White Balance

What is white balance?  White balance (WB) is the process of adjusting the colors in an image so they are realistic and accurate. Our eyes have no problem with white balance, but cameras can have problems.  As my students know I place emphasis on getting the exposure correct in the camera.  It’s equally important to get WB correct and make the best choice in your camera.

If the WB is not correct your photos may have a blue, orange or yellow cast . These color changes are caused by the color temperature of the light sources in the photo and the camera’s difficulty in choosing the correct setting.

The chart below illustrates how the Color Temperature  varies with different light sources.

wb-chart

Each of the six photos below were taken using different camera white balance presets.

The photos below were taken on a sunny day (no clouds) at about 10 AM.  As can be seen the Auto WB (AWB) and Sunny preset yielded the similar results.  Makes sense, right? Sunny day!

p3062750
AWB
p3062751
Sunny

 

 

 

 

 

 

 

But what happens when you use the wrong preset? In the next four photos I used the Shade, Cloudy, Tungsten (domestic lighting) and Florescent settings. You will note that with each of these settings the photos have yellow or blue casts when compared to the photos above.  Here the camera was set to the wrong WB for the lighting conditions.

p3062752
Shade
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Cloudy
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Tungsten
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Florescent

 

 

 

 

 

 

 

 

 

 

 

 

 

OK, with AWB the camera did a good job of determining the correct white balance. So why not use it all the time? I would agree under some conditions it works well, however there are cases when AWB just doesn’t work.

The AWB photo (below left) gave a result that is too yellow.

In the photo you will see a card is propped up against the lamp.

Gray-card
Gray card

Professionals sometime use something called a ‘gray card’ to assist in
getting a reference point for the correct WB.  A gray card can be purchased, if you want, at most photography stores or online.

In the photo (below right) I used the gray card and the levels adjustment in Photoshop** to correct WB. I could have used the card to create a custom WB setting in my camera, but didn’t because I wanted to easily compare results. (See your camera manual for how to do custom  WB with your specific camera)

OLYMPUS DIGITAL CAMERA
Original AWB
OLYMPUS DIGITAL CAMERA
Corrected using Photoshop

 

 

 

 

 

 

 

I  then re-shot the photo using the camera’s Tungsten WB setting as you see in the photo below, the results are similar to the Photoshop** corrected photo, though a little less yellow cast which personally looks more natural to me.

OLYMPUS DIGITAL CAMERA
Tungsten WB Preset in the Camera

A second example below left, was taken by a friend, using AWB . The colors of the four rings are turquoise, purple, cobalt blue and red.  As can be seen, the AWB didn’t do a good job of getting the colors correct. I learned the photo was taken with lighting from a table lamp. Using a white balance correction in Photoshop** I shifted the color temperature towards yellow, Tungsten. This improved the colors, but further color adjustment would be required in Photoshop** to be able to better distinguish purple and cobalt blue rings.  If the Tungsten WB  had been used in the original photo, colors would have been closer to the actual from the start.

P1090434P1090434-2

 

 

 

 

 

 

Summary: What does this all mean?   I believe the best choice is to use your camera’s WB,   presets, i.e. Sunny, Shade, Cloudy, Tungsten and Florescent.

However, when taking photos outside in generally sunny, partly cloudy or a mixture of sunny and shady conditions AWB should work satisfactorily most of the time.  Otherwise, I’d use the WB presets, your choice and preference.  Explore the different WB’s available on your camera for different lighting situations and see what works best for you.

Using the WB presets is specially important for indoor available light photography i.e. Tungsten and Florescent.  In the case of mixed lighting,  where you have both natural i.e. sunlight and indoor lighting it becomes a little trickier. I’d recommend taking photos with both AWB and the appropriate WB for the indoor lighting.  In the case of mixed lighting, the use of the gray card should be helpful. When using a flash indoors I’d recommend setting the camera for Flash WB.  I’ll share my thoughts on flash photography in a future blog.

The links below will give you greater detail on How to Set a Custom WB.

Using a Gray card to set white balance

Setting Custom WB Video

** When I use the term Photoshop, I’m using it generically to mean any photo post processing software that allows for making corrections to your photos.
See my prior blog post Photo Processing Software if you wish additional information on photo processing software.


If you have any Questions please feel free to contact me

FOLLOW TOM WIGGINS PHOTOGRAPHY

 

 

 

 

 

 

 

 

Exposure Compensation

In my last blog post, I introduced Auto Exposure Bracketing (AEB) and Exposure Compensation.

