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From simple lens to complete system
A how-to of perfect combinations 


In order to obtain the maximum possible performance from a lens it must be adapted optimally to the camera or the largeformat
imaging sensor. So what is the best way to create a perfectly combined system consisting of lens, helical focusing mount, camera adapter and possibly one or several extension tubes?

As a rule, the magnification factor ß’, defined as the negative ratio of image to object size, and the object-to-image distance OO’ (distance between object and sensor “g+b”) are specifi ed by the imaging task at hand. For enlarging images (ß’= -1...-5) it is recommended to use the lens in reverse position, i.e. to mount the front of the lens to the camera. How to adjust or convert to the reverse position is described in detail on this page.

The flange-to-image distance, i.e. the distance between the contact surface of the lens and the camera flange, required for the selection of the extension tubes and the helical mount, can be calculated as follows: In the table in the attached data sheet the fl ange-to-image distance for infinity is named, to which the displacement for the magnification factor is also added. The displacement is calculated as focal length multiplied by magnification factor. If, for example, a lens with 40 mm focal length at a magnification factor of 0.1X is to be used, the displacement from infinity is 40 x 0.1 mm = 4 mm.

The flange-to-image distance (distance between lens and camera) consists of the flange-to-image distance of the camera (distance of the sensor to the attachment surface of the lens) and the total length of the camera adapter, helical mount and any necessary extension tubes. In order to have adjustment reserves in both directions, the calculation should assume a mean length of the helical mount. This is, for example, 23.4 mm for the UNIFOC 12. The length of the extension tubes is determined by subtracting the known quantities flange-to-image distance of the camera, length of the adapter and the mean length of helical mount extension from the flange-to- image distance.

Select lens for a optical system

Differences between a V-Mount and a thread
Due to the 360° circumference V-groove a lens with a V-Mount connection can be fixed securely and quickly in any position using set screws. This also makes it simple to align the best azimuth position, which is marked for the lenses for line scan applications, with regard to the sensor. With a thread, on the other hand, it is practically impossible to set the best azimuth position due to the thread cut and the defi ned pitch.

Special aperture setting characteristics
As the starting apertures of the individual macro lenses with V-mount differ, the aperture ring of the lenses uniformly carries the numbers 1 to 6. In position 1 the aperture is fully opened. With each further number the aperture is closed by one f-stop. Half f-stops are indicated by a dot. 

Conversion to the reverse focus position
To switch from normal to retro position, an adapter is required which is screwed into the filter thread of the lens.



Optical Filters

Optical filters help to improve optical quality. They are provided with detailed technical parameters and have passed a strict quality assurance procedure.


V38-Lenses (PYRITE)

The V38-lenses have a compact and robust metal mount, with precise iris adjustment and locking mechanism as well as a filter thread. With a special adapter the lenses can even be reversed for magnifying images. The lenses are available with focal lengths from 28 mm to 120 mm and cover sensor diagonals from 30 mm up to 90 mm depending on the focal length. Their optical performance is optimized for typical working distances at machine vision applications.


Focussing Mounts

The V38-lenses have no built-in focusing mechanism. Therefore a separate focusing mount is needed. Schneider-Kreuznach is offering four focusing mounts with V38 interface:

UNIFOC 12 V38/V38 17.4-29.4 mm

UNIFOC 7 V38/V38 20-27 mm

UNIFOC 7 V38/M58x0.75 20-27 mm

UNIFOC 5 V38/C 19.2-24.2 mm

We also offer a larger UNIFOC 25 for situations where smaller UNIFOCs may cause vignetting when used with large sensors. Special adapters are available for the V38 system.


Extension Tubes

The V38-lenses have no fixed back focal lengths and also cameras differ in their flange-to-image distances. Therefore the extension length of the lenses must be adapted individually to the current image task. This is done by extension tubes, which can be combined in different lengths. They are installed between lens and camera. Extension tubes are available in different sizes.

Extension Tube.png

Camera Adapters

Special camera adapters are available that connect the V38-Mount-System interface to a variety of camera mounts. Types and extensions are shown below.


V-38 Products


PYRITE 2.8/28 V38 1097781    
PYRITE 2.8/35 V38 1097782    
PYRITE 2.8/40 V38 1097232    
PYRITE 4.0/45 V38 1097783    
PYRITE 2.8/50 V38 1097301    
PYRITE 4.0/60 V38 1097302    
PYRITE 4.0/80 V38 1097276    
PYRITE 5.6/80/1.0x V38 1097785    
PYRITE 4.5/90 V38 1097789    
PYRITE 5.6/100 V38 1097303    
PYRITE 4.5/90/0.3x V38 1097784    
PYRITE 5.6/120/1.0x V38 1097277    
PYRITE 5.6/120/0.75x V38 1097786    
PYRITE 5.6/120/0.5x V38 1097787    
PYRITE 5.6/120/0.33x V38 1097788    
UNIFOC 7 V38/V38 20-27mm 1001041 V38/V38 20-27 mm
UNIFOC 7 V38/M58x0.75 20-27mm 1054532 V38/M58x0.75 20-27 mm
UNIFOC 12 V38/V38 17.4-29.4mm 11726 V38/V38 17.4-29.4 mm
UNIFOC 5 V38/C 19.2-24.2mm 1011634 V38/C-Mount 19.2-24.2mm
EXTENSION TUBE V38/V38 6mm 20176 V38/V38 6 mm
EXTENSION TUBE V38/V38 8mm 20177 V38/V38 8 mm
EXTENSION TUBE V38/V38 10mm 20178 V38/V38 10 mm
EXTENSION TUBE V38/V38 25mm 20179 V38/V38 25 mm
EXTENSION TUBE V38/V38 50mm 20154 V38/V38 50 mm
EXTENSION TUBE V38/V38 75mm 20155 V38/V38 75 mm
ADAPTER V38/C 6.5mm 20052 V38/C-Mount  
ADAPTER V38/TFL 6.5mm 1098491 V38/TFL-Mount  
ADAPTER V38/L 6.5mm 20054 V38/Leica  
ADAPTER V38/M42x0.75 6.5mm 20053 V38/M42x0.75  
ADAPTER V38/M42x1 6.5mm 20059 V38/M42x1  
ADAPTER V38/M42x1 35mm 1001692 V38/M42x1  
ADAPTER V38/M58x0.75 10mm 1018385 V38/M58x0.75  
ADAPTER V38/F 9.3mm 21610 V38/Nikon  
ADAPTER V38/M37x0.75 3.5mm 1100587 V38/M37x0.75  
ADAPTER V38/M40.5x0.5 3.5mm 1100588 V38/M40.5x0.5  

Assembled System

Save valuable time and effort by choosing an assembled system. Our expert technicians handle the assembly process, allowing you to focus on running your business without having to worry about manual configuration.

Our assembled systems include our full range of products such as lenses, optical filters, camera adapters, extension tubes and more. These components are carefully assembled in our facility to ensure precise integration and optimal performance.

With the example of the V38-series our Technical Report shows you how it works and why it really helps you. 

Optical system schema



Get in Touch

Please do not hesitate to contact us if you have any questions. Our dedicated team is here to help you every step of the way.
Whether you need assistance with product selection, technical specifications, or general inquiries.

Jos. Schneider Optische Werke GmbH
Ringstraße 132
55543 Bad Kreuznach | Germany

Tel: +49 (0) 671 601 205
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