Film frames partially darkened using flashgun handheld. Why?

Hello,

For the first time, I used flashgun handheld while photographing in the streets like Bruce Gilden. When I developed a couple of b&w films (Kentmere 400), I noticed that the upper side of several frames was quite dark or not flashed. Pls, check the attached file. The phenomenon isn’t only obvious in frames in a row, but also in single ones.

Gear used: Zeiss Ikon ZM, Voigtlander 28mm lens, Metz 44 AF-3N Mecablitz connected to the camera by a remote flash cord. I had set the flashgun to manual mode and 85mm zoom due to the general short distance. Despite the fact that the Ikon ZM’s sync speed is 1/125, I used several times 1/250. Though I don’t remember if I used 1/250 in any of these spoiled frames. However, the flashgun flashed as usual.

Do you think that this happened due to bad synchronization of the flash with the camera’s curtain? namely should I stick to the camera’s sync speed?

Any other idea for this malfunction?

Thanx in advance!

You really need to stick to the synch speed, or slower. I'd bet that the bad frames were from when you shot at 1/250 sec.

Iridium said:

Do you think that this happened due to bad synchronization of the flash with the camera’s curtain? namely should I stick to the camera’s sync speed?

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Yes, it appears your camera is not synchronizing with your flashgun. Stick to 1/125th of a second for flashes.

If the camera has a focal plane shutter and it seems to from your description then the shutter speed max is the sync speed. Any speed above this will result in what I think you are describing as one of the curtains is closing but there is no light left from the gun i.e. above a certain shutter speed the two curtains move across the frame in the form of a slit. When it is daylight this is fine as there is always light present but at night or even in dusk conditions there isn't any light or not enough for the scene to properly register through the moving slit

pentaxuser

You got a shutter with a horizontal slit, running upwards. When the 1st section reached the top and released the flashlight meanwhile the 2nd section had started and already covered 1/3 of the frame height.

The exposure time you chose was too short.

Thanx guys. Now learned my lesson!

two problems

It appears you have two problems. When the camera manual says that the strobe sync is a certain shutter speed or lower, they are not just flapping their lips, so to speak. You need to pay attention to this. Also, you have set your strobe to cover what an 85mm lens would cover but you are shooting with a 28mm lens. As we used to say, you are cruising for a bruising. Your logic is flawed when you say you set the strobe at 85mm due to the short distances. This has nothing to do with distance, it has to do with how wide an area the flash will cover.

But as the example above shows, a too short exposure time could be used deliberately. To avoid blur from remaining continous lighting on the price of cropping, so to say.

snapguy said:

It appears you have two problems. When the camera manual says that the strobe sync is a certain shutter speed or lower, they are not just flapping their lips, so to speak. You need to pay attention to this. Also, you have set your strobe to cover what an 85mm lens would cover but you are shooting with a 28mm lens. As we used to say, you are cruising for a bruising. Your logic is flawed when you say you set the strobe at 85mm due to the short distances. This has nothing to do with distance, it has to do with how wide an area the flash will cover.

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Just a couple of questions. As this lens is 28mm, should I always set the flash's reflector position (zoom) @ 28mm, regardless the distance of the subject?

And...when I make the calculation for the right f/stop aperture, shall I round off the result to the closer smaller real f/stop (lighter aperture)? If I get for example the result f14, shall I choose f11 or f16?

Yes, do use the 28mm reflector position if you are using a 28mm lens, unless you don't care to light the entire 28mm field of view.

No, set your aperture half way between f/16 and f/11. Most lenses do have a half stop position; some actually have third stop positions for aperture.

I would also ask if you intend to use this as fill flash or is the flash supposed to be providing all your lighting?

If you are using flash for fill then Kentmere 400 is too fast of a film for this type of work.

Assume you are trying to shoot someone who is 3 meters away. Since your flash guide number is 44, this means your aperture is 14 (or 16 if you need to round up.)

If you assume that your normal daylight scene is already Sunny F/16, then you would have to set your shutter speed to 1/500 seconds. This is way beyond the ZM's synch speed.

Even if it is a cloudy day and your meter shows f/8, you are right on the edge of what you can get away with here. Better hope the sun doesn't come out.

If your intent is to shoot fill flash on the street during the day, go get some ISO 100 film and you will have a better chance. Better yet, get ISO 50, like Pan F.

I prefer to use my Contaflex or Yashica Mat for fill flash work. Both of these cameras use leaf shutters that will synch seamlessly with your flash all the way to 1/500. But even then I don't use ISO 400 film.

Iridium said:

Just a couple of questions. As this lens is 28mm, should I always set the flash's reflector position (zoom) @ 28mm, regardless the distance of the subject?

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When mounted on camera the the lighting cone of the flashlight best should be the same as the viewing cone of the lens, or at least not smaller, unless you want vignetting.

