Shutter speeds between 8 s and 40 s are indicated by the permanent lighting of the UNDER LED, while speeds outside the 1/1000 s to 40 s range are indicated by the flashing of the LED at OVER or UNDER. In this case the shutter is set for 1/1000 s or 40 s. If shutter speeds of 1/15 s and slower are formed, the use of a tripod or other steady surface is recommended.

Shutter release

After shutter speed has been checked in the viewfinder the shutter is operated by fully depressing the shutter release (22). When pressure is removed from the shutter release the electronics are automatically switched off.4www.butkus.org

With slow shutter speeds the removal of pressure from the shutter release does not affect the exposure procedure. In this case the electronics are switched off when the shutter cycle has been completed.

If the cycle needs to be broken off prematurely with a very long shutter speed (e. g. after an accidental shutter release), the shutter speed dial (21) should briefly be turned to B.

Locking the metered value (exposure lock - AEL)

If the subject features extreme contrasts (e. g. people wearing dark clothes in sunlit snow or a light-colored object in front of a dark background), the exposure value can be determined by individual metering of the most important element in the picture from close up. The value obtained in the close-up measurement is stored, and the image section can then be changed without another shutter speed being set.4www.butkus.org

To store the metered value first depress the shutter release (22) slightly (camera is cocked) to initiate the metering process, and then briefly press the memory button (12) to lock in the metered value (LED at "AEL" is lit).

No new measurement is made before the shutter is released, and the shutter speed will correspond to the locked value. The locked value is erased when pressure is removed from the shutter release and the electronics are switched off.

Exposure compensation

Another way of influencing the exposure individually is by using the exposure compensation system (10, 26). Such compensation is necessary when the character of the object varies greatly the norm, e. g. with dark objects in front of a light background (+1, +2) and with bright objects in front of a very dark background ( - 1, - 2).

Lift the film speed dial (10) and turn the exposure compensation indicator (26) to the desired value.

An LED (+/-) on the left side of the viewfinder image indicates that the shutter speed is overridden. Starting from the initial position the shutter speed is reduced in the ,,auto" mode by 1 or 2 exposure factors when the dial is set to + 1 or +2, respectively. The speed is correspondingly increased when the dial is set to -1 or -2. The dial can be set to half factors. At the limits of the film speed range - 12 ASA and 3200 ASA compensation by two factors is also possible.

However, the compensation cannot extend the shutter speed range beyond the speeds of 111000 s and 40 s. Remember to return the dial to the neutral initial position after exposure-compensated shots. The LED (+) will then go out.

Semi-automatic mode
If you want to shoot at a particular shutter speed, for reproductions or scientific work for example, set the PRAKTICA BX 20 to semi-automatic mode. Fixed shutter speeds from 1 s to 1/1 000 s and the B setting for any length of time are available. Select the speed you want using the shutter speed dial (21) this automatically changes the camera operation to semi-automat/c mode. As with automatic shutter speed control, the camera's electronics are switched on by gentle pressure on the shutter release.

The shutter speed can again be checked using the LEDs in the viewfinder: While the LED corresponding to the set shutter speed flashes, the shutter speed required by the lighting conditions, the film speed and the selected aperture is shown at the same time by a steadily lit LED (two adjacent LEDs light up for intermediate speeds).

To match the two, alter the aperture or shutter speed until the LED is lit steadily. There is no LED display for the B setting. The fixed shutter speeds will not be changed by the described correction procedure.4www.butkus.org

Holding the camera
The illustration shows the best position in which to hold the camera. It should be held steadily and tightly, the elbows should be supported against the body. In this way blur free pictures will be achieved.

Flash photography
If the available light is insufficient for handheld shots (e. g. indoors) or if the subject has to be additionally brightened up, flash should be used. All fitting electronic flash units can be used, computerized or not.
Just push the flash unit onto the hot shoe (23); the electrical connection is thus made.
For electronic flash without computer control set the shutter speed dial (21) to

. The speed will then be 1/100s.

If a dedicated computerized flash unit is pushed onto the hot shoe and the shutter speed dial (21) set to "auto", an LED at the viewfinder edge (at

) will signal flash readiness, and the "auto" indication will go out. Flash readiness will also be indicated in the case of a computerized flash unit when the dial is set to

..

Correct exposure is guaranteed by the camera's TTL light metering system: the reflected flash light passes through the lens, is evaluated by the camera computer, and the flash is cut short at the right moment via the cableless hot shoe connection - genuine automatic TTL metering also for flashes.

The "flash O.K." signal (film is correctly exposed) is derived from the flash readiness indication. If the LED at

lights up again immediately after exposure, the correct amount of light has struck the film. The O.K. signal of the flash unit should be observed in cases deviating from the norm. Flash readiness is retained even if the memory key is pressed and the green LED at "AEL" signals the locking of the metered value. Exposure compensation signaled by the LED at (+ / -), is taken into account by the automatic flash system.

