Ikonta 520 novar

This is a medium format camera (i.e. takes 120 film) from Zeiss Ikon.  It is a half-frame camera - 6 x 4.5 cm negative - which is half of a standard 120 frame of 6 x 9 cm.

Ikonta 520, front view

lens: Novar
focal length:  75mm
apertures: f6.3 to f32
focus range: 4'6" to infinity (that is the scale, actually about 4 feet)
lens fitting: fixed
shutter: Derval
speeds: 1/25, 1/50, 1/100, B, T
flash: n/a
film size: 120

The body is made from cast aluminium.  This body casting is shared between the Ikonta 520, Bob 510 and Nettar 515. It is quite hard to understand why Zeiss Ikon shared the body between three different camera lines instead of calling them all Ikonta (the oldest name) seeing as Bob, Ikonta and Nettar all come with a range of lenses and shutters and can be considered to be one range in effect if not in name.

So, this Ikonta.  The lens is a Novar which is a triplet and performs surprisingly well once stopped down to f8 or smaller.  Ikontas were also available with Tessars at a higher price and wider aperture Novars.  The Novar on this camera is quite a slow lens with a maximum aperture of f6.3.  The focussing is front cell only, rather than the whole lens moving (giving not quite so good image quality) and the focussing scale is in feet indicating that the camera is an official import into the UK.

The shutter is an everset Derval (everset means it does not need cocking before firing as a Klio or Compur would).  This is a fairly crude (and so cheap) shutter with two blades only and only offers three speeds: 1/25, 1/50 and 1/100.  With a slow lens like this camera has, faster shutter speeds would have been superfluous, particularly with the slow, by modern standards, films available in the 1930s.

Detail of rim-set shutter adjuster on Derval shutter

The shutter is a dial set shutter which means that the speed adjustment is by a dial set above the shutter housing.  More modern shutters have a rim set adjuster which is a ring around the shutter housing.  This shutter does not have a V (=Vorlaufwerk) setting for delayed action and as is usual with cameras made before the late 1940s, there is no flash connection or synchronisation.

As I mentioned, the maximum aperture is rather small at f6.3 but the minimum aperture is surprisingly small - f32 - so the range of exposures possible is still respectably large.

A standard photograph with this camera (as with the Bob 510 and Nettar 515) is in portrait format and in this orientation the shutter release is underneath the camera and is uncomfortable to use.  To take landscape pictures, the camera must be used on its side and the shutter release is on the side and easy to use.

Exa IIA however

Exa IIA front view

lens: Meyer Domiplan
focal length:  50mm
apertures: 2.8 to 22 in 1/2 stops
focus range: 0.75m to infinity
lens fitting: Exakta bayonet
shutter: vertical cloth focal plane
speeds: 2, 4, 8, 30, 60, 125, 250
flash: bulb or electronic
film size: 35 mm

Externally, this is very like the Exa Ia; it has the usual Exakta trapezoidal shape.  The layout on the front fascia is the same - shutter release on the left at the top, PC connector on the right at the top.  The lens fitting is the standard Exakta double bayonet (an internal bayonet for short focal length lenses and a larger external bayonet for longer focal length lenses).

There are differences, however.  The IIa has a fixed pentaprism and eye-level viewfinder with a Fresnal focussing screen with a split-image centre.  The shutter is now a vertically running cloth focal plane shutter rather than the strange mirror shutter of the Ia.  Along with the more standard shutter comes a larger range of shutter speeds  - eight speeds with the fastest  now being 1/250 seconds.

The removable back/base is exactly the same as is the shutter lock on the left of the viewfinder.   Another change is that the rewind knob is now a fold-out crank.

Exa IIa, rear view

With a vertical focal plane shutter, it should have been possible to increase the flash synchronisation  speeds but they are rather slow - 1/15 for bulbs or 1/30 for electronic flash.  The fact that bulb flash needs a slowest synch speed suggests that the only synch available is as the first shutter curtain starts to move, bulb synch relying on the shutter being still fully open when the flash bulb reaches full intensity.

The Exa IIa came with a Meyer Domiplan lens rather than the Carl Zeiss Tessar that was standard with the Exa Ia.  I have yet to see the results from this lens but it has the reputation of delivering good results when stopped down.

