Indoor Flash Question

Hey all,

I was shooting a family bridal shower the other day, and decided I would set my SB-700 flash in a darker room corner and use my D750 in commander mode to light up that corner while taking pics!

However, when I fired the flash, the corner of the room would brighten to a normal level, but the rest of the room went very dark, light it was night-time. I had the SB-700 set to TTL, 0 compensation.

I know there is probably something stupid I messed up as far as the camera settings, but for the life of me, I couldn't figure out. Does anybody have any ideas of how I was being an idiot?

Thanks in advance!

GESWhoPhoto wrote in post #18464826
Hey all,

I was shooting a family bridal shower the other day, and decided I would set my SB-700 flash in a darker room corner and use my D750 in commander mode to light up that corner while taking pics!

However, when I fired the flash, the corner of the room would brighten to a normal level, but the rest of the room went very dark, light it was night-time. I had the SB-700 set to TTL, 0 compensation.

I know there is probably something stupid I messed up as far as the camera settings, but for the life of me, I couldn't figure out. Does anybody have any ideas of how I was being an idiot?

Thanks in advance!

I'm a Canon person so let me just ask some basic questions and you can convert and answer in Nikon speak:

1) What were you 'camera' setting for the actual camera?

2) Did you use a semi-automatic mode that pegs the ISO at say 400?

3) Do you re-call what your in-camera light meter was saying your exposure settings were - i.e. how much below 'proper' exposure was the camera reading and relying on 'flash' to light the scene?

4) how did you position your flash to bounce the light to brighten the room? - do you have a picture that shows the bright corner & dark room with exposure data?


If I had to guess, and again I'm a Canon person, is that there was no amount of ETTL, bounced in the way you were bouncing it, that could properly light your very underexposed ambient settings - i.e. you were probably 3 stops under exposed for ambient and you got a properly exposed corner (where you don't really need it)


A better setup would likely to have been:

1) set your camera exposure data for 2/3rds to 1 stop under ambient
2) use a on camera flash, bounced up and rear at a similar FEC -2/3rds stop
3) set up your corner kicker on Manual - 1/8th to 1/4 power, bounced up into a white ceiling, and adjust your ambient exposure, after a few tests, for this light - i.e. so that your in camera ETTL is not affecting this kicker

Set your flash compensation (fec) lower and leave the exposure compentation at 0 or higher if needed to catch more ambient light.

GESWhoPhoto wrote in post #18464826
However, when I fired the flash, the corner of the room would brighten to a normal level, but the rest of the room went very dark, light it was night-time. I had the SB-700 set to TTL, 0 compensation.

I am assuming from your description that the corner with the flash in it was illuminated nicely, but the rest of the room was rather dark compared to that corner! That is to be expected.
You are seeing the Inverse Square Law of flash, in which the intensity of light diminishes by the Square of the Distance...light at 8' from flash is 4x dimmer than light at 4' from the flash.
If you want the more distant stuff to be 'not so dark', the only thing you can do is to either

• lower shutter speed and/or use bigger aperture diameter (smaller number) to capture MORE AMBIENT light, or
  
• place a second light source at the darker corner
  

Thanks for the replies thus far, everyone!

I don't think I explained the situation as well as I could have.

I was using aperture priority mode at a relatively wide setting (4.5 I believe?). The room itself had plenty of light, and I was taking pictures that were very well-balanced before trying off-camera flash. I configured my camera in wireless commander mode and placed the flash in a dark corner of the room (one that was darker when I was balanced for ambient light), and all of a sudden, my pictures would have that corner very bright, and the rest of the room dark, like it was night-time. I didn't think adding an off-camera flash would affect my exposure for the rest of the room, but apparently I was wrong!

I figured I may have had some obscure flash option wrong or something of that sort.

GESWhoPhoto wrote in post #18465367
Thanks for the replies thus far, everyone!

I don't think I explained the situation as well as I could have.