Positioned off the camera you either can position the light in front of or sideways behind the camera depending on the relation between the cones from camera and light.

Pioneer said:

If you are using flash for fill then Kentmere 400 is too fast of a film for this type of work.

Assume you are trying to shoot someone who is 3 meters away. Since your flash guide number is 44, this means your aperture is 14 (or 16 if you need to round up.)

If you assume that your normal daylight scene is already Sunny F/16, then you would have to set your shutter speed to 1/500 seconds. This is way beyond the ZM's synch speed.

Even if it is a cloudy day and your meter shows f/8, you are right on the edge of what you can get away with here. Better hope the sun doesn't come out.

If your intent is to shoot fill flash on the street during the day, go get some ISO 100 film and you will have a better chance. Better yet, get ISO 50, like Pan F.

I prefer to use my Contaflex or Yashica Mat for fill flash work. Both of these cameras use leaf shutters that will synch seamlessly with your flash all the way to 1/500. But even then I don't use ISO 400 film.

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Great info Mr. Pioneer! In the case of fill-in flash with my Ikon ZM, I could use the smaller flash unit that I have with GN 20. I also have a Mamiya 7II which has leaf shutter in the lens.

In the fill-in flash, daylight and leaf shutters case, do I use the indications (speed and f/stop) of the light-meter or make any compensation according to the flash settings?

By the way, how do I calculate the ISO factor for 160 ASA?

I found how the ISO factor is calculated. (Square root) √ISO/100. The ISO factor for 160 ASA, for example, is 1.26.

Thus, if someone wants to find the correct GN for any ISO number the formula is GN2=GN1*√ISO/100

The term "ISO factor" is completely new to me.

AgX said:

The term "ISO factor" is completely new to me.

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I saw it in a couple of sites. Perhaps, the term is not correct. However, I got how these unique numbers (factors) are calculated for effective guide numbers in terms of ISO.

My guess is that the "ISO factor" would be a multiplier that you would use to calculate the Guide number of a flash for a film of one ISO when you know the Guide number of the flash with a film of another ISO.

Yes, but instead of using some formula one just could use factor 1.4 for each full stop deviation from reference film speed (1.2 for a half stop).

Iridium said:

Great info Mr. Pioneer! In the case of fill-in flash with my Ikon ZM, I could use the smaller flash unit that I have with GN 20. I also have a Mamiya 7II which has leaf shutter in the lens.

In the fill-in flash, daylight and leaf shutters case, do I use the indications (speed and f/stop) of the light-meter or make any compensation according to the flash settings?

By the way, how do I calculate the ISO factor for 160 ASA?

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Fill flash in daylight is used to smooth out the contrast in your photograph.

You use your light meter's reading to set the exposure for the scene and then you are using your flash to help bring up the light in the shadows. So use the light meter to set the initial exposure.

Then determine the distance to your main subject and use that information to set your aperture.

Your flash really doesn't care what your shutter speed is. All it knows is how much light will be reflected back to your film by the distance. It uses this information to tell you what your lens opening (aperture) has to be for the light from the flash to register.

The advantage to the leaf shutter over the focal plane shutter is that the leaf shutter always opens all the way to expose the film. The focal plane shutter adjusts the shutter to be a slit traveling across the film at a higher speed. The disadvantage to the leaf shutter is that it can only reach a certain shutter speed, usually 1/500.

In general fill flash works best when the following factors apply:
- You are closer to your subject (3 meters is better than 6 meters.)
- You are using slower film (ISO 50 is preferrable to ISO 400.)
- You are using a stronger flash (44m Guide Number is preferrable to 20m Guide Number.)
- You can synch with the flash at a higher shutter speed (1/500 is better than 1/50. 1/125 is about the minimum.)

I personally find fill flash to be most useful on sunny days when there are lots difference between shadows and light. Example is a sunny day and a pretty woman with a sun hat. A normal exposure leaves the face in shadow. Expose normally and then use the flash to fill the shadows under the hat.

Using flash (artificial light) really is not complex. But it is an additional skill with its own language. If you are interested in learning I suggest you take the lessons in Lighting 101 at www.strobist.com.

Pioneer said:

In general fill flash works best when the following factors apply:
- You are closer to your subject (3 meters is better than 6 meters.)
- You are using slower film (ISO 50 is preferrable to ISO 400.)
- You are using a stronger flash (44m Guide Number is preferrable to 20m Guide Number.)
- You can synch with the flash at a higher shutter speed (1/500 is better than 1/50. 1/125 is about the minimum.)

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Once again very helpful Mr. Dan. I feel grateful.

However, using my Zeiss Ikon with 1/125 synch speed on sunny days along with a 100-200 ASA color film, a flashgun with 20m GN, I reckon, fits better than my stronger 44 GN one. Or should I lower down the power of the big flash. Right?

