Flash synch speed and exposure with thrystor speedlights

[Domino]

Hi guys 🙂

i am new here, mostly shooting digital until recently (started doing weddings also with Minolta AF film cameras 3🙂 ) and i felt in love with folders... 🙂

i've cleaned and serviced a bit my Kodak Vollenda that was sitting on shelf for some time (today iam gonna develop the first roll ) and got my hands on Moskva 5 in a neat conditions (pretty stiff that small focusing ring tho)
it works nicely but as i am an event/wedding photographer to much extent, i wanny try flash with it.... i got couple of old thrystor auto flashes (Metz 45 CT-1, National 3057 and Porst tm35 Vario) and although i understand how to operate them, i wonder how to do it with folders with leaf shutters which enables to use various shutter times without typical plane shutter limitations of this and later periods. BUT - as the shutter time obviously affects exposure - how does it work with folders? i set my film speed, desired f-stop/zone aaaaand the flash will adjust the power for the settings automatically.... but in various cameras, not to mention those with leaf shutter, the flash synch is or can be different.....
i probably do NOT have some basic knowledge here 😀 or missing some obvoius fact that escapes me because of shooting digital 😉

BTW few samples from Moskva, just a test roll, using phone as lightmeter at first and then guestimating happily 😉

 

[Solinar]

I'm wondering - does the Vollenda even have a PC connection on the shutter assembly?

If it does, unless you use a bracket - you'll have to hold the flash in one hand and the camera in the other, which is not a very stable situation.

BTW you have a good photographic eye for composition.

 

[randy stewart]

flash expsoure

flash expsoure

I have to assume that whichever folder you are using, it has a PC or other trigger cable connector to the flash unit. Ideally, when you trip the shutter it opens to expose the film at whatever f-stop you selected based on non-flash lighting conditions. If you connect the flash, it will also trigger to add light to the scene. First, the shutter must fire the flash while it is open. On old cameras, this cannot be assumed, since many old shutters were timed to fire the flash before the shutter opens (to allow a flash bulb to burn up to full intensity before the shutter opens). The electronic flash is so fast that it can fully fire before this type of shutter opens. Look for an "X" setting in the shutter, or just look through the lens from back of camera for the flash. For your type pf flash, set your used f-sop on the flash control, and it will adjust the flash output by measuring your scene like a light meter. The flash can be your only light source, or you can use it to add exposure to existing natural light (fill flash).

 

[johnnyrod]

As said, you need to check if it is synced correctly. Connect the flash, open the back of the camera, and fire the shutter while pointing the camera at a wall. Look through the lens while you are firing it. If it's X sync (instant X for Xenon) then you'll see the shutter flash through the lens. If not then you'll just see an instant of the wall. X sync is mechanically simpler but back then people used flash bulbs that needed a 20ms or so warm-up time so M sync fires before the shutter, and won't work with X. Alternatively they just fitted X sync and you couldn't use shorter shutter speeds than say 1/30.

It's a leaf shutter so you can use any shutter speed you like, unlike curtain shutters.

Shooting with flash means taking two pictures at once; the ambient light and the flash light. With a thyristor flash you can set it to auto and set the f-stop as per the table vs. ISO. The flash then fires for a duration until the thyristor has seen enough light and shuts off. You can set it to manual but you need to set the f-stop according to the distance as well as ISO, as further away the light has dispersed more than close up. I usually just go with auto for indoor shooting.

Fill flash is another thing, this is where you add flash to a scene with good ambient light to illuminate dark shadows e.g. a face in bright sunlight. It needs experimentation but an easy start is to use two stops darker than the table tells you e.g. f8 where the flash says f4. Meter for f8 and your film ISO and set the shutter speed accordingly. Your ambient light will be metered right but you will have 1/4 (2 stops reduced) of the flash as well. I use Pocket Light Meter app for metering, on iPhone. Better flashes allow you to choose the output power but cheaper ones like mine mean you can only compensate by selecting high/low and the f stop.

Finally (sorry for the lecture!) the flash duration is way shorter than any shutter speed, maybe 1/8000th, so aperture is the only control over flash, shutter speed makes no difference.

 

[drewbarb]

Some lovely photos here.

As for using flash, first you need to remember that the shutter speed isn't a factor in calculating your exposure the same way it is with available light. Flash exposure is determined entirely by the aperture setting. As long as your flash fires while the shutter is completely open and your aperture is set for the correct f-stop to match your flash output, your exposure in the flashed areas will be correct at any and all shutter speeds (up to the maximum flash sync speed of your camera- so with leaf shutters this generally means all speeds, while on cameras with focal plane shutters just up to the max sync speed).

