2017 PHOTOCHALLENGE, WEEK 34: Starbursts

This week’s challenge is to capture a starburst in your camera. Starbursts are also known as sun stars and sun flares. They are created by the diffraction of strong points of light, e.g. the sun, the full moon, street lights, candles, etc. Some people love starbursts in photos and some do not, so the goal of this challenge is to learn how to control them when you are out taking photos. Important: Protect your eyes – never look directly at the sun! I use Live View on my camera for any shots pointed into the sun.

Sunrise over Independence Monument “Sunrise over Independence Monument” by Jeanie Sumrall-Ajero

As I mentioned, starbursts are created by the diffraction, i.e. the bending of light waves, of strong points of light. It happens when a wave hits an obstacle or very small opening. In fact, the smaller the opening, the greater the diffraction. So think about the things we have control of when dialing in the exposure of a shot: shutter speed, aperture and ISO. Which one of these has to do with the opening? The aperture, of course!

Backlit Leaves “Backlit Leaves” by Eric Minbiole

With a DSLR, we can control the amount of starburst with the aperture setting. The higher the f-stop number (i.e. the smaller the opening), the greater the starburst effect. I find that it usually starts appearing around f/16 (though it may appear with smaller f-stop numbers on long exposures).

Inner City Viaduct_session2a “Inner City Viaduct_session2a” by Stephanie Adams

In order for the starburst to show up best, it’s important that there be some contrast between the point of light and the surrounding scene. In my lead photo you can see the star rays appear much more pronounced against the landscape than the bright sky. In the nighttime photo below, pretty much the entire background was dark, so all of the starbursts appear symmetrical.

Behind the Bandstand
“Behind the Bandstand” by Jeanie Sumrall-Ajero

If you are using a point-and-shoot camera that doesn’t allow you to adjust the aperture (such as a phone), you’ll have to do a bit more experimentation but it should be possible to capture starbursts. Since you don’t have the option of adjusting the size of the opening, you’ll need to find an obstacle to diffract the light. In the experimenting I did with my phone, I found that something solid like a tree trunk, rock formation, building, statue, etc. worked well. The trick is to partially obscure the light with the subject so that part of it needs to “bend” around the object. When using this technique, the intensity of the starburst will vary among different cameras and looks a bit more diffuse than a starburst created with a DSLR.

phone-camera-example
Starburst taken with Samsung Galaxy S4

As always, don’t forget the fundamentals of photography when capturing your starburst photo this week. Think about composition, lighting and of course proper exposure. If your scene has high contrast (e.g. you are taking a photo into the sun), you may want to use HDR to capture detail in both the shadows and the highlights of your image. Don’t forget to use histograms to dial in the correct exposure. The only thing special about the histograms this week is that they will most likely show a (possibly small) spike on the right side since the brightest part of the starburst will be pure white without any detail.

Starburst photo histograms

For more information on how to capture starbursts, the following links are particularly helpful in explaining how and why the effect is created:

6 Tips to Create Compelling Star Effects, Sun Stars, Starbursts, or Sun Flares in Your Photographs

HOW TO CAPTURE STARBURSTS IN YOUR PHOTOS (includes video)

This week’s challenge:

  • Capture a starburst in camera by finding or creating a composition with strong point(s) of light.
  • Important: Protect your eyes if the sun is your light source! Never look directly at the sun – not even through the viewfinder on a DSLR. Compose your shot using Live View on the LCD of your camera.
  • Do not use an app (or other post-processing) to add a starburst effect.
  • Please post the histogram for your photo in the comments under your post.

Our friendly community guidelines are pretty simple:

  • Post one original photograph (Your Image) shot each week per theme posted on this blog to Google+Facebook, or Flickr (or all three). Tag the photo #photochallenge and #photochallenge2017
  • The shot should be a new shot you took for the current weekly theme, not something from your back catalog or someone else’s image.
  • Don’t leave home without your camera. Participating in the 2017 PhotoChallenge is fun and easy.
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2017 Photochallenge Week 27: High Key

This week’s challenge is to capture a high key photo. Technically “high key” means that the majority of the tonal range of the image is in the light tones. Please note that high key is not simply an over-exposed image! Just as with low key images, it takes some thought and planning to capture an effective high key image. For this challenge, I want you to set up and capture a high key image in your camera, not create one from a “normal” photo in post-processing.