Here I would like to explain more about using Exposure Compensation  plus-neg.

The photos below were taken using AEB in Aperture Priority Mode i.e. the camera determines the shutter speed. (Note: I targeted the train station using spot metering)

A total of five photos each one exposure value (EV) apart were taken. It’s important to note the change in the speed for each of the EV changes and how the histogram shifts right or left with the change in EV.

As you decrease the exposure by  1 EV the photo gets darker and the speed increases i.e. doubles 1/250 to 1/500.  If you increase the exposure by 1 EV the photo gets brighter and the speed decreases 1/250 to 1/125.  For a decrease by 2 EV the speed doubles again from 1/500 to 1/1000 and if you increase by 2 EV the speed changes from 1/125 to 1/60.

Normal (1/250 sec)

-1 Exposure Value (1/500 sec)

+ 1 Exposure Value (1/125 sec)

+ 2 Exposure Value (1/60 sec)

-2 Exposure Value (1/1000 sec)

Digital cameras allow you to set  EV Step to either 1/3, 1/2 or 1. (See your camera’s manual on how to set the EV step for your particular camera.)

In the photos below I adjusted the camera by +1/3 EV each time.  As you can see the difference in each photo is very slight.  Therefore, I believe an EV step of 1/2 would have been sufficient as there is only a very small change in each of the exposures.

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+ 1/3 EV
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Normal
P2182740-.66
+ 2/3 EV

Remember the goal is to get as close to ideal exposure as possible.  While you have the ability to make corrections to exposure, along with contrast, highlight and shadow detail using photo processing software, it’s important to get the exposure correct in the original photo. When making changes to exposure on your computer/tablet there is the potential to add noise that will degrade the quality of the image.  Had I chosen a different metering mode the image results would/could have been slightly different, but that’s a topic for a future blog post on metering modes.

Below you will find two links that provide additional details on exposure compensation: http://www.picturecorrect.com/tips/exposure-compensation/

http://www.picturecorrect.com/tips/understanding-exposure-compensation-in-photography/

 FOLLOW TOM WIGGINS PHOTOGRAPHY 

AE Bracketing

In a previous blog on Histograms, I included photos where I had used Auto Exposure Bracketing (AEB).   So why and when would you use AEB?  I see a couple of times when it really makes sense: 1) when you are not sure what is the best exposure set-up under changing light conditions, 2) when you have high contrast lighting such as in night photography.

When AEB is used, the camera will automatically adjust either aperture, speed and/or ISO while keeping the other two constant depending on the camera shooting mode you are using.  I believe that setting the ISO and aperture and having the camera bracket the exposures by changing the speed provides the best results under most circumstances.  In fact, when using AEB I use aperture priority for most of my photographs.  Using aperture mode allows me to have better control of what is in focus and the depth of field of my photos.  Actually, aperture priority is my go to mode for 95% of my photos.  Your camera’s user manual will go into the specifics as to how to set your specific model for AEB.

Examples:

1) Several years ago on a trip to Amsterdam, my wife and I took a boat trip through several of the canals.  As we traveled along the canals, we were moving from shadows, to cloudy and  sunny conditions.  I set the camera up to do AEB with three exposures: normal, plus one f-stop and neg one f-stop.

Photos above are unprocessed Raw Files

 

Also the camera was set to use continuous focus (CF) and multi-exposure mode, so  when I depressed the shutter button all three photos were taken one after another.  Why didn’t I just take a single photo and correct the exposure when I downloaded it to my computer? When you make adjustments to your photo on the computer, there is always the potential of increasing the noise in the original photo.  So, it’s important to get the best exposure possible when taking the photograph.   I could have accomplished the same correction when I shot the original photo by using the exposure compensationplus-negfeature, but when you’re standing on a moving boat it’s impossible to make the exposure compensation correction and still capture the picture.  The continuous focus (CF) and multi-exposure mode, is just as I recommended in my blog on Photographing Children , where I wanted to stop the motion of a constantly moving child.  Here I wanted to compensate for the moving boat.

2) I’ve used AEB in night photography because it often presents a high contrast situation, i.e. bright lights and dark shadows. In situations like this it’s important to use a wider range of F stops: normal, plus 2 F stops, and neg 2 F stops.   This technique is referred to as High Dynamic Range (HDR).

Always use a tripod as the exposures can be long.  It’s imperative that you also use a cable release, or remote triggering of the camera.  Any contact with the camera will cause the images to be blurred. In the example below the exposure times ranges from 0.6 to 10 seconds.

