Shutter Speed

Shutter speed refers to the amount of time that your image sensor is exposed to light. Refer back to my earlier post on the anatomy of a DSLR, and you’ll see that the shutter is in front of the image sensor. So, the “faster” your shutter speed, the less time light (which is the image) is hitting the image. “Slower” shutter speeds, means that the image sensor is exposed for a longer period of time.

Shutters are normally very fast… fractions of a second. That’s all the light you need to make a photo. Shutter speeds range from about 1/6000^th of a second to about 8 seconds. The light you have available to take a picture, determines how you set your shutter speed. 8 seconds, (denoted 8” on the back of the camera) would be used for incredibly low light (ie, Taking pictures of the stars). 1/6000^th of a second (denoted 6000 on the back of the camera) would be used for taking pictures when there is a lot of light available (ie, middle of the day, pointed at the sun).

Under normal, daytime conditions, I shoot in the range of 1/60^th to 1/3200^th of a second. I generally try to use the fastest speed that the light will allow. The faster the shutter, the less chance I will cause the image to be blurry by shaking the camera. This type of blur is called “motion blur”, and causes everything in your pictures to appear out of focus. If I’m going to hand-hold my camera (not use a tripod), I won’t set it below 1/60^th of a second. It is next to impossible to hold still enough at this speed.

Take a look at the three photos below to see the effects of shutter speed. I’ve kept all the variables the same (Subject, time of day, aperture, white balance, iso camera location) except shutter speed.

This image has the “fastest” shutter speed. 1/2500^th of a second.

This image is a little slower. 1/2500^th of a second.

This is the slowest image 1/800^th of a second.

Notice that the photos get darker the faster the shutter speed is. This is because less light is hitting the sensor. 1/2500^th of a second’s worth of light vs. 1/800^th of a second.

So, when shooting in the manual mode, I set the aperture, and then adjust the shutter speed until the image is exposed properly. The camera will also do this automatically for you if you shoot in Aperture Priority Mode.

Photography: It’s all about Light

When thinking about photography, it all really comes down to light. That’s what goes onto the cameras sensor, and that is what makes an image. Exposing the perfect picture comes down to your ability to control the light that comes into the camera. There are three settings on your camera that really control the light coming in.

1. 1. Aperture: The size of the “hole” light comes through to your sensor
2. 2. Shutter Speed: The amount of time light is being captured by the sensor
3. 3. ISO: The sensitivity of your sensor.

I’ll cover each of these in separate blog posts. But being able to control these three settings are what will enable you to capture that perfect shot. These all three come together to become the “exposure” of the picture. You’ve probably heard the term “overexposed” or “underexposed” before. By changing aperture, shutter speed, and ISO, you can control the amount of light in the picture and get the perfect exposure.

Below are three examples of exposure:

Underexposure

Overexposure

Correct Exposure

Adobe Photoshop Lightroom: A great way to organize images.

Full Disclosure: I work for Adobe, so I may be biased… however, I don’t recommend anything I don’t use myself.

I’ve been using Photoshop Lightroom for over a year now, and I still love it. Prior to finding Lightroom, I’d been taking digital pictures for about 8 years, and had never come up with a system that I liked for storing and cataloging images. I’d tried using Windows Explorer file system, iPhoto, and up until last year, I was pretty happy with Picasa, but Lightroom has blown them all away.

There are several functions in Lightroom beyond just organizing (all of which I love), but for just remembering what/where/when you took a picture, the Library module in Lightroom is awesome. Right from importing your photos from you camera, it keeps everything in one place. For safety, it automatically makes copies of your pictures for auto-backup. (having lost a lot of data, I can’t stress this enough).

I’m gonna spend a lot of time talking about Lightroom in this blog as I learn more. It is super powerful and has tons of features that’ll probably take me months to learn, however if you use it as nothing more than just an organizer, you’ll still be happy.

A couple things to point out: Lightroom 2 is available for a free 30-day trial from Adobe.

Also, to get started using the software, I highly recommend the Lynda.com training It’s done by Chris Orwig and really helped get me going with the software.

Using Autofocus

The ability for a camera to automatically focus is awesome. The fact that your camera can look at an object, determine if it is sharp enough, and change the focus blows me away every time. When I first got my DSLR cameras, one thing I’ve noticed is that it was unpredictable on what it would focus on. I’d look through the viewfinder, and want to focus on the person in my shot, and it would focus on some leaf in the foreground. Or it would focus on the closest person instead of the person in the middle. Turns out, my Nikon has some settings for the focus mode that I didn’t know about. The factory had it set to focus on the closest object, regardless of where it was. This wasn’t working for me, because I didn’t always want the closest object in focus.

What I’ve done to simplify my life and make my autofocus only focus on what is in the direct center of my viewfinder. Looking through my Nikon, (D40) I have an indicator that looks like:





These boxes are the focus area indicators. I’ve changed the settings in the back menu (check your manual to see what menu), so that only the center square is put in focus.

