SB 910 over exposing?

I'm using it with a D600. When I put a subject in the shade and try to balance it against a sunny background the subject is often over exposed. Sometimes I need to dial in almost -2 ev on the camera. I've done some experimenting and I've dialed the exposure comp. on the flash unit down two and even three stops and noticed no difference so I quit trying that.

 

I'm watching the distance scale and my subjects are always within the limits. I normally use center weighted but I've also used spot, metering off what I think is a midtone and sometimes matrix.The flash is set to TTL and sometimes TTL BL.

 

I'm constantly using the exposure comp on the body, dialing it up and down. Sometimes the subject is overly lit, sometimes under, and then sometimes the image is spectacular, pefectly exposed. Is there something obvious I'm missing here?

I-TTL BL (balanced lighting) only works with matrix metering. In CW and especially spot metering the flash will take precedence over the background. That's assuming the metering spot is on the subject.

 

Having said that, after numerous tries to get consistent results out of i-TTL, I've given up on it and use either manual or Auto Aperture mode.

 

I tried again the other day, just using the popup flash on the D800 in i-TTL + matrix metering. Total garbage! I had to fiddle with flash compensation every time I changed subject distance. I tried the same series of subjects and distances with a cheap old Cullman Auto Aperture flash with almost perfect exposures every time. Certainly far closer than i-TTL got without adjustment.

 

So my advice would be to go manual. Especially if you just want subtle fill. A bit of experimentation should show what output setting you need to use at, say, 1 metre, 2m and 3m etc. subject distance.

 

Auto aperture also works well for fill. You just set the aperture on the flash to 2 or 3 stops wider than the aperture you're actually using. I.e. if you're shooting at f/8, then set the flash AA to f/4.

And yet to so many people today if a flash doesn't support TTL it's useless.

At rodeo_joe 1, I read your answer and will read it a few more times, and also show my daughter who insists that I'm using too much flash!

 

When I was using my F4s and even my F100 it was easy to fool the flash. If I was close to the subject my daytime balanced fill worked okay on auto but virtually all of my nighttime fill flash work was done in manual off a tripod. Sometimes it would take me almost two mniutes to set it up but nearly all of my shots turned out well.

 

I will contiue to work on it, finding what works the best and also try to recognize when to use matrix and when to use centerweighted and spot.

Bebu, I fear the lesson of "The Emperor's New Clothes" will never be learnt by some people.

I think the flash designers assume an indoor, somewhat reflective closed environment is the most common where flash is used. Indoors you light the subject but also the interior to some extent so the result is that the flash affects almost the whole picture. In an outdoor environment if you're doing, e.g., a whole body portrait, much of the scene will appear not to reflect light back to the camera since ("the walls") it will be far away, and your subject may be overexposed (since the meter is trying to read the whole scene, not just your subject). So, if your subject is small in the frame, TTL flash probably won't help. Try to set the flash on manual and test exposures by trial and error or by using a flash meter.

By the way I always set the ambient exposure to manual mode when using flash. This limits the number of variables and it is easier to keep things in control. I do a test shot of the scene without flash and may leave it ever so slightly underexposed and then add flash.

Perhaps you should post some examples so we can better guess what may have gone wrong. I find the Nikon system a bit confusing at times but fairly reliable. I assume you are aware of the fact that, depending on custom setting e4, ambient exposure compensation may get added to the dialed-in flash exposure compensation. Thus, if you change the ambient EC, you may also be changing the effective flash EC.

If I shoot a subject in the shade and try to balance against a sunlight background (pretty much why I bought the powerful SB 910 rather than use the built in pop-up flash) and the subject is overexposed, I have dialed ec on the flash down to -3 and saw no difference. That's why I asked if I was missing something.

 

Here are two shots, everything is the same except I dialed -1.5 ec on the second shot. I spot metered off the center girl's dress.

 

 

Here are two more. Matrix metering.

 

6049 looks a bit washed out, 6050 I dialed down 1 stop.

 

Joseph, between the two sample images immediately above, the top one (with the subjects looking towards their left, our right) seems to be overexposing overall. The background is at least one stop over-exposed.

 

I am not sure that the subjects were entirely in the shades. If you would like to add some fill flash, I would start with -2 stops on the flash and then adjust up or down a bit, by 1/3-stop increments.

