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How best to determine the initial amount of fill flash for a properly exposed bright, daytime, outdoor portrait?
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Oct 1, 2022 23:29:49   #
Shooter41 Loc: Wichita, KS
 
Half a century ago as a beginning photographer, I took a photography class where the instructor had made arrangements in advance for everyone to take one picture of a pretty, female model at our local park. He instructed us to use our on-camera flash to fill in the shadows of our daytime, backlit model. Having never done that before, I had no idea what settings I should use on my cheap kit camera and 50mm lens that came with it. Earlier I had read in the manual to use a shutter speed of 1/125 second to synchronize with the flash. Everyone was shooting Kodak Tri-X, 400 ASA, black and white film, with all kinds of different cameras. I had no idea how powerful my flash was, so I just moved in close enough for a decent composition and set the aperture to F5.6 since that was near the middle range and the ASA at 400.
When I got home and developed the film, I realized that the model had worn shiny makeup and my flash was too close to the subject and I had clipped the highlights on her face. I realized that I would have gotten a better exposure and less composition if I had stood further back from the subject or set the aperture to F8.0 and kept the same distance. In today's world with modern digital, mirrorless cameras, with the ISO; shutter speed; aperture; distance from the subject and power setting on the flash all changeable, how should an excellent photographer initially set up her/his camera before taking the first picture and checking the histogram when doing outdoor, backlit with sunlight, portrait?
(1) Begin by taking a spot exposure reading of the subject's face.
(2) Set your aperture to create the depth of field you want.
(3) set your shutter speed to sync with the flash because the flash stops all movement like 1/1000th to 1/2000
second shutter speed
(4) set the ISO to "Auto" so that the correct exposure occurs.
After taking the first picture and reading the histogram, you have the options of:
(a) moving slightly forward or back to increase or decrease the amount of light from the flash that reaches the subject.
(b) opening or closing the aperture to increase or reduce the flash on the subject (c) raising or lowering the ISO from what the "auto" ISO shot recorded from the first image.
Please feel free to suggest other options I never thought of. Shooter41


(Download)

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Oct 2, 2022 00:55:58   #
Cheapshot Loc: California.
 
There are several way to do this depending on the end effect that you would like. Here is one way. Compose your backlit picture. From the camera take an exposure reading and set your camera keeping the shutter speed below 1/200 so it will sync. with your flash. If necessary use your shutter speeds (keeping shutter at sync. speeds or below) and ISO to to make necessary adjustments for a normal exposure. Now your subject (model) is going to look like a silhouette but the background with normal exposure. So...you will need to fire some light in there to brighten her up. Adjust the power on the flash to get the proper amount of light on your model. Fire some test shots adjusting the power on the flash until it is at a level you desire. I personally do not like blown out backgrounds as they are like staring into the sun and distract from the subject. Good luck!

Reply
Oct 2, 2022 03:12:07   #
Wallen Loc: Middle Earth
 
Do not set the camera to Auto ISO. This is one of the times you want everything under control, so full manual on all settings, keeping the shutter speed below the flash sync speed.

Then simply expose for the background you want, then chimp and adjust the power of the flash. Thats it.
Note that moving closer or further away from the subject will change the effect of the flash, same as adjusting it up or down.

Reply
 
 
Oct 2, 2022 07:06:04   #
MrPhotog
 
The mood of the photo can be affected by the amount of fill flash. Depending on the power of the flash, You can get anywhere from very harsh shadows (with no fill) to gross overexposure.

Assuming daylight and ‘sunny 16”, with a 100 ISO FILM I’d set my camera to f/16 and sync at 1/125 second.

For family groups or portraits of women: The flash power would be set to give an exposure 1 stop less or f/11. With men, I might want a bit more contrast and use less of a fill light. I’d set the flash to give a f/8 exposure.

With a focal plane shutter that only syncs at 1/60 (or 1/50 on a Leica) My lens aperture would be f/22 and the flash would be a stop brighter.

With digital things are a bit more interesting. I’m not finding that the ISO speeds on my digital cameras match the results of film at the same ISO ratings.

To say this another way: Sunny 16 is not giving me the best exposure on digital. My digital cameras are suggesting something more like f/11 or f/8 in full sun. The histographs and pictures look fine with what should be (to my mind) overexposure, so I’m happy with the results, and don’t really trust the ISO dial.

Despite that, The flash amount is one to two f/stops under whatever my camera is saying. Of course I see the result a lot faster than even a Polaroid test, so I can dial in more or less power from the strobe as needed—up to the max power.