Great Blue Herons - High Key “Great Blue Herons – High Key” by Jeanie Sumrall-Ajero

High key photography is all about the lighting. It’s challenging because it requires you to overexpose the background while keeping the subject properly exposed. Interestingly, the lighting is somewhat similar to that of silhouette photos: the background needs to be much brighter than the subject. The goal is to open up (i.e. lighten) the shadow tones of the subject without blowing out the highlight detail AND have a white background behind the subject. While you might be tempted to use a subject that is white or light colored to create your high key photo, you will find it easier to capture a white background if your subject is darker.

If you have a drab cloudy sky or fog or even snow, you may be able to capture a high key wildlife image. Have you ever tried taking a photo of a bird against a cloudy sky? If your camera is set to Auto, it usually turns the bird into a silhouette, right? But if you up the exposure compensation by 2-3 stops, you will find that the sky turns pure white and the bird looks properly exposed. A similar thing happens in snow or fog. So if you are lucky enough to have inclement weather this week, it might be the ideal time to try a high key wildlife shot.

Dice “Dice” by Eric Minbiole

High key photos have an upbeat, happy feel to them. That’s why you often see them in product and stock photography. In fact, take a look at all of the product photos on Amazon – they are all “high key” photos! If you sell things online, this is a really good skill to have in your photographic toolkit.

Anne-Charlotte - High Key “Anne-Charlotte – High Key” by Antoine Robiez

High key portraits are also extremely popular. Most high key portraits are created in a studio with 4-5 light sources – two are used to light the background and 2-3 are used to light the subject. However, it is entirely possible to create a high key portrait using natural light. You can either have your subject in the shade with the background in full sun or you can position your subject with the sun behind them. Check out the links below for more details if you want to try this.

Wheat field “Wheat field” by Sarah Horrigan

High key landscape photos can be tough to find and capture in the camera, but they are very effective when you do. Again if you have snow or fog or overcast skies in your weather forecast this week, you might get lucky. This is probably the most difficult subject for the challenge this week because it is so dependent on the right lighting conditions. Remember, I don’t want you creating a high key effect in post processing – I want you to capture it in the camera as best you can.

Of course no exposure related challenge would be complete without taking a look at the histograms of high key photos. Notice how they are all heavily weighted to the right? In fact, a couple of them are stacked up against the right side. This indicates that the highlights are blown-out, which is exactly what we want in this case because it ensures that our background is pure white. (Note that landscape photos with no obvious distinction between subject and background won’t have blown-out highlights but the majority of the histogram still in the right half of the tonal range.)

high-key-histos

Another thing to notice is that all of these histograms extend pretty far to the left. That shows that the images have high contrast. (Not all high key images are high contrast, but a large percentage are.) Thus, you can use the histogram on your camera to tell you whether you’ve captured a high key image. You might also find it useful to turn on “highlight alerts” in your camera’s menu if you have that option. This will tell you when you have successfully blown-out the background, but will also warn you if you’ve gone too far and have blown-out the highlight detail of your the subject as well.

This week’s challenge:

  • Capture a high key photo in the camera.
  • Do not simply over-expose a normal scene and call it high key. I want you to find or create the lighting necessary to capture a well-exposed, high key image in the camera.
  • You can tweak the exposure in post-processing (in fact, you pretty much have to if you shoot RAW), but I want you to focus on capturing the correct exposure in the camera which means the histogram should be mostly in the right half of the histogram and likely even stacked up against the right side.
  • Please post the histogram in the comments under your photo.

For more information on how to take high key photos, I found the following links particularly helpful while doing research for this challenge:

How High Key Photography Works: 3 Must Know Tips
Understanding Histograms – Low-Key And High-Key Images
High-Key Nature Photography
High Key, Low Key
4 Tips for a Perfect White Background in High Key Photography (including a video that explains how to position lights for portraits in a studio setting)

If you want to try taking high key portraits in natural light, I found the following two videos helpful:

Natural light photography tips – High key portraits under a tree canopy
Outdoor GOLDEN HOUR Portrait Photography Tips – Using Natural Light

Don’t worry if you don’t have any studio lights or flash units. I did a little experimenting in front of a window and came up with a setup that should work for anyone with a small subject such as a product, figurine or flower. (You could even use this setup for a portrait if you used a larger piece of fabric.) I taped some white fabric (it would be better to press the wrinkles out or you could also use white paper) to a window with the sun shining through and placed my subject (a silk flower) in front of it. The sun made the white fabric very bright and in turn, the fabric acted as a shade for the flower so that it was much darker than the fabric behind it – the perfect setup to blow-out the background! I also used a reflector to bounce some light onto the front of the flower to fill in the dark shadows. (You could use another piece of white paper or cardstock instead of a reflector.)

