Principles of Exposure: Capturing Action and Controlling Motion Blur

Exposure: Shutter Speed, Aperture, ISO:

Exposure is the measure of light falling on the media, be it film or CCD. It's controlled by three factors namely shutter speed, aperture and sensitivity of the sensor (ISO). Let me try to explain each of these in a greater detail.

Shutter Speed is the amount of time the shutter screen remains open, in other words, it is the duration for which the light hits the media. Shutter speed is the feature of the camera and not the lens. Faster the shutter speed, lesser the duration for which light hits the sensor, so lesser amount of light is captured.

The shutter speeds range from 1/4000th of a second (1/8000 on a pro camera) to 30seconds, with a special "B" (bulb) mode wherein the shutter could be kept open as long as the photographer wishes (of course, constrained by battery).

The shutter speed controls another most important aspect - freezing the subject in time. Simply stated, you shoot a speeding car with slow shutter speed, you tend to see the trails of the car resulting from motion blur. On the other hand you shoot the same car with higher shutter speeds, the car will appear as though it is stationary. In case you're wondering what magic, the photographer has done to capture those long trails of headlights, the answer is simple: he would have just kept the shutter open long enough to capture the trails.

When you're shooting with slower shutter speeds (under 1/100th of a second) holding the camera, it is highly likely that you end up with a blurred photograph. Why? It's obvious that when you're shooting at lower speeds, even the slightest camera shake will contribute to the blurring of the photograph. Solution for this problem is to mount the camera on a tripod or try to find a platform nearby to place the camera and shoot.

The answer for the question "What shutter shutter speed to use for a particular shot?" is "It entirely depends on the kind of shot and it can't be generalized". If you're shooting birds, wildlife, sports, street shots etc. which require the moment to be captured tack sharp use high shutter speeds. Night shots, trail capture, abstract photographs, light painting, milky waterfall photographs etc. require slow shutter speeds.

Aperture is the feature of the lens and has nothing to do with the camera, except that the aperture values are set/controlled by the camera. As the name itself suggests, aperture is an "opening" at the rear end of lens through which the light enters the camera. Earlier days, the lens barrel had an aperture ring to set the required aperture values, but these days the aperture could be controlled by the knobs on the camera or changing a setting on the digital menu of a DSLR.

The maximum and minimum value of aperture depends, as mentioned earlier, on the lens and not on the camera. You may find a lens with aperture as big as f1 or f1.4 or as small as f45 or f64. Aperture is measured in terms of f-stops and hence the f. It's notated f/1.8 or f/5.6 as well. As you can see the size of the aperture is inverse to the value of f-stop, higher the f-stop smaller the aperture, smaller the f-stops bigger the aperture. So at f1.8 the light received by the medium will be more than f5.6; least light will be received at the smallest aperture say F22 of F45 or whatever your lens supports.

Like shutter speed, aperture also controls one other aspect, apart from the amount of light, it's called Depth of Field (DOF). You maybe confused by amateur photographers who are fond of terms like DOF, Bokeh, Hyperfocal distance etc. Just remember this rule of thumb & don't get lost in the jargon: Bigger the aperture, smaller (shallower DOF) the region of focus; smaller the aperture larger (deeper DOF) the region of focus. You may, therefore, want to open up the aperture for a portrait shot wherein you want a focused and sharp face and blurred background and close down the aperture for a landscape shot wherein you want the entire landscape to be focused. Also in macro shots, the amount of DOF is very critical since the available DOF is very less. DOF is used sometimes to give artistic effects to the photographs.

Photo credit: Seth Wilson 2013

Portraits would come out well with bigger apertures (smaller f-stops) for it makes the subject really sharp against a background of soft background, Also night shots usually require bigger apertures which would allow lot of light to enter.

Landscapes need smaller apertures (bigger f-stops) for most times it wouldn't have a specific focus point. Smaller apertures help on a very bright day to cut-off excess light entering (of course this could be controlled by shutter speed too).

