Petri 7s rangefinder

I recently made a decision to add a few rangefinder cameras to my collection. I have had a Minolta Uniomat for a few years and recently bought a Zorki 4. These two cameras represent the two lines of rangefinders that were available in the world of film.

The Zorki is from the line of interchangeable lens rangefinders that follow on from the Leica. Most of these are fairly straight copies of Leicas - all German patents were declared void after the end of WWII - with varying degrees of development.

The Uniomat is from the other - fixed lens - line. These fixed lens rangefinders are cheaper, though never cheap. Not having an interchangeable lens means they can - and do - have between-the-lens leaf shutters.

Petri 7s - front view [(C) John Margetts]

My collection of fixed lens rangefinders now numbers five (I am only including those with a coupled rangefinder) - Vitomatic II, Contessa LKE, Uniomat, Minister III and now this Petri 7s.

This Petri 7s is exactly the same size and shape as the Minister III - I could almost suspect they used a common casting for the body. The weight is not too different, either - 632g with a film loaded.

lens:  Petri

focal length:  45 mm

apertures: f2.8 to f16

focus range: 0.8 m (2.6 ft)

lens fitting: fixed

shutter: Petri MVE

speeds: 1 s to 1/500 s

flash: PC socket

film size: 35mm

The top plate of the Petri 7s is uncluttered. On the left is the rewind crank. This is the now standard fold-out crank which I personally find hard to use. The crank pulls up to allow for the insertion/removal of the film cassette.

Petri 7s - top plate [(C) John Margetts]

Just left of centre is the accessory shoe. By the time this camera was designed (1963) this was usually for a flash gun. It is a cold-shoe - accessory shoe contacts had to wait a further decade to become standard. To the right of the accessory shoe is the light meter window. This is fairly small - the actual window is 5 mm diameter - and incorporates a lens to make seeing the needle and mark possible.

Next along is the shutter release button. This is fairly large - no bad thing - and is threaded for a standard cable release. On the rear right-hand corner of the top plate is the frame counter. This is also a bit on the small size but still usable.

The front of the camera is dominated by the shutter housing. This is fairly large for a fixed-lens camera - the size is necessary because of the light meter sensor around the lens (as in the Yashica Minister III). 

Petri 7s shutter housing [(C) John Margetts]

The lens is a 45 mm f2.8 lens. It has no name on it apart from Petri. A green 'C' signifies that it is a coated lens - normal for the time - but does not tell us if it is multi-coated or single coated. As far as I can find out, it is a Tessar copy - four elements in three groups for the technical minded.

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Blog (C) John Margetts 2014
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The shutter housing has several controls on it. There are the expected control rings - focus, aperture and shutter speed - a flash synchronisation selector (X or M), a delay action lever, film speed selector and a PC connector for the flash. The shutter housing carries the name 'Petri MVE'. The shutter itself is a leaf shutter which means it is quiet in use - excellent for street work.

Above the shutter housing is an elongated window containing the rangefinder window and the viewfinder window. The viewfinder is a reverse Galilean finder (like looking through a telescope the wrong way) and the image is coloured a pale green. On the right-hand end of the front, just below the shutter release, is another window but one that does not seem to have any purpose - perhaps for a facility intended but not implemented. The viewfinder has bright lines with parallax markings. It also has a repeat of the light meter needle. This is much easier to see than the one on the top plate. It is not, however, easier to use as it is very hard to distinguish between the shutter speed and aperture rings by feel.

Petri 7s spurious window [(C) John Margetts]

The rear of the camera is plain. There is the eyepiece of the viewfinder and the film advance lever. The base of the camera is also plain. It contains a tripod boss in line with the centre of the lens (1/4" Whitworth is what I usually say, but it could well be modern enough to be 1/4" UNC. The ISO standard for tripod threads is UNC rather than Whitworth but there is not much difference between the two and Class 1A threads (to be tightened by hand) are sloppy enough to be interchangeable between Whitworth and UNC), and a recessed button to allow for rewinding the film.

Petri 7s rear view [(C) John Margetts]

Using the camera is quite easy. Setting the film speed for the light meter is a matter of rotating the black tab in front of the shutter speed ring - this is on the lower right of the shutter housing. The selected film speed appears in a small window in the shutter speed ring to the left of the fastest shutter speed. This is in both DIN and ASA and goes from 11 DIN/10 ASA to 24 DIN/200 ASA. (ASA is broadly but not technically the same as ISO) This seems a bit of a slow range by today's standards but when the camera was made, it would have covered all the films likely to be used.

To set the exposure, you can either set the required shutter speed and then rotate the aperture ring until the meter needle is centred, or set the required aperture and adjust the shutter speed ring, again until the needle is centred. The meter is a selenium meter which means it does not need batteries. These can deteriorate if left exposed to light for many years but this one is still fine (actually, I have never come across a selenium meter that was not fine - I think the deterioration thing is mostly theoretical rather than real-world).

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Blog (C) John Margetts 2014

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The focus ring has a large knob on the left-hand side which makes focussing with the left hand easy. There are two options for focus - scale focus or rangefinder. For scale focus, there is a big drawback in that there is no depth of field scale which makes my usual hyperfocal method impossible. The focus scale is in both feet and metres.

Using the rangefinder is not as easy as it could be. Petri have tried to make the rangefinder clear by colouring the viewfinder field a pale green and the rangefinder spot yellow. In my camera, the rangefinder spot is rather faint. In good light it does work, though, and it is quick to focus if you have suitable verticals in the frame.

The shutter release works easily without needing undue pressure but without being too much of a hair-trigger. The film advance moves about xx degrees and makes a very definite 'clunk' as it cocks the shutter.

The only other thing worth noting is that there are strap lugs at either end so I can carry the camera on a strap around my neck without needing to use the ever-ready case.

Test pictures.

I am testing this camera with Fomapan 200 Creative film - it is also a test of the film, to some extent as I have never used it before.  I have a 17 metre roll of film and can cut off the amount I need - I am using a 12 exposure length for this test.  This should save me quite a bit of money compared to buying colour film and paying to have it developed.  I should have developed the film in the next few days and will post the results here when I have done so.

27/10/14

As well as testing the camera and film, I am also testing my developing of the film - it is basically developed OK but I can tweak it somewhat in the future to improve contrast. There are some horizontal lines visible - these are scanning artefacts due to the emulsion being a bit on the thin side.

Flooded ex-gravel pit.

The Strait, Lincoln

Steep Hill, Lincoln

Angel Coffee House, Lincoln - hand held in natural light.

Wooden bridge to test the rangefinder - I focussed on the larger wooden upright.