This is description of this part:
LOMO 140 - 200 mm photo tube / camera adapter with adjustable length - but also fitting many other microscopes from Carl Zeiss Jena, Meopta, Olympus, IOR and others.
The tube allows a camera or a camera body to be attached to a trinocular head or directly to the microscope body, even when there is no trinocular head.
Basic technical parameters of this tube:
Manufacturer: LOMO (ЛОМО)
Colour: black, rings and barrel chrome-plated
Tilt angle: none, this is a straight tube
Internal optics: none - not even a deflecting prism
Mounting to the trinocular head or microscope body: ring dovetail (male part)
Dovetail diameter: 41 mm
Type of connection at the output: empty tube / barrel
Tube diameter at the output: 23.2 mm internal diameter
Length of the barrel / tube: variable
Length adjustment: yes - the barrel is extendable, with a scale from 140 to 200 mm and a knurled locking ring
This is the version with adjustable tube length. A scale from 140 to 200 mm is engraved on the extendable barrel, with a reference line and intermediate divisions, and the setting is locked with a knurled ring. This gives two things at once. First, a continuous change of the image scale - the longer the tube, the larger the image falling on the sensor or the film, so the framing can be adjusted without changing the objective. Second, and more importantly, the ability to work with objectives computed for different optical tube lengths: 160, 170, 180, 190 and 200 mm. Carl Zeiss Jena and LOMO objectives are computed for 160 mm, Leitz Wetzlar for 170 mm, some objectives of metallurgical and measuring microscopes for 190 or 200 mm - here you simply set the barrel to the right value and the objective works under its design conditions, instead of delivering an image with residual aberration.
Since the adapter has an empty barrel with an internal diameter of 23.2 mm on the output side, a projection eyepiece of that diameter can be placed in it, or a so-called "USB eyepiece", that is a digital microscope camera. Adapters between the 23.2 mm barrel and the M42 thread are also widely available, and from the M42 thread you can move on to any other mount: Nikon, Canon, Sony and others.
Such a tube can be mounted directly on the microscope body instead of the head. A dovetail seat with a diameter of 41.0 - 41.5 mm is found, among others, on the microscopes:
- LOMO
- Carl Zeiss Jena
- Meopta
- IOR
- Reichert Biopan
- Olympus CH
It is also often used in microscopes with a slightly larger seat, among others Zeiss West Germany, Leitz Wetzlar, PZO, Will Wetzlar, Hund Wetzlar.
The "compatibility" section gives an example list of microscopes this tube fits, although it is not a complete list.
The last photo shows a LOMO Erudit microscope with this photo tube and a projection eyepiece mounted. It is an example of use.
What is this part needed for?
- if you need a tube that allows a camera or a camera body to be attached to a trinocular head
- if you need to attach a camera or a camera body directly to the microscope body, because you have no trinocular head or want to photograph without splitting the light
- if you have objectives computed for a different tube length than your microscope - 170 mm from Leitz, 190 or 200 mm from a metallurgical microscope - and want to finally use them under their own conditions
- if you want to change the framing and the image scale without changing the objective and without swapping the projection eyepiece
- if you want to choose the magnification so that the image fills the camera sensor and the dark corners disappear
- if your old photo tube has been lost, sold separately or has a damaged connection
