Tuesday, 19 July 2016

Praktica BC1 electronic

This was one of my better buys from Ebay. I have two BC1 bodies, a Prakticar 50mm lens and two straps for £5.00. With one camera, the internal meter agrees with my hand-held Ikophot light meter. The other is six stops or so out. It is quite possible that this is down to dirt on the meter sensor. As the meter is not accessible without removing the top plate and the controls on there, I shall not be having a look.
Praktica BC1 (C) John Margetts

lens: Prakticar 50 mm f/1.8
focal length:  50 mm
apertures: f/1.8 to f/16
focus range: 0.45 metres
lens fitting: BC bayonet fitting
shutter: metal, vertical focal plane shutter
speeds: 1 seconds to 1/1000 plus B (defaults to 1/90 with no battery)
flash: hot shoe + PC socket
film size: 35 mm


I am going to be quite fast with this description. SLR cameras have a pretty much standard layout and there is not a lot to be gained from repeating this is detail for each camera. 

So, right to left on the top of the camera:

Frame counter. this resets to zero when the camera back is opened. The main numbers are in white. The even numbered frames have numbers and the odd numbered frames only have dots. Frames 20 and 36 are in red as these were the standard lengths of films. the frame counter will go to 37 and then stops even though the camera will still advance the film beyond 37 exposures. 

Next is the film advance lever. this moves through around 135 degrees to advance the film one frame. The lever has a parked position where it is flush with the camera body. In use, it sits slightly proud of the body which makes it easier to use. It is black plastic and is quite comfortable to use.

The shutter release button. It is chrome plated and threaded to accept a standard cable release. Around the chrome button is a black collar which can be turned clockwise to lock the release button.

Just left of the shutter release button is the shutter speed selector. This has a green automatic setting which is how the camera is intended to be used. In this position, the camera selects the shutter speed to achieve correct exposure. The camera is not restricted to the standard range of shutter speeds and can select intermediate values to get the exact shutter speed required. There are also manual speeds available. These are the standard sequence up to 1/1000 seconds. The shutter is electronically controlled and in the absence of electric power the shutter works mechanically at 1/90 seconds - which is also the flash synchronisation speed.

The printed disc is missing from the shutter speed selector
Almost centrally is the pentaprism hump.  On top of this is the accessory shoe with 'hot shoe' electrical contacts. This has the standard central contact and a second, smaller, contact for the Praktica computerised flash gun. Connecting the Praktica flash automatically sets the shutter to 1/90 seconds. Cold shoe flash guns will also work as there is a PC socket as well as the hot shoe connector.

Left of the pentaprism hump are two buttons. The first is black with a chrome collar. This has two functions. It is used to test the battery (doesn't seem to work on my camera, even though I know the battery is good). Its second function is to lock exposure if you wish to set the exposure away from your area of composition - such as pointing the camera down to avoid the sky, pressing this button and then raising the camera to take the shot. There is also a small chrome button which is used to release the exposure compensation ring.

On the far left is a multifunction knob. The outside lifts and rotates to set the film speed. This is in both DIN and ASA and runs from 12 to 36 DIN or 12 to 3200 ASA. Above this is the exposure compensation ring. This runs from +2 to -2 stops and will only turn if the chrome button is depressed. In the centre is the rewind crank. This is of the folding varietal that was now normal at the time this camera was made. This crank lifts to unlock the camera back and release the film cassette.

