And there’s more! – How about tilting the lens?
Theodor Scheimpflug was (according to http://en.wikipedia.org/wiki/Scheimpflug_principle) an Austrian who in 1904 patented an idea describing how to gain maximum focus when swinging or tilting the lens panel in the cameras of the time. If you stand facing a flat object, such as a building, hold the camera with the back exactly parallel to the building,and focus correctly, the whole building will be in sharp focus even at maximum aperture (if the lens is good!). However, in most cases, the picture will not be very interesting. But if you stand on the pavement (US readers: sidewalk) looking down the street with the building on your right side, but you then rotate through 45°, you are likely to get a more interesting view of the building within its environment. However, at maximum aperture only a small part of the building will be sharply in focus, with the bits that are closer to or father from that point going increasingly out of focus.
Enter Herr Scheimpflug.
|Imagine that this is an aerial view looking down on the situation that
we just described.
The line at the bottom is the front of the building that you want to photograph.
You are standing holding the camera at the position and angle shown by the arrow “Film plane (back of camera)”. If for some reason you need to use a large aperture, you have no chance of getting most of the building in focus.
However, if you could swing the lens sideways (rotating it through its vertical axis), the focus would improve.
Thank you, Herr Scheimpflug.
However, when he took out his patent over 100 years ago, achieving this was easy with many cameras: the film (or usually glass plate) was held at the back of the camera in a wooden back, the lens was held in a flat wooden plate at the front of the camera, and between the two there were flexible leather bellows. Just design a way of swinging the front, and the focussing problem is solved. Voilà, as the French say! In fact, cameras were designed in which you could swing (from side to side) tilt (backwards and forwards) and shift (raise, lower, or move sideways) both the front and rear standards. Moving the front changes the focus, moving the back changes the shape of the image, to correct (or even cause!) distortions.
You can still get such camera. I made one, using a kit manufactured
by Bender in the USA.
||The results are superb, but the camera is very large and awkward to
carry and use, and setting up a shot is slow.
Bender’s website is here.
(Note that the camera kit is supplied without any lenses.)
So, if you want to use a regular Medium Format SLR film camera, what do you do?
Buy a tilt-shift lens made by Hartblei! (easiest for most people from Michael Fourman at Kiev Camera)
Hartblei use the 45mm Mir 26 optical components in three different mounts:
And here it is on a Pentacon Six:
There appears to be another tilt/shift version of the 45mm Mir lens, this one produced by Richard Wiese of Hamburg, Germany, with the name “Technoplan”. You can visit the Wiese-Fototechnik website here.
[C386-6A: 45mm Super-Rotator, 55mm Arsat shift and 65mm Hartblei shift lenses
together in one photo, so that their relative sizes can be compared.]
The Super-Rotator tilted in use
For the non-shifted performance of the 45mm Mir 26 lens, I would refer you to the Wide-Angle lens tests section. Of course, even apart from the shift and tilt capabilities, there are some major differences.
As reported on the page on shift lenses, the expected barrel distortion did not prove obvious with this lens in most real-life situations.
For a report on results obtained with this lens, click here.
When trying to mount the 45mm Hartblei Super-Rotator and the 65mm Hartblei shift lenses on my 35mm SLR via the standard East German Pentacon/Praktica adapter, I discovered that it was impossible to lock the adapter onto the lens, as the locking ring wouldn’t rotate. (Come to think of it, rotating the locking ring on the Exakta 66 had been difficult!) This was because the three lugs against which the locking ring mates were fractionally too thick!! Grinding them down a little resolved the problem.
There were no such problems with the 55mm Arsat shift lens.
Restrictions on movements when a shift or tilt lens is used on an Exakta 66 with the Exakta 66 TTL metering prism
There are some restrictions on some movements with shift and tilt lenses when mounted on an Exakta 66 with the Exakta 66 TTL metering prism in place, as this extends quite a way forward of the original front plate of the camera. None of these movement restrictions occur with any of these shift lenses if the camera is used with the standard Exakta 66 waist level finder or the Exakta 66 non-metering prism.
The restrictions are as follows:
Hartblei 45mm Super-Rotator
It is difficult to rotate the tilt control (but there is no problem to change the degree of tilt) once the lens is on the Exakta 66 if a metering prism is on the camera, as the front of the prism fouls the tilt lever. However, there are no restrictions on shifting in any direction when the Super-Rotator is mounted on the Exakta 66 with a metering prism, as the shift mechanism is further forward with this lens than with the other shift lenses. Also, if required, the tilt ring can be rotated prior to mounting the lens on the camera.
Arsat 55mm Shift Lens
It is not possible to shift the 55mm Arsat lens very far up when it is mounted on an Exakta 66 with the metering prism, as the front of the prism limits movement. However, as the default shift direction is sideways (to the left as viewed from above), and as the format is square, it is not a problem to rotate the camera through 90 degrees, as we are accustomed to doing with 35mm and other rectangular-format cameras, in order to take the photograph.
Hartblei 65mm shift lens
The maximum upwards shift is 4mm when the metering prism is on the camera. Shift sideways or down is unrestricted. Further, it is difficult to mount this lens on the Exakta 66 with the metering prism because a ring on the lens presses against the bottom of the metering prism.
These problems are in fact caused by the modification of the original Pentacon Six specification by the designers of the Exakta 66. It is for the same reason that it is not possible to mount the Carl Zeiss Jena 1000mm mirror lens on the Exakta 66 with metering prism.
To go back to the section on Other Accessories, click here.
To go on to the next section, click below.
Next section (Test of the Super-Rotator Tilt-Shift lens)
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then choose the range of lenses that you want to read about.
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choose the focal length that you want to read about.
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© TRA December 2005, December 2012