Exposure trouble shooting

cmerc4 · Jan 28, 2012

I've been playing around with my camera and flash (nikon d3100 and sb700) but can't get consistent exposure. My setting are manual: iso 800, f11, 1/200, and 0 exposure compensation. I'll take a picture and it will be well lit and look nice, but then the next one will be underexposed, even though I'm taking a picture of the same thing, with the same focus. I've tried spot/center/matrix metering and get the inconsistent results on all setting. I've also tried alternating the flash between ttl and manual. What am I missing? Thanks!

480sparky · Jan 28, 2012

Is the camera set to AutoExposureBracketing?

MTVision · Jan 28, 2012

Are you moving? Staying in the same spot?
With TTL it might change since its not being controlled by you but in manual - if nothing is changing - I would think your exposure should stay the exact same.

MLeeK · Jan 28, 2012

Replace the batteries in the flash. Don't rapid fire.
It sounds as if your flash is putting out it's max power for the first flash and isn't fully recovered to put out full power for the second.

A flash will eat batteries 100 times faster than the toys that make the noise... You might get a hundred shots out of a set if you are shooting at full power.

KmH · Jan 28, 2012

TTL flash is inconsistant even when used by experts, which is why experts are wary of using use it. Just a slight change in where the camer is pointed can make quite a difference in what settings the not very intelligent camera/flash unit decide need to be used.

It could be that the flash unit isn't fully recycling as MLeek suggests.

You leave out a lot of pertinent info, like what kind of batteries are in the SB-600 which has a bearing on how quickly it can recycle, the shooting mode you are using, and the metering mode being used.

cmerc4 · Jan 28, 2012

Thanks everyone, I'm pretty new to this, but I did mention I was in manual, and that I tried the 3 metering settings (centered, matrix and spot) and had the same issues.
I think mLeek is right on the money, because I just checked and the batteries are nearly dead.
Thanks again!

sdrphotography · Jan 29, 2012

I agree with the comments above - also your iso is set to 800 - this will create a lot of noise - you could do with setting it down to 200, 400 at the most.

MLeeK · Jan 29, 2012

sdrphotography said:
I agree with the comments above - also your iso is set to 800 - this will create a lot of noise - you could do with setting it down to 200, 400 at the most.

You keep repeating about this in every post. It's not always true and high ISO IS an option now. 800 is not considered high ISO anymore. I routinely shoot at ISO 12800 without a problem. I do have to remove some noise in adobe camera raw, but I have printed some LARGE prints with no problem also. It's a matter of knoweldge of how to use your camera at high ISO's.
So, instead of repeating this semi-false statement how about you learn something new here?

ISO 12800 on a canon 50D. This is printed as a 16x20 and hanging in the school. Beautiful, no noise problem. Click on it for the larger size to inspect a bit closer

Snaps · Jan 29, 2012

I may be wrong, but I believe TTL flash usually only applies when the camera is in auto or program mode......

MLeeK · Jan 29, 2012

Snaps said:
I may be wrong, but I believe TTL flash usually only applies when the camera is in auto or program mode......

No. TTL will kind of make your camera into auto in manual mode. It goes on what the meter reads and adds the amount of flash that is needed to make exposure.

Snaps · Jan 29, 2012

Must be just my camera then.......

MLeeK · Jan 29, 2012

About the only time that would be true is if you had a flash that was not compatible with your camera's TTL system

cmerc4 · Jan 29, 2012

This convo helps me a lot. I am not going to use ttl. I would like to shooting with a lowered iso, but I'm shooting a toddler so my shutter speed can't be any slower, and I don't want a shallower dof because my lens min is 3.5 and I keep reading that optimal performance should be a few stops away. Again, shooting a toddler who is trying to run away makes it tough enough to focus using f11 for dof lol.
Oh, and I replaced my batteries and the inconsistency is fixed.

MLeeK · Jan 29, 2012

Your shutter can be slower. Flash stops motion. F/11 is incredible overkill.
At 10 feet from the subject, 55mm, f/5 you have over 2 feet of DOF. At 18mm at f/5 and 10 feet away you have over 169 feet of DOF to work with.
F/11 is INCREDIBLE overkill: 10 feet away, 18mm INFINITE begins at f/5.6.
You can easily drop down your aperture to 5.6, but if you are scared 7.1 is great.