ISO is the measure of sensitivity of the media (film) and digitally is a camera dependent feature. ISO values are typically in the range of 100 to 3200 (on a pro camera it can have an extended range from 50-102400)

When the ISO is set to 100 the sensor is the least sensitive, it can sense less light. When it's set to 1600 or 3200, the sensor can sense a much more light. Which means for a given condition if ISO 100 gives a standard exposure with F8.0 & 1/250th of a second, ISO 1600 may give a standard exposure at F8.0 & 1/1000th of a second. ISO comes very handy while shooting hand-held under low light conditions, it gives an advantage of slightly faster shutter speeds which helps in avoiding motion blur.

An obvious question may arise to a novice, "Why should I shoot at low ISO when higher ISO gives an advantage of faster shutter speed?" Though ISO seems to be such a cool feature, it carries with it something very undesirable - NOISE. Higher the ISO, higher the noise.

Brighter the ambience smaller the ISO (unless you want grainy effect), darker the ambience higher the ISO.

To Make It Easy Just Remember The Rule of Equivalent Exposure: Each Change In ISO Is Equal To One Full F-Stop

Imagine you've pointed your camera at a scene and it's recommending the following settings:

1. A shutter speed of 1/100s 
2. An aperture of f/5.6 
3. A sensitivity setting of ISO 400 

We could make the photo appear twice as bright by doing any of the following:

1. Doubling the shutter speed to 1/50s 
2. Doubling the area of the aperture by increasing it one full f-stop, to f/4 
3. Doubling the sensitivity setting to ISO 800 

Any of these could be described as increasing the exposure by 1 stop.

Likewise, to make the scene appear half as bright, we can reduce the exposure by 1 stop by taking one of the opposite steps: 

1. Halving the shutter speed to 1/200s 
2. Halving the aperture area by reducing it one full f-stop, to f/8 
3. Halving the sensitivity to ISO 200. 

Note that we use the word "stop" even when we're not adjusting the f-stop (aperture) setting. It's just become a general term to mean a factor of 2.

That's about it. For even more information, read this page here at Cambridge In Colour.

Key Assignment 5: Capturing Action

Students, your new assignment is a challenge for you to demonstrate an understanding of the basics of exposure through capturing action and controlling motion blur. Create images that meet the criteria listed below

Assignment Deliverables:

This pelican was shot with a fast shutter speed to capture it in motion, even the water droplets splashing up are frozen in time. Photo credit Will Tierney 2015

1- Object Frozen in Time: Create 2-3 images of a moving object that is frozen in mid-action, this image must show no motion blur. For each image write a short description of the process used in taking the photo, what settings were used to create the visual effect and describe the affect the image may have on the viewer.

A fire spinner creates a silhouette of herself through motion blur. Photo credit Seth Wilson 2005

2- Object in Motion: Create 2-3 images that show an object in motion. The moving object must show motion blur. For each image write a short description of the process used in taking the photo, what settings were used to create the visual effect and describe the affect the image may have on the viewer.

3- Tracking Motion: Create 2-3 images that shows an object in motion with the background behind the object showing motion blur. For each image write a short description of the process used in taking the photo, what settings were used to create the visual effect and describe the affect the image may have on the viewer.

4- Zoom Blur: Create 1 image that shows zoom blur by cranking the zoom and taking a photo at the same time, try it a few times and post your best. For each image write a short description of the process used in taking the photo, what settings were used to create the visual effect and describe the affect the image may have on the viewer.

Post all images with accompanying written content to the flickr group when complete.

Due by following thursday...

- Mr.W

Advanced Students: Double Exposure and Multiple Exposure Photography

Hello Students,
For this project you will be exercising two artistic photography techniques, double exposure and multiple exposures.

Assignment Requirements:

• Create 1 double exposure image or portrait, must utilize juxtaposition as the driving concept in the choice of images you are combining
• Create 1 multiple exposure image or portrait. Must contain at least 4 exposures/images combined into 1
• Create 1 artistic double exposure (blending of images) using white/clean backdrops, paper filters, experimentation, research and creativity, also Photoshop

What is Double Exposure?

