Praktica BX 20
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Praktica BX20 English
Praktica BX20 Bedienungsanleitung
Praktica BX20 instrucciones para el uso
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Introduction Technical features Guide to individual parts Preparing to take pictures Inserting the battery Checking the battery Opening the back Inserting the film Closing the back Preparing to shoot Setting the film speed Taking pictures Automatic shutter speed control Preselecting the aperture Automatic mode, indication |
Shutter release Locking the metered value Exposure compensation Semi-automatic mod e Holding the camera Flash photography Changing the lens Focusing Depth-of-field indication Infrared photography Release button Locking the release button Self-timer Changing the film Care of the camera |
With the PRAKTICA BX 20 you have bought a high-quality 35 mm SLR camera
that combines ease of operation with a versatility ideal for any kind of
creative work.
The shutter speeds are automatically controlled within the range from 1/1000 s
to 40 s.(seconds)
In addition, the camera's microelectronics permit the use of fixed shutter
speeds between 1/1000s and 1s as well as unlimited shutter speeds with the B
setting. TTL light metering with open aperture and, thus brightest
viewfinder image is made possible by the electronic transfer of the aperture
setting from the lens to the camera.
The PRAKTICA BX 20 is also equipped with a system which, if a dedicated computerized flash unit is used on the camera, measures the light coming in
from the flash unit, makes a split second evaluation, and closes the shutter as soon as the right amount of light has struck the film. It goes without
saying that conventional electronic flash units can be plugged onto the camera as well. Manual corrections of the automatically controlled shutter
speeds are possible for the purpose of deliberate overexposures and underexposures.
LEDs on both sides of the clear and bright viewfinder image indicate the shutter speed to be expected, limits, mode of operation (automatic or
semi-automatic), memory function, exposure compensation and flash readiness including the O.K. signal for dedicated computerized flash units. The
bottom of the finder image provides information on the preselected aperture and whether the shutter is wound or not. The PRAKTICA BX 20 accepts an
auto winder and the wide range of PRAKTICA accessories.
FEATURES
· SRL camera for a frame size of 24mm x 36mm open-aperture TTL metering system with
electronic aperture setting transfer
· automatic electronic shutter speed control (stepless) in the range from 1/1000 s to 40 s
· change-over from automatic to semi-automatic mode possible; fixed speed range from 1/1000 s to 1 s
· electronic TTL metering system for flashes and correct dosage of light for dedicated computerized flash unit,
X synchronization (approx. 1/100s)
· flash readiness indication (and "flash O.K."
signal) in viewfinder image
· LED information on expected shutter speed in viewfinder
· indication of overexposure or underexposure
· aperture setting displayed at bottom of viewfinder image
· shutter "winding" information
· manual exposure compensation of + 2 exposure
factors, indication of compensation by red LED at,, + a
· locking of metered value and indication there of
by green LED at "AEL" - (automatic exposure lock)
· self-timer (approx. 10 s) with starting button
serves also as stop-down lever for depth-of-field checking
· focusing system comprises Fresnel lens with
innovative diagonal triple wedge, microprism ring and ground glass ring
· viewfinder image shows approx. 95 per cent of
picture sides
· PRAKTICA bayonet (flange focal length 44.4mm
internal diameter 48.5 mm)
· connection for motor winder
· film information holder on camera back
· indication of battery condition in viewfinder
· power source: 6V primary battery
(e. g. PX281Mallory)
(Webmaster: a note stuck inside the manual
states 4-LR44, 4-SR44 [Silver Oxide batteries - longer lasting]
or PX28
battery [basically two SR-44 batteries in one cell] also a note about a new
battery holder).
All of these are common batteries available in large
department stores or camera stores.
· silicon photo element as light sensor
· metering and control range: 0-17 EV at 100ASA and
aperture 1.4
· dimensions of body:141mm x 88mm x 49mm
· weight of body without battery: 510 g
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1. Filter thread |
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12. Memory and battery check key 16. Lens positioning mark 17. Lug for carrying strap 18. Rewind release 19. Index for automatic mode 20. Shutter release lock
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23. Hot shoe with center contact 28. Film take-up spool 29. Film sprocket 30. Shutter blades |
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34. Lid of battery compartment 35. Tripod socket 36. Guide way for motor winder 37. Coupling for motor winder 38. Catch for motor winder 39. Contacts for motor winder 40. Mark (for insertion of battery compartment lid) |
Inserting the batteries
A 6 V source is required to power the whole electronic system. It may be an
alkali-manganese, silver oxide (SR) or lithium battery.
