Leica M2 Flash (1600 film push)

tron_ · Jan 20, 2019

Hello,

I'm in the market for a flash for my Leica M2 (I shoot with a Carl Zeiss 35mm 2.8 Biogon lens that stops down to f/22). I almost always push my Tri-X or HP5+ to 1600 but lately I've been shooting late at night and want to incorporate a flash into my system to illuminate my subject on occasion.

My camera has a PC sync port which I can trigger a flash with, however I'm having a hard time finding an appropriate flash for my setup. I need an auto flash that I can set to 1600 and shoot at approximately 1m without blowing out the subject. I can only stop down to f/22 and the film sync speed on my M2 is 1/50 so I'd need a flash that can be powered way down so it doesn't overpower the subject.

Any ideas on what I should do or what my options are?

Thanks!

AgX · Jan 20, 2019

You do not need to set the film speed at a classic auto-exposure flash. You actually only set one of the offered auto-aperture settings.
The actual aperture to set at your camera you will find at the uncoupled calculator disc/slide at the flash

As these typically do not extent to ASA 1600, you just pick the nearest value and adjust instead by setting a resp. smaller aperture at your camera.

MattKing · Jan 20, 2019

You can add something like a diffuser or other light modifier to the flash head to cut intensity.

AgX · Jan 20, 2019

MattKing said:
You can add something like a diffuser or other light modifier to the flash head to cut intensity.

-) a diffuser would only reduce the luminosity over the angle of view. Within its range the the auto-exposure control would take care of this. Thus still over-exposing.
-) a density filter over the flash metering cell would have effect, but to the contrary side, thus over-exposing even more.

MattKing · Jan 20, 2019

AgX said:
-) a diffuser would only reduce the luminosity over the angle of view. Within its range the the auto-exposure control would take care of this. Thus still over-exposing.

For clarity, an auto-exposure flash that permits setting f/11 for 400 ISO film will give correct exposure if the camera is set to f/22 for EI 1600 film. I was assuming that the OP was having trouble with the flash being too bright for the short working distance - 1 meter - and I was proposing a diffuser to bring the illumination down.

John Koehrer · Jan 20, 2019

OP's looking for a flash .
Would a 283/285 with a variable power module be able to reduce the power far enough?
This would have to be used in manual though.

AgX · Jan 20, 2019

Matt, we both are right. Depending on what the OP wants-

I saw this

tron_ said:
I need an auto flash that I can set to 1600

and thought he has difficulties in operating his flash as such.

Basicallly the auto-exposure function should take care of the rest. However there may be a problem with the distance range that function still can work within.
Yes, in such case one must reduce output to bring it back into ths range, either by diffuser or a kind of ND filter ofer the reflector or by swivellingh it andf employing indirect lighting.

This auto-exposure range may even be larger than the calculator makes believe, for instance with Metz 45 flashes, where the calculator gives no min. distance at all, but the manual gives specific numbers in addition.

tron_ · Jan 20, 2019

Yes I'm essentially worried about the flash being too bright for my working distance and film speed. I had a look at the newer Nikon flashes and I'm worried even those will be too bright because the aperture settings only go to f/16 I believe.

For example an old flash I pulled off the shelf states for 400 speed film at 1m the aperture should be f/32. This means for my 1600 speed film the aperture would have to be much smaller than my f/22 max allowed by my lens.

I think the diffuser might be my best bet. I was thinking of using my old Nikon SB-600 so I pulled the manual and was having a hard time figuring out the math.

Here's the GN table:

GN Equation:

Aperture Equation:

ISO Factor:

Here's where I'm having a hard time. Right now according to the top table for a 35mm lens I need to be a minimum of 3.8m from the subject at 1/64. For a GN of 1/64 using the aperture equation with an ISO sensitivity of 4 and a distance of 1m I'm getting (1/64)*4/1m which is giving me an aperture of 0.0625 which is f/16?

AgX · Jan 20, 2019

We must not mix up two things: the smallest aperture the camera can be set at, and the smallest aperture the flash offers.

If the camera's smallest aperture is still too big for what has been read off the flash or calculated, than in any case there must be light reduction, either at the flash or at the lens.
If the smallest aperture is used a auto-exposure flash offers then it depends, as said above, on the flash control how close the subject may come. Either look for this information in the manual or do tests and see what happens exposure wise. Even cheap flashes from the 80s got output indicators, but to my understanding these only inform that the output was enough and not that it was too much.

AgX · Jan 20, 2019

As a side note:
I have to qualify this statement technically

AgX said:
You do not need to set the film speed at a classic auto-exposure flash. You actually only set one of the offered auto-aperture settings.
The actual aperture to set at your camera you will find at the uncoupled calculator disc/slide at the flash

Technically this only applies on those flashes that got auto-aperture settings without aperture figures at them, the actual aperture figures are then found on the uncoupled calculator. (e.g. 45 CT-1)
Some flashes though got true aperture figures as settings (e.g. 45 CT-4) and here the film speed is set actually electronically into the flash.