I was using aperture priority mode at a relatively wide setting (4.5 I believe?). The room itself had plenty of light, and I was taking pictures that were very well-balanced before trying off-camera flash. I configured my camera in wireless commander mode and placed the flash in a dark corner of the room (one that was darker when I was balanced for ambient light), and all of a sudden, my pictures would have that corner very bright, and the rest of the room dark, like it was night-time. I didn't think adding an off-camera flash would affect my exposure for the rest of the room, but apparently I was wrong!

I figured I may have had some obscure flash option wrong or something of that sort.

Even though you said everything above, it is best / most reliable to post a picture with EXIF detail to see if what you think you did was actually what happened. By being in AP mode, you are allowing the camera to adjust exposure, how it wants, not how you want - thus you really need to see what actual exposure was - not what you thought it was. Most Flash users, at least in the Canon world, shoot in Manual Mode so as to exactly set the exposure that they want given the picture they see in their mind - not saying that you can't use Aperture or Shutter Priority, and then use EC to select your Ambient Exposure, but adding this as another random variable, to the Flash Exposure, and with FEC on top of that, isn't the best idea (not saying this is what happened to you but showing us a picture, with actual real settings, or just replicating it again in your house for the same effect would be useful.

Not trying to be unhelpful but more info is needed (at least for me)

GESWhoPhoto wrote in post #18465367
Thanks for the replies thus far, everyone!

I don't think I explained the situation as well as I could have.

I was using aperture priority mode at a relatively wide setting (4.5 I believe?). The room itself had plenty of light, and I was taking pictures that were very well-balanced before trying off-camera flash. I configured my camera in wireless commander mode and placed the flash in a dark corner of the room (one that was darker when I was balanced for ambient light), and all of a sudden, my pictures would have that corner very bright, and the rest of the room dark, like it was night-time. I didn't think adding an off-camera flash would affect my exposure for the rest of the room, but apparently I was wrong!

I figured I may have had some obscure flash option wrong or something of that sort.

Your camera in Av should have taken the f/4.5 and then (for the chosen ISO setting) picked a shutter speed so that the exposure WOULD record ambient light sufficiently bright in the shot, AND ALSO flashed the speedlight to make the main subject fully bright as well.

But as already stated, it would be good to POST a photo with intact EXIF data embedded (do not choose the 'output for Web' option which strips off EXIF)

Thanks for the feedback, everybody! It sounds like I royally screwed the pooch by deleting those pics. Will make sure to save whatever I am confused about next time it happens (probably very soon)...

So it sounds like manual for off-camera flash is muy importante. I really need to learn more about flash in general.

the metering mode makes a big difference.

if the corner of the room is in the frame, the camera will probably try to keep that area from being completely blown out, even at the expense of having the rest of the frame underexposed.

keep the big blast of light from the flash out of the frame and results should be much better.

After setting up the flash, were the people (your subjects) properly exposed in a now dark room? Or were your subjects in the dark as well?

On a canon camera, once you turn on the flash in Av mode and not in high speed sync, I believe (not 100% sure) the iso locks at 400. (see edit) You were probably at a higher iso without the flash, but then, after the camera adjusted to iso 400, the flash at full power still wasn't enough to light the entire room properly.

You could have noted the settings that were working without the flash, put your camera in manual mode at those settings, then simply added the ettl flash to that ... adjusting the flash exposure compensation as needed.

edit: I don't have my camera here, but I think I said this wrong. If my camera is in "auto iso" mode, it would lock to iso 400 if I added a flash. Otherwise it would stay at whatever iso I had put it on.

Ah, those are all good ideas. Thank you very much! I could really benefit from researching flash further. Are there any references you all can share with me to get me started on learning these kinds of concepts? I have been told to read the strobist blog.

Sadly, I don't know of the perfect place to go. Strobist is great, but it's also like me leading you to the worlds largest library and saying, "The answer's in one of those books".

kmilo wrote in post #18465806
Sadly, I don't know of the perfect place to go. Strobist is great, but it's also like me leading you to the worlds largest library and saying, "The answer's in one of those books".

