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A few on-camera flash questions

Hi all. I am shooting my 3rd wedding on the weekend and am still learning every time. Tried hard to find someone to shadow/assist before I did my first wedding alone but seems the demand for that is very high in my areas and business is tight so threw myself into the deep end,against my will! So here I am now learning on the go. So far the brides are happy...

I am doing my practising with flash now, and have a few questions. I shoot on-camera flash (will learn off-camera soon and as budget allows), Nikon D750, SB900 and SB700. I have now set my camera exposure compensation to "background only" which sets apart my flash and ambient control as I understand it, which is different from how I have been shooting. I shoot mostly in M mode (except for e.g. ceremony) and TTL flash except when I do for e.g. table group shots where I've set up and a different group comes to sit in the same spot, same lighting etc. Then I'll switch from TTL to manual flash.

1) First question: I know to set ambient light first (this is now for indoors, low light for e.g. first dance). But this was my problem - the ambient always feels too low to get a "good exposure". It's way more than 2 stops underexposed when I am at my slowest possible shutter speed. That was on my 50mm F/1.4 @ f/3.2 (or some other bizzarre fstop...stress), D750, ISO pushed to 2000, shutter was about 1/50th. So what to do when you already have a very dark ambient and then the flash blasts everything? You set your flash (TTL) exposure down to -2? I just didn't feel the FEC did enough...and I was a good distance from my subjects (within flash range). So I feel I don't get a lot of control or ambient when I use the flash. 

The same problem goes for when I am practising in my flat - I set the shutter speed to 1/250th, and then to 1/15th, and the ambient light seems to not change at all (it is a small flat though, could be light from flash still affecting ambient?). Just feel I need to be able to control the exposure more than I currently manage to?

2) Second question: Is separating exp compensations better for exposure control? I haven't been in enough situations to know which is better, but it seems better to be able to control one at a time without ambient and flash both being controlled at once?

3) Third question: Whether I am in M or A, when I set exposure compensation on camera, it does nothing to change my shutter speed, only changes the histogram very very slightly. I know it shouldn't change the shutter speed in M, but I was under the impression it changes the shutter in A mode to compensate. As soon as I switch flash off, it changes the shutter speed in A mode when I dial in exp compensation. 

4) Fourth question: How do I know what the range of the flash is when I bounce it, or does this not matter as much as when the flash is pointed straight at the subject (which seldom happens). I know the "source" (wall,roof) is further away then so it probably doesn't matter too much?

Your advise would be much appreciated.



  • Neil vNNeil vN Administrator
    Hi there Danielle 

    Re question 1: 
    You need to remember that when you use flash, there are essentially two exposure - ambient and flash. So it is quite okay for your ambient to be under-exposed. Most often, this is what you want. 

    Check this article for more:

    You set your FEC according to how much flash you want. If you feel you are getting too much light from your TTL flash, dial it down via the FEC setting. 

    You control the ambient with the combination of your shutter speed, aperture & ISO.  The flash doesn't come into this. The flash is a separate entity ... which is also affected by aperture & ISO. But you will have a better understanding between the balance of ambient and flash if you consider them as two separate exposures. 

    With the example of the results in your flat, I think the flash is just dominating entirely in such a small space. 

    Re question 2: 
    I am not following your question here. If you shoot in manual exposure mode in your camera, neither the overall exposure compensation, nor the FEC will affect your ambient exposure. 

    Re question 3: 
    The way your shutter speed behaves in Aperture Priority when you use flash, depends on your specific camera and flash.  There is also a setting in your menu which will dictate the lowest shutter speed your camera will use when you are using flash 

    Re question 2: 
    There is no easy way to know the range of your flash when you bounce it.  Experience counts here.

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