Using the three photos above, I combined them using Photoshop’s HDR Merge, and then cropped, sharpened and increased the clarity.

 

hdr_5

Private/Semi-private lessons are available see Classes

Basic Camera Controls You Should Know

A week ago on Saturday morning, I held a photo walk in Fells Point, one of the oldest sections of Baltimore. The early morning light provided a lot opportunities for good photos in different lighting situations. When we completed the walk I asked if there were any questions? The students felt they would like a cheat-sheet on camera controls.

[At the end of this post there is a Link to a one page PDF copy of the
Camera Controls Cheat-Sheet.
]

Shooting Modes: 
Automatic (Auto) – Camera sets speed and aperture to what it determines to be the optimum exposure for the selected ISO.
Program (P) – Camera sets speed/aperture, but you can change the combination of aperture and shutter speed while still at the optimum exposure for the selected ISO.
Aperture (A) – You set the aperture and the camera determines speed for the selected ISO.
Speed (S/Tv) – You set the shutter speed and the camera determines aperture for the selected ISO.
Depth of field (DoF) – Remember a larger aperture, lower f stop (f/3.5), gives a shallow DoF. Smaller aperture, higher f stop (f/16), gives a wider DoF.  The closer you move to the subject, the DoF gets shallower. As you move further away the DoF gets wider.
aperature
ISO – Controls the camera’s light sensitivity.  The higher the ISO number used, the greater the sensitivity, the better the camera’s ability to shoot in low light conditions. However, higher values may give the photo a grainy appearance.  I recommend not using Auto ISO. From my observations of students photos, I see the quality of the photo suffers because Auto ISO often allows for too slow a shutter speed and results in a blurred photo when the camera is hand-held.

Metering Modes:
matrixEvaluative/Matrix/ESP– Determines exposure based of the entire image.

c-weight

Center-Weighted – Determines exposure based on the subject and  background lighting with a bias to the subject.

spot

Spot – Determines exposure based on the small area in the center. Best for strongly back-lighted subjects.

AF Target Selection – Camera’s today provide sophisticated focusing capabilities with as many as 11 to 153 individual points determining the image focus.

I prefer more control and recommend to my students to use a single point centered in the viewfinder.  The image to the right provides a good example of when you don’t have the camera set to a single focal point. The woman behind the children is in sharper focus. In using the single point focus, you align the center point to your subject then depress the shutter button half-way locking in the exposure.

Exposure Compensation –  plus-negIn some situations you could get better results if you manually compensate the exposure automatically set by the camera. In bright sun on snow objects will seem darker than their natural color.  Adjusting toward + will make the subject brighter and closer to their real shade.

img_1124 img_1124-2

flash Flash Compensation – Adjusts the intensity of the flash.  This may be required when shooting a close-up or distance objects.

Camera-Controls-Cheat-Sheet

Histograms: A Simple Explanation

Digital Cameras have an important feature that you couldn’t get in the days when film cameras were the only choice.  Now you get instantaneous feed back as to the quality of the exposure when it’s displayed as a JPEG image on your camera’s LCD screen. In addition, cameras give you several choices of information that can be displayed, such as  shutter speed, aperture, lens parameters, “blinkies” called highlight warnings (or highlight alerts) and histograms.   I recommend you set up your camera to be able to view the histogram along with the JPEG.

[At the end of this post there is a Link to a printable PDF copy of the text of this blog]

In my last blog I shared this photo and its associated histogram below.

As I noted then, the photo was underexposed.

Below you will see a series of photos and the associated histograms, each with a different exposure. I had set my camera to shoot in AE Bracketing mode.  Here the camera shoots a series of photos. In this case, three photos are each 1 exposure unit apart (more about how and why you might want to use AE Bracketing in a future blog).

1 Stop underexposed

Normal Exposure

1 stop overexposed

As you can see from the above photos as each gets brighter the corresponding histogram shifts to the right. Ideally, you would like to see the histogram all the way across, but that doesn’t happen all the time. The shape of the histogram is a function of the tones (bright/dark areas) in the photo. I’ll provide a few examples at the end of this blog, so you can better understand this concept.

Now, looking at both the 1 stop overexposed and the normal exposure photo, I decided that the correct exposure should be somewhere in-between. I made the adjustment you see below on my computer using Lightroom/Adobe Camera Raw. I could have accomplished the same correction when I shot the original photo by using the exposure compensationplus-negfeature on my camera. More about the use of exposure compensation in a future blog.