The back of the camera has two items. At the top is the viewfinder eyepiece. This is nice and large and is surrounded by a rectangle of hard black plastic - which is why my glasses get horribly scratched. The view in the viewfinder is plenty large enough and good and bright. The main focusing screen is a Fresnel lens  - which is why it is bright - and in the centre is a ring of plain ground glass. Inside this ring is a second ring of micro-prisms as a focusing aid and in the very centre is a 'triple wedge' which is a very nice variation on a split-image focusing device. This works very well.  Down the left side of the focus screen is a list of shutter speeds. With the shutter speed selector set to 'automatic' a red LED will light beside the selected shutter speed. If you set the shutter speed selector to a shutter speed, the set speed will have a flashing LED beside it and the suggested speed a steady LED. At the bottom of the viewfinder  is the selected aperture - this is reflected from the lens through a small window on the front of the pentaprism hump.
shutter speeds in the viewfinder

Below the viewfinder eyepiece there is a holder for the end of the film carton to act as a reminder of the film in use.

On the front of the camera are various items. Towards the top on either end are lugs for attaching a neck strap. More or less centrally, is the lens mount. This is a three bayonet mount with three electric contacts for reading the aperture setting (I assume this is in Octal giving a range of eight possible f/stops).

Add cap
To the right of the lens mount is the lens release button. This is black with a prominent red dot. To fit a lens, the red dot on the lens is aligned with this red dot and the lens inserted into the mount and turned clockwise. To remove the lens, this button is depressed and the lens turned anti-clockwise for removal. Above the lens release button is a slider that moves vertically. Pushing this lever up closes the lens diaphragm so the photographer can see the depth of field of his selected aperture. This lever works by engaging with a lever on the lens which is used by the camera to stop down the lens when taking a picture. Right by the lens mount is a second lever. This one turns rather than slides and rotates anti-clockwise to set the self-timer. The timer to actuated by pressing the small black button on the middle of the lever. This gives a delay of 6 seconds on my camera. On the left side of the lens mount is the PC socket for a 'cold shoe' flash gun.

There are also several items on the base plate. Almost centrally, is the ubiquitous tripod boss - 1/4 inch Whitworth/UNC. In front of this is the battery compartment. This takes a A544 6v battery - still readily available. On the right-hand end of the camera is a connector for a motor-drive. This consists of a mechanical screw connector, two electrodes and a locating hole. As I do not have the motor-drive, I can say no more about this.

The lens that came with the camera is a Pentacon Prakticar lens. Its focal length is 50mm - so 'normal' for 35 mm photography (ie se pretty much the same view as a human eye) and its maximum aperture is f/1.8. Its minimum aperture is f/16. The focal range is from 0.45 metres to infinity.  As was usual with film cameras, there is a DOF scale printed on the lens which, among other things, makes hyperfocal focusing much easier than it is with modern digital lenses. The throw of the focusing helical is somewhere around 300 degrees - ie you need to turn the focus ring through 300 degrees to go from minimum to maximum. This makes it easy to focus accurately but hard to focus quickly. There is also an infra-red marker. If you are using infra-red film, focus is not quite the same as with visible light so you have to focus normally and then move the focus marking to the red dot. For instance, if you are focused on 8 metres move the 8 from the usual red line to the red dot.  Both the line and the dot are visible on the photo below. The lens is multi-coated which is as we would expect from any lens from this period.

Saturday, 2 July 2016

Pentaflex SL from Pentacon

This Pentaflex SL is a cut-down version  of the Praktica Nova camera. It is missing the slow shutter speeds - this camera only goes down to 1/340 seconds which is slower than I ever go to so the even slower speeds are no loss. It is also missing the light meter. As the camera is fully manual, this is no loss. It is actually easier to use a dedicated hand-held meter rather than using the whole camera as a hand-held meter. The only non-manual part of this camera is the aperture - you set the required aperture and the diaphragm closes as you take the picture.