Concerning a recalculation of aperture to set at the camera, both systems are of same effect.
However concerning the min. distance the systems differ. The former has a fixed min. distance per auto-aperture setting, with the latter that distance varies per film-speed to be set.

tron_ · Jan 20, 2019

I think I may have to head back to the drawing board here again since I'm pretty lost at this point haha. Here's a hail Mary attempt before I retreat. I found a thread online about a guy who planned to use a Hama hot shoe adapter and a sunpak PF20XD flash.

Since this flash states "A3" mode is for ISO400 and f/11. This means ISO1600 and f/16 should be fine. But how would my requirement of ~1m work? Would I just have to experiment with possibly stopping down to f/22?

AgX · Jan 20, 2019

You did not understand what I wrote above.

"A3 mode is for ISO400 and f/11. This means ISO1600 and f/16 should be fine."

Yes, but within the range the autoexposure of this flash. As this is not given, you have to try it. If at your distance there will be overexposure:

-) reduce the light output or input as described above by trial and error
or
-) set the flash to manual at max. setting, and purely calculate the aperture (with the apertures of your camera being the limiting factor)
-) set to manual and reduce the output by that turning knob by trial and error

Bill Burk · Jan 20, 2019

With a flash you wouldn’t need to push. In fact you could switch to a 100 speed film and have fine grain at night.

But you could also bounce the flash.

AgX · Jan 20, 2019

I assume that in general he needs that pushed film speed, but on occasions wants, with same film, to go quite close.

And to give an an example for a flash: the 45 CT1 can go at small aperture setting as near as 0.5m, independant of film speed.

summicron1 · Jan 21, 2019

Vivitar made some really good flash units -- 286 model, i think -- that had a thrysister circuit that works like a light meter to read the subject and cut the flash off when the subject had enough light at the appropriate time -- and it had levels of flash power so you could select one of three lens openings to use with the flash.

The thrysister worked fairly close-up, too -- certainly to the minimum disiance of a leica lens focusing. It also preserves the charge of the capacitor in the flash unit to it doesn't take too long to recycle.

and you could set it to use 1600 asa film, too -- with that sort of film speed you'd get some pretty far reach with one of the wider-open power settings.

I see a lot of discussion up above me here on guide numbers -- I never understood those. I just popped the flash on, set the lens opening for what the flash calculator said to set it at, set the speed at 1/50, and fired away.

I wouldn't use flash and push to asa 1600--pushing film also heightens contrast, adding flash to that would be interesting, at least. I'm with the guy who says if you use flash, use slower film.

Maybe you'll end up carrying two camera bodies.

MattKing · Jan 21, 2019

tron_ said:
Since this flash states "A3" mode is for ISO400 and f/11. This means ISO1600 and f/16 should be fine. But how would my requirement of ~1m work? Would I just have to experiment with possibly stopping down to f/22?

Actually, if the flash is set to A3, ISO 400 and f/11 would be equivalent to EI 1600 and f/22, not f/16.
That flash will have a sensor on the front which will adjust the flash output, based on how much light bounces back from the surroundings and the subject. Essentially, it cuts the flash off after it has put out enough light - and it does that very, very quickly.
The oldest and simplest versions of those auto flash circuits made those adjustments by basically diverting any electrical energy not needed for the tube, and dumping it somewhere where it is wasted. The more recent and complex "thyristor" circuits recycle that energy back into the capacitors, allowing for much quicker recycling times.
The auto circuits have some limits. If you are too close (and 1 meter may be too close), there will be lots of light, and some of those circuits may not be able to shut off the flash tube quickly enough, which leads to over-exposure. It is somewhat surprising that there are no indications on that flash as to which the minimum and maximum recommended distances are.
You can help prevent that over-exposure by manually dimming the usable light, by using diffusion or bounce or ND filters or anything that prevents the full output of light intensity from reaching the subject.
The auto ranges available on that flash don't enable you to approach the matter another way - a smaller f/stop or a camera filter that cuts the amount of light reaching the film.
Other flashes have more choices in ranges, but those flashes tend to be bigger.
By the way, that "A3" is just a code and most likely has nothing to do with the international paper size of "A3".

AgX · Jan 21, 2019

summicron1 said:
Vivitar made some really good flash units -- 286 model, i think -- that had a thrysister circuit that works like a light meter to read the subject and cut the flash off when the subject had enough light at the appropriate time -- and it had levels of flash power so you could select one of three lens openings to use with the flash.

All autoexposure flashlights work this way:
Metering during exposure and then when sufficient by electronic switch cut off the flashtube. What kind of electronic switch they employ, tube or thyristor, basically does not matter for autoexposure.

The different settings at automode not necessarily imply a variation of power level, but a dfifferent meter setting.

AgX · Jan 21, 2019

MattKing said:
By the way, that "A3" is just a code and most likely has nothing to do with the international paper size of "A3".

It just means "Auto-Setting #3" or "Auto-Aperture #3" in the sense of "third out of three".

John Koehrer · Jan 21, 2019

For a SWAG the GN is usually rated at 10 feet(US) so the GN of that flash would be 35. IE: at 10 feet use an aperture of 3.5.
More sophisticated units would have GN in DIN and ISO on their calculator dial.

Leica M2 Flash (1600 film push)

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