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DSLR News - February 2009 In last month's issue of this newsletter, I discussed the pros and cons of buying a "modern" digital SLR vs. getting an "older" model. An astute reader noticed that there was a lot of different ways you could interpret "modern" and "old" at least when it comes to digital SLR cameras. First, let me clarify what I deem as "old" vs. "modern" (just in case I use these terms again without qualifying them). For me, a modern digital SLR is any camera released within the PAST year. Right now, I consider any camera released in 2008 as a modern digital SLR. By contrast, any camera released in 2007 or prior is "old" in my book. While it doesn't seem that the passing of one year should make something "old", this is the way it goes with digital SLRs. Once a year, the technology makes some type of big leap forward, but then it takes another six months to a year for that technology to be widely adopted. Take the live view LCD: this feature was first introduced on the Olympus E-330, which was released in 2006. By the middle of 2007, many new cameras included a live view LCD, and by the middle of 2008 EVERY new camera had this feature. This meant that if you compare cameras released in 2008 with those released in 2007, you'll find that only a handful of the 2007 models have live view. If you decide to purchase a "modern" (i.e. 2008) camera, then you can rest assured that live view will be included and can focus your comparative energies on other features of the camera instead. And now, to really clear things up, I give you this: a digital SLR timeline. This timeline is available as a PDF download (you'll need Acrobat Reader to view it), and it provides you with some history of the digital SLR going back to 2005. For each year, I list the cameras that were released, present a brief checklist of features, and then add some notes about the camera. Digital SLR cameras that represent milestones in the timeline are highlighted, so that you can clearly see when a new technology was introduced. This timeline should give you a pretty clear sense of every digital SLR that is available to you. If you decide that you don't need all the features available on the modern cameras, then you save a HUGE chunk of money by picking up an older model.

In This Issue DSLR Timeline SLRs of 2009 Aperture II Depth of Field II Photo Links Latest SLR Guides Nikon D90 Nikon D60 Canon Rebel XSi Pentax K20D Canon 40D Olympus E-510 Nikon D80 Canon Rebel xTi Nikon D40 Digital SLR Terms Megapixels Stabilization ISO / Image Noise Sensor Dust Crop Factor RAW vs. JPG Continuous Photos Autofocus Points Aspect Ratio Lens Terms Focal Length Prime vs. Zoom Maximum Aperture First vs. Third Party SLR Lens Features Canon Lens Glossary Nikon Lens Glossary

Digital SLR News

While several new digital SLRs have been rumored for release in 2009, nothing is official yet.

Throwing caution to the winds, I'm going to provide you with more information about these rumored cameras, since many past rumored cameras that I've seen have all eventually been released.

The first new camera is yet another in the Sony ALPHA line. Sony is still trying to play catch-up with the big two: Canon and Nikon.

As such, they have been releasing new camera models for photographers of all skill levels: beginners (A200), Intermediate (A300, A350) and Advanced (A700, A900).

Now the rumor mill is abuzz about a new 15 megapixel Sony digital SLR (the A800 maybe?) that sounds like it will be a competitor to Canon's 50D (also a 15 megapixel DSLR). Expect this new camera from Sony to include: dust control, a live view LCD (that might flip out from the camera body), built-in image stabilization, dynamic range control and face detection autofocus. It might even have Sony's smile detection shutter release (if they really pack on the features).

The other new cameras are not actual digital SLRs: they fall into the hybrid class of camera known as Micro 4/3rds.

In 2009, expect to see a second Micro 4/3rds digital camera from Panasonic (their first was the DMC-G1) but this time with the addition of a video capture feature.

Also expect to see some new Micro 4/3rds digital cameras from Olympus (partnered with Panasonic) with a very unique look. The new Olympus cameras will look much more like compact cameras, but with all the advantages of a digital SLR (minus the optical viewfinder).

Look for many new cameras to be announced right around March, since that is the month for PMA - a massive annual trade show that often includes a slew of new camera announcements.

Beginner Tutorial - Aperture

In last month's newsletter, I provided an introduction to aperture.

Here's a quick summary of that information:

• Aperture indicates whether the opening in your lens is wide open or narrow
• Your digital SLR communicates with the lens via electronic contacts
• You can control the width of the opening by changing the aperture setting from the camera
• A small aperture number (2.8) represents a WIDE opening in the lens
• A large aperture number (22) represents a NARROW opening in the lens
• Aperture numbers follow a standard scale called f-stops.

The aperture f-stop scale looks like this:

f/2.8, f/4.0, f/5.6, f/8, f/11, f/16, f/22

(note: I just noticed that the scale that I provided in last month's newsletter is NOT correct - it contains f/3.5, which is not part of the standard scale)

Now, this particular scale shows each aperture number changing by something called a full stop of light.

When the aperture changes by a full stop, the amount of light landing on the camera's sensor is either doubled or halved.

Example:

• f/2.8 lets in twice as much light as f/4.0
• f/4.0 lets in half as much light as f/2.8

Once you realize that the lens aperture can be changed by full stops, a question arises: what about half stops?