Someone has attempted a repair on this camera. There are two screws missing from the top plate and the cover of the pentaprism has been messily glued in place with Uhu glue. Having said that, the camera seems to be functioning as it should - test film might say otherwise, of course.

lens: n/a
focal length:  n/a
apertures: n/a
focus range: n/a
lens fitting: M42
shutter: horizontal cloth focal plane
speeds: 1/30, 1/60, 1/125, 1/250, 1/500
flash: F and X PC sockets - no shoe
film size: 35 mm

The description:

The camera body measures 150 mm by 48 mm and 95 mm high. It weighs 562 g - not as heavy as some SLR cameras but not up to Olympus OM standards. On the right of the top plate, where we would expect it, is the film advance lever. This is not on a ratchet so has to advance the film in one sweep. The lever moves through about 185 degrees to advance one frame. Around then advance lever is the frame counter. This is reset to -1 when the camera back is opened. It counts up - the highest marked frame number is 36 but the scale moves to an unmarked 40 - above this the film still advances but the counter does not move. In the centre of the rewind lever is a film reminder. This has five options: B&W; colour negative, daylight; colour negative, tungsten; slide film, daylight and slide film, tungsten. In the corner of the advance lever is a small chrome button to disengage the film advance mechanism to allow the film to be rewound.

Camera with Soviet lens attached

Between the advance lever and the pentaprism hump is the shutter speed selector. This goes from 1/30 to 1/500 seconds which is a quite adequate range, plus B. As mentioned above, the slower speeds have been removed from this model.
Blog (C) John Margetts

The pentaprism hump is just left of centre. To the left of this is the rewind crank. This is of the small folding variety that was ubiquitous by this time and I find hard to use. Around this is a film speed reminder. As this is a meter-free camera, there is no need to set this but with a memory like mine it is well worth the bother. 

Front of the camera showing the lens mount

The front of the camera is dominated by the lens mount. This is a M42 mount - a 42 mm by 1 mm pitch thread also known as the Pentax thread although it was introduced by Zeiss Ikon with the Contax S. Just inside the mount at the bottom is a lever actuated by the shutter release button which closes down the diaphragm on automatic lenses. If you wish to use older manual lenses which might foul this lever, it can be disabled by lifting the mirror and sliding a red stud to one side. most automatic lenses have a manual/automatic switch which will act like a DOF preview button if required. Also visible inside the mount is a piece of black cloth at the top. I have never seen this before and I am not sure why it is there.
Front and top plate layout

To the right of the lens mount are two PC connectors for flash. the connector nearest the lens is synchronised for F type bulbs and next to that the PC connector is synchronised for electronic flash (marked X).

PC connectors
Left of the lens mount is the shutter release button. I generally prefer the release button to be on the top plate but this is well placed on the front and nicely angled - it works well. The button is threaded for a standard cable release and is knurled - the button can be turned to lock the button to prevent accidental exposures.

The rear of the camera is unadorned. At the top is the viewfinder eyepiece. This looks like it is designed to take an attachment of some sort. The viewing screen is plain ground glass with no focus aids. The ground glass is fine enough and then image bright enough that focusing is quite easy. The image seems to be very close to life size (judging by keeping both eyes open while looking through the viewfinder with a 58 mm lens attached).

The leatherette on the back is embossed with the Ernneman Tower - the logo of Pentacon. There is also Pentacon's quality mark - a triangle with a "1" inside indicating first quality.

The only item on the base is a tripod boss - the standard 11/4 inch UNC (Whitworth on older cameras) thread, This is right over on the left which is a strange place. The ideal position for a tripod is under the node of the lens - this would entail the lens maker fitting the tripod boss here as some do. The next best place is is line with the centre of the lens. The position of this tripod boss puts most of the weight of the camera to one side - not good for level stability and not good for panning on the tripod.

Base of camera
The back is opened by a catch on the right end of the camera. The back has velvet light seals along both the hinge and the catch but not along the length of the back. Light is kept out by the back being sufficiently recessed into the body. This gives the camera a distinct advantage over Japanese cameras of the same age which all require new foam light seals by now. Not this camera!

Judging by the exposed metal around the film gate, the body is made from an aluminium alloy rather than the more usual brass of the time. This will be why the camera is on the light side.

This camera will be tested with film over the next few days and I hope to have the results in place by next weekend.