I’ve included a photo of my setup below along with the resulting high key photo of a silk rose. I was very happy to discover that it required almost no post-processing, so this setup should work for just about everyone assuming you have sun – and if you don’t, then use the cloudy sky as your background. It should produce a similar result.

window-setup

Our friendly community guidelines are pretty simple:

  • Post one original photograph (Your Image) shot each week per theme posted on this blog to Google+Facebook, or Flickr (or all three). Tag the photo #photochallenge and #photochallenge2017
  • The shot should be a new shot you took for the current weekly theme, not something from your back catalog or someone else’s image.
  • Don’t leave home without your camera. Participating in the 2017 PhotoChallenge is fun and easy.

2017 PHOTOCHALLENGE, WEEK 22: SILHOUETTES

The challenge this week is to capture a silhouette in the camera. In silhouettes, the subject is black with little to no detail and the rest of the photo is normally exposed. (This is almost the exact opposite of our previous low key photo challenge where the subject was dramatically lit and the background was mostly dark.) Because the subject has no detail in a silhouette photo, it’s important that the subject itself be recognizable and maybe even tell a story.

Rocky Mountain Dawn
Rocky Mountain Dawn by Jeanie Sumrall-Ajero

The trick to getting a good silhouette is that the subject needs to be backlit (with the front in shadow) and the background needs to be lighter than the subject. You’ve probably run into this situation when trying to take photos of a tree or a bird against a cloudy sky. Often times the sky turns out light gray or even white and the subject remains black with almost no detail. This week we are trying to achieve this effect on purpose! If you have a nice sunrise or sunset, that can add some beautiful color to your silhouette photo.

Blackbird Silhouette
Blackbird Silhouette by Jeanie Sumrall-Ajero

City skylines, interesting architecture, amusement parks, trees, etc. can all be great subjects silhouetted against the sky. If you don’t have a beautiful sky to work with, you can create dramatic black and white silhouette photos instead. If you are taking photos outside with human subjects, I recommend that you find a good composition first and then place your subject in the frame. Positioning the camera low to the ground (or your subject(s) up on a hill or on a wall or table) will ensure that your subject doesn’t have a horizon line running through them in the resulting photo.

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Untitled by Khánh Hmoong

In addition to using the sky as your background, you can use sunlight reflected on water. Notice that the children in the following photo are below the horizon line and silhouetted against the water. You could also use boats, birds, docks, bridges, etc. as subjects silhouetted against water.

... silhouettes
… silhouettes by Carlo Scherer

Street photography is another possibility. The trick here is that you need to find a wall that is in bright light while the subject is in shade in order to capture a silhouette in the camera.

[ broken symmetry ]
[ broken symmetry ] by Riccardo Romano
If you aren’t able to get outside this week, think about composing a silhouette photo in a window or open doorway. Remember the exposure issues in our Windows Looking Out photochallenge earlier this year? Use that to your advantage this week! Expose for the outside light and anything on the inside will fall into deep shadow (as long as the subject doesn’t have any inside light shining on it.)

Waiting at the window
Waiting at the window by Lovro67

How do you know when you’ve captured a well-exposed silhouette photo? The histogram! For silhouettes you want the black clipping, i.e. stacked up against the left side of the histogram. Unlike low key photos though, it is your subject that is being clipped and the rest of the image can fall anywhere in the full range of the histogram. Even though the histogram shapes of the example photos are widely different, there are two things in common to note among the histograms:

  • they are all stacked against the left side which indicates a nice black silhouette with little to no detail, and
  • they extend the full range of the histogram indicating good contrast and exposure.

histos

This week’s challenge:

  • Capture a silhouette photo in the camera. This means finding or creating the correct lighting conditions with the light behind the subject. (You do NOT need to shoot directly into the sun, but if you do please protect your eyes!)
  • You can tweak the exposure in post-processing (in fact, you pretty much have to if you shoot RAW), but I want you to focus on capturing the correct exposure in the camera which means the histogram should be stacked up against the left side and extend across the entire range of the histogram for good contrast.
  • Please post the histogram in the comments under your photo. They will be wide ranging this week and it will give us practice “seeing” what they tell us.