Edited May 23, 2017 by ShunCheung

I always have great results using Nikon automatic fill flash. On the flash set compensation to -1.7 as a starting point and the flash mode to iTTL BL. On the camera select Matrix metering and set the sync speed to 1/250 FPS (Custom Setting e1). The latter is important to prevent overall overexposure due to a low shutter speed. On cameras with pop-up flash, be sure the flash comp on the body is set to zero

 

That's pretty much it. I've never used a D600, but it's worked for me with the D2h, D200, D300, D500, D750 and D7200. The only Nikon DSLR I've used that had flash issues was the D1, in which the flash implementation was widely acknowledged as being broken.

 

Danny W.

Danny, setting 1/250 s (Auto FP), or 1/320 s (Auto FP) in menu e1 doesn't fix the flash shutter speed. All it does is tell the camera+flash at what shutter speed to change from X-synch to FP (HSS) mode.

 

As far as I can see there is no way to command the camera to fix the flash shutter speed at 1/250th. You can set a lower limit at 1/60th (menu e2) and a high limit at 1/250th, but in any auto mode the camera can, and will, vary the flash speed between those limits.

 

The only way to be sure the camera uses 1/250th or 1/320th is to set the speed manually in M or S mode. In A or P mode the camera is free to choose any old shutter speed it likes above the minimum speed set in menu e2. That's if an FP capable speedlight is fitted. With a non-FP flash the camera is capped at 1/250th or 1/320th.

 

In low light the camera will default to 1/60th, or whatever speed has been set in menu e2, when a speedlight is fitted or the BI flash is popped up.

 

In short, the only way to be certain of a high synch speed is to use manual or shutter-priority mode and set the speed yourself.

Edited May 23, 2017 by rodeo_joe|1

If you want to fix the shutter speed and let the autoexposure take care of the aperture, shutter priority mode allows you to do that.

 

However, here I think it's best to use manual exposure for the ambient to avoid uncontrollable variations.

Danny, setting 1/250 s (Auto FP), or 1/320 s (Auto FP) in menu e1 doesn't fix the flash shutter speed. All it does is tell the camera+flash at what shutter speed to change from X-synch to FP (HSS) mode.

 

As far as I can see there is no way to command the camera to fix the flash shutter speed at 1/250th. You can set a lower limit at 1/60th (menu e2) and a high limit at 1/250th, but in any auto mode the camera can, and will, vary the flash speed between those limits.

 

The only way to be sure the camera uses 1/250th or 1/320th is to set the speed manually in M or S mode. In A or P mode the camera is free to choose any old shutter speed it likes above the minimum speed set in menu e2. That's if an FP capable speedlight is fitted. With a non-FP flash the camera is capped at 1/250th or 1/320th.

 

In low light the camera will default to 1/60th, or whatever speed has been set in menu e2, when a speedlight is fitted or the BI flash is popped up.

 

In short, the only way to be certain of a high synch speed is to use manual or shutter-priority mode and set the speed yourself.

 

When you set Auto FP, there is no upper limit to shutter speed when the flash is on--especially outdoors, this is important to prevent your ambient exposure from overexposing. I don't want the shutter speed to get stuck at a top of 1/250, in fact, exactly the opposite.

 

The downside is that you lose power at higher shutter speeds, but this is a better result than having a limit to the shutter speed.

 

Danny W.

"When you set Auto FP, there is no upper limit to shutter speed when the flash is on--especially outdoors, this is important to prevent your ambient exposure from overexposing."

 

I thought I said almost exactly that. Except obviously you can't go higher than 1/8000th or whatever the camera's top speed is.

 

None of Nikon's built-in popup flashes support Auto FP though.

 

There's a misconception that FP mode lets you overpower daylight more easily with flash. In fact using FP mode gains you nothing in flash-to-ambient ratio. For example: you set 1/250th and f/11 for a daylight exposure. Moving to 1/500th the aperture has to change to f/8, and you'd think you'd need half the flash intensity for the same lighting ratio, but nearly all of that drop in flash power is "lost" to FP pulse mode. You may even have to increase the flash output. At 1/1000th you need f/5.6 and the exact same flash power, because now the flash exposure is also regulated by the shutter speed. Ramp the shutter up to 1/8000th and you still need the exact same flash power. There's no nett gain in flash to ambient ratio.

 

Now if the flash was "maxed out" delivering fill or trying to compete with daylight at 1/250th X synch, then it'll almost certainly be lacking sufficient power at FP speeds.