I like you. Lmao. Your honesty is refreshing.

Well, with a Canon, I'd check your custom settings...could be your "flash sync spd when in Av priority" custom setting...from the Canon 7D manual, if this custom setting is on 1 or 2...

1: 1/250-1/60 sec. auto. When flash is used with Av, this prevents a slow flash-sync speed from being set automatically in low-light conditions. It is effective for preventing subj blur and camera shake. However, while the subject will be properly exposed with the flash, the b/g will come out dark.

2: 1/250 sec. (fixed). The flash-synch spd is fixed to 1/250 sec. This more effectively prevents subj blur and camera shake than with setting 1. However, the b/g will come out darker than with setting 1.

I just did a little experiment in AV mode on my Canon 5DSR with a Master Flash on body (Canon 600EX-rt) and a Slave flash in the corner (another Canon 600EX-rt).

I say the following about my observations having never shot Flash in any mode other than manual so I was a bit surprised what I saw - and it wasn't consistent when I switch to Shutter Priority.
- First of all, when in AV Mode, if you put the AV Flash mode in Camera at either 1/60-1/200 or at 1/200 (not the auto mode), and you place the ISO at any specific level (not Auto ISO), then at least with the Canon 5DSR, you will get no indication that the flash cannot expose the image properly (even if only the off camera flash is enabled) - the Exposure Meter will show middled (assuming you don't have any EC dialled in) and there is no warning, in anyway, that proper exposure cannot be achieved
- in contrast, if you switch is Shutter Priority, the at least with the Canon 5DSR, you will see a blinking Aperture until you lower the Shutter enough to achieve proper exposure (no such indication is given in AV mode which I find surprising) - but in Auto AV mode for the Shutter speed, it will drop the Shutter to whatever level is needed for proper exposure
- the last point may explain 'some' of the issue from the original question
- with the above said, even if I didn't know this, and my camera stayed at 1/60, F4, ISO 100 (when real exposure was 1/15, F4, ISO 4000), a full 6+ stops underexposed, then my flash (a 60 Guide Number Canon 600EX-rt - which is stronger than the SB700 Guide Number 28) was able to, if properly angled into a white wall and white ceiling corner - and then bouncing everywhere) able to achieve basically good room exposure (all because of the flash bouncing everywhere - it wasn't perfect but it was ok)
- so, I would argue that the SB700 should have been able to do some of this if the flash had a good white ceiling and wall to bounce off and was angled correctly to do so (which my guess is that it wasn't) - the room i used as a test was 25 feet by 20 feet

To the original post, when you do anything the first time, and something goes not perfectly, we often semi panic and can't see the solution even if it is obvious afterwards. The room was dark because you didn't have enough exposure - if your camera's meter wasn't showing you this (just as the 5DSR in AV mode with selected SS of either 1/60-1/200, or 1/200) does, then next time, turn off the flash, or turn camera to manual mode, find out what real exposure should be, and then THINK - how much of the ambient do I want to use - my answer, outside of anything that is a studio, is a lot - because that captures the environment that people will remember being in. So, once you know exposure, set your SS, AP and ISO to use at least 80% of the ambient lighting - or (-1 1/3 EV to -2/3rds EV) - that will be a good range to blend with. AFter you have got this done, then think about how you want the additional flash hitting your targets faces - the worse outcome is an on board flash using a computer's version of good ETTL exposure throwing photons at lightspeed straight at your subjects faces - it just doesn't look good unless you like the flash bomb look. So your idea of bouncing the light up into a white ceiling, using as wide angle beem as possible to diffuse the light as much as possible is best (doesn't sound like you did this) and then additionally, using an onboard flash, in ETTL, dialled back by -2/3rd EV and bounced into a close wall or ceiling or both - gives you a second and more local slight to work with.