How much the available light shows up (or doesn't) in your images will be dictated by the shutter speed/aperture combination as usual, but the flash exposure will be the same at all speeds. You simply choose shutter speeds based on how you want your pictures to look (how much available light you want to render or not, how much blur you want to see in the non-flashed areas). You can use flash with longer shutter speeds, using available light to "fill in" backgrounds and shadow areas, or shorter ones to make them darker. As long as you set your aperture setting and flash thyristor to match each other, the flash exposure will be correct, and as long as your aperture setting and shutter speed are correct for the available light, that will be right, too.

With leaf shutters you can generally use flash at all shutter speeds. Sometimes there's an upper limit based on the flash's capability or whether it can be triggered at the right time, (see Andrew from Austin's post below) but most speeds even up to 1/500 should work if your shutter has an electronic flash setting (as opposed to flash bulb setting; again, see the post below). Where using flash with leaf shutters is especially useful is in bright light, to get flash to fill in shadows and still have available light render correctly, or even be overpowered by the flash a little. At the other end of the spectrum, shooting flash with slow speeds in dark situations to get as much available light as possible into photos is helpful. When I shot a lot of weddings I used slow shutter speeds with flash in dark situations a lot. Speeds down to 1/15th and even slower can look nice if the subject it still, or if you don't mind a little blur at the edges of flashed subjects and/or in the backgrounds. You can even use this effect to your advantage creatively. I used 1/30th and 1/60th (or 1/50th with Leicas, of course...) routinely, and sometimes depending on the situation and the action, I would shoot as slow as 1 second, hand-held and come up with some really cool images.

You can practice and see these effects experimenting with your digital camera. Even though it doesn't have a leaf shutter, you can get a sense of how the range of different shutter speeds will affect your exposures. Try shooting some flash pictures at all shutter speeds from very slow up to the maximum flash sync speed for your camera. Shoot in dark situations and in brighter light and see what it does, then translate that for your film cameras. Just remember to use the correct aperture setting for the flash output and also keep in mind how that will balance the available light with your selected shutter speeds.

Lastly you'll need to consider the mechanical connection; your old leaf shutter lenses may have PC ports, two prong sync connectors, or something else. As long as you have the correct cords it should work. Good luck and have fun!

 

[Solinar]

Finally (sorry for the lecture!) the flash duration is way shorter than any shutter speed, maybe 1/8000th, so aperture is the only control over flash, shutter speed makes no difference.

The difference between the two speeds is an important consideration. A modern thrystor controlled flash on its auto setting can fire for as short as 1/30,000 of second, which is about 33 microseconds.

Most Compur and Prontor shutters from the period before 1949 were not engineered for an X synch, a.k.a. an electronic strobe. Even if they are equipped with a PC terminal, the shutters made before 1949 will definitely need to be set to 1/30th of second - which means you'll also need to use some slow speed film, if you are working outdoors on a sunny day.

The old-school single use flash bulbs were like witnessing a nuclear blast. Although they were extremely bright - magnesium filament flash bulbs took several milliseconds to reach peak intensity. Consequently, the older leaf shutters from this period were engineered, so that the initial triggering the flash bulb would occur before the shutter could fully open. The point being that this delay could be problem when using modern thyristor controlled Speedlight.

 

[charjohncarter]

Here is what I have taped to my auto flashes:

fill flash
1. Check flash unit auto settings f stops, choose
2. Set camera to 1.5 stops closed from chosen f stop
And then set shutter for ambient light.
3. Shoot, if it is a fill flash situation.

This will let you set up your camera and flash for an afternoon party with only having to focus.

 

[johnnyrod]

John how do you find that using auto mode outdoors? Some people say it's a bit pointless as you don't know how much flash light you're going to get, I don't know if that's just pessimistic. I've dabbled with it but not really enough to have a good grip on it. I use the same method, but have used 2 stops, not really much different.

 

[charjohncarter]

Mostly, I use a Vivitar 2600 D and it works, I also built a set-up to use two Minolta 320x but I have to dial that one in (using non-auto setting on the flash) so I use it only with digital.

2600-D on Olympus 35RC:

Tmax400 at 250 by John Carter, on Flickr

2600-d with a digital camera with manual F stop setting:

Pentax K1 Vivitar 2600-d by John Carter, on Flickr

This is my two Minlota 320x set-up on a digital camera again with manual Fstop setting:

St Elizabeth Golf 2014 by John Carter, on Flickr