2011-11-05

Nikon D5100 White Balance

The How and Why of setting White Balance with a Nikon D5100.  This article deals with a Nikon DSLR camera, but the concepts are useful for all digital cameras.   Edited 2012.12, clarifying various paragraphs.

Photographs take on the color and hue of the light the photo was taken in.  You may have noticed this.  On overcast days, or under dark overhands or foliage, your photos may have a distinct blue tint.  Indoors, photographs may be unnaturally warm (red).  Fluorescents may appear as a variety of unnatural colors.

Your eye (brain) automatically compensates for most of these color shifts but, by default, the camera records the scene as-it-is.  You can use a setting called White Balance to color-correct the scene, setting the colors to "how they are supposed to be."

Digital cameras have an "Auto White Balance" and it can make a guess about the light, but you will get better photographs by balancing the pictures manually.  This article explains how and why to control the white balance.  This is sometimes called Color Correction.

Contents:
  • Examples - White paper under incandescent
  • When to White Balance and when not to
  • Setting White Balance Manually with White Sheet of Paper (recommended)
  • Using Pre-configured White Balance (sunny-day, cloudy-day, etc.)
  • Using Auto White Balance
  • Turning off White Balance
  • "Mood" lighting
  • Histograms

Examples with a White Sheet of Paper

Incandescent lighting (a standard old-fashioned light bulb) has a warm color to it -- verging on yellow or red.  This warmth is caused by the burning filament in the bulb.  Under normal conditions, people instantly become acclimatized to the light and the brain ignores the color. But from an outdoor (blue-ish) lighting, looking inside of a house, you can see the warmth, which is visible to both you and your camera.

See this article for an example of open-shade color correction:  Still Life with Mussels.

As an experiment, you can test how your camera and its auto-white-balancing behaves by photographing a sheet of white paper. 

With the camera in automatic exposure and auto white-balance, it will likely miss both the color correction and the exposure.  Admittedly, all-white subjects cause other exposure problems, but it is easy to separate the color shifts from metering errors.  In these examples, pay attention to the color.

None of the photographs in this article were manipulated with a photo editor and all were taken under incandescent lighting.




Correct WB and Exposure
Photograph A is how the photo should appear.

A white sheet of paper, a white book, and an apple -- on a light-grey desktop.  The paper is bright white.  With manual "white balancing" and manual exposure compensation, this picture appears as the mind's eye saw it -- even though it was taken under an incandescent light.   

As an aside, the overall whiteness of the scene fools the meter.  Because of this, the picture was over-exposed +2 stops to compensate.  This would be a metering problem regardless of the light, type of camera, film, etc., and is a separate issue, covered in this imageLiner article:  Using an 18% Grey Card.  


Photographs B - Auto White Balance + Manual Exposure Compensation

In this photo, the camera was to over-expose +2 stops, compensating for the white paper, solving the under-exposure problems seen in photos C and D, but the "white balance" was left in "Auto"  (Auto White Balance). 

As you can see, the Auto White-Balance still has a red hue.
Compare this with the all-auto exposure (no white balance, no color correction), illustrate below.  Even with a white balance, the all-"auto" is red (and underexposed):


Photograph D was taken under the worse possible conditions:  The camera was set for a Daylight (not Auto) white balance and there was no exposure compensation to counteract the white-subject's metering error.  The red is overwhelming and even I was surprised at this photo. 



Real-World White Balance

Except for bright, sunny days, almost all photographs can benefit from White Balancing.
This is especially true if artificial lights are used. 

Consider white-balancing in these situations where the color of the light can often look unnatural in the final photograph:
  • Outdoor shots underneath overhangs or shade
  • Cloudy, overcast days
  • Artificial lighting
  • Indoor under a cold, wintery window light
  • Scenes with a brightly-colored backgrounds or colored reflecting surfaces
  • Scenes with a lot of white (snow, concrete, etc.)
  • If you want the objects as their 'true' color

However, for artistic reasons, do not white-balance in these conditions: 
  • Sunrise / Sunsets
  • Candle and firelight
  • Neon and other light sources that are in the photograph
  • "Mood" lighting
For each of these, consider forcing white-balance to 'direct sunlight' (daylight) -- do not allow Auto to adjust.

Use Auto in these conditions:
  • Average day-light (no need to white balance; leave on Auto)
  • If using a Flash when the entire frame is within the flash's range
  • When you are too lazy to do otherwise




Setting White Balance

Follow these steps to set the Nikon D5100's White Balance.  Other cameras have similar steps.

There are three ways to control White Balance:

A. Manual (recommended)
B.  Pre-Sets (choosing a camera's fixed style, such as "cloudy day")
C.  Auto

White Balance can only be set when the camera is in one of these modes:  P,S,A or M.

For reasons only Nikon understands, automatic modes, portrait, landscape, etc,  use Auto White Balance and cannot be manually set.  I suppose this is because these modes were intended to be used by non-technical photographers.

However, if you are reading this article and are concerned about White Balance, you should already be in one of the P,S,A or M modes.