This lens, like the Tessar, automatically stops down the aperture when the shutter release is pressed.  Exa lenses manage this by means of a lug on the lens barrel that covers the shutter release on the camera body.  The shutter is activated by pressing this lug which in turn presses the shutter release.

On the Domiplan lens, this lug is hinged and so presses the shutter release through an arc.  Because the release is not pressed straight in it can cause internal damage to the release mechanism.  This is made worse if the lug does not exactly line up with the shutter release so that it presses on one side of the release button.

shutter release lugs - Domiplan on left, Tessar on right

There is a further fault with the Domiplan.  As mentioned above, the release lug is hinged and this hinge dries out with time.  When the lubricant has dried out, the lug will not always return to its rest position after a photograph is taken.  This means that the aperture does not re-open to f2.8, leaving the viewfinder dark.  In use, this is easily remedied by flicking the lug with the shooting finger but it is annoying, nonetheless.  I have applied clock oil to this hinge and it is showing signs of freeing itself up.

4 February 2013:  Having run a test film through this camera, it is difficult to assess the camera's performance.  All the pictures ended up bright green.  This could not have  been down to the camera - it is an SLR and I would have seen the green through the viewfinder.

There are three possible causes for this green - defective development, defective film or defective scanning.  The staff in the lab assure me that mine is the only film to have come out green and so they do not think it was their development.

Defective scanning is a possibility but I would think it to be an automated process and if they have not changed any settings then the scanning process should not produce any colour cast.

The third possibility is a defective film.  The film I used was Agfaphoto Vista plus 200 ISO, made under contract in Japan by, I think, Fuji-film.  Reputable makes of film should be reliable but in any factory process it is possible for the occasional item to escape the quality assurance system.

I am thinking that the reason for the green cast in my test film is the middle one - a defective scan - looking at the negatives, there is evidence of all three colours on the perforated rebate of the film (these are the frame numbers in magenta (the negative of green) and test lines in red and green (the negatives of cyan and yellow)) so it looks like at least part of the film has the requisite colour layers in the emulsion and the development has developed these correctly.  When I have time, I will scan the film myself to check the scan quality.

In addition to the green colour there are other problems which are definitely down to the camera.  At the bottom of each picture is a very over-exposed strip - this equates to the top of the film in the camera.  As the shutter travels vertically from bottom to top, this is most likely caused by the second shutter curtain hesitating slightly at the end of its travel.  This might cure itself with use which is quite common with 'stiff' mechanisms in old cameras.  I also need to be aware that I used this camera in sub-zero temperatures.  The lubricant in the shutter will be thicker at these temperatures and the shutter might well work better in warmer weather.

CMF Comet S italian camera

CMF Comet S

This is a cheap Italian camera which uses 127 film.  The makers is Bencini which is an Italian firm.  At the time this particular camera was made, the firm was called CMF Bencini.  They were made in Milan.

lens: apertures:

focus range: 3 feet - infinity

lens fitting: fixed

shutter: simple

speeds: 1/50

flash: PC connector, M synch

film size: 127

The camera is small and light.  it is made from an aluminium alloy which is nicely polished.  It is small, measuring 10.5 x 7 x  6.5 cm.  It is a very simple camera with only two controls.  You can focus the camera - the range is from 3 feet (circa one metre) to infinity - and you can set the shutter to 1/50 seconds or B.

It is a half frame camera using 127 film.  The negative size is 3 x 4 cm which is approximately twice the size of 35mm.  You get 16 negatives on a roll of 127 film.

Lens barrel detail

The speed selector is unusual in that it is a tab that is pulled out from the lens barrel; see photograph.  The speed selector is on the right of the picture - also visible is the PC connector for flash.  This is synchronised for bulbs only so not too much now.

The viewfinder is very small - the eye piece only measures three millimetres across.  It is the smallest viewfinder I have ever seen.  However, it is still usable once I take my spectacles off.

As a roll film camera, it is necessary to look at the red window on the back when winding on to set the next number in the red window.  As this is a half-frame camera, each number is used twice - there are two red windows - first in the left hand window and then in the right hand one.  the picture shows the two red windows, one either side of the maker's name.

Again as is always the case with roll film  (120 and 127 size) you do not need to rewind the film.  At the end of the roll, you wind the film on until all the backing paper is on the take-up spool and remove the film and spool together and stick the end of the film down with the sticky tab provided.  The spool the film came on is then used as the new take-up spool.