For more information on how to take silhouette photos, I found the following links helpful:

How to Photograph Silhouettes in 8 Easy Steps
14 Tips for Shooting Stunning Silhouettes
Silhouette Photo Tutorial: 7 Tips for Success (video – outdoor silhouette portraits using an iPhone)
“5 Tips for Amazing Silhouettes” with Erika Thornes (video – outdoor silhouette portraits)
One Light Silhouette: Take and Make Great Photography with Gavin Hoey (video – indoor studio setup and process)

Our friendly community guidelines are pretty simple:

  • Post one original photograph (Your Image) shot each week per theme posted on this blog to Google+Facebook, or Flickr (or all three). Tag the photo #photochallenge and #photochallenge2017
  • The shot should be a new shot you took for the current weekly theme, not something from your back catalog or someone else’s image.
  • Don’t leave home without your camera. Participating in the 2017 PhotoChallenge is fun and easy.

2017 PHOTOCHALLENGE, WEEK 15: LOW KEY

Your challenge this week is to capture a low key photo in the camera. “Low key” means that the majority of the tones in the image are in the shadows. “In the camera” means that I don’t want you creating the low key effect in post processing. Low key does not mean low contrast. In fact, the most effective low key images have high contrast. It takes thought and intention to capture a dramatic low key image.

2017WEEK15-lead-photo-1024px
Peruvian Lily by Jeanie Sumrall-Ajero

Low key photography is all about the lighting. At first you might be tempted to simply capture an underexposed image and call it low key because it is dark, but that produces a low contrast image and is not what this challenge is about. Instead think about lighting only the parts of the subject that you want to include in the photo and letting the rest fall into dark shadow with little or no detail. The shadows dominate the photo but don’t define it.

365.338 - Low-Key Gaj
365.338 – Low-Key Gaj by Al Ibrahim

There are many options for subjects in low key photography. Portraits are particularly popular. They tend to mimic the Chiaroscuro style of painting from the Renaissance and Baroque periods. Chiaroscuro is created by light hitting the subject from a particular direction. It is the reflection of the light on the subject – not the light itself – that is captured. Many modern day photographers create this using a single flash unit, but it is entirely possible to create the effect using either natural light or some other form of directional light: flash light, computer/tablet screen, etc.

Mate en clave baja (Low key)
Mate en clave baja by Dani Vázquez

Macro and still life images can really come alive when captured low key. Have you ever been out on a walk and noticed a single flower being lit by sunlight while the area around it is in the shade? This is the perfect setup for a low key macro shot. Of course you can create that sort of set up in a studio as well. The trick is to shine a directional light only on the subject (not on the background) so that you get a nice dark or even black background behind your subject.

Rockwell Falls on a Rainy Day
Rockwell Falls on a Rainy Day by Eadie Escobar Minbiole

Low key landscape photos can be tougher to find and capture in the camera, but they are very effective when you do. The trick is learning to see how the light plays off the landscape and capturing that instead of capturing the source of the light. This is probably the most difficult subject for the challenge this week because you don’t have control over the light and I don’t want you creating the low key effect in post processing – I want you to capture it in the camera.

So how do you know that you’ve captured your photo correctly in the camera? With the histogram, of course! Let’s take a look at the histograms of the above photos. Notice how they are all heavily weighted to the left? In fact, the ones with black backgrounds are stacked up against the left side. If you remember in the past couple of histogram challenges I’ve encouraged you to avoid stacking up against the left or right sides to avoid losing detail in the shadows or highlights. But in the case of many low key photos with pure black backgrounds, the whole point is that there is no detail in the shadows and that is reflected in the histograms being stacked up against the left side.

histograms

Also notice that all of these histograms extend pretty far to the right. That indicates that the images have high contrast. (The histogram for a low contrast image would not extend much past the middle of the histogram range.) Thus, you can use the histogram on your camera to tell you whether you’ve captured a low key, high contrast image: heavily weighted towards the left but extending almost all the way to the right.

This week’s challenge:

  • Capture a low key photo in the camera.
  • Do NOT simply reduce the exposure compensation of a normal scene and call it low key. This will produce a low contrast image. I want you to capture a high-contrast, low key image in the camera.
  • Do NOT use post-processing to make a normally exposed photo look low key. The goal is to find or create a scene that is already low key and capture it in your camera.
  • You don’t need to post the histogram this week because I figure by now you know how to find it, but if you would like to post it please do as I find it helps everyone to become more familiar with them.