Manual White Balance with a Sheet of Paper

Method A: Manually Setting White Balance - Recommended Method


In my opinion, the pre-set WB settings (incandescent, shade, etc.) are barely acceptable.  More accurate balances can be set by manually calibrating with a white sheet of paper.  This only takes a minute and the results are always better than the camera's auto white-balance.


You will be taking a calibration photo and this photo will set the correct White Balance for the current lighting conditions.  You will need a sheet of white paper and about 60 seconds of your time.


1.  Confirm the Camera's mode dial is in P,S,A, or M.  You cannot be in Auto-Program, Sports, Portrait, etc.

Have a sheet of white paper handy.

2.  Press "Menu"

In (green) Shooting Menu, select "White Balance". 
Right-arrow to move to the next menu:


Important: You cannot use the "i" menu to manually configure or set the 'Pre' white balance -- even though the "i" menu has a "Pre-set" choice.  "Pre" (as in Pre-set Manual) was an unfortunate name for this choice -- "manual" would have been better.  The name "pre-set" is easily confused with the factory-pre-sets, such as "cloudy-day", "shade", etc. 

3.  In the list, scroll to the last item. 
Select "PRE - Preset Manual"

4.  Press Right-Arrow to select. 

5.  Highlight menu choice "Measure" (OK).  If prompted to overwrite, choose Yes.

6.  In the view-finder, compose on a sheet of White Paper. 
  • The sheet must be in the same quality of light as the subject 
  • For Nikon, the paper must occupy most of the frame
  • Angle the sheet slightly so it partially faces the light source and the camera, with no glare
  • You do not need to be perfectly focused on the paper 
  • Do not cast your shadow on the sheet

7.  Press the shutter to take the calibration photo of the white paper.

Confirmation Prompts:
The video will show "Data Acquired"
The View Finder will show "Gd" (Good).
Note: The calibration photo is not stored on the memory card.

"Pre" (Pre-set manual) white balance is now set.

Photograph your actual scene normally.
Re-calibrate white balance if the nature of the light changes.
You do not need to re-calibrate if the subject or composition changes.


Note: You cannot use the "i" menu to calibrate the PRE White Balance, but you can use the menu to return to the last-recorded calibration. 


Cautions:

These cautions are true with all white balance settings.
  • White Balance remains in effect until changed. It is easy to forget to un-set.  It can wreak havoc on your remaining photos. 
  • Important: White balance settings even survive turning the camera off.  Remember to return WB to "Auto" when you are done.
     
  • There are no view finder indicators showing white balance has been set, but you can see the setting on the Video display ("WB").  When Viewing/Previewing a photograph's Information Panel, White Balance is indicated in the Statistics.
     
  • Switching to an Auto-P (Green) (or any of the Scene modes) forces white balance to Auto -- no matter what was previously set.  When the camera returns to PSAM mode, the selected white balance is returned as last-set. 


White Paper vs Grey Cards

A white sheet of paper (or any other uniformly white/grey object) can have some writing or other variations on it, but a clean sheet is best. Some will argue that a white sheet of paper is not precise and is "too white," blowing out the highest registers.  This may be true, but the results I have seen are far better than doing nothing and there is something to be said for inexpensive and handy.  Future articles will attempt to quantify this.


Kodak Grey Cards:  Technically, the paper does not have to be white.  Ideally, it would be a few percentage points less than pure white.  It turns out any uniform, neutral (non-colored) grey would work but finding a "neutral colored" card is hard; I'm still looking.

Standard 18% grey cards can be used, but they are too dark (hard to calibrate in dim light) and most have a slight coloring which can throw off the calibration.  The cards were designed for printing and exposure compensation -- not for white balancing. With all this said, I often use the back-side of my grey-card (a 90% white).


Method B. Using Pre-configured White Balance, e.g. "Cloudy Day":

The camera has a series of pre-configured values, such as "Incandescent", "Cloudy Day", "Shade", etc.  I have never used these values, preferring setting them manually.

1.  Confirm the camera is in P,S,A or M mode.

2.  Press the "MENU" button, open the Shooting Menu (Camera icon), scroll to "White Balance." 

3.  In the White Balance menu, note these options:

Choose from one of the following:










Note: The camera also supports setting the White Balance from a previously-stored photograph.  Ignore this option because the white-paper method is faster and more accurate.
 
Although there is a Fluorescent setting, it probably won't work because of the myriad of different colored lights and some lights give out multiple color spectrums.  Use the manual method, described above, but even that may be hopeless.  Consider using a flash if the subject is close.

Method C:  Auto White Balance:

The Camera's AUTO White Balance attempts to choose the color correction, but as illustrated at the top of this article, it is less-than-perfect.  However, I will use it in bright daylight or when using a flash.  But almost all other times, you should take more control. 

Setting "Auto" White Balance:
1.  Press the "MENU" button,

2. Open the Shooting Menu (Camera icon), scroll to "White Balance."




An alternate path to this same setting is to press the "i" Menu, which opens the Information Display.  Press "i" a second time to place the editing cursor on the adjustable menus.  Scroll to "WB" near the top, right).  Click OK.