With digital cameras that allow high speed sync at extremely short shutter speeds, even modestly sized strobes can deliver fill light for the the large apertures available. If my daylight exposure is 1/2000 at f/4 then the flash would only need to give enough light for a f2.8 exposure to provide the fill.

Reply
Oct 2, 2022 08:04:22   #
tcthome Loc: Keansburg , NJ
 
Wallen wrote:
Do not set the camera to Auto ISO. This is one of the times you want everything under control, so full manual on all settings, keeping the shutter speed below the flash sync speed.

Then simply expose for the background you want, then chimp and adjust the power of the flash. Thats it.
Note that moving closer or further away from the subject will change the effect of the flash, same as adjusting it up or down.


Glad Shooter41 started this thread. I don't have much experience with flash & don't really shoot portraits but I have a couple of questions. 1- I find for my personal taste that a lot of times the light from the flash is to white for portraits. Would you suggest a warming gel or maybe a manual white balance adjustment. 2- I read some of Bryan Petersons book Understanding Flash Photography. In it he might say something like & at F8 my flash tells me 10' is the correct distance. Where do you get the correct distance info from. I usually only use flash sometimes for macro or flowers & just move around at different angles & distances & decide what I like when I get the photos on the computer but was just wondering about the distance thing.
Thanks for any replies.

Reply
Oct 2, 2022 09:33:31   #
dpullum Loc: Tampa Florida
 
Thank you Shooter. Your directions are one of those things that we should keep on 3x5 file card or on our smart phones. Cards are great for keeping directions of techniques we use rarely... spring and fall flowers. During the hot summer and cold winter we may forget our refined details; while cards may hide they do not forget.

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Oct 2, 2022 10:10:49   #
Wallen Loc: Middle Earth
 
tcthome wrote:
Glad Shooter41 started this thread. I don't have much experience with flash & don't really shoot portraits but I have a couple of questions. 1- I find for my personal taste that a lot of times the light from the flash is to white for portraits. Would you suggest a warming gel or maybe a manual white balance adjustment. 2- I read some of Bryan Petersons book Understanding Flash Photography. In it he might say something like & at F8 my flash tells me 10' is the correct distance. Where do you get the correct distance info from. I usually only use flash sometimes for macro or flowers & just move around at different angles & distances & decide what I like when I get the photos on the computer but was just wondering about the distance thing.
Thanks for any replies.
Glad Shooter41 started this thread. I don't have m... (show quote)


Those things you asked for are among the reasons why I advocate all manual and then shoot & chimp when dealing with flash. On a side note, in a (studio) setting, one may find the constant on lights to be easier to set-up and use.

About gels/filters:
If you find the flash too white for your preference:
-In JPEG setting, adjust the white balance in the camera.
-In RAW, adjust the white balance in post.
If you encounter and want to subdue a multiple cast light source, then use gel to filter/subdue unwanted color cast. Some scenes may benefit from polarizers.


Gel is good for film & for adjusting a scene which is lighted by different sources/colors of light.

The white balance in a digital camera allows us to adjust for the shade as we like. With film cameras, there is no in-camera white balance adjustment. That job is done with gels.
But if you encounter multiple shades of lighting striking your subject and wanted to control it, then the in-camera white balance may not be enough. What you can do is use a gel to filter the light to balance the scene or make it generally of one shade which can be easier to shift/adjust to something else at post.


About flash:
To answer your question directly, aside from the exposure settings of the camera, that distance will depend on how powerful the flash was set and the modifier on the flash like zoom settings, reflectors, diffusers, bounce, etc. Personal knowledge & experience with situations and your gear would tell more.

Generally speaking, a "point" source of light will spread out and hit a surface. Imagine a candle lighting a wall. If we half the distance of the candle to the wall, we might expect the illumination to increase in half, and if we double the distance, the illumination to be decreased in half too. But not is not the case.
If we half the distance, the increase in brightness would be more than double, and if we increase the distance twice, the dimness would be more than half what we started with. This is due to the inverse square law that affects illumination.

We do not have to compute for these or dream of the mumbo jumbos. Make it simple, just keep in mind that the power and distance of light source will affect the amount of light reflecting on the subject. If the flash power setting is constant, close is more and away is less. Do a test shot then adjust the power of the flash or move the light closer or away as needed or desired.

We need to include the control of distance & position of our lighting in our shoot so the exposure would be consistent. If the photographer, in looking for a better composition and has a flash on his camera, steps forward, then expect the exposure to change, possibly overexposing the subject. The reverse is true if he steps back.
Parts of the subject getting near the light set-up will have similar effects. If somehow, she raises a hand and it comes near your lights, that hand will be more exposed.

