES
Samyang f/8	f/8	77mm	88mm	123mm	320g	avg?	1.7m	72mm	YES
Samyang f/6.3	f/6.3	119mm	98mm	133mm	705g	avg?	2m	95mm	YES
ProOptic Maksutov	f/5.6	105mm	220mm	255mm	1220g	good	1.5m slow but microtune	none	YES

Table of Contents

super telephoto mirror lenses

introduction

mirror lenses on mirrorless cameras

mirror lenses

2000mm

1000mm or more

600-800mm

500mm

<500mm

cheaper designs

comparison of 500mm mirror lenses