Wide angle adjustment device
A wide-angle setting device is an accessory for setting the distance of wide-angle lenses on large-format or floor-mounted cameras in photography . They were produced in the second half of the 20th century by companies such as B. Linhof or Plaubel made.
purpose
Large format lenses do not have their own focusing mount for focusing. In order to bring an object into focus for recording with the camera , the entire lens must be moved axially here. The wide-angle lenses used in large format photography are rarely modern retrofocus designs. With this design, the posterior lens element is very close to the film plane when the distance is set to infinity (∞) . There is therefore a risk of the lens touching the film or even damaging it.
In addition, the axial path from infinity to the shortest meaningful distance setting is then only a few millimeters with these lenses. There are three constructive solutions to the problem:
- manual adjustment of the complete front standard including lens via the floor or the optical bench of the camera
- the use of an adjusting screw between the lens and the front camera standard
- the use of a wide-angle adjustment device between the lens and the front camera standard
use
In order not to have to adjust the entire front standard when focusing - and thus, for example, to change the already set tilt or shift - either an adjusting screw or a wide-angle adjusting device is used between the lens and the front camera standard . The latter is adjusted by means of a precision screw via a parallel guide and additional bellows .
Types
The Plaubel company has a setting mount with a worm gear for the Peco Profia , in which the lens is axially displaced. This is permanently connected to the respective lens board. Here, however, because of the immediate proximity, there is often the risk that operating elements of the shutter are touched and adjusted during use or that the shutter is even accidentally triggered because the lens rotates during adjustment.
. By the company Linhof three versions exist of Weitwinkeleinstellgeräts with parallel guidance for cameras from model Technika III :
- For the objective standard of the 13 × 18 cm (5 × 7 ") Technika and boards in the format 128 × 128 mm and with a front holder for lens boards in the format 96 × 98 mm from the 9 × 12 cm (4 × 5") Technika.
- For the 9 × 12 cm (4 × 5 ") technical center with front mounting of circuit boards from the 6 × 9 cm technical center.
- The third variant was offered for the 6 × 9 cm Technika and has no front board holder. It takes firmly mounted closures of size Compur # 00 in a hole; z. B. for focusing the Schneider Angulon f / 6.8 65mm wide angle lens.
These devices are no longer offered. Today (2013) Linhof only offers adjusting screws with a fixed plate, similar to the earlier Plaubel versions. However, the objective is only shifted axially here.
Advantages disadvantages
The entire focusing distance of the lens can be set very precisely with the axial adjustment; manual setting by moving it on the walking floor leads to setting errors. The advantage of the wide-angle setting device compared to the old type of setting screw is that the lens is only adjusted axially here and the effect of polarization filters or rectangular sun visors or compendia is not impaired, as the lens no longer needs to be rotated for setting.
For use, additional, recessed lens plates usually have to be purchased to compensate for the device's own height. A direct connection to the rangefinder that may be built into the camera is not possible with these constructions. The focus is controlled here exclusively via the focusing screen on the back of the camera.
See also
literature
- Hermann Brix: Large format photography, tools and experiences . Lindemanns, 2003.
- Jim Stone: A User's Guide to the View Camera . [English], Prentice Hall, 1997.
credentials
- ↑ Price list 2012 from Linhof Munich with reference to the previously produced wide-angle adjustment devices, p. 16, lens plates 6 × 9 ( memento of the original from September 7, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