3.  In the White Balance menu, choose Auto.


Turning Off White Balance

White Balancing cannot be turned off -- the camera's JPG mode will always attempt some form of white balancing, either in a pre-set or auto-mode.  In any case, when done with any manual setting, return the camera to Auto WB because the setting is so easy to forget.

A.  Using either the MENU or "i" menus, select White Balance (see above)

B.  In the scrollable list, choose AUTO

Confusion Alert:
The D5100 MENU, 'Shooting Menu,' "White Balance," is confusing.  When you return to the WB setting, the menu starts with "PRE - Preset Manual" at the top of the scrollable list.  It is not obvious the up/down arrow keys will take you to AUTO.  (Note: in the "i" menu, it is obvious how the menu should be used.)












"Mood" Lighting

There are times when Auto should not be used. When shooting for "mood" lighting -- where the color of the light is important.  In these conditions, do not allow the camera to use Auto -- and somewhat counter-intuitively -- do not choose Incandescent or any other White Balance setting.

Situations like sunsets, candle-light, street lighting, etc., require a somewhat exaggerated color balance.  In other words, with Auto (or any of the pre-sets), the camera will try to make the scene appear "normal" -- when in fact, you want the color. In these instances, manually force the camera to a pre-set "Daylight," accentuating the color.

In other words, "auto" is not daylight.

A.  Using either the MENU or "i" menus, select White Balance (see above)

B.  In the scrollable list, choose Direct Sunlight (Daylight)



Fine Tuning White Balance:

The built-in pre-configured values (incandescent, flash, cloudy, etc.) can be fine-tuned to a warmer or cooler color than the offered defaults.  You might consider using this when selecting Direct Sunlight (Daylight) and "warming it up" for a portrait. 

This option is only available from the MENU button (not the "i" menu) and is only available for the built-in pre-configured values.  Sadly, these steps will not work with the Manual/White Paper method and this cannot be used when using any of the Scene exposures.

1.  Using "MENU", choose a Pre-Set White Balance, such as "Direct Sunlight"

2.  While highlighting the choice, press the Right arrow.



3.  Use the arrow keys to set a more pronounced color cast.

Note: The center ("0,0") is for the selected pre-configured value.  In other words, Incandescent, cloudy, Daylight, etc., all start at their own (0,0).  When making fine-tuned adjustments, Nikon does not show the selected value numerically.  


This concludes the White Balancing article.
The remaining sections are technical details about the illustrated photographs.



Histogram Details on the Example Photos:

Readers may be interested in the example photograph's histograms.  The on-camera histogram shows Picture D (incandescent light, no White Balance (daylight) and no exposure compensation) like this.

The chart shows the photograph was generally under exposed, with almost all the pixels on the left sides.  The pixels appear by volume and almost all are the "Red" variety.  Picture C (Auto WB, no EC) would show a more centered histogram, but with very few pixels on the right side of the charts due to under-exposure.






Picture A (correctly exposed with manual White Balance, +2 stops EV) as this:

where all colors have approximately the same number of pixels and all the pixels were in approximately the same place -- indicating a mostly-white subject.  Because it was over-exposed two stops, most of the pixels were on the far-right, compensating for the meter's inability to understand the all-white-scene. 




* You cannot blindly accept that you want all of your pixels in the center of the chart.  In this case, knowing the nature of the subject, it is acceptable (required) to have most of the pixels on the far-right of center.  A perfectly-centered histogram does not mean the picture is "perfectly exposed."



What About Color Correction in the Editor:

Can you color correct in your photo editor.  Of course.  But assume you took 100 pictures that day.  You would have to color correct them all.  As long as you are shooting in JPG (not RAW), it may  save you more time if you color-correct when the photo is captured.  (Admittedly, some editors allow you to batch-apply one color setting to all photographs in the session, making this less of an issue.)

With RAW, all bets are off and all corrections are done in the editor.  When White Balancing in the editor, you essentially don't care the color cast when the photo was taken (RAW doesn't even allow you to care), but you must, at least in one of the photos, have a reference shot of a known, fixed color (see Whibal link below, as well as other products).  Unfortunately, this type of card cannot be used for exposure compensation.

The workflow on post color-correcting are different and will be described in a separate article.


Related Links:
imageLiner: Using an 18% Grey Card for exposure Compensation
Reference: Color Temperatures

Article showing color correction in open shade, shadow, blue hue
Still Life with Mussels

There are several commercial products that claim to help with White Balancing.  All of these have my interest, but not yet my dollars.  I'm inclined to purchase WhiBal but in the back of my mind, a white sheet of paper has been doing a fine job.

Commercial link:
WhiBal White Balancing Card ($30 - 50, sized various)
Whibal Purchase (oddly, a different site)
The first link opens to a tutorial.  This product is designed to White-balance in editing software but would work very well, replacing the white paper described in this article.


Commercial link:
DotLineCorp White Balance Disks ($20)
I have not tried these products, but am somewhat interested.  On the other hand, a sheet of white paper works fairly well.  There are also inexpensive white balance lens caps.

Commercial link:
ExpoImaging ExpoDisk on Amazon and others ($100).  A lot of people use the lid from a Pringles Potato Chip can, claiming they get the same results.


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