OLYMPUS DIGITAL CAMERA
Corrected Photo + 1/2 exposure unit.

corrected-histogram

Other photos and histograms examples:

The Tybee Island Lighthouse photo is correctly exposed. Notice how the histogram fills almost the entire width.

In this photo, taken at Mount Saint Michel in France, the area on the left side of the histogram corresponds to the dark areas surrounding the opening.  As you see, this area is along the vertical axis and indicates there is some loss of shadow detail.  Here’s another opportunity to use exposure compensation in the field. If you can’t make the correction in the field there is some good news.  It is possible you can recover some of the shadow detail using Lightroom/Adobe Camera Raw or other photo processing software.

The Patton Memorial in Avranches, France is over-exposed.  Here you see the histogram is shifted way to the right.  When this occurs you need to make the adjustment using the exposure compensation feature on your camera.  Why? Because it is almost impossible to recover highlight detail using photo processing software.  You always need to try to expose your photos to the dark side so that the highlights are not over-exposed as in this photo.

 Link to PDF Histograms: A Simple Explanation

Below I’ve provided two links so that you can explore histograms further.

Using histograms in photography from Picture Correct

Using Histograms in Digital Photography from Picture Correct.

The Basic Camera Functions You Need to Turn Off or Enable.

dsc00668I’ve been teaching basic digital photography for a number of years and have students with just about every make and model camera. I have come to the conclusion that the camera menus are getting more complicated. The features are more numerous than it is practical to learn without many months/years of study. In fact, some features remain automatically activated even when you shoot in other than full automatic mode. These observations were recently magnified when I taught a couple who had just purchased a new camera and were heading to Africa for their honeymoon in a little over two weeks.  I was able to spend a total 3 hours with them over two evenings.

img_8685
1/20 Sec. @ f 3.5 ISO 3200

This photo is one of the first pictures taken with their new camera in full automatic mode. The photo is underexposed. The histogram shows that clearly!**

histogram

In addition the photo is blurry.  Why?  The shutter speed of 1/20 sec that was determined by the automatic mode is too slow for the camera to be hand-held. I always recommend not shooting with the camera hand-held at any speed less than 1/50 or 1/60 sec.  This works well for a normal lens (18-55 mm), but for telephoto lenses you should use a speed at least equal to the 1/focal length (i.e. 150 mm focal use 1/150 sec, 500 mm use 1/500 sec).

My advice to all students is turn off the automatic features.  The full automatic mode will, for some percentage of the time, will  give you unacceptable results as the photo of the bull dog shows.

OLYMPUS DIGITAL CAMERAI emphasize the use of aperture priority mode as it allows you to better control the depth-of-field (DoF). By controlling DoF you can take control of what is in focus and what is not in focus.  Controlling DoF allows you to blur the background and make your subject standout, as can be seen in the photo to the left.

In aperture priority the camera automatically sets the shutter speed based of the aperture selected and ISO you have chosen. If the photo is too dark or blurred, you then adjust the ISO higher to get a correctly exposed and sharp photo.  To do this you will need to disable Auto ISO (consult your camera manual or search the internet for a video on how to do this).

Today’s DSLR cameras provide sophisticated focusing capabilities with as many as 11 to 153 individual points determining the image focus.

I prefer more control and recommend to my students to use a single point centered in the viewfinder.  The image to the right was supplied by one of my students and provides a good illustration of when you don’t have the camera set to a single focal point. The woman behind the children is in sharper focus. Clearly the camera was set to multi-focus point mode. In using the single point focus, you align the center point to your subject then depress the shutter button half-way locking in the exposure. While still holding the shutter button you re-position the camera to the desired composition and then full depress the button to complete taking the picture.

I was very pleased to see how good the couple’s photos turned out.  I can see that they made a real effort to follow the basic techniques we had worked on together. Below are some of the photos they shared with me.  All were shot using aperture priority.  I am impressed how sharp and well exposed their photos are under different lighting conditions, even the one that was shot at 1/20 sec is good.  They really did a great job.

dsc03331
1/125 sec @ f /6.5 ISO 16000
dsc01696
1/640 sec @ f /9.0 ISO 400
1/125 sec @f/6.3 ISO 400
1/125 sec @f/6.3 ISO 400
1/20 sec @f/6.3 ISO 200
1/20 sec @f/6.3 ISO 200

 

 

 

 

 

 

 

 

 

 

 

Private/Semi-private lessons are available see Classes

** In a future blog, I’ll be explaining how to utilize the histogram to improve your photos.

Photographing Children

f3.5, 1/250 sec. Lens FL 40 mm, ISO 100, Distance to subject 5 ft.