Yes, aperture numbers can also be broken down into a half-stop scale:

f/2.8, f/3.5, f/4.0, f/4.5, f/5.6, f/6.7, f/8.0, f/9.5, f/11, f/13, f/16

While a simple half-stop scale might make the most sense, most digital SLR cameras are actually set up by default to change aperture in third-stop increments:

f/2.8, f/3.2, f/3.5, f/4.0, f/4.5, f/5.0, f/5.6, f/6.3, f/7.1, f/8.0, f/9.0, f/10, f/11, f/13, f/14, f/16

Let's take a quick break from the numbers and talk about HOW you actually change the lens aperture using a digital SLR camera.

• First, you have to set the camera in a mode that allows you to change aperture - a good one to start with is "Aperture Priority" mode (often marked as "A" or "Av")
• In order to change the aperture value, you have to spin the main command dial which is located near the shutter release under your index finger

All main command dials don't just spin freely: they "click".

Let's say that your digital SLR is one of the many where aperture numbers are broken down into third-stops. Let's also say that currently your aperture is set to f/8.0.

Now, if you want to OPEN the lens by a full stop, you click the main command dial three times in one direction to go from f/8.0 to f/5.6. If you want to NARROW the aperture back down to f/8.0, you click the main command dial three times in the opposite direction.

The reason that you have to click three times is because of the third stops.

• f/8.0 to f/7.1 = +1/3 stop of light
• f/8.0 to f/6.3 = +2/3 stop of light
• f/8.0 to f/5.6 = +1 full stop of light
• f/5.6 to f/6.3 = -1/3 stop of light
• f/5.6 to f/7.1 = -2/3 stop of light
• f/5.6 to f/8.0 = -1 full stop of light

Before we wrap things up on aperture control for this month, a word about customization: the factory default setting for most digital SLR cameras is to use a third-stop aperture scale.

However, some cameras allow you to customize the scale and change from third-stops to half-stops if you so desire. Both work equally well, the third stop scale just provides you with a slightly finer level of aperture control.

Intermediate Tutorial - Depth of Field

Last month, I talked about how changing the aperture helps you to control the depth of field in your photos.

The summary:

• A wide open apertures creates shallow depth of field
• A narrow aperture creates deep depth of field

This month, we'll talk about the other two variables that have an impact on depth of field: the focal length of your lens and the distance between the camera and the subject.

Here's the high-level overview for lens focal length:

• Long focal lengths (telephoto) create shallow depth of field
• Short focal lengths (wide angle) create deep depth of field

Let's take a look at a photographic sample to make this clear. In both images, the other two variables that affect depth of field (aperture and distance) are kept constant. The lens aperture is set to f/5.6, while the distance from camera to subject is about 5 feet (1.52 meters).

The left image is taken with a lens focal length of 28mm while the right image is taken at 135mm. Note how the background is significantly more out of focus in the image shot at 135mm than at 28mm.

Now that we've illustrated how focal length affects depth of field, let's take a look at the impact of camera-to-subject distance.

• A short camera-to-subject distance creates shallow depth of field
• A great camera-to-subject distance creates deep depth of field

For these two images, the lens focal length was set at 28mm. The lens aperture was set to f/5.6.

The left image is taken from 5 feet (1.52 meters) away from the subject while the right image is from about 1 foot (0.3 meters) away. Again, you should see a pretty big shift in the depth of field.

Now, let's combine the three variables together into an integrated whole.

Imagine that you are taking shots of a subject from about 10 feet away (3 meters) and that your lens is set to an 18mm focal length. In this case, both the focal length and the camera-to-subject distance are working to create a lot of depth of field.

Key Point: changing your aperture setting in this case won't have a pronounced effect on your image.

This is for all you folks out there who change aperture values constantly and have yet to clearly see how the aperture affects depth of field.

If you change just ONE other variable in the scenario above, you should immediately see how different apertures affect depth of field. Let's say that you keep the focal length constant at 18mm, but you move to within 2 feet of your subject.

Now, a change from aperture f/4.0 to f/16 should have a pronounced impact on how your image appears.

Conversely, you can also stand in one spot and zoom in on your subject. Once the lens focal length is 55mm, an aperture change should be quite easy to spot.

Every shot you take involves an on-the-spot judgement about what these three variables should be.

• Landscape photographers use wide angle lenses (18 to 28mm) paired with narrow apertures to achieve extreme depth of field
• Portrait photographers use standard lenses (50 to 100mm) to make depth of field more shallow
• Macro photographers (who need to get right up next to their subjects) have to use narrow apertures to get any depth of field at all

If you're limited by one variable (say you only have a wide angle lens attached to the camera) then you must achieve the depth of field that you desire by using the other two. Deep depth of field is pretty easy to achieve with a wide angle lens, but if you want to blur a background, you'll have to set the aperture wide and get right up close to your primary subject.

Photo Links

In Conclusion

The PMA trade show is right around the corner here (March 3-5) and I'll be writing up all of the new cameras announced in next month's newsletter.

I've also reviewed the results of my Camera Guide Poll and the cameras that everyone would most like to see reviewed are the Canon Rebel XS and the Canon 50D. I hope to get my hands on both of those soon, and will announce when the guides are available in this newsletter.

Until then, happy picture-taking!

--Chris Roberts, Your Digital SLR Guide