To avoid incorrect exposures with flash when the surrounding light is bright, check by switching off the computerized flash unit that the shutter speed corresponding to the surrounding light is slower than 1/125 s. See also the operating instructions for the flash unit for detailed information.4www.butkus.org

Changing the lens
Press the unlocking key (2) and turn the lens anticlockwise as far as it will go. Remove the lens from me camera.
Insert the PRAKTICA lens in such a way that the red marks (16 and 2) on the camera and lens are opposite each other. Press the lens against the camera body and turn clockwise until the locking pin is heard to engage.

By using the PRAKTICA adapter all original PRAKTICA lenses with the M 42x 1 thread can be connected. Lenses of other makes with the M 42x 1 thread must be suitable for PRAKTICA cameras and equipped for metering at working aperture.

The PRAKTICA BX 20 also works automatically with screw-thread lenses, the only difference being that the light metering is made at working aperture.

Focusing
Focusing is possible with the triple wedge system, the microprism ring or the ground glass ring.

1. Triple wedge
The wedge system allows highly accurate focusing. Optimum sharpness is achieved when the contours and lines flow naturally. Incorrectly aligned edges indicate that the image is out of focus.

2. Microprism ring
The image is correctly focused when the image inside the grid is c/ear and flicker free.

3. Ground glass ring
Especially useful in photomacrography and photomicrography and when using lenses with a small relative aperture (greater than 4). The image must a p pear clear and sharp in the ground glass ring.

Depth-of-field indication

The limits of the depth of field for the selected aperture can be read off from the depth-of-field scale (15) on me lens. Example: distance 3 m, aperture 8 - depth of field ranges from around 2 m to 5 m.

Infrared photography
Infrared photography requires a slight correction to the focusing: match the distance determined in focusing with the infrared index (see arrow) on the lens.

Release button

For ease of operation several functions have been combined in the shutter release (22). When the camera is cocked gentle depression of the shutter release until pressure is felt switches on the automatic system and the LEDs for shutter speeds or flash readiness (with special flash units). Further pressure will release the shutter.

Locking the release button
Accidental shutter release and unnecessary use of power as a result of unintentional pressing of the shutter release button when the camera is cocked or not can be avoided by locking the release button.

To this end, the lock (20) below the shutter speed dial is fumed in the direction of the arrow. To unlock turn in the opposite direction.

Self-timer

Cock the shutter, swing the self-timer cocking lever (4) in the direction of the arrow 1 as far as it will go, and release by pressing starting button (3) as shown by arrow 2. The delay period is approximately 10 s. Do not cock the shutter while the delay mechanism is running.4www.butkus.org

If a motor winder is attached to the camera and switched on, several frames can be exposed during the delay period with fast shutter speeds. If this is not desired, the motor winder should be switched off.

To avoid incorrect metering in the automatic mode the eyepiece should be covered with the eyepiece coyer supplied.

Changing the film
The frame counter {5) indicates the number of frames which have already been exposed on a film. If all the frames on a film have been exposed (red mark at 20 or 36), change the film.

Press in the rewind release (18) until it locks, fold out the rewind crank (8) and turn in the direction of the arrow until increased resistance followed by easy movement indicate that the film has been fully rewound. Pull the rewind button (9) all the way up to unlock the back. The film cartridge can now be removed. Do not change the film in bright sunlight

Attention! If more frames are exposed than are indicated on the film pack, it is possible that the cocking lever cannot be swung all the way. Do not use force. Rewind the film as described above, then swing the cocking lever fully out.

CARE OF THE CAMERA

· Protect the camera from impact, dust and moisture.
· Clean the cartridge and spool compartments, the film track and the back from time to time with a soft brush.
· Do not use organic solvents such as spirit or varnish thinner to clean the camera.
· Do not expose the camera or lens to aggressive vapors.
· Remove fingerprints from the lens and eyepiece surfaces with lens cleaning paper.
· Do not touch the mirror, field lens or shutter blades. Such contamination can only be removed by a service workshop.
· Use an optical brush for dust removal, or blow out
· Do not expose the camera to very high or low temperatures for lengthy periods. Avoid, for example, placing the camera in a car window in direct sunlight
· The camera should be suitably protected from extreme cold.
· When using the camera near the sea or on the beach, protect it from salt water, spray and sand.
· Avoid sudden changes in temperature. These may lead to the formation of condensation and thus to corrosion damage.
· Never attempt to make your own repairs to the camera. Consult a service workshop where necessary.

Your PRAKTICA BX 20 has an improved battery compartment lid.
Please note the following when inserting the battery:
Push the lid (34) in the (changed) direction of the arrow and open it.
Close the lid after battery insertion and lock it.4www.butkus.org

Please note carefully all the instructions contained in this booklet. Incorrect handling of your camera can lead to damage not covered by our guarantee.

Further development of the PRAKTICA BX 20 may result in some aspects of the camera deviating slightly from those given here.