I know what you are saying, “what if I don’t want the center to be in focus, what if I want something on the right or left to be in focus. I that case you put the item you want to focus on in the center brackets, press the shutter button half way down and then re-compose you image. This blog talks about some of the other features of autofocusing that I won’t rewrite here: http://www.kenrockwell.com/nikon/d80/af-settings.htm

I also noticed that sometimes the camera wouldn't focus, it just kept searching, and never finds a focus distance. The autofocus in your camera uses lines of contrast to focus. So you need to look at the edge of an object to get the camera to focus. It you are trying to focus on something all the same color, the camera won’t know how to make it sharp

Apologies for Being Absent

It’s been pretty obvious that I’ve been neglecting my blog. I’m going to make an effort to update it more regularly. Just because my entries stopped, didn’t mean my interest in photography has waned. I’ve still been shooting and learned a couple new things along the way. I’d like to ask a favor of my readers, please make comments. I’d love to hear your feedback on what I’m writing.

Becoming Master of Your Domain: Camera Modes

One of the first things that new camera owners start to play with on their DSLR is the little Mode Dial on the top of the camera:

Nikon



Canon


Everyone is always tempted to just put it on Auto, and leave it, but here’s what these different Mode Dial symbols mean (I’m going to focus on Nikon and Canon):

Nikon	Canon
P	P	Program Mode: this is almost automatic, but allows you to change a couple settings like ISO and white balance. It is a way to override some of the decisions your camera’s auto sensor is making.
S	Tv	Shutter Priority: You chose the shutter speed, and the camera selects an appropriate aperture value. This is a semi-auto mode, but it is great for getting a specific effect. For example, it you want to get a crystal clear picture of a track runner, you need a fast shutter speed to stop the runner. Otherwise you will get a blur. In this mode, you set the shutter speed fast, and the camera picks the appropriate aperture to get enough light.
A	Av	Aperture Priority: You chose the aperture value, and the camera selects an appropriate shutter speed. This is a semi-auto mode, but it is great for getting a specific effect. For example, it you want to take a “selective focus” picture of a flower (flower in focus, background out of focus) you need a wide aperture (low f-number). This will put the flower in crisp focus, and have the background all out of focus. The camera then compensates with the correct shutter speed to let the right amount of light in.
M	M	Manual: Allows everything to be set by the user. I shoot most of the time in this mode.
Auto	Green Box (Auto)	Auto: “photography for dummies”. This setting uses the camera’s image sensor to decide all settings. It usually gets close, but I’ve found that I can usually do a better job controlling brightness, white balance, and shooting style using the Auto Mode
Icon	Icon	Scene Select: the second half of the camera mode dial has little pictures on it that are meant to specify a shooting scenario. They basically change some of the pre-set features for each scene type. I find them useless.

Anatomy of a DSLR

Now that you have your DSLR, lets look at the pieces that make it work. Below is a very crude diagram of a DSLR. I’ve called out each of the major components:





1. Lens Hood: this is used to flag light from the lens. I’ll cover what flagging means later, but we want to block extra light coming in from the sun or lamps from hitting our lens, and only have the light from the subject enter the lens.

2. UV filter: this is a little filter that covers the front of your lens. These are about $20 and protect you lens from scratches (it’s much cheaper to replace the UV filter than the whole lens).

3. Focus ring: enables you to manually focus the lens. When you are in auto-focus mode, you won’t need to use this at all. Depending on you lens/camera, it can also be located at #5.

4. Zoom: changes the zoom of the lens, brings objects closer or further away.

5. Focus ring: see #3

6. Prism: A mirror to reflect what is being seen by your lens up to you eye.

7. Diopter: a slider next to the viewfinder that allows you to adjust the focus. This is used for people who need corrective vision. (most people just leave it alone and look through the lens with their glasses)

8. Viewfinder: Look through the viewfinder to see what you have in frame.

9. Shutter: The shutter is what allows the light to hit your image sensor for a set length of time.

10. Image Sensor: the film of the digital camera. This captures the light, and converts it to the digital image.

11. LCD: The screen on the back of your camera that allows you to modify the camera settings and review your images after you captured them.

12. Mirror: is in the down position to allow the image to be reflected up to the viewfinder. When you press the shutter button to take a picture the mirror flips up and lets the light through the shutter onto the image sensor.

13. Aperture/F-Stops/Diaphragm: Aperture, is measured in f-stops. This is the hole in the lens that allows the light to pass through. It is made up of blades that form the diaphragm. The larger the f-number, the smaller the hole in the diaphragm is. I will cover how this works in detail later.

14. Lens elements: allows the lens to focus and gather the light onto a point source (in this case, the image sensor)

15. Objective Lens: This is the front lens.