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Webmaster: On the left is an example of two PX-28 batteries from a Ricoh manual. This is how the batteries should go looking down at the camera. Not sure where the positive marks are on the body so this could be backwards. If using 4-SR44 batteries you should have two bumps going in one direction and two in the opposite. |
Four button cells (e. g. LR 44) in a battery case (order no. 961 363) will
also do. (the bumps on the batteries are the negative sides, the two bumps
should go in the same direction)
Under normal conditions, a fresh battery lasts for about 2 years. To insert
the battery, push the battery compartment lid (34) in the direction of the
arrow and swivel it out Wipe the contacts in the battery compartment and those
of the fresh battery with a dry cloth. Press the plus pole of the battery
against the spring contact (polarity marks in the battery compartment) and tip
the battery in. Close the lid and let it click in.
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The contacts of the battery and in the compartment should be
checked from time to time, and cleaned if necessary. Low temperatures have an
adverse effect on the battery; it should therefore be suitably protected in
cold weather.
If the camera is not used for an extended period, the battery should be
removed.
Checking the battery
The shutter must be wound. Press shutter release (22) and then memory key
(12). If the LED indication is bright the battery still has a sufficient power
reserve. When the battery is spent, the LEDs on the right side of the
viewfinder image will go out. The battery condition can not be checked in the
B and 
setting.
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Opening the back
Pull the rewind button (18) up as far as it will go to unlock the back Open
the back completely the frame counter (5) will automatically return to the
starting position.
Inserting the film
Before the film is inserted the shutter speed dial should be set to a fast
fixed shutter as otherwise a slow shutter speed may be formed in the "auto"
mode. The winding lever is blocked until the shutter has completed operation.
Do not use force! An undesired slow shutter speed that may have formed
in the "auto " mode can be cut short by changing from "auto" to B. Such a slow
speed is also obtained in the "auto" mode when the shutter is released without
a lens being connected to the camera.
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Put the film cartridge into the cartridge compartment (31).
Press the rewind button (9) back in all the way; turning it if necessary.
Insert the film leader at least 1 cm into the slit in the take-up spool (28).
Carefully operate the winding lever until the teeth of the film sprocket (29)
engage in the film perforation.. Swing the winding lever fully out and let it
return. Release the shutter.
Closing the back
Press the
middle of the lock side of the back against the camera body until the lock is
heard to engage.
Preparing to shoot
The winding lever (6) may be swung out a little way without starting the
winding procedure. This readiness position increases the handling reliability
when taking rapid picture sequences. Swing the winding lever as far as it will
go, return and press the shutter release (22). Repeat the procedure and
continue to do so until the automatic frame counter (5) indicates frame 1.
Information on whether the shutter is wound or not is given at the bottom of
the viewfinder image:
* aperture reflected into viewfinder appears red -shutter is not wound
* aperture reflected into viewfinder is colorless -shutter is wound
Proper film advance can be checked by making sure the rewind button (9)
rotates as the winding lever (6) is moved.
If you shoot with a winder attached to the camera refer to the instructions
for use of the PRAKTICA winder made by VEB PENTAGON DRESDEM
We shad not be liable to you for damage caused by using a winder of different
make.
Setting the film speed
Press the unlocking key (11) and turn the film speed dial (10) until the film
speed given on the pack (ASA value) matches the index of the compensation
indicator (26). The flap from the film pack can be put into the memo holder
(33) as an additional aid to the memory.
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Automatic shutter speed control In the "auto" mode, the PRAKTICA BX20cperates automatically in a stepless shutter speed range from 1/1000 s to 40s. The shutter speed is electronically controlled in consideration of the lighting conditions, the preselected aperture and the film speed. LEDs at the edge of the viewfinder indicate the controlled shutter speed. Should the shutter speed range be exceeded, OVER or UNDER is indicated. |
The TTL metering system automatically takes into account all factors influencing the exposure such as focal length of the lens, filters and
extensions.
If lenses with the 42x1 PRAKTICA thread are used with an adapter, light metering is automatic at working aperture.
Preselecting the aperture
The desired aperture is set against the mark on the lens by fuming the aperture setting ring (13). The set aperture is displayed at the bottom of the
viewfinder image.
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If lever (4) is moved in the direction of the arrow, the diaphragm is stopped down to the aperture set, and the depth of field can be assessed in the viewfinder. |
Automatic mode, indication
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Set the shutter speed dial (21) to "auto". The electronics are switched on by slight pressure on the shutter release (22). In the viewfinder image the shutter speed calculated by the automatic system is shown by an LED display. If it appears unsuitable for the subject, it can be corrected by selecting another aperture. LEDs are allotted to selected speeds between 1/1000 s and 8 s, with intermediate values being indicated by the simultaneous lighting of two adjacent diodes. |
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Shutter speeds between 8s and 40s 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. |
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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. 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. |
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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. |
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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). |
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The speed will then be 1/100s. )
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 .. 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.  |
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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. |
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For ease of operation several functions have been combined in the shutter release (22). When the camera is wound, 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. |
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Advance the shutter, swing the
self-timer winding 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 wind the shutter while the
delay mechanism is running. |
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