Many other stuffs, gears, modifiers & settings can change the effect but I'm sure by the time you get to use those, you have mastered the basics well and it would not be of much trouble.

Reply
 
 
Oct 2, 2022 12:47:14   #
tcthome Loc: Keansburg , NJ
 
Wallen wrote:
Those things you asked for are among the reasons why I advocate all manual and then shoot & chimp when dealing with flash. On a side note, in a (studio) setting, one may find the constant on lights to be easier to set-up and use.

About gels/filters:
If you find the flash too white for your preference:
-In JPEG setting, adjust the white balance in the camera.
-In RAW, adjust the white balance in post.
If you encounter and want to subdue a multiple cast light source, then use gel to filter/subdue unwanted color cast. Some scenes may benefit from polarizers.


Gel is good for film & for adjusting a scene which is lighted by different sources/colors of light.

The white balance in a digital camera allows us to adjust for the shade as we like. With film cameras, there is no in-camera white balance adjustment. That job is done with gels.
But if you encounter multiple shades of lighting striking your subject and wanted to control it, then the in-camera white balance may not be enough. What you can do is use a gel to filter the light to balance the scene or make it generally of one shade which can be easier to shift/adjust to something else at post.


About flash:
To answer your question directly, aside from the exposure settings of the camera, that distance will depend on how powerful the flash was set and the modifier on the flash like zoom settings, reflectors, diffusers, bounce, etc. Personal knowledge & experience with situations and your gear would tell more.

Generally speaking, a "point" source of light will spread out and hit a surface. Imagine a candle lighting a wall. If we half the distance of the candle to the wall, we might expect the illumination to increase in half, and if we double the distance, the illumination to be decreased in half too. But not is not the case.
If we half the distance, the increase in brightness would be more than double, and if we increase the distance twice, the dimness would be more than half what we started with. This is due to the inverse square law that affects illumination.

We do not have to compute for these or dream of the mumbo jumbos. Make it simple, just keep in mind that the power and distance of light source will affect the amount of light reflecting on the subject. If the flash power setting is constant, close is more and away is less. Do a test shot then adjust the power of the flash or move the light closer or away as needed or desired.

We need to include the control of distance & position of our lighting in our shoot so the exposure would be consistent. If the photographer, in looking for a better composition and has a flash on his camera, steps forward, then expect the exposure to change, possibly overexposing the subject. The reverse is true if he steps back.
Parts of the subject getting near the light set-up will have similar effects. If somehow, she raises a hand and it comes near your lights, that hand will be more exposed.

Many other stuffs, gears, modifiers & settings can change the effect but I'm sure by the time you get to use those, you have mastered the basics well and it would not be of much trouble.
Those things you asked for are among the reasons w... (show quote)


Thank you for this generous reply.

Reply
Oct 2, 2022 13:50:14   #
Alphabravo2020
 
Shooter41 wrote:

(4) set the ISO to "Auto" so that the correct exposure occurs.


Love the shot. I am just now learning to add fill flash and reflected light to my outdoor portrait work.

I will say that AutoISO has not worked well for me on back-lit subjects. I think the reason is that the metered area is much larger than one would think causing backlight to be included in the calculation. Also, any bright light spilling around the subject has a greater effect on the calculation than the the same area on the darker subject. I agree with the previous recommendation to stay manual ISO for this situation.

Reply
Oct 2, 2022 15:04:26   #
stan0301 Loc: Colorado
 
The Disney photographers set their flashes to two stops under and you can bet it was well researched

Reply
Oct 2, 2022 19:15:31   #
Shooter41 Loc: Wichita, KS
 
Cheapshot wrote:
There are several way to do this depending on the end effect that you would like. Here is one way. Compose your backlit picture. From the camera take an exposure reading and set your camera keeping the shutter speed below 1/200 so it will sync. with your flash. If necessary use your shutter speeds (keeping shutter at sync. speeds or below) and ISO to to make necessary adjustments for a normal exposure. Now your subject (model) is going to look like a silhouette but the background with normal exposure. So...you will need to fire some light in there to brighten her up. Adjust the power on the flash to get the proper amount of light on your model. Fire some test shots adjusting the power on the flash until it is at a level you desire. I personally do not like blown out backgrounds as they are like staring into the sun and distract from the subject. Good luck!
There are several way to do this depending on the ... (show quote)


Dear Cheapshot...Thank you for a detailed step by step walk through. You did good! I don't like blown out backgrounds either. Shooter41

Reply
 
 
Oct 2, 2022 19:21:34   #
Shooter41 Loc: Wichita, KS
 
Wallen wrote:
Do not set the camera to Auto ISO. This is one of the times you want everything under control, so full manual on all settings, keeping the shutter speed below the flash sync speed.