For more information on how to take low key photos, I found the following links particularly helpful while doing research for this challenge:

The Complete Beginner’s Guide to Shooting Low Key
Low-Key Photography for Beginners – Enter the Dark Side
How to Create a Low Key Portrait using Natural Light
Low Key Photography Tips
Macro: How to Take Low-key Close-ups
20 Outstanding Low and High Key Photographs

Our friendly community guidelines are pretty simple:

  • Post one original photograph (Your Image) shot each week per theme posted on this blog to Google+Facebook, or Flickr (or all three). Tag the photo #photochallenge and #photochallenge2017
  • The shot should be a new shot you took for the current weekly theme, not something from your back catalog or someone else’s image.
  • Don’t leave home without your camera. Participating in the 2017 PhotoChallenge is fun and easy.

2017 PHOTOCHALLENGE, WEEK 9: RED

Everyone did a great job in our last histogram challenge! However, I noticed some confusion in the comments that I thought would make for a good follow-on challenge. Before we go any further though, I want to reiterate that the shape of the histogram is not important. There seemed to be some confusion about this. The truth is that there is no ideal shape for a histogram. What is important is that the width of the histogram should typically span the entire tonal range without blocking up against either side. (There are of course exceptions to this rule and we’ll explore some of those later in the year.)

rmnp-with-histo

Rocky Mountain Rainbow – Jeanie Sumrall-Ajero

Some of you followed this guidance perfectly in the last histogram challenge and yet you felt your image looked overexposed. You’ll be happy to know your eyes were not deceiving you! The answer can be found in the RGB (colored) histograms. In my last challenge I asked you to focus solely on the Luminosity histogram. That works fine for most photos, but can be inadequate for photos with a strong color cast (such as a sunset) or a predominant color (such as a red flower) as in the example below:

overexposed-red-with-luminosity-histo

Hopefully the above photo looks overexposed to you. The red tones look blotchy without a lot of detail. However the Luminosity histogram looks fine – maybe even a bit underexposed. To figure out this apparent discrepancy, let’s take a look at the individual RGB histograms. (The RGB histograms give us information about the individual red, green and blue colors that make up every color in your photo.) It doesn’t take a whole lot of sleuthing to discover that the Red histogram has a spike at the far right side, i.e. detail is blown out in the red tones of the photo.

overexposed-red-with-rgb-histo

Blown out detail in the red tones is a fairly common issue with digital cameras. Luckily it’s easy to adjust for it once you know how to identify the problem. If you are ever concerned that you’ve lost detail in your photo, take a look at the RGB histograms. If you see a spike on either side of any of the histogram, you’ve found the culprit. To correct the issue, you simply need to adjust the exposure compensation on your camera until you no longer have any spikes blocked up against the sides of the histograms.

red-flower-proper-with-histos

Anthurium – Jeanie Sumrall-Ajero

Note: The spike on the left side of the histograms above is on purpose. This is one of those exceptions to the rule that I mentioned above. In this image I wanted the background to be solid black, i.e. no detail. So in this case, the spike tells me that I achieved that effect. The important aspect of the histograms above is that there are no spikes at the far right side of the histograms, so no detail has been lost in the lightest parts of the image.

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Optional info: If you’d like to know the technical details behind why the Luminosity histogram sometimes fails to give a complete picture, read on. If not, skip down to the next line of asterisks for this week’s challenge. This is not required reading. 😉

To better understand why the Luminosity and Red histograms look so different, let’s compare the color and grayscale versions of the overexposed photo. In particular, focus on the two areas where the red detail is most blown out.

overexposed-red-vs-gray

If we look at the gray (luminosity) value of those two points, it should be obvious that they are squarely in the darker mid-tones, i.e. nowhere near white.

midtones

If you think about it, this makes sense. Imagine a red color and then imagine that same tone in B&W. It would not be white or anywhere close to white, right? That is why the Luminosity histogram is insufficient as the only tool for determining proper exposure. The Luminosity histogram reflects only the gray values of an image, but it is entirely possible that a single color may get blown out even though the color itself is in the middle of the Luminosity range. Luckily our cameras give us the tools we need to spot this problem so that we can make adjustments while we’re taking our photos: the RGB histograms.

