Minox BL camera is basically a B model with the addition of a CdS (cadmium sulphite) light meter attached. It replaced the selenium one found on the Minox B, and this was an improvement most welcomed. The CdS cell is more sensitive to the light, thus providing a better light reading and results. This particular camera here has the serial number 12104098, made in 1972-1973.
The meter is semi-coupled and of a needle matching type, and its use is not very different from that of a Minox B or a Minox light meter: point the meter to the subject, press the button for a few seconds, and then take your finger off it. When you depress the button, it locks the needle, as per Minox B needle, so you can take your camera off your eye and match the red pointer over the needle. When this is done, you have set your shutter speed, and you may photograph your subject.
Being essentially a mechanical camera with an added battery-operated meter, the BL is a camera that enjoys the best of both worlds: without a battery, you are basically operating a pure mechanical device. The meter is powered by a 675 cell battery (see the Minox Battery chart here), or a battery adapter; if the battery dies or for some reason the meter becomes unusable, use the camera just like you would use a Minox A or B. Flash photography with this camera is available, in the same fashion as with the other 8×11 Minox cameras.
As the production of Minox BL was run only for a year or so, and given the camera had a CdS meter, Minox BL is a much sought camera. With less than 18.000 units produced between 1972-73, it is seen as a highly collectible, selling for prices well beyond those asked for other Minox cameras, especially if the meter is still active and working. The meter in many of these cameras is now either not working at all or having issues. It is advisable to use only the recommended batteries for the meter, if you have a working one. It will pay greatly in the long run.
Minox BL, Ilford FP125 @ 100, Romania
If you need the manual for this Minox BL camera, you may read it and/or download it here.