 

OK, so you gain the ability to use a wider aperture, but exactly the same thing could be achieved by using an ND filter or lowering the ISO and staying in X synch mode.

 

The OP has a problem with overexposure. If the flash is keeping the shutter speed too low, that could be a cause. Using Auto FP eliminates that possibility.

 

Danny W.

"If the flash is keeping the shutter speed too low, that could be a cause."

 

But the OP apparently gets correctly exposed shots by using minus compensation. So it can't be lack of shutter speed, otherwise the background would remain blown out.

 

Joseph, do you realise you can fine tune the metering in all 3 metering modes separately? If consistent overexposure is the issue, then consider putting some "permanent" negative correction in the metering fine tune menu b6.

 

I have matrix metering dialled down by 0.7 EV in the fine tune menu. I find it otherwise tends to overexpose and blow highlights far too easily.

Edited May 23, 2017 by rodeo_joe|1

The first photo is overexposed overall, so it could be Matrix metering calibration, A simple test would be to turn off the flash, take a photo, make sure the overall exposure is about right regardless of dark shadows on the subjects, turn on the flash and aim it straight up or to the side and shoot again, then aim it at the scene and shoot again.

 

Danny W.

Good suggestions all! A few suggestions here that did not occur to me. I will note these suggestions and work on them.

 

When I referred to my setting up with my film cameras and getting good results, that sort of echoed what rodeo_joe said about manual. Almost can't go wrong. Again, I appreciate everyone's responses.

The first photo is overexposed overall, so it could be Matrix metering calibration, A simple test would be to turn off the flash, take a photo, make sure the overall exposure is about right regardless of dark shadows on the subjects, turn on the flash and aim it straight up or to the side and shoot again, then aim it at the scene and shoot again.

 

Danny W.

 

I like that idea Danny. Except Nikon speedlights are too clever for their own good! They have a switch that detects when they're tilted or swivelled, and that turns off any distance calculation mode. That may well feed through to the camera and change its exposure.

 

In order to keep the same ambient exposure, I think you'd have to leave the flash pointed forward and just blank it off with a piece of card.

I like that idea Danny. Except Nikon speedlights are too clever for their own good! They have a switch that detects when they're tilted or swivelled, and that turns off any distance calculation mode. That may well feed through to the camera and change its exposure.

 

In order to keep the same ambient exposure, I think you'd have to leave the flash pointed forward and just blank it off with a piece of card.

 

That sounds like a plan.

 

Danny W.

You have the potential to control subjects and background independently in your gear. So drive the train. Adjust shutter speed in manual not exceeding your max sync speed to get the desired background density with the flash off. Then turn flash on and try approximately -2 on the flash compensation for fill. Take a test shot and adjust the flash compensation. If for some reason the flash can't be adjusted any further down, use the inverse square law and move a step or 2 back. That won't change the bg exposure controlled primarily by shutter speed.

I appreciate this post is probably long dead? But having same issues with SB910 that never occurred with SB700. I like Bob_Bill's suggestion as often even compensating at -3, still too bright (how can they call this TTL metering?), but if you use the inverse square law; won't the flash become a harsh spot light?

but if you use the inverse square law; won't the flash become a harsh spot light?

Que?

A direct speedlight is always a harsh spot light unless you diffuse it in some way. The specular facial reflections shown in the OP's example shots are witness to that.

 

On camera direct flash is an ugly light, and there's no getting away from it. It needs diffusing to give a pleasant result, but with more than one of those little clip-on translucent caps.

 

There's good reason that high-end wedding shooters and the like encumber themselves with umbrellas or softboxes, and the stands - or assistants - necessary to hold them.

 

Anyhoo, with a modern flash that dials down to 1/64th or 1/128th, there shouldn't be any need to increase the subject distance.

 

"But having same issues with SB910 that never occurred with SB700."

 

That could be because the SB910 is one whole stop more powerful than an SB700, which might struggle to give sufficient fill in strong daylight. Or it could just be because Nikon's i-TTL is flaky and inconsistent IME. I never use it, and rely on manual or Auto-Aperture mode.

 

If you want a nice subtle fill, stick the flash into AA mode and set its aperture to 2 or 3 stops wider than what you have the camera lens set at. E.g. you're shooting at f/5.6, but you tell the flash to expose for f/2.8.

Edited July 23, 2019 by rodeo_joe|1