 

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If you haven’t already guessed, the challenge this week is to take a photo of something RED and also post both the Luminosity and Red histograms in the comments:

  • At the very least, the color red should dominate the photo. If desired, it might completely fill the frame.
  • Think “bright red”. While there are some stunning images with deep red tones, this week I want you to focus on making the red tones as bright as possible without losing detail.
  • You will have an easier time if your red object is not shiny, but your choice of subject is up to you.
  • Please post both the Luminosity and Red histograms in the comments under your photo. (You can post the Green and Blue histograms as well if they are part of the same display as the Red histogram.)

What you will need to complete your challenge:

  • A camera with the ability to show the RGB histograms when reviewing photos on the LCD –or– a phone app which does the same. Some cameras show the RGB histograms right along with the Luminosity histogram, but other cameras show them on a different screen. You’ll need to look in the instructions for your camera. Here are some iPhone apps and here are some Android apps. (Be sure to read the app details to make sure it has a histogram. A “live histogram” means that the histogram is active while you take the photo, but may not be viewable afterwards. If that’s the case, you can simply take a screenshot to capture the histogram while your camera app is on.)
  • Knowledge of how to change the exposure in your camera or camera app. This may be needed if you find that your histogram is not optimal and you need to adjust your exposure. If you don’t know how to do this, look up “exposure compensation” in the manual for your camera.
  • The easiest way to capture the histograms on your camera LCD is to simply take a photo with another camera.

The rules are pretty simple:

  • Post one original photograph (Your Image) shot each week per theme posted on this blog to Google+Facebook, or Flickr (or all three). Tag the photo #photochallenge and #photochallenge2017
  • The shot should be a new shot you took for the current weekly theme, not something from your back catalog or someone else’s image.
  • The posted image should be a still image or an animated GIF, not a video.
  • Don’t leave home without your camera. Participating in the 2017 PhotoChallenge is fun and easy.

2017 PHOTOCHALLENGE, WEEK 6: PROPER EXPOSURE USING THE HISTOGRAM

My focus this year will be on Proper Exposure: what it is and how to achieve it. Have you ever wondered why some photos seem to “pop” and grab your attention while others don’t? There can be many reasons why, but often it’s a matter of proper exposure. Proper exposure maximizes contrast and the human eye is drawn to contrast.

Each of the following images has a problem with the exposure. The first image is underexposed, i.e. there aren’t any light pixels. The second image is overexposed, i.e. there aren’t any dark pixels. The third image isn’t too light or too dark, but it looks flat because the darkest parts are just dark gray (not black) and the lightest parts are light gray (not white) resulting in an image that looks somewhat lifeless. This can sometimes happen in shade or cloudy skies.

three-problems-no-histo

In general, a properly exposed image means that lightness values run the full gamut from black to white (instead of dark gray to light gray). There are always exceptions to the rule, but this is very often the case.

color-flowers-proper-exposure

Rainbow Bouquet – Jeanie Sumrall-Ajero

But how do we know for sure when we have the proper exposure? Simply relying on how the photo looks on your camera LCD or phone does not always give you a true representation of the photo. Luckily there is a tool called the Histogram that gives you the information you need at a glance.

What is a histogram? It’s simply a bar chart. As an example, imagine that we want to create a tile mosaic of a sunflower. Because we’re focusing on exposure (i.e. luminosity or lightness values) let’s make the image B&W so that it’s easier to “see” the luminosity values. To further simplify things, let’s reduce the number of lightness values to 10. If we were to count the number of tiles of each value and display those counts in a bar chart, it would look like the chart below:

sunflower-mosaic-with-histo

This is the essence of a histogram: a bar chart which shows the number of pixels in a photo of a particular luminosity value (which runs along the bottom of the chart). The difference is that the histogram of a photo has 256 luminosity values – 0 (black) to 255 (white) – instead of just 10. However if you compare the histogram of the photo with the simple bar chart from the mosaic image, you can see that the basic distribution is the same.

sunflower-bw-full-with-histo

It’s important to realize that there is no ideal shape for a histogram, i.e. you are not trying to get a “bell curve”! The histogram is a tool to help you understand how well exposed a photo is. Looking at the histograms of the three images we started with, you start to see what a histogram can tell you. When the histogram is weighted heavily to the left, the photo is typically underexposed. When it is weighted heavily to the right, the photo is typically overexposed. When it doesn’t stretch across the entire luminosity scale (from 0 to 255), the photo lacks contrast and appears flat.

