Saturday, March 14, 2009

Random Tip- RTFM


Last tip for a while. I'm guessing you have some catching up to do so this is probably the most useful tip I can give you. I'm not kidding.

Go find the manual that came with your camera and put it in the bathroom. Just read random stuff. Even if you don't know what everything means keep at it. You will start to piece it all together.

People generally use the manual to find out how to do something they want. However, more often I find out how to do something I never even thought about. Like White Balance bracketing.

Get shooting.

PS- if you don't know what RTFM means, google it.

Thursday, March 12, 2009

Choosing The Best Aperture- f8 And Be There

As I mentioned in a previous post I recommend you start shooting in Av mode. Aperture will come to be the single most factor that determines the look of your photo. As you get more accustomed to using it you will get used to the relationship it has with shutter speed.

So which is the best f-stop? Sometimes it will be obvious. For some nature shots you will “stop-down” to f11 or so for a large DOF. Other times you will shoot wide open at 1.4 for effect.

You don’t always get a choice though. If you are at a party and it’s dark you are going to be shooting as far open as you can. If you are shooting your son playing soccer you are going to want something in the neighborhood of 11 or 16 to ensure that they remain in focus as they move around. Using a wide open aperture with a shallow DOF makes like difficult for focusing. Especially on a moving subject.

Think about it- if your DOF is 12 inches then any slight movement will result in a blurry shot. If your DOF is 12 feet then you have a certain safety net to work within before your subject is out of focus.

But here is the absolute second best tip I can give you- if there is any doubt in your mind set your aperture to f8. Ask a National Geographic photographer how to take a great shot and they will reply “f8 and be there.”

And the absolute best tip? Your lens will likely be at it’s absolute sharpest, best possible looking when it is dialed into about 2 stops down from maximum. That means that your 1.4 lens will look fantastic at 2.8. Your 5.6 will probably be best at f11.

So when you are tempted to go hog wild and blow everything out of focus by using 1.4, give 2.8 a try. You’ll be thrilled.

Lenses- Zoom V. Prime


WARNING- This post is long.

Okay this one is important so make sure you read carefully. People will often ask me about which lens to buy for their new DSLR. There are far too many variables to consider to answer that question in a straightforward manner but the short cut is- A PRIME LENS.

Unless you opted for an upgrade you probably received an 18-55mm zoom lens with your new DSLR. Not a terrible lens but very basic. It will cover a decent range of focal lengths and aren’t very expensive. As such they are limiting.

Basically a zoom lens is one that has variable focal lengths that you can “zoom” through. You can shoot a wide angle at 18mm, somewhere in the middle at 35mm or tighter at 55mm. Nice to have options.

The downside of the zoom lens is that there is a lot of glass that goes into making them and if you want a nice, clear lens they are EXPENSIVE. Really expensive.

And the really expensive ones don’t tend to zoom very much. For instance- 16-35mm or 70-200mm. Less than 3x zoom. Lenses that zoom through a larger range need to give up image quality to compensate for the versatility. That’s just the way it is.

Take the 18-200 for example. Goes from very wide to really tight. Seems to do everything. Except take sharp pictures. They are probably reasonable but they’re not fabulous. Add to that the autofocus. Cheaper lenses that cover wider ranges tend to focus slower.

And here comes the big one. I cannot stress this feature enough. Maximum Aperture.

In order to keep costs reasonable to the average consumer these zoom lenses don’t open up very wide to let enough light in. You will see a lot of them advertised as “4-5.6” (some will say “3.5-5.6” but really there isn’t much difference here).

Why two numbers? Well at the wide angle of the lens (18mm) you will be able to achieve a maximum aperture of 4 and at the telephoto end (55mm) you will only be able to open up to 5.6. That isn’t very good. In between the 18 and the 55 the max aperture will scale itself between 4 and 5.6. This would be referred to as “slow glass”.

Slow Glass means that the max aperture isn’t very wide. Fast Glass means the opposite. A top-shelf zoom lens will be considered fast if it has a max aperture of 2.8. And these lenses usually have a consistent maximum from one end to the other. Very nice.

When you use slow glass you give up a lot of your options when it comes to exposure. Since you are not letting all that much light in you are forced to slow down your shutter speed causing motion blur, or crank up the ISO causing excess grain. Or often times you end up doing both. (You might actually use the built-in flash in this scenario. You’ll quickly find that the built-in flash resides slightly north of useless).

