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A History of my Photography

Pentax 645



Pentax 645 Medium Format Camera

Pentax 645 with 80-160mm lens.

    Back when I was researching the Pentax 6x7 I found one fairly common suggestion. Instead of getting a spare 6x7 get a 645 instead. I has more modern exposure control, a motor drive and isn't very expensive. Originally I was looking for a 645N because it had a real shutter speed knob, but they are still relatively expensive.

    I have noticed that new Pentax medium format cameras have disappeared from the market. The Pentax web site no longer lists them as products and the big camera houses have been clearing out their stock. So Pentax has gone the way of Bronica and Contax and no longer makes medium format SLR's.

    An eBay vendor I watch started dumping the Pentax 645 gear. This camera was very inexpensive so the risk level was low. The vendor has a good reputation so I felt there was little risk. I bought the camera body, a lens and a 200 and 120 back.

Front view of the Pentax 645 with the 8-160mm f 4.5 lens.

    After running a couple of rolls of film through the camera all I can say is that if the 6x7 had some minor quirks this camera is quirkiness defined. Here is a list:

        1. The grip with the power switch and release button is removable but the finder is fixed.
        2. The finder has an LED display instead of LCD.
        3. There is a lithium battery in the bottom that cannot be changed by the user.
        4. Exposure compensation can only be set in full f stop increments.
        5. Bulb and sync shutter speeds are separate modes.
        6. The up down buttons to set shutter speed that was used on Pentax 35mm cameras was copied here.
        7. No exposure lock.
        8. No TTL flash when using leaf shutter lenses.

    Feature that improve over the 6x7 are listed here:

        1. Center weighted metering rather than average metering
        2. Mirror produces so little vibration there is no need for mirror lock up.
        3. Shutter is also very smooth and syncs at 1/60 second.
        4. TTL flash metering.
        5  Shutter speed, aperture and program auto exposure modes.
        6. User changeable focusing screens.
        7. Can use Pentax 6x7 lenses with adapter.

Front view of the camera without a lens showing the electrical contacts and the mirror. The button on the lower left of the body is the lens removal button.

    The Bronica ETR was the "pioneer" of the 6 x 4.5 format. It was a fully modular camera like its 6 x 6 predecessors with interchangeable backs, finders lenses and film advance options. Pentax was not such a pioneer and built a camera with the only option being interchangeable lenses. While I don't find interchangeable finder that necessary an option, interchangeable backs would have been great. Instead they made the handgrip removable. Why?

View of the controls of the Pentax 645. The three buttons on the left work in conjunction with the two gray arrow button on the right to set Exposure compensation, film speed and exposure mode. The LED button turn on the viewfinder readout LED displays and the button below it with the circle turn on the illumination for the top LCD. A wheel below these buttons selects between single or continuous motor drive operation. The power on/off switch is on the right and the chrome button is the shutter release.

    The Pentax 645 uses interchangeable film holders that cannot be changed in mid roll. Copying the other medium format camera makers they made separate backs for 120 and 220 film. I have compared my 120 and 200 film holder and could not find any difference mechanically. Couldn't they have made just one moded with a selector. A better system would have been programming into the camera so that when you first load a film back you have to select film type and ISO speed before you can advance the film?. Fully interchangeable backs with film type and speed set on the back would have been even better.

Rearview of the Pentax 645 showing the viewfinder eyepiece and a 220 film back

    Unlike the 6 x7 which has no double exposure capability in the camera body, the 645 has a double exposure knob to set double exposures. This might have been an important feature in the last century but these day the best way to do double exposures is in post processing after digitizing the film images. The camera also has a crude system for manually winding the film to clear the camera in case the batteries go dead or the camera dies.

Left Side of the Pentax 645. The second tripod socket is to the left with the manual wind socket above and to the left of it. The multiple exposure knob and indicator are in the lower right and the PC connector is on the upper right.

 One of the weirdest features is the lithium battery for memory retention that leaves the control system always powered on. Combine this with the fact that the manual specifies that this battery must be changed by a Pentax service center. And to make sure of this the battery cover is fitted to require a spanner wrench to open it not a coin. Most power however comes from 6 AA cells located in the grip.

Bottom view showing the main tripod socket with the manual wind knob stowed in it holder towards the rear The black circle below the tripod socket is for the lithium battery.


Pentax 80-160mm F 4.5 FA Lens

Side view or the 80-160mm f 4.5 zoom lens.

    When I bought the 645 the same vendor was selling several of these lenses each a day apart. I wanted a lens to test the camera and also try all the exposure modes, so I bought this lens after waiting a few days to get a better price.

    This lens is one heavy piece of glass! With it mounted on the camera the combined weight is so great that I wouldn't want it hanging around my neck. It's not small either taking 77mm filters. But it covers from normal focal length to the 2X normal that is the best portrait focal length. I focuses down to a meter and it works well with close up lenses for macro work.

Front of the 80-160mm lens. It uses 77mm filters.

    This series of lenses is designed to be set to the A position on the Iris ring and controlled from the camera. Only in manual mode would you want to manually set the Iris on the lens and the shutter speed on the camera.

Rear view of the 80-160mm lens Pentax uses a mixture of electrical contacts and mechanical linkages to communicate between lens and camera.