How to test Minox lens Resolution of COMPLAN, MINOX, MINOXAR

-- martin tai (martin.tai@capcanada.com), December 21, 1998

Answers

Resolution of COMPLAN /MINOX LENS

Photographing a next neigbour's wall or a car parked on the street many be conveniet, but is not a proper way to test lens resolution. Using eye ball to test lenes is like weighting chicken with bare hands

Resolution figure is not popular with analog cameras. But now resolution figures show shows up in all sorts of scanners and digital cameras.

Lens Test Chart

Test chart with graduated target from 15 lpmm to 100 lpmm continues bar pattern and other test diagrams is necessary for meaningful test

. Chasseur d'Image Mire Test chart is an exellent test chart.

Chasseur d'Image ISO Lens test chart

You may download USAF chart from photo.net

USAF chart

When I tested Minox GT-E, the film plane to test chart distance = 50 x focal length or 50 x 35mm = 175 cm, AGFA HDC 100 color print film ( the film I use regularly for GT-E );

for Minox B/C, I set the film plane to test target distance beyond 50x focal length, because the resolution of Minox 8x11 lenses are well over the limit of Chasseur D'Image chart (or any other charts) at 50x focal length.

The film to chart disttance was chosen as 133 cm ( middle point between 1 meter and 2 meter ) on my metric Minox scale (For middle point values of Minox focusing scale, see related thread)

Kodak Techical Pan film (my stardard film for Minox subminature cameras ), developed in 1:80 Rodinal Special.

-- martin tai (martin.tai@capcanada.com), January 30, 1999.

Minox 8x11 Camera lens test

I recently testedthe resolution of Minox lenses

Test Chart: Mire-test Chasseur d'images

Film:Kodak Techical Pan 4.5 milEstar-AH base 150' roll slitted into9.5mm Minox film.

Developer:Agfa fine grain BW developer Rodinal-Special 1:80 dilution, 15 minutes 20 degree C.

Microscope:Olympus microscope 10x objective, 10x eyepiece.

The follwoing are the resolution figures.

Minox C , "MINOX" lens15mm/f3.5 163 line-pair/mm on film.

Minox B,"COMPLAN" lens, 15mm/f3.5 177 line-pair/mm on film

Note: MINOX lens is the lens in C, LX, TLX, and Minox enlarger III.

COMPLAN lens also for: III, IIIs, B and Minox enlarger II

COMPLAN hasa very slightly curved film plane.

Base on 320 lpmm resolution of Techpan, the aerial resolution ofMinox lens is estimated atabout 360 lpmm average

If higher resolution film is used, the on film lpmm will certainly goes up.

-- martin tai (martin.tai@capcanada.com), January 30, 1999.

COMPLAN and Minox lenses are the sharpest general purpose photographic lenses. No 35mm or MF lens approaches the sharpness of these lenses. For example, Canon EF USM 50mm f1.4 lens has a top resolution about 80 lpmm, a Nikkor S-AF 50mm/1.4 has top resolution of 64 lpmm. Of course, 35mm lens has the advantage of bigger format. Precisely of the superb sharpness of COMPLAN and MINOX, good 8x10" enlargement is not only possible, there are many Minox experts around the world regularly enlarge Minox pictures to 16x20". ( I have'nt reach that level yet ). Dr. William White claimed in his book that there were even Minox murals.

-- martin tai (martin.tai@capcanada.com), January 31, 1999.

"The lens resolving potential of ultra-miniature cameras is illustrated by the performance of the 4-element lens of the Minox. A test pattern the size of the Minox negative image is projected through each lens to a screen size of approximately 4x5 1/2 feet. Any lens which does not project this pattern sharply from edge to edge is rejected. " Joseph D. Cooper: the new ULTRA-miniature photography" Universal Photo Books.

-- martin tai (martin.tai@capcanada.com), February 08, 1999.

Dr. Whilliam White claimed in "Subminature Photography" that COMPLAN lens is sharper. My sharpest picture came from COMPLAN of Minox B, other Minox IIIs users have similar experience. My lens test showed that COMPLAN is indeed slightly sharper. However, COMPLAN lens has a curved film plane and curved presure plate, which seems to cause more scratch across negative, MINOX lens with its flat presure plate seems seldom cuases scratches, for that reason I prefer MINOX lens. Optically, uneless I am really really focus very acurately, ie mount the camera on tripod, measure the object disttance with a measuring tape, and even bracket the distances then compare under a microscope, otherwise there is really no visible difference.

-- martin tai (martin.tai@capcanada.com), February 13, 1999.

Minox literature proclaims the lens for the new Minox ECX to be the sharpest lens in serial production!

How does it compare to the Complan or Minox lens?

-- Bob Woods (woorob@msn.com), April 19, 1999.

The MINAR lens on ECX is new design by Leica, from what I heard, it is sharper then previous design. It is quite possible the MINOX has quietly put the new lens in latest MINOX CLX and TLX. But IMO, unless you use ultra fine grain film such as Fuju Super HR, and enlarge it to 11x14 with good enlarging lens, or perform a lens test using test chart and view under microscope, it is hard to notice difference with naked eyes.

-- martin tai (martin.tai@capcanada.com), April 20, 1999.

Examaple of high resolving power of COMPLAN LENS

Original size

Enlarged to 3.5x5"

2 cm from bottom right corner is a sign post, which has a street sign, only 0.1mm on film 1.5mm on print.

Enlarged 200x

Each character is only 0.02 mm width. A typed page can be packed in to 1.5x 2mm on film. With the 720 lpmm film from http://www.gigabitfilm.de, or 600 lpmm Agfa Copex Rapid, higher resolution is possible

-- martin tai (martin.tai@capcanada.com), October 16, 2000.

Performance Index of Minox

Performance index = lpmm x format dimension divided by camera weight in g

The following is a few examples 




    CAMERA      lpmm   format length   weight   performance per g
    Minox TLX    170       11           98        17
    M6+50 'LUX   95        36           835        4
    Hassy 503cx  75        56           1520       3

Minox TLX not only has the sharpest photographic lens, but also has by far the highest performance index of 17 vs only 4 of Leica of M6

-- martin tai (martin.tai@capcanada.com), July 22, 2001.