Mirror pre-release is also known as Mirror Lock Up or MLU. The theory is that when an SLR’s mirror swings out of the way as the shutter is released, as it hits the top of the mirror box it creates vibrations that degrade the image. In over twenty years of taking pictures with the Pentacon Six, I have not found this to be a problem in general picture taking. However, some would disagree with me, and since the late 60s various manufacturers have offered a mirror lock up or pre-release on their cameras.
In 1968 the Minolta SR-T 101 35mm SLR had a nifty button for this, and the manufacturers suggested using it when taking macro photographs – where the degree of enlargement combined with the slow shutter speed could presumably result in degradation of the image. If you changed your mind about a shot after winding the mirror up, you could wind it back down.
In Medium Format, the Hasselblad 500C offered a mirror lock up, which you could not, however, cancel. If you decided you didn’t want to take the picture after all, you could insert the dark slide, remove the back, and fire the shutter. Then re-cock the shutter to bring the mirror back down, replace the back, and remove the dark slide. Slow, but it worked.
Why is all this necessary? Because, once the mirror is up, you can’t see anything through the viewfinder! You have in your hands a sophisticated Single Lens Reflex that is worse than a box camera! And there isn’t even a “sports finder” that fits the Hasselblad – or the Kiev 88-6.
Exakta 66 & Pentacon Six
Starting with the Exakta 66 Mk III, the manufacturers fitted a mirror lock up or pre-release. As with the Hasselblad 500C, it can’t be cancelled once activated. And as you can’t remove the back on an Exakta 66, once you’ve released it, you have to fire the shutter – but you could at least fit a direct vision finder in order to re-compose. The mirror pre-release uses a lockable cable release, connected to a new cable release socket on the back of the top plate, just under the advance lever.
[C311-17: the mirror pre-release socket on the Exakta 66]
I had the Mk II / Mk III advance lever installed soon after the mirror pre-release upgrade. This is slightly longer than the original Mk I lever, and much easier to use. I suspect that using the smaller Mk I lever with the new cable socket just below it might not be too convenient.
It seemed to me that using the prism viewfinder with a cable release sticking out of the back of the camera was also a little inconvenient, or even uncomfortable. A good friend in California came to the rescue by sending me an angled extension for the cable release socket. This works beautifully, and the location of this socket no longer causes any problem at all.
[C311-18: The mirror pre-release socket, with angled cable release extension and lockable cable release]
Of more interest, Pentacon Service in Dresden offers to fit the mirror pre-release to the Exakta 66 Mk I and Mk II, and to the Pentacon Six! I have had my Exakta 66 Mk I and my Pentacon Six TL upgraded by them, and am pleased with the result. While making the upgrade, Pentacon serviced each camera.
[C311-16: The mirror pre-release cable socket installed on the back of my Pentacon Six.
The case still comfortably fits with this in place, and its location does not interfere with cocking the shutter
– one has to bring the thumb to the advance lever from above, not below, with the Pentacon Six.]
Operation of this mirror pre-release is cumbersome but useable. Pentacon recommend it for slow shutter speeds, very long lenses and macro work. In all these cases, the camera will be mounted on a tripod, a virtual pre-requisite for using a mirror lock up or pre-release.
How does it work?
1. Cock the shutter. Compose and focus.
2. Insert the lockable cable release supplied with the upgrade into the new socket on the back of the camera.
Tension the cable release (i.e., press in the plunger gently as far as it will go without using excessive pressure) and lock it, using the little locking knob on the end of the cable release. Nothing happens. Nor should it!
3. When ready to fire, press the camera’s shutter release in the usual way. The mirror will flap up quietly, but the shutter won’t fire. (Nor should it!)
4. Unlock the knob on the cable release. The shutter will fire.
5. Remove the cable release and then wind on. You are ready to start again.
Never wind the shutter with the mirror up cable release in place, or you will damage the camera.
Like any mirror lock-up or pre-release system, this is designed for slow, methodical working. Most users will never need it. But for some shots it may make a vital difference to the sharpness of the image.
Note that it is not possible to install the mirror pre-release on any version of the Praktisix, as the design of these cameras is quite different.
Installers of Mirror Lock Up / Mirror Pre-Release
Pentacon Service in Dresden are the original designers and installers
of this modification. You can contact them at:
Enderstrasse 92 [note slight change to address]
Tel: 00 49 351 25 89 213
or 00 49 351 25 89 286
e-Mail: email@example.com or firstname.lastname@example.org
|Suspension of Pentacon Six & Exakta 66 Servicing and repairs
by Pentacon Dresden
It is with the greatest regret and sadness that I have to report that late yesterday I received the fully unexpected news that Jürgen Frenzel, the Pentacon Six and Exakta 66 specialist at Pentacon Service in Dresden has without advance warning suddenly died. He was the one person on their staff who serviced and upgraded these cameras.
They are therefore having to suspend repairs and service for these cameras at the present time. They still offer a repair service for the lenses and also for other Pentacon cameras such as the Praktica series.
They are trying to find another specialst workshop that they can recommend. As soon as I receive any further information on this, I will post it here.
Jürgen Frenzel had worked at Pentacon in Dresden for at least 30 years. I extend my deepest sympathy to his colleagues, friends and family.
Jürgen Frenzel in Dresden, April 2012
Picture taken by me on a Pentacon Six TL
that had been serviced and upgraded by him
Rolf-Dieter Baier offers an alternative mirror pre-release system for the Pentacon Six, but I have no personal experience of it. At the time of writing, you can find details of his system here (in German) or here (in English).
Kiev 60 and Kiev 88-6/Kiev “B.i.G.-Six”
and other variations of the Kiev 88 from Hartblei, Michael Fourman and others: various mirror pre-release versions are available, and reviews from users range from satisfaction to frustration. Visit the Kiev Report website or Kiev Camera for more information (see the Links page)
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© TRA February 2002, September 2012