three-problems-with-histo

While there is no ideal shape for a histogram, in general the most eye-catching photos have a histogram that covers the entire luminosity scale from 0 (black) to 255 (white). Note that the histogram for the good exposure is more spread out than the low contrast one. The left (dark) and right (light) sides of the histogram are more filled out which indicates that the dark areas of the image have gotten darker and the light areas have gotten lighter, thus increasing the contrast.

good-exposure-with-histo

There are two exposure issues that cannot be corrected in post-processing: clipped (aka blown-out) shadows and highlights. “Clipped” essentially means that there is no detail in the very darkest or very lightest parts of your image. Referring to the histogram when you review photos on your camera can help you avoid both situations! If a histogram has a tall spike pushed up against the right edge, your photo has blown-out highlights that you will not be able to recover in post-processing. I’m sure you have seen this in landscape photos where clouds look like white blobs in the sky without any texture in them. Alternatively, if a histogram has a tall spike pushed up against the left edge, your photo has blown-out shadows. Of course, you can have both of these situations in the same photo.

In the photo below you can see that the vast majority of the image is very dark and the histogram shows that with a large spike on the left. In the upper right corner however, there is a section of the sky that is pure white and has lost detail. You can see that in the smaller (but tall) spike on the very right of the histogram. This is a great example of what NOT to do, but at times it is unavoidable. (We’ll be covering how to handle this type of exposure challenge later in the year.)

clipping

The human eye does not easily forgive the loss of detail in the lightest parts of a photo and it is best to avoid clipped highlights unless your goal is to purposefully make a gray sky look white. The human eye is more forgiving of clipped shadows, but don’t expect to be able to lighten those shadows to pull out any detail in post. It is best to avoid clipping on both ends of the histogram!

I encourage you to play and experiment with a bunch of different photos this week. I’ll be referring to histograms throughout my challenges for the rest of the year so you’ll want to get comfortable with them. If you want to read more about them, here are some helpful articles. Remember we’re focusing on the Luminosity Histogram in your camera, not in post-processing (though the concept is the same).

The challenge this week is to take and post a well-exposed photo and also post the histogram in the comments:

  • Take your photo OUTDOORS during daylight hours and do not include any sky in your photo. (Sometimes sky can throw off the exposure. We’ll work on that in a future challenge.) If you have sun, I encourage you to take a photo both in sun and in shade to see how that affects your exposure (and histogram).
  • The actual subject is wide open this week, but don’t forget all of the other rules for good composition, depth-of-field, etc. This might be a good week for macro since you can’t have the sky in your image.
  • Post-processing is fine, but the goal is to get the exposure as perfect in camera as you can. If you do post-process, it would be interesting to see both the before and after histograms for your image.

What you will need to complete your challenge:

  • A camera with the ability to show a Luminosity Histogram when reviewing photos on the LCD –or– a phone app which does the same. Here are some iPhone apps and here are some Android apps. (Be sure to read the app details to make sure it has a histogram. a “live histogram” means that the histogram is active while you take the photo, but may not be viewable afterwards. If that’s the case, you can simply take a screenshot to capture the histogram while your camera app is on.)
  • Knowledge of how to change the exposure in your camera or camera app. This may be needed if you find that your histogram is not optimal and you need to adjust your exposure. If you don’t know how to do this, look up “exposure compensation” in the manual for your camera.
  • Knowledge of how to take screenshots to capture the histogram of your photo. If you don’t know how to take screenshots (aka screen captures), you can do a search for your phone model or operating system (Windows or Apple) along with “screenshot” to find instructions for how to do it. Or you can simply take a photo of the histogram on your camera LCD or your computer screen.

The rules are pretty simple:

  • Post one original photograph (Your Image) shot each week per theme posted on this blog to Google+Facebook, or Flickr (or all three). Tag the photo #photochallenge and #photochallenge2017
  • The shot should be a new shot you took for the current weekly theme, not something from your back catalog or someone else’s image.
  • The posted image should be a still image or an animated GIF, not a video.
  • Don’t leave home without your camera. Participating in the 2017 PhotoChallenge is fun and easy.

2016 PHOTOCHALLENGE, WEEK 52: GUEST POST – TIME STACKING

GUEST POST – TIME STACKING by Jeanie Sumrall-Ajero

I’ve been fascinated by time stacked images for some time now so it seemed like a great idea for a challenge. What is time stacking? Essentially it is a time lapse except all of the frames are layered on top of one another in just one image instead of creating a video. The technique is commonly used for astrophotography (star trails), car trails and waterfalls but it can also be use to create amazing landscape images.

