Exposure compensation with studio flashes

[ZeroJohn]

Hi photography enthusiasts,

some days ago i transformed my room into a small home studio for taking portrait photos.

During the first photo session i noticed that i had to turn the exposure compensation to a minimum (-5.0 until -4.0) on my nikon D5500. I use 2 studio flashes, the flashes (with softboxes) are already turned to a minimum. So when i had the Exposure compensation higher than -4.0 (means from -3,7 until +5 of course) the photos were too bright, even with the flashes turned to the lowest possible setting. The flash compensation doesn't change anything. Is that normal or am i missing something?

Edit: I shoot with aperture mode, could that be the problem, should i use manual mode and higher the shutter speed??

Thanks for every help.

 

[astroNikon]

What is your Shutter, Aperture and ISO
Can you give some examples with EXIF ?

 

[ZeroJohn]

What is your Shutter, Aperture and ISO
Can you give some examples with EXIF ?

I edited my original post before noticing your reply.
I use aperture mode (1,8 until 3,0 for portraits), so the shutter speed is on auto. ISO on automatic too. What is EXIF?

I'm quite new at taking photos, i don't know every specific words yet.

 

[tirediron]

Flash Exposure Compensation (FEC) will only affect either the camera's built-in speedlight or a compatible hot-shoe flash. It will NOT affect studio lights. It sounds like your lights may simply be too strong for the space you're working in. For typical home-studio use, 250 watt-seconds (w/s) is more than adequate, in fact, in my studio I'm shooting at 100 ISO, and f5.6-8 and usually using no more than 200-250 w/s split up between 2-4 lights.

In order to make this work you either need to use a smaller aperture (larger f #), or put neutral density filters on your lights to reduce the output.

 

[ZeroJohn]

Flash Exposure Compensation (FEC) will only affect either the camera's built-in speedlight or a compatible hot-shoe flash. It will NOT affect studio lights. It sounds like your lights may simply be too strong for the space you're working in. For typical home-studio use, 250 watt-seconds (w/s) is more than adequate, in fact, in my studio I'm shooting at 100 ISO, and f5.6-8 and usually using no more than 200-250 w/s split up between 2-4 lights.

In order to make this work you either need to use a smaller aperture (larger f #), or put neutral density filters on your lights to reduce the output.

I have only 180W it seems. My room isn't big, but i have just enough space to take a full portrait of an around 180-190 cm tall model with a 35mm lens (crop factor x1,5=52,5mm for a full frame cam). But i guess i answered my question myself, couldn't it be the problem that i always used aperture priority mode with automatic shutter? If i use manual i can use a faster shutter speed to reduce the brightness of the photo, can't i?

 

[tirediron]

For best results you should be shooting in manual. Remember that when you're dealing with flash, each frame is really two exposures. One for the ambient light (if any) which is affected by the shutter speed, and one for the strobed light (flash) affected by the aperture. Shutter speed has no affect on flash because of how short the duration of the light pulse is (usually less than 1/1000 sec, and can be as little as 1/10,000 sec).

Your camera has a 'flash snyc speed' - probably 1/250, but check your manual to be sure. This is the maximum shutter speed you can use and still expose the entire frame. Any higher and you will see a black band creep in from one side and get larger as you increase the shutter speed. In short, set your camera to manual, your ISO as low as it can go natively (IE, don't use "Low 1, 2, etc) and control your exposure using your aperture only.

 

[Overread]

The camera meter can only read ambient light; that is constant light that is falling on the subject all the time. Flash light appears in the scene as a tiny fraction of a second and only after the shutter has been pressed. As a result the camera meter has no idea about the intensity of the flash lighting being added to the scene.

When in any priority mode; program mode or full auto the camera has control over some/all settings which means that it will set its settings based on the ambient exposure not the flash exposure. Now exposure compensation can sometimes get around this because regular exposure compensation can tell the camera to under expose based on its meter reading; for a subtle use of flash this might work well.

However for flash dominated lighting you want to be in manual mode; you set the aperture and shutter speed and ISO to what you need for the shot - balancing your lighting to suit.

Note that you can't just up the shutter speed; most cameras have a flash sync speed of around 1/200sec or 1/250sec. Any faster and you get black lines as the shutter curtains move over the sensor (Faster shutter speeds and the bottom curtain starts moving before the first has fully opened). Thus you've got the ISO and the aperture to play with (as well as adjusting your flashes of course).


So try manual mode and experiment.



note many flashes have a mode called high-speed sync which allows faster shutter speeds by the flash firing a small burst of little flashes (most times you won't "see" this with your eyesight so it still appears to be one flash). This has a cost though and reduces the power of the flash; it also won't work off-camera unless you've a cable connection or a wireless that supports the feature.

 

[ZeroJohn]

Ok, thanks to both of you, i got it. I'll go to sleep a little less stupid tonight

But there is one thing still bothering me, i don't want to use a smaller aperture, i want to keep the background blurry or even a part of the model!?
Next session i'll try on manual, keeping the iso 100, the shutter speed 1/200 (it's the flash sync speed), and adjusting the exposure compensation while keeping the aparture large. I won't keep stupidly on this settings, i'll experiment, but i think what i could understand from you too, this might be the best thing to start with. Correct me if i'm wrong.

 

[astroNikon]

move the subject further away from the background and you can use a smaller aperture.

you need to understand depth of field more, so use a calculator such as this one ==> A Flexible Depth of Field Calculator

then you know when things will start to get blurry. BUt using a large aperture you also increase the problem of the subject being OOF except for a small sliver of the focus point, assuming yo uare fairly close.

 

[tirediron]

....But there is one thing still bothering me, i don't want to use a smaller aperture, i want to keep the background blurry or even a part of the model!?...

This is photography; you don't get to have your cake and eat it too. To achieve a large aperture, you will need to either use the neutral density gels I mentioned, or get strobes with a lower power output.

 

[smoke665]

The OP indicated he was in a "small" studio/room, and I don't see anything mentioned about the distance of the lighting to the subject. The OP also indicated he was new to photography, could there be a possibility that he has his lights to close?

 

[tirediron]

...could there be a possibility that he has his lights to close?

You can do that?

You're right, moving back could help to reduce the problem (but can create other problems). I assumed that since it was a small home studio, the lights were probably all the way back now. That may well be incorrect...

 

[table1349]

Two things will make your life a whole lot easier in the studio. First buy and read this.

Second, add one of these to your studio kit.

 

[ZeroJohn]

That's right, as i said, the studio is small, i can not really move the subject away from the background.
But thanks to you all, i learned some things i didn't knew before and which i gonna use at probably the end of the week then i'll give my feedback.

 

[fmw]

OP, I have the same problem. I use two mono lights on my small product light tent. They are set to lowest power. I shoot at maximum synch shutter speed and f16 to f22 depending on the subject. I don't have any wiggle room at all unless I use my macro lens which stops down to f32. The next step, as Tirediron says, is to use neutral density filters either on the lights or the camera lens.

Studio strobes aren't automatic. None of the flash capabilities of the camera deal with them other than providing a synch terminal. Set the camera shutter at maximum synch speed or slower. Set the aperture to the f-stop that provides the desired exposure. All this is manual. Some experimentation will get you where you want to go.

I should mention that the distance between the lights and the subject affect more than exposure. For traditional portraiture you want fairly soft lighting. That means making the light source large and putting the lights as close to the subject as you can while keeping them out of the frame. You are handling the light source size by increasing it with the soft boxes. You can also reduce the light by increasing the distance from the subject but you will also harden the light quality at the same time. I don't mean to complicate things for you. I'm just trying to give you some studio lighting basics.