A couple of days ago I posted a message here wondering about using an external flash unit with the Leica Minilux Zoom. The main reason I got this little camera was for its hot shoe. There was a dilemma because the camera has no manual aperture control. So using an external flash was a mystery, which sadly no one could solve, other than to suggest to get the CF.

Well, I talked to Leica today and finally found out exactly the whole deal on how the hot shoe works on the Minilux Zoom.

The first thing is that the CF in no way "communicates" with the camera other than just signal to it that it is ready to fire. This alerts the camera that an external flash is connected. Any other flash that has this flash ready signal can do the same thing.

Anyway once the camera knows that an external flash is connected it first disables the built in unit and fires the external flash at full (or fixed B but the same) power. Before the external flash is fired, the camera uses the distance information from either the autofocus or the manual focus and the film speed to calculate the correct aperture to be set. This is ingenious. Better than TTL even, in my opinion. So regardless of whether the subject is bright or dark no compensation need be applied. The correct amount of light will be sent to the film as based on the distance and flash power.

Of course these internal calculations are based for a flash unit with a guide number of 20M, which is the guide number of the CF. So if one is to use another flash unit then one has to find one that also has a guide number of 20M or one that can be set to 20M. So if you have one with a guide number of 40M, then you have to set it to 1/4 power. If the unit has a guide number of 28M then you have to set it to 1/2 power and so forth.

But what if you want to use a high power flash in a high power setting? Say a unit with a 40M guide number, as an example. This would need a 2 stop correction. Since the camera assumes it is a 20M unit like the CF it would set the aperture to f5.6. We would need to somehow fool the camera into setting this to f11. How about using the EV compensation? Well according to the Leica rep, this would not work as that is only for ambient light. So we must find another way.

One way is to fool the camera into thinking it has a faster film. So if one is using 100ASA film, then if we can fool it into thinking it has a 400ASA film then we are fine. Since the camera is DX only, you canBt easily change the film speed. But you can do this using some tape to cover up some squares and change the DX codes yourself. This is one way and is easy to do.

Of course if you do use this method then one must remember to set the camera to +2EV for shots that are non-flash or else they will be under exposed.

So this method can work but admittedly it is a pain.

Anyway I am glad that at least I now know how the external flash on the Minilux Zoom works. Sadly unless you are using the CF it is quite a pain. This is a shame since Metz makes the 34CS2 which is almost as small as the CF, cheaper and a good 1 stop more powerful, with a guide number of 28M.

All Leica had to do was to have a custom setting for flash type. All one had to do then was enter the guide number of your flash unit and it would have worked like a charm!

Thanks for your time!

-- Sol Campbell (solcam31@hotmail.com), October 30, 2000

Answers

As ingenius as it may be, its an old way to calculate exposure with flash, and many of the $75 rangefinder cameras from the 1970's had exactly the same system. Actually better, because you could use any flash and there was a place to set the guide number of the flash on the camera. Taping the DX code and having to use compensation on every other frame without flash as you mentioned above seems a clumsy way to to be using a flash on an expensive camera.

-- Andrew Schank (aschank@flash.net), October 30, 2000.

The Konica Hexar uses the same "Flashmatic" system, but allows you to manually set the GN. Too bad Leica left this out.

Distance-based GN flash exposure, which avoids the problems of reflective metering, is much better in many applications, IMO. It also doesn't require a proprietary interface, so any flash gun can be used. (The ability to use any flash is also one of the simple joys of using a manual camera. Too bad Leica spoiled this with the M6 TTL.)

TTL flash is old technology that was invented before autofocus was available to provide distance information. I suspect that the only reason C & N haven't switched to flashmatic is because they have a lot of $$$ invested in TTL flash, and because they enjoy selling photographers a new flashgun (or licensing their proprietary interface to Metz and others) every time they get a new camera system.

-- Joe Buechler (jbuechler@toad.net), October 31, 2000.

In theory the flashmatic system could be better, but it does assume that the flash's stated guide number is accurate (not necessarily true at all), the battery was fully charged when fired (i.e. is giving the stated GN of output) and finally assumes the flash tube gives the same output throughout its life (which may not be true either). I think these may be some of the reasons for the popularity of the more simple ttl flash systems. Of course, don't even ask about multiple flash systems, or two-flash-in one strobes, or bounce flash in which case ttl is a clear winner.

-- Robin Smith (rsmith@springer-ny.com), November 13, 2000.