Sunset - Time stacking example

Layering a series of landscape photos containing clouds gives a wonderful sense of movement to a landscape image. This image is a time stack of 56 photos taken 10 seconds apart. For colorful clouds, take photos of a sunset. (This technique won’t work very well at sunrise, so be sure to take photos at sunset if you want some color in your clouds.)

Wrath of a Thunderstorm

For those of you short on time or patience, you can use fewer photos in your time stack. This is just 15 photos taken 5 seconds apart. There are two elements that determine how smooth or jagged the movement in the clouds appears: (1) the amount of time between each shot and (2) how quickly the clouds are moving. If the clouds are moving quickly and you want a smooth look, you’ll need to take more photos. If the clouds are moving slowly, the interval between shots can be larger. Having said that, it’s nearly impossible to guess what your image will look like once all of the photos are stacked and that’s half the fun of it!

Time stacking example (29 photos)

Unfortunately, not everyone will have amazing clouds to photograph this week. Not to worry! In this photo my initial goal was to smooth out the water, but then I realized that I caught the gulls in flight as well. Not only did the size of the flock seem to grow, but their flight patterns in the sky seemingly appeared out of nowhere when I stacked the photos. This is a time stack of 29 photos taken in just 10 seconds, i.e. burst mode. (Note: If you want to try this technique with flying birds, you will need to find white birds or at least birds that are lighter than the sky behind them. It won’t work otherwise.) I included one of the photos used in the stacked image so that you can see the difference between a “normal” image and the stacked version of the same scene, particularly the water, the number of birds and the flight patterns of the birds in the sky.

Waterfall - Time stacking example

Another use of the time stacking technique is to fill out waterfalls or other moving water. If you find a waterfall that doesn’t have much water, you can make it look fuller by stacking a few photos together. Again I have provided both the stacked image (on top) and a single image from the stack. The difference is most visible in the water going over the large rock just to the left of center, but if you look closely you’ll see that the volume of water looks fuller throughout the stacked image.

Car trails - Time stacking example

Or you could stack a few photos of light trails from cars. It doesn’t take many photos to make a road look really busy! This image was created from four stacked photos.

Star trails - Time stacking example

And of course if you love astrophotography, this would be a great challenge to show off your skills with star trails. This image was created from three 15-minute exposures.

For more inspiration be sure to check out the amazing time stacked photos of Matt Molloy, a pioneer of using this technique for landscape photography: http://flic.kr/s/aHsjCgruXn (There is one of a smoke stack that I think is way cool!)

HOW TO DO IT

Taking the photos

  1. You’ll need a tripod. If you don’t have a tripod, you can search google for DIY tripods.
  2. For best results, use Manual Mode on your camera and set both the ISO and White Balance to something other than Auto. Basically you want all of the photos in your series to be taken with the exact same settings.
  3. Make sure your exposure it set to capture as much detail as possible in the lightest elements of your scene, i.e. don’t blow-out the highlights. It is the highlights that will be creating a pattern in your stacked image, so you want to capture as much detail in the light areas as possible.
  4. If you have an intervalometer feel free to use it, but for the purposes of this challenge I had just as much luck counting to 5 or 10 between my shots and taking the photos without an intervalometer. Regardless of the method you choose, be sure to be consistent with the time between each photo (especially for cloud photos – waterfalls and car trails are more forgiving).

Processing the photos

If you do not have Photoshop, I’ve put together a video tutorial explaining how to stack your photos in www.pixlr.com (a free online photo editor). The technique I show in the video should work with any photo editor as long as it supports layers and layer blending modes. I encourage you to watch it even if you have Photoshop since you might pick up a tip or two.

If you have Lightroom and Photoshop, there are numerous tutorials and videos available showing how to do time stacking.

In addition, Matt Molloy has written a tutorial explaining his technique at http://iso.500px.com/time-stack-photo-tutorial/. I encourage you to read through it for more details from his perspective.

When posting your photos this week, it would be fun to also post a single photo from your time stack as a comment so we can see the difference time stacking makes.

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About the author: Jeanie Sumrall-Ajero is intensely curious about life and loves to explore it through the lens of her camera. She has dabbled in photography from time to time throughout her life, but it wasn’t until this past year when she took a semi-sabbatical from work that she decided to explore photography more seriously as a creative art form. Jeanie’s Flickr page can be found at www.flickr.com/photos/the-digital-jeanie/.