Iridium said:

Once again very helpful Mr. Dan. I feel grateful.

However, using my Zeiss Ikon with 1/125 synch speed on sunny days along with a 100-200 ASA color film, a flashgun with 20m GN, I reckon, fits better than my stronger 44 GN one. Or should I lower down the power of the big flash. Right?

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Not necessarily. The higher power flash gives you much better flexibility. My experience in working with flash is that you can never have too much power. If I could comfortably carry around high powered studio flashes I would, but it just isn't practical. I will however work with flash bulbs occasionally as they put out so much more light then your typical electronic flash will. Remember the power of your flash is all about distance. The power extends your practical reach. Small electronic flash units will only work for you up close. Stronger ones extend your reach.

I usually select half power on my electronic flash, sometimes even one fourth power based on my judgement of the light in the shadows. But if your flash doesn't have power adjustments then just select an aperture in your normal exposure that is one stop less than what your flash computation recommended. Example, you selected 1/125 and f8 because f8 matched the flash exposure and 1/125 matched that aperture for a normal exposure. Just tighten up the aperture to f11 instead. Of course you will need to slow down the shutter speed to 1/60 as well. Your shutter speed has no effect on fill flash, but it does maintain your normal exposure for the ambient light of the scene.

It sounds far more confusing when you read about it but is much easier in the doing. Just grab your camera, your flash, and go play. When you are playing just remember, you are exposing normally during the day as if you have no flash. All the flash is there for is to lighten up the shadows. You can't destroy anything but with a bit of practice you can certainly improve it.

Pioneer said:

Not necessarily. The higher power flash gives you much better flexibility. My experience in working with flash is that you can never have too much power. If I could comfortably carry around high powered studio flashes I would, but it just isn't practical. I will however work with flash bulbs occasionally as they put out so much more light then your typical electronic flash will. Remember the power of your flash is all about distance. The power extends your practical reach. Small electronic flash units will only work for you up close. Stronger ones extend your reach.

I usually select half power on my electronic flash, sometimes even one fourth power based on my judgement of the light in the shadows. But if your flash doesn't have power adjustments then just select an aperture in your normal exposure that is one stop less than what your flash computation recommended. Example, you selected 1/125 and f8 because f8 matched the flash exposure and 1/125 matched that aperture for a normal exposure. Just tighten up the aperture to f11 instead. Of course you will need to slow down the shutter speed to 1/60 as well. Your shutter speed has no effect on fill flash, but it does maintain your normal exposure for the ambient light of the scene.

It sounds far more confusing when you read about it but is much easier in the doing. Just grab your camera, your flash, and go play. When you are playing just remember, you are exposing normally during the day as if you have no flash. All the flash is there for is to lighten up the shadows. You can't destroy anything but with a bit of practice you can certainly improve it.

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Well, I have done some practice with daylight and I understood how it works and what I have to correct. However, I get confused when I have to deal with available light and my Mamiya 7. Let's say that the lightmeter reads f8 - 1/4 speed and my subject is 2m away. Then according to my flash GN, I have to use at least f16. Moreover, 1/4 is too slow for handheld. If I decide to change my speed to 1/60, then what f-stop should I use in order to lighten up my subject and keep some ambient light around?

Another question: My flash can zoom from 28mm to 105mm. Should I stick to my lens Focal Length or may I use also different F.L. depending on the situation?

Thanx again!

Depends on the situation and what you want. At the 28mm setting, the flash will throw a 75° cone of light. If you don't need that wide an area lit, from the point of view of the flash, change it to suit what you want illuminated and what you don't.

As far as mixing light, you need to figure out which source is the key and which is the fill. When your camera says 1/4s @f/8, your key is going to have to be flash if you want to work hand-held. If your flash exposure calls for f/16 in that situation, you need to turn your flash power down or you aren't going to be able to capture any ambient light to speak of (since your exposure will be at least five stops under for the ambient light).

Also, remember that shutter speed doesn't affect flash exposure. Set the aperture for flash and the shutter for ambient. The balance you strike between the two is a creative decision.

markaudacity said:

Depends on the situation and what you want. At the 28mm setting, the flash will throw a 75° cone of light. If you don't need that wide an area lit, from the point of view of the flash, change it to suit what you want illuminated and what you don't.

As far as mixing light, you need to figure out which source is the key and which is the fill. When your camera says 1/4s @f/8, your key is going to have to be flash if you want to work hand-held. If your flash exposure calls for f/16 in that situation, you need to turn your flash power down or you aren't going to be able to capture any ambient light to speak of (since your exposure will be at least five stops under for the ambient light).

Also, remember that shutter speed doesn't affect flash exposure. Set the aperture for flash and the shutter for ambient. The balance you strike between the two is a creative decision.

Click to expand...

I got it thanx!