ISO and setting white balance manually

[mikeci]

Hi All,
I am using a Nikon D700 and for my photo class the professor wanted the class to take the wb off auto and set it for the scenes we would be shooting. We were to set the iso at the max the camera would allow. Which in my case was 6400 w/o going into the hi 1 & 2 settings.
Instead of using the camera's generic wb adjustments I decided to set the manual adjustment w/ a expodisc. Here's the rub; try as I might the camera would not lock the wb at iso 6400 I had to reduce the iso to around 500-600 then the camera would lock the wb.
first question is; By changing the iso does/did this affect the wb?
next question is; Why didn't the camera allow me to set the manual white balance at such a high iso?

Thanks,
Mike

[Dave Humphries]

Hi Mike,

My wild guess would be the expodisc was either over or under exposed at the high iso for the lighting you were in at the time.

However, that is a guess only and might be unfounded. If so, it answers both your questions.

I have to say I would set it manually depending upon the light source; e.g. tungsten, shade, flourescent, etc.

Now, a manual setting might have been the prof's aim anyway - what you're doing is swapping one sort of auto-WB for another

Or maybe that is what he wanted you to do, your question doesn't make it clear (perhaps he didn't either )

Hope that helps,

[Clactonian]

What mode are you using? I'm surprised if that happens in anything other than auto or programme mode (not that I would expect it even then), but what do I know ... whilst I have a couple Nikons I haven't got a D700!!

[mikeci]

What mode are you using? I'm surprised if that happens in anything other than auto or programme mode (not that I would expect it even then), but what do I know ... whilst I have a couple Nikons I haven't got a D700!!

The entire camera is in manual mode focus included luckily when you turn off the auto focus you still have the range finder otherwise most of my shots would look like it was taken by a drunken prom queen.
Mike

[Colin Southern]

Hi Mike,

Are you pointing the Expodisc at the scene, or back towards the light?

[mikeci]

Hi Mike,

Are you pointing the Expodisc at the scene, or back towards the light?

I tried it both ways. I also tried pointing up at the sky but not directly into the brightest part of it. (i.e sun). I made sure the exposure was correct but nothing worked at iso 6400. I dropped the ios down to 500 or 600 readjusted the exposure and it seemed to work.

Mike

[Steve S]

Mike when setting the WB with an expodisk, first set you're exposure for the shot. Take a couple of test shots first and get the exposure where you want it.(manual mode is best and leave the ISO where you want it) Next, move to the location of the subject and point the camera back to where the photo will be taken from. Turn the auto focus off and place the expodisk over the lens and take a shot.(leave the exposure where you have previously set it in manual mode) Use this shot for your WB (sorry don't know how to set it for a nikon). After it is set, move back , and take the shot and you should have the proper white balance.

[Steve S]

I just read you're last post, at iso 6400 you're camera was probably over 8000 for a shutter speed and why it wouldn't work. Try it in a darker area and it should work.

[mikeci]

I just read you're last post, at iso 6400 you're camera was probably over 8000 for a shutter speed and why it wouldn't work. Try it in a darker area and it should work.

Hi Steve,
I tried pointing at a dark area, the shutter was at about 2000. it still didnt work and if it did work the wb would have been wrong for the shot I was going to take. I'm going to try it again (when it stops raining) and take exact notes of all my settings & findings. If I still can't set the wb at 6400 and above I'm going to email Nikon and see if they have an answer.

Mike

[Colin Southern]

Mike when setting the WB with an expodisk, first set you're exposure for the shot. Take a couple of test shots first and get the exposure where you want it.(manual mode is best and leave the ISO where you want it) Next, move to the location of the subject and point the camera back to where the photo will be taken from. Turn the auto focus off and place the expodisk over the lens and take a shot.(leave the exposure where you have previously set it in manual mode) Use this shot for your WB (sorry don't know how to set it for a nikon). After it is set, move back , and take the shot and you should have the proper white balance.

Um ... getting a bit confused here. The Expodisc does white balancing AND Exposure. To use it you point it at the LIGHT SOURCE with the camera on Av mode - take the shot - then (after setting the custom white balance) you stick it on manual exposure and dial in exactly the same shutterspeed (assuming ISO and aperture set the same). Basically the Expodisc lets through 18% of the light.

[mikeci]

Um ... getting a bit confused here. The Expodisc does white balancing AND Exposure. To use it you point it at the LIGHT SOURCE with the camera on Av mode - take the shot - then (after setting the custom white balance) you stick it on manual exposure and dial in exactly the same shutterspeed (assuming ISO and aperture set the same). Basically the Expodisc lets through 18% of the light.

yup Colin,
That's exactly what I did but untill I turned the iso down the camera kept saying "no good". Go figure. the other question that no one answered is; does the wb shift when you change iso?
Mike

[Colin Southern]

yup Colin,
That's exactly what I did but untill I turned the iso down the camera kept saying "no good". Go figure. the other question that no one answered is; does the wb shift when you change iso?
Mike

Hi Mike,

So long as you're not using a flash, I wouldn't expect any WB shifting (I don't know for sure, but I can't think of a reason why it would).

Perhaps the high ISO shot contains too much noise for the camera to make a good WB decision on?