Trying to wrap my mind around TTL bounce flash with a film camera.

[Theo Sulphate]

...
If you're using a focal plane shutter, the shutter speed must be slower than the duration of the flash.

If the shutter closed Before the flash turns off, a portion of your frame will not be exposed by the flash.

Take a look.
https://fstoppers.com/originals/demystifying-high-speed-sync-68527

To elaborate further: You want the shutter (first curtain) to be fully open (across the entire film gate) before the flash fires. Likewise, you don't want the second curtain to move across the film gate until the flash is done. By keeping the shutter speed at the sync speed (e.g. 1/250) or at a slower speed (e.g. 1/125), that guarantees the entire frame of the film is uniformly exposed during the flash interval.

 

[Mainecoonmaniac]

To elaborate further: You want the shutter (first curtain) to be fully open (across the entire film gate) before the flash fires. Likewise, you don't want the second curtain to move across the film gate until the flash is done. By keeping the shutter speed at the sync speed (e.g. 1/250) or at a slower speed (e.g. 1/125), that guarantees the entire frame of the film is uniformly exposed during the flash interval.

Yes. I wonder if leaf shutters have higher sync speeds?

 

[pentaxuser]

Not a chance..sorry. No tupperware on my flashes.

This looks as if it will fulfil functions that an open flash will not such as an even light, avoidance of red-eye etc in situations where bounce is not practical. Whether it is worth the money compared to a cheaper elasticated white cloth over the flash is another matter.

What's the specific problem with a tupperware-type of attachment?

pentaxuser

 

[Chan Tran]

Yes. I wonder if leaf shutters have higher sync speeds?

Yes most leaf shutter cameras sync with flash at all speeds but their highest speed is usually only 1/500

 

[Pieter12]

Yes. I wonder if leaf shutters have higher sync speeds?

High-speed synch only works on certain modern cameras, and is not really necessary for most fill-flash except maybe sports in brightly-lit situations. Probably not many film cameras, as the OP is asking about, will do high-speed synch. Most of the time Focal plane shutters usually synch at 1/125 or 1/250. Leaf shutters will usually synch to 1/1000th, still slower than any portable flash unit.

To elaborate further: You want the shutter (first curtain) to be fully open (across the entire film gate) before the flash fires. Likewise, you don't want the second curtain to move across the film gate until the flash is done. By keeping the shutter speed at the sync speed (e.g. 1/250) or at a slower speed (e.g. 1/125), that guarantees the entire frame of the film is uniformly exposed during the flash interval.

The flash duration is almost always much shorter than the shutter speed. For example, the Nikon SB-910 flash duration ranges from 1/880th (full power) to 1/38,500th (1/128 power)! The issue is synch speed. Most focal plane shutter film cameras will synch up to 1/125th or 1/250th, faster than that you will encounter problems. Some digital camera have high-speed synch when used with dedicated flash units, but not any focal-plane film cameras that I am aware of. A leaf shutter will synch at all speeds, I believe.

 

[MattKing]

Most of the time Focal plane shutters usually synch at 1/125 or 1/250.

Careful with this. Many focal plane shutter cameras - particularly older 35mm and medium format - have slower maximum synch speeds. 1/60 or even 1/30 in some cases.

 

[Mainecoonmaniac]

High-speed synch only works on certain modern cameras, and is not really necessary for most fill-flash except maybe sports in brightly-lit situations. Probably not many film cameras, as the OP is asking about, will do high-speed synch. Most of the time Focal plane shutters usually synch at 1/125 or 1/250. Leaf shutters will usually synch to 1/1000th, still slower than any portable flash unit.

The flash duration is almost always much shorter than the shutter speed. For example, the Nikon SB-910 flash duration ranges from 1/880th (full power) to 1/38,500th (1/128 power)! The issue is synch speed. Most focal plane shutter film cameras will synch up to 1/125th or 1/250th, faster than that you will encounter problems. Some digital camera have high-speed synch when used with dedicated flash units, but not any focal-plane film cameras that I am aware of. A leaf shutter will synch at all speeds, I believe.

From my experience, most strobes I've used have a longer flash duration at higher power settings. You'll have to watch your sync speeds at higher power settings. Also, as for using strobes with ambient lighting, the higher power settings will usually result in darker backgrounds from the strobe intensity is brighter than daylight.

 

[Theo Sulphate]

Yep. All the above is good info. I'm used to sync speeds of 1/60 and 1/30 on focal plane shutters, so the 1/250 on an FE2 is amazing (though I realize it travels vertically, so the distance it has to cover is less).

And flashbulbs are a whole different situation - it'd be fun to try some day.

 

[Chan Tran]

Yep. All the above is good info. I'm used to sync speeds of 1/60 and 1/30 on focal plane shutters, so the 1/250 on an FE2 is amazing (though I realize it travels vertically, so the distance it has to cover is less).

And flashbulbs are a whole different situation - it'd be fun to try some day.