Double exposure with a traditional film camera involved exposing 2 different images to 1 piece of film. The effect creates an overlay of 2 images into 1, the areas of dark and light combine. With digital camera's we can take 2 different photos and combine them into 1 by using Photoshop's layers. See examples below:

Composer Karlheinz Stockhausen, double exposure made using a film camera, 1980 by Claude Truong-Ngoc / Wikimedia Commons 

Double exposure made using a film camera

What is Multiple Exposure?

Multiple exposure is when a camera is timed to take an exposure at different intervals of time, creating a series of images into 1 image. With a digital camera we can take multiple images and combine them with photoshops layers and some clever use of the Eraser Tool. See examples below:

A multiple exposure image created with photoshop

A multiple exposure composite image of a lunar eclipse taken over Hayward, California in 2004.

What is an Artistic Double Exposure?

When you pay attention to the light and dark areas you can have some amazing results with double exposure. Photoshop lets us combine and erase and change the way our layers blend together. Try to achieve an artistic effect seen below. Can you figure out how the images below were created? The examples below were made by the artist Dan Mountford. Clean backdrops to the individual elements  is important, the architecture needs clean skies behind them and the portrait does as well, plus the "blends" are created with filters/paper close to the lens to block out part of the exposure in the example below. Others are created differently, see if you can reverse engineer the methods used and try to replicate them yourself.

Link: Gallery of Artistic Double Exposures
Tutorial: Artistic Double Exposures in PS
Tutorial: Aneta Ivanova Double Exposure Method in PS

Photo Credit:Dan Mountford

Photo Credit:Dan Mountford

Student Work Samples: Double and Multiple Exposures

Photography and Color: Theory and Application

Color Theory Part A - Research and Slideshow:

Create a slide show using google doc slides, or any presentation software you prefer. Complete a slideshow that demonstrates the concepts and topics listed below. 

Assignment Specifications:

Create a slideshow that displays examples of the images listed below. Use the internet to research and find the images and incorporate them into your slideshow. Be prepared to discuss how the images achieve their appearance, is it caught in camera or created in post processing? How does the color dominance in the image affect the mood or emotion of the image, does it communicate a story and is the story altered by the color dominance?

• Show 3 images that display Primary Colors
• Show 3 images that show Secondary Colors
• Show an image that displays Complimentary Color
• Show an image that displays Analogous Color
• Show an image that displays intense or saturated color
• Show an image that displays desaturated or muted colors

Make your presentation visually interesting and be ready to present and discuss the images you are showing.

Presentations are due by the following thursday, email them to your instructor or turn in via usb thumb drive for credit.

Color Theory Part B - Color Palette Generation From Photograph:

In the study of color theory, primary colors refer to the 3 or 4 color combinations that all other colors can be derived from. In photography, an image can have cool, warm, light, dark, saturated or unsaturated primary colors. In this short project we will extract the colors that make up our image. From that palette we can choose pleasing color combinations for layout purposes.

Step 1: Choose one of your own images you have taken for this to use in this exercise

"Wearever whale" Image created by Seth Wilson 2012

Step 2: Navigate to this online palette generator, and upload your image as a JPG file. Here is the link : http://www.cssdrive.com/imagepalette/

Make sure you click "choose file" and upload your image....

Look for this link near the bottom of the page...

Step 3: After your image is done uploading, look at the palette it created for you, then download that palette as a Photoshop ICO File.

Step 4: Now switch over to photoshop. Create a document about 1000X900 pixels at 72 dpi. Copy-paste your photo into it, scale it down and leave some room on your document for your color palette. You will be creating shape layers and filling them with color from your custom color palette.

Step 5: On your Color Swatch / Sub-Menu, choose Replace Swatches...

Step 6: Navigate to the Photoshop ICO file you downloaded from the palette generator website.

Your color swatch tab should show your custom color palette loaded up, with no other colors available (you can change it back by choosing "reset swatches" from the submenu later on).