Then simply expose for the background you want, then chimp and adjust the power of the flash. Thats it.
Note that moving closer or further away from the subject will change the effect of the flash, same as adjusting it up or down.


Dear Wallen...I agree. No auto ISO for these circumstances. However, half a century ago, putting my camera on "Manual" scared the heck out of me. Expose for the background and adjust your flash two F-stops less than your exposure sounds pretty good to me. Shooter41

Reply
Oct 2, 2022 19:31:20   #
Shooter41 Loc: Wichita, KS
 
MrPhotog wrote:
The mood of the photo can be affected by the amount of fill flash. Depending on the power of the flash, You can get anywhere from very harsh shadows (with no fill) to gross overexposure.

Assuming daylight and ‘sunny 16”, with a 100 ISO FILM I’d set my camera to f/16 and sync at 1/125 second.

For family groups or portraits of women: The flash power would be set to give an exposure 1 stop less or f/11. With men, I might want a bit more contrast and use less of a fill light. I’d set the flash to give a f/8 exposure.

With a focal plane shutter that only syncs at 1/60 (or 1/50 on a Leica) My lens aperture would be f/22 and the flash would be a stop brighter.

With digital things are a bit more interesting. I’m not finding that the ISO speeds on my digital cameras match the results of film at the same ISO ratings.

To say this another way: Sunny 16 is not giving me the best exposure on digital. My digital cameras are suggesting something more like f/11 or f/8 in full sun. The histographs and pictures look fine with what should be (to my mind) overexposure, so I’m happy with the results, and don’t really trust the ISO dial.

Despite that, The flash amount is one to two f/stops under whatever my camera is saying. Of course I see the result a lot faster than even a Polaroid test, so I can dial in more or less power from the strobe as needed—up to the max power.

With digital cameras that allow high speed sync at extremely short shutter speeds, even modestly sized strobes can deliver fill light for the the large apertures available. If my daylight exposure is 1/2000 at f/4 then the flash would only need to give enough light for a f2.8 exposure to provide the fill.
The mood of the photo can be affected by the amoun... (show quote)


Dear MrPhotog...Thank you for introducing me to "sunny16." I had never heard of it before. Same goes for different lighting for men and women. I feel the same about not trusting my digital ISO dial over eyeballing the image for myself to get what I am looking for. The histogram does a better job for my tastes in exposure. I seem to detect that you have been doing photography for quite a while. Thanks for sharing. Shooter41

Reply
Oct 2, 2022 19:35:07   #
Shooter41 Loc: Wichita, KS
 
tcthome wrote:
Glad Shooter41 started this thread. I don't have much experience with flash & don't really shoot portraits but I have a couple of questions. 1- I find for my personal taste that a lot of times the light from the flash is to white for portraits. Would you suggest a warming gel or maybe a manual white balance adjustment. 2- I read some of Bryan Petersons book Understanding Flash Photography. In it he might say something like & at F8 my flash tells me 10' is the correct distance. Where do you get the correct distance info from. I usually only use flash sometimes for macro or flowers & just move around at different angles & distances & decide what I like when I get the photos on the computer but was just wondering about the distance thing.
Thanks for any replies.
Glad Shooter41 started this thread. I don't have m... (show quote)


Dear tcthome...Thanks for mentioning Bryan Peterson's book on "Understanding Flash Photography." Never checked him out before. Even my current flash doesn't tell me anything. I have to figure it out for myself while looking carefully at the histogram. Appreciate your comments. Shooter41

Reply
Oct 2, 2022 19:37:41   #
Shooter41 Loc: Wichita, KS
 
Alphabravo2020 wrote:
Love the shot. I am just now learning to add fill flash and reflected light to my outdoor portrait work.

I will say that AutoISO has not worked well for me on back-lit subjects. I think the reason is that the metered area is much larger than one would think causing backlight to be included in the calculation. Also, any bright light spilling around the subject has a greater effect on the calculation than the the same area on the darker subject. I agree with the previous recommendation to stay manual ISO for this situation.
Love the shot. I am just now learning to add fill ... (show quote)


Dear Alphabravo2020...Using fill flash with camera set on "auto" hasn't worked out well for me either. Taming the "Manual setting" is one of the most important achievements a photographer can do, in my humble opinion. Thank you for your comments. Shooter41

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