 

Recently I conducted a private lesson with a student who has an 18 month old and was struggling to get good pictures.  Several of my students over the past year have had the same issue.  I thought maybe it was time for advice on what I’ve learned.

I recalled a question I’ve gotten several times over the last 10 years from relatives and friends, “How did you get such good pictures of your granddaughter?  Everything I take is blurred and out of focus”.

The answer is, some of it just luck, but having the camera set up correctly surely helps.

  1. Set your camera’s Auto Focus mode to continuous focus (CF).
  2. Set your Focus point to a single point centered in the viewfinder.
  3. It’s also good to set the camera to multi-exposure mode.  In doing so, as long as the shutter button is depressed fully, the camera will continue to take photos.  While this will fill your memory card more quickly I have found that at times I’m able to get better photos.
  4. Set your camera shooting mode to speed (Tv/S depending on your manufacturer).
    In this mode your camera will set the aperture automatically.
  5. ISO Setting to 200
  6.  Set your shutter speed between 1/250-1/500 of a second to start. For indoor photos you likely need to use a flash and/or raise your cameras ISO setting to 400/800 or higher. (Note: the owner’s manual will provide details as to setting up your camera for higher ISO setting when using a flash).
  7. With your camera set as in 1-6 above, you can then move your camera following your child’s movements. The camera will maintain the correct focus as long as the focal point is on the child.    Remember this only works when you have the shutter button depressed halfway. Then, when you are ready to take a photo, you depress the shutter button fully.

 

Remember to get down and take the photos at your child’s level.

img032
A scanned copy of a 40+ year old photo of my son.

The image below was supplied by one of my students and provides a good illustration of when you don’t have the camera set to a single focal point. The woman behind the children is in sharper focus, clearly the camera was set to multi-focus point mode.

 

Photo Processing Software

Recently one of my former students, Jonathan, inquired about photo processing software.  He was particularly interested in Adobe Lightroom, but was concerned about the best way to get started.  He thought it looked too complicated, which at some level I would agree, however once you understand the basics most of the image enhancements and corrections you need to do routinely become second nature.  When I began using a digital camera over 15 years ago, I used both Photoshop Elements and Paint Shop Pro.  I eventually, after learning the basics, locked in on Photoshop Elements, then after several years Adobe Lightroom and Photoshop.  I have a colleague who has used Paint Shop  and his work is simply brilliant!   My advice is to start with Photoshop Elements, it relatively easy to learn. The following link is a little out dated it does outline several other choices. Beginner photo editors for windows.  While the link is for Windows, several of the programs listed also work on a MAC.  I also understand, as photographer friends have told me, that Snapseed works well on both the iPad, Kindle and Android Tablets, but frankly I have no experience editing on these platforms, as I prefer to use the computer for all photo processing.

Adobe Lightroom provides an excellent way of cataloging and non-destructively processing your photos. This link provides a short summary of the best-non-destructive editing-software-for-photography from Photographylife.com

 

Haze Removal

One of my former students Keli K., sent me a few photos that she took on her vacation to the Grand Canyon.  I was very pleased to see how well the photos were composed and that the overall exposure was close. Correct exposure is one of the items I teach in my classes. However, each of the photos could be made better from a little post processing in Adobe Camera Raw/Lightroom.

Original Image:

Roadtrip

Corrected Image:

Roadtrip-Corrected-2

See red ovals for the location of the controls used.

All corrections were accomplished in the basic panel of Adobe Camera Raw or Lightroom:

  1. Auto Correct Tone (digital cameras generally bias the exposure to the left by about a 0.5 exposure unit, this corrects the exposure)
  2. Move black slider to the right to remove lost shadow details.
  3. Adjust Clarity, Vibrance and then adjust Saturation slightly to increase overall color.

Clarity adds contrast to the midtones, and makes your image look sharper, even though it doesn’t actually add sharpening.

Vibrance is a smart-tool which  increases the intensity of the muted colors and leaves the well-saturated colors alone.  Vibrance also prevents skin tones from becoming overly saturated and unnatural.

Saturation is a uniform increasing in  intensity of all colors in your photo regardless of the starting point of the colors. This can result in clipping, (over saturation of certain colors resulting in loss of detail in those areas). Over saturation causes skin tones to look too orange and unnatural.

.