I believe the FE2 was the first camera with focal plane shutter and a sync speed of 1/250. The FM2 introduced shortly before it was 1/200. Later the FM2n also has 1/250.

 

[AgX]

Yes most leaf shutter cameras sync with flash at all speeds but their highest speed is usually only 1/500

Yes, today focal plane shutters may have a synch speed of 1/250 or even higher.
But in the 70s that was 1/60 and in the 80s 1/125 with very few exceptions like T90 with 1/250.
Thus back then leaf shutters had their benefits.

 

[M Carter]

Regarding the old Vivitar 285's - long-story-short, my TTL-capable (Nikon DSLR) was down for repair, had an event where I needed on-camera flash. Grabbed my old 285 and stuck it on my (samsung NX1) mirrorless digital and used the auto function on the 285, camera to manual, and set my f-stop via the calculator dial on the side. Worked fantastically, just like the old days. That technology was really pretty solid.

 

[darkroommike]

Thanks Mike, I'll start there.

One question; if I want more flash in the mix can I dial the exposure down a stop and the flash compensation up a stop? That way it starts to look like the key light?

Sure, it's not to my taste but I see it done that way.

 

[BrianShaw]

Careful with this. Many focal plane shutter cameras - particularly older 35mm and medium format - have slower maximum synch speeds. 1/60 or even 1/30 in some cases.

This is true and a good correction (and even more accurate if Nikon F-3’s 1/80 synch speed is also mentioned) but only part of the issue being discussed. At the strobe duration rate Pieter cites it really doesn’t matter much. Even at a lower number that is often cited, 1/440 sec, it only potentially impacts the highest shutter speeds as someone already pointed out.

 

[BrianShaw]

Regarding the old Vivitar 285's - long-story-short, my TTL-capable (Nikon DSLR) was down for repair, had an event where I needed on-camera flash. Grabbed my old 285 and stuck it on my (samsung NX1) mirrorless digital and used the auto function on the 285, camera to manual, and set my f-stop via the calculator dial on the side. Worked fantastically, just like the old days. That technology was really pretty solid.

Same experience here, to the point where I often use Old Vivitar rather than newer TTL flash.

 

[BrianShaw]

...

And flashbulbs are a whole different situation - it'd be fun to try some day.

Actually, it’s about the same but more exaggerated. The issue of flash duration vs shutter speed is an efficiency issue - a mismatch. With electronic strobe that mismatch occurs under only a few combinations of conditions. With flash bulb that mismatch occurs under a lot more (some remarkabley common) conditions. To the point where flash bulb exposure is often expressed in tables and when expressed in a single GN there are myria caveats. There are even slide rules to support resolving the “best” flash bulb exposure. But that’s a different thread... just thought I’d touch on it since you brought it up and I find that to be a fascinating practical problem.

 

[Sirius Glass]

Hi,
I've done a lot of off camera and bounce flash with digi. I find it very easy but not so easy to translate that knowledge to film.

Let me explain.
I normally shoot manual camera settings and TTL bounce flash. I got spoiled by just looking at the LCD and using that to adjust the mix of ambient and flash using the flash FEC.
Now I need to KNOW what the heck I'm doing because there isn't instant feedback.

Does anyone shoot this way? With your camera on manual and your flash on TTL?

If the sensor on the flash works just use it. If there is no sensor or the sensor does not work add the distance from the flash to the bounce point to the distance from the bounce point to the subject. Then take the sum and divide it into the Guide Number for the f/stop.

 

[wiltw]

Does anyone shoot this way? With your camera on manual and your flash on TTL?

Did lots of that back in the 1990s when I was still shooting weddings on 645, using Bronica ETRSi on manual (or on Auto exposure for ambient light which was bright enough) combined with Metz flash plugged into the Bronica TTL control electronics.
Back in the before-digital age, we had to depend upon our gear without chimping (sadly seen so much today) and rely upon learned skills and reliability of equipment.

If I pull out my Olympus OM gear, I use the OM-4 with same Metz flash plugged into the Olympus Metz adapter for TTL flash exposure automation

I think both of the above (film TTL) are Orders of Magnitude more reliable than the modern nTTL crAp we have today from the camera companies! Even I chimp, just to make sure than nTTL has not unpredictably failed me yet again. I put the flash into 1970-vintage Photosensor Auto if I do not have time to chimp digital, yet I want more predictability! The in-viewfinder flash exposure OK confirmation was a good visual reminder that the equipment thought it got it right (unlike the lack of OK confirmation in digital TTL). With digital TTL, shoot five consecutive shots of the same subject at the same aperture and shutter speed with nTTL flash, and likely as not one of the five will be overexposed suddenly for no comprehensible reason !

 

[rpavich]

Ok...did the test suggested. I shot a portrait of my wife at the following settings:
No compensation.
+1 stop
+2 stops
-1 stop
-2 stops
No compensation but dragging the shutter at 1/30.
No compensation but dragging the shutter at 1/8.

I found that 0 compensation looked great but the background was very dark.
I found that I liked getting more ambient light in by dragging the shutter also.