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Why are my studio pictures dark when I use a slave flash
John writes:
Hi DIYPhotography,
I am using a D70 for my studio shots, and one external optical slave flash. When I take a picture, the internal flash shoots, and triggers the external flash, and yet my pictures are dark.
Can you help me?
John
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This is what DIYPhotography.net has to answer
Hi John,
I do not know your entire setup, buy my guess is that your internal flash unit is set on iTTL.
When the flash is set to iTTL it shoots a short pre-flash to measure the strength of the flash needed for the shot. That pre-flash is done before the curtain opens. After the curtain opens, a stronger strobe is shot. And here is the catch, when the main strobe triggers your slave, the slave is uncharged, after the pre-flash discharge.
Here is what you can do to override the problem. Set your internal flash unit to manual at 1/16th of its strength. Now, place a small paper between the flash and camera body, so the internal flash will have a lowest impact on the final picture as possible.
Regards,
you are welcomed to ask more questions via the feedback form
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Comments
What's the ISO, share more details
Can you just share more details about the matter ?
Just tell us iso, aperture, EV, etc.
Plus send an example if you can.
C
More info
Hi Constantin,
Usually I shoot my Studio photos at 200/320 ISO and a relatively small aperture (f/13-18) this is to gain maximal DOF. I set the exposure time to 1/300 or faster. since the flash will give the main light, I can go this fast.
here are some shots of my daughter, taken with those parameters.
Try and play a bit with those values to get the results you want.
Good luck with your stock image site.
Cheers,
Udi Tirosh.
Dark photos when firing in camera and slave flash together
I had the same problem. Photos were dark when in camera flash and slave flash were triggered at the same time. And would be brighter when triggered individually.
I was even beginning to wonder if it is possible that the light frequencies of two flashes can even each other out to cause a darker picture!!!! :)
The reason was because my camera would shoot a pre-flash (ETTL-II) to meter the flash. At the same time the slave flash engages, brightens up the scene and causes the flash meter to think that a very low flash setting is required for good exposure!
Now the slave flash is out, lens opens up and camera flash fires at the low setting it has been fooled into using.
2 solutions solved my problem. One was to push the FEL lock, Flash Exposure Lock, button once (the "*" button my Canon) before each shot. This makes the pre-flash flash one time and locks in the correct flash exposure for the on camera flash. Then when the actual shot is taken the on camera flash and slave fire at the same time.
The second solution for me was to just set the slave flash to "S2" which waited until the second flash before the slave flash fired.
thanks
Thanks for your comments on this website. I was pulling my hair out trying to use my new flash slave, which is now working a treat.
Very greteful.
Tim
measuring flash
Hi,
I have an SB-600 on my D70 and I'm an amateur photographer. Using a flash/light meter, how can I measure the flash output from my SB-600? You read where photographers say to set your flash 2 stops under your exposure. I'm curious how I can measure that with a meter. thank you!
Measuring flash
I am also an amateur photographer, using a D70 and SB800, the cousin to the SB600.
From my reading and experimentation, in automatic mode the camera is driving the intensity of the flash. So presumably you do not have to know the output of the flash. The meter is deciding how much light is falling on the subject. Smaller aperature (f22), more light; larger aperature (f2), less light. The flash is automatically instructed to produce more or less light. Again with many objects, colors and lighting condition, the camera's meter is doing a good job of producing the "correct" amount of light.
To test the alternative, set the flash to manual and take a picture. It is quite amazing to me the amount of light the SB800 can put out when unconstrained.
Having said that, you can override the amount of light in two ways.
First is to set the exposure compensation on the camera.
For instance shooting dark objects, the camera's on board metering incorrectly sets the needed lighting. By going up or down 1.0 stops, the image is "correctly lighted". Sitting here without my camera, I really cannot recall which way to go for a dark object. Similarly an all white object eg wedding gowns, the exposure compensation needs to be corrected in the other direction. This applies whenever you are shooting them, with or without a flash.
The neat thing about the SB800 and I am presuming the SB600, they will be compensate according to the camera settings with the flash on automatic. No need to correct the flash, just adjust the camera.
I would suggest shooting a dark object eg a black toy bear from +5 to -5 in 1 or 1/2 or 1/3 stop increments. The exposure compensation (EC) shows up in the viewer and in the photo's image data, so you do not need to take extensive notes. Look at the resulting images and what is working.
I was doing this with the camera and flash in close proximity to each other. I shoot with a flash bracket, so the flash is up to 18 inches from the camera, but is in the same plane and about the same distance to the subject.
Second, you can set the flash for exposure compensation. On the SB800, you see the EC (EV?) value in the top right corner. The default is zero. This setting is added (subtracted) from what the camera's meter is suggesting. Again the flash is in automatic mode.
I am assuming this is useful if the flash is located off the camera or you are looking for a special effect. Or if you have more than one flash. Or the flash is filling a large space. Or the flash is aimed away from the subject. Or if you are using a diffuser over the flash to add back the amount of light lost from passing through the differ.
Experimentation is the key. Try a range (+5 to =5) using the same aperature and speed. Digital film is so cheap.
Third, you could go full manaul.
Get a good exposure meter. I use the digi pro F. Set up the camera and flash, and determine the setting manually. There is other equipment to facilitate setting off the flash and the meter, etc. Obviously you can set the flash in manual mode -- and you determine its output. You can still trigger the flash from the camera. More experimentation.
Personally, I am sticking to the automatic mode until I start using experimenting with studio strobes.
Mike.
Radio Slave Flash Trigger Problems...
First of all I have a (cannon rebel xti)
I bought light strobes and with it came a radio slave flash trigger. Which I can place on top of the camera so that when I take photos the light strobes fire flash.
Well my problem is that when I take a shot, the photos come out completly WHITE =(...
Can anyone explaine to me how to fix this or what to do?
I will be very thankful.
Dark picture when using two flash.
Hi. When I use the 580EXII in ETTL and the camera in manual, set to 1/60 f/8 ISO 100 and the old Sunpack 544 in manual set to 1/4 to 1/2 of light, my pictures (not all the time) go darker. Any help would appreciate. Thanks.
Dark picture when using two flash.
Hi. When I use the 580EXII in ETTL and the camera in manual, set to 1/60 f/8 ISO 100 and the old Sunpack 544 in manual set to 1/4 to 1/2 of light, my pictures (not all the time) go darker. Any help would appreciate. Thanks.
Two steps to resolve this problem:
1) Use FEL (Flash exposure lock "*") function before each shoot. Only recommended in a studio because the use of this function discharge your batteries very fast. The flashes will shoot every time you use FEL.
2) Use both flashes in manual mode. Your primary light set to 1/4 to 1/2 (for example) and your secondary (the flash in your camera) in 1/4 to 1/2 too. You can use the same setting for both lights or if you prefer, your primary in 1/4 and your secondary in 1/8. Your camera for ASA 100 is 1/60 in f/8. Star whit this settings and make your test. Remember use diffusers.
Pictures too bright
I bought light strobes and a radio slave flash trigger. I was trying to test the lights but when I take a shot the oictures came way too bright. Can you tell me the correct settings for eihter the camera or the strobes thanks
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