With cheap zoom lenses no good, and good zoom lenses too expensive (think $1500-$2000) then what do we do? Go for a prime lens.

A prime lens is also called a fixed focal length. Basically it means you can’t zoom. Whatever focal length you buy is the one you are stuck with.

But the upside is that it requires less glass and is therefore more reasonably priced and far sharper than a zoom lens. It also opens up to far greater maximum aperture. Depending on the price and the focal length this will be in the neighborhood of 1.8.

Now is the time for full disclosure. I am a total Prime Lens Snob. If it were up to me I would always shoot with prime lenses but alas that is not always possible. Some situations require a zoom lens.

The other upside to a Prime Lens is that it will make you a better photographer. It takes one of the factors out of the equation and can be less confusing when learning. It also forces you to get moving around to be more creative.

But the two best features are that the giant aperture makes for really shallow DOF (everyone’s favorite) while simultaneously letting a lot of light in quickly. Fast Glass.

Consider that the full f-stops are 1.4 - 2 - 2.8 - 4 - 5.6 - 8 - 11 - 16. Each one of those stops allows for exactly twice as much light to pass through the lens into the camera. That means that an f-stop of 1.4 will let in 16x as much light as f5.6. SIXTEEN TIMES!

So rather than have a slow shutter at f5.6 at 1/15th of second, you get f1.4 at 1/250th. Auf wiedersehen motion blur.

If you own a Nikon go buy the brand new 35mm f1.8. It was recently announced and may be hard to find. Lists for $200 in the US.

If you own a Canon go buy the 50mm f1.8. Much easier to find. They go for under $130 in Canada. I own this lens. I used it to make the photo seen above.

There are a few more options. I also own the Sigma 30mm f1.4. They make it for both Canon OR Nikon. They are a little more expensive at about $600 but I like mine a lot.

Wednesday, March 11, 2009

DOF- Putting It Together

Now that we understand the various factors involved in controlling our DOF let's put it all together and look at two different shots taken of the same scene.

In the first shot we wanted to see everything so we shot it at a wide angle (17mm), stopped down our aperture to f22 and focused the lens on the tree in the middle. Huge DOF.


In the second we wanted to go the other way so we shot it at 50mm, opened the aperture up to f1.8 and made sure the mug was very close to the camera. The focus is on the lettering.

Tuesday, March 10, 2009

DOF Factor 3- Distance

The last contributing factor to our DOF is probably the most overlooked. Here we will quickly discuss how the subject’s distance from the camera comes into play.

Basically the closer the subject is to the camera, the shallower our DOF will be. As it moves further away our DOF will increase.

(NOTE- make sure to keep your subject at least as far away as the minimum focus distance for your particular lens. Lenses can only focus so close. It will probably tell you on the lens somewhere)

The following shots were all made at f2.8 with a 30mm lens.

Notice how the blurring of the background increases as the orange nears the camera.




DOF Factor 2- Aperture

Now that you’re familiar with how the focal length affects the depth of field let’s take a look at another component- Aperture.

Not only does a small aperture (large number) limit the amount of light that comes in through the lens, it gives us a deep DOF. A large aperture (small number) allows a lot of light to come through but gives a very shallow DOF. How deep and how shallow will still depend on the focal length we are using.

Here are some examples. All 4 of these shots were taken with a 30mm prime lens. In each case the focus is on the dial of the second parking meter.

f16 Gives a very deep DOF.


At f8 it is narrowing.


Even smaller at f4.


In this shot at 1.4 you can see how having a large aperture (small number) really shrinks the DOF.

Monday, March 9, 2009

DOF Factor 1- Focal Length

Focal length is the proper term for “zoomed-innedness”. Or something. For our purposes focal length refers to the length of the lens. It doesn’t really behave like that but it’s a pretty convoluted mess that you are free to check out at Wikipedia if you want. But seriously, it will just confuse you.

So a short lens is a wide angle. A long lens is telephoto. A zoom lens is one that does both. Cool?

Your DOF is greatly affected by the focal length you choose. Wide angle lenses have a deep depth of field. Telephoto lenses have a shallow depth of field.

Long story short- if you want narrow DOF then zoom in as far you can. Here are some samples.

I shot all three of these photos at f11. The first one has a focal length of 17mm. A wide angle. We can see a deep DOF.


The next one I shot at 50mm. The background is getting soft.


And the last one was shot 85mm. Much softer background.