Step 7: After your palette is loaded, use a shape tool to draw a square, circle etc...

Step 8: Draw 1 object, then switch to the Move Tool and Option-Drag a copy....

With the Move Tool selected, and your object Layer selected... hold the option key and drag your copy...

Step 9: Continue this process.. each time you create a new object, select a new color from your custom palette by clicking on the swatch. Then you can use the Option-Delete command to fill with that color, or go to the Edit Menu / Fill / Using Foreground Color...

Continue this process until you have 20 different objects... fill these objects with the most dominant colors you see in your custom swatch palette.

Final Step: Add your name and some cool title text to your design and save it as a JPG and post to the group.

- Mr.W

The Brenizer Process, AKA Bokehrama

Hello Students,

Your new assignment is to create an example of the Brenizer Process, also called Bokehrama. This hands on lesson will introduce and guide students in the process of creating a panoramic stitch to mimic a large format image. Popularized by Ryan Brenizer, it has become a popular method for portrait, auto and wedding photography. This process uses standard equipment to replicate the large format look, this is a great project for creating compelling and creative portraits that won't break the bank!

This image was created with over 40 different exposures and combined with Photomerge, cropped and processed for the final result. Photo credit: Seth Wilson, 2017

The "Brenizer Method" Seamless Photo Stitch:
The Brenizer Method is named after Ryan Brenizer, a wedding photographer who invented the method, uses it in his wedding photography and teaches it to others as well. The advantages to this method is it produces a very high resolution images, essentially mimics a lens that has an f-stop of 1 and produces great bokeh. The process to create a successful Bokehrama image is in 2 parts, capturing and processing. Read the detailed instructions below before attempting to create your own.

Camera Capture Process:

• Use a DSLR or similar camera with exposure control.
• Find an environment with elements that will show depth with detail along the fore, mid and backplane. This will show off the method best.
• Stand in one place and dial in your camera exposure, then lock it down, including white balance.
• Set your lens/aperture to it's widest setting for the shallowest depth of field
• Focus on your subject/center area, use autofocus to dial it in, then switch to manual. You don't want the camera to c
• oks good your ready for photoshop!
• hange focus between shots
• Frame your subject and take some test shots, make sure the light is good and the subject is framed tightly, if not move yourself forward or backward to frame your subject/area
• Take your photo framing your subject in the center.
• Move slightly to the right and take an overlapping shot, keeping the camera steady, continue shooting in a grid pattern to the left, top, bottom, bottom right, bottom left, etc. 
• Make sure each shot overlaps with the previous for blending.
• Up to 40 exposures can be used for a large image. More is better so you can crop the best area after combining.
• Review your shots and make sure each one overlaps and the exposures aren't changing between shots, if it looks good you are ready for Photoshop

Photo Stitching Process in Photoshop:

• Move all of your exposures from the camera and copy them to your computer and place them in a new project folder.
• Launch Photoshop and go File > Automate > Photomerge
• Click the Browse button and navigate to your folder of images, use Command-Shift to select all of your images at once and load them into Photomerge. Alternatively you could use Command-A for Select all.
• Click OK to start the process. Photomerge may take up to 30 minutes or longer depending on the size and number of photos you are combining. The processing speed of your computer also affects the speed of this process, allow appropriate time for the computer to complete it's work.
• If your Photomerge is successful, you will see your finished and combined image.
• Crop your photo, use the Crop Tool in the Toolbar. Hold Command while you click-drag with the Crop Tool to create a perfectly square crop.
• Save your image to your folder as a Photoshop file.
• Use your Photoshop skills to modify your image as desired for creative results and make it cool!

Tutorial 1: Brenizer Method Tutorial
Tutorial 2: 5 Steps to the Brenizer Method
Link: The Brenizer Method Page
Link: Brenizer Method used for pet portrait photography

"Portrait of Ray" created with the Brenizer method and photomerge from 30 images plus post-processing in Adobe Photoshop

Have fun!

  - Mr.W