framed realitybokeh

The Exposure Triangle – Aperture

Marius Waldal — Tue, 02 Feb 2010 19:30:52 +0000

For me, aperture is the most important setting in day-to-day photography. The reason is that aperture is the setting that has the greatest impact on what you see in a photo. By controlling the aperture, you decide what parts of the scene should be in focus.

Hips on green velvet, by Marius Waldal

What is aperture?

F-numbers
Not to be confused with the f-word, the f-numbers identify the size of the aperture opening, or rather; the opening’s size in relation to the lens’s focal length. Simply put, if the lens’s focal length is 10 times the diameter of the aperture opening, you’re at f/10. So, a 50mm lens at f/4 has an opening of 12,5mm.

This means that two lenses with different focal lengths (i.e. a wide angle lens and a tele lens) that are both set to f/10 will have totally different sizes on the aperture openings. A 600mm lens set to f/2.8 must have a huge opening (214mm!) compared to a 30mm lens at f/2.8 (about 11mm) to allow the same amount of light to reach the sensor.

That’s why those professional tele-lenses are sized like bazookas, and why nature and sports photographers (and paparazzis) all suffer from back-aches.

The aperture is the opening – the hole if you like – in the lens. The opening is adjusted by a diaphragm that controls the size of the hole, stopping various amounts of the light entering the lens from passing through to the sensor/film (the focal plane). Thus, the various aperture sizes refer to “f-stops”.

What many inexperienced photographers have problems grasping is the concept of the f-numbers, or more precisely, the seemingly unintuitive “reverse scale”: higher f-number means smaller opening. The f-number scale is actually dimensionless, meaning that f/4 or f/16 does not refer to a specific size, like 4 and 16 millimeters. If you like techie-stuff, read why in the box to the right. If not, just accept this fact and move on!

What happens when you adjust the aperture is that you increase or decrease the amount of light that is allowed to reach the sensor. This means that wider apertures allows for faster shutter times. Large-aperture lenses is therefore often referred to as fast lenses.

Aperture controls depth of field

While larger aperture makes your lens faster, it also reduces your depth of field (DOF). In some situations, this can be limiting. But most of the time, this is something you can actively choose to use to your advantage.

Small thoughts, by Marius Waldal

A typical example is portrait photography. Usually, you want your subject in focus, with any other elements in the scene blurred out. This effectively separates your subject from everything else. And sometimes you don’t even want your whole subject to be in focus, as this portrait of my son exemplifies.

Another example is macro or close-up photography. You want the viewer’s attention only on your subject, or maybe just a part of it.

The parts of the photo that are not in focus, is called bokeh. Shallow DOF in a photo may create large amounts of bokeh. In many situations, this can be used actively to “paint” a background for your subject, like in the top photo where the green bushes in the background are so blurred out that they create a soft green colored background.

In other situations, you want as much depth in your photo as possible, e.g. you want most or all of the scene to be sharply focused. The most notable type of scene is of course landscapes. To achieve this you would use a small aperture, like f/16 or even f/22.

The corners of the triangle affect each other

Getting a good grip on all the corners of the triangle is essential, as adjustments to one have impact on the others.

Adjusting the aperture one stop wider or smaller doubles or halves the amount of light reaching the sensor, respectively. Following the same pattern, adjusting the shutter speed one step up or down has the same effect. Let’s say your light meter says your settings will produce a correct exposure. You realize that your aperture is so large that your depth of field will be too shallow for the scene you want to capture. By stopping your aperture down two stops, you need to increase your shutter speed equally two stops to achieve the same exposure. These two settings follow like hand in glove.

But this metaphor is actually not very good, as there is a third element here; the ISO. Your ISO setting has the same effect on exposure “correctness”, meaning that if you stop down your aperture 1 stop, you can go from ISO 100 to ISO 200 to achieve the same exposure.

Shooting in aperture priority mode

Normally when I’m out shooting, I first decide what aperture will fit the scene. If the lighting conditions are not complex (as with strong reflections, large dense shadows etc), I sometimes go for aperture priority mode (A or Av on the mode wheel, depending on your camera). This is faster, as I don’t have to constantly adjust the shutter speed as I move around exploring the scene from different angles. The camera measures the light and determines the shutter speed automatically. This will give me a consistent scene and depth of field and save me some time (and also ensure I don’t freeze my fingers off during the winter. Today, it’s minus 16 degrees (celcius) outside!).

Hettie, Nettie and Lettie, by Marius Waldal

Notice that in the above photo, only the middle duck (Nettie) is in focus. The other two are slightly out of focus, while the background is completely thrown out, revealing only a hint of what is there. When photographing these ducks I had to react quickly to movements, so I chose to use aperture priority mode to reduce the hassle whenever I found a nice scene. As you can guess, the ducks didn’t hold this lineup for a long time…

Although I normally shoot in full manual mode, I’ll definitely recommend those of you that are taking the step from fully automatic to manual modes to use this as a starter. It will give you less to think about, and at the same time all the benefits of shooting in RAW (you are shooting RAW, right? If not, stay tuned for an upcoming article on RAW!).

Full stops and fractional stops
On most digital cameras, the selection of apertures is larger than the original f-stop scale. Below is a table showing the list of one-third fractions, the most common selection today. The full-stop numbers are marked with darker background:

1.0

1.1

1.2

1.4

1.6

1.8

2.2

2.5

2.8

3.2

3.5

4.5

5.0

5.6

6.3

7.1

As you can see, if your budget lens starts at f/4.0, you’re missing out on about half the scale! Remember that each full stop doubles the amount of light reaching your sensor.

Large-aperture (fast) lenses

Most “budget”-type zoom lenses are relatively slow, with a maximum aperture around f/4.0. For Canon, if you step up to the “L” lenses, they start at f/2.8. Primary lenses are often even faster.

If you need a lens to take photos hand-held in low-light (like in a wedding, I would recommend a 50mm primary. Canon has three of these:

Canon EF 50mm f/1.8 II – This lens is very fast, and extremely cheap. If you want a fast lens but don’t have the money for it, this gives you a lot of speed for a low price.

My recommendation, though, would be this lens:
Canon EF 50mm f/1.4 USM – This is a very sharp lens with good quality, and with a price that can be justified by many. I use this myself, and I love it.

Canon has an L-series 50mm as well, for those of you with serious needs (or seriously fat wallets):
Canon EF 50mm f/1.2 L USM – This is a high quality lens aimed at professionals, and priced accordingly.

Conclusion

When adjusting your exposure, the aperture is the setting that will more often than not have an “artistic” impact on your composition. Using large aperture will create areas of bokeh in your photo. It is also the most important setting for portrait photography, to separate your subject from the background.

Nevertheless, the two other settings on the exposure triangle, shutter speed and ISO, are settings that you need to know innately to be able to adjust correctly and fast for any given scene. So stay tuned for articles on these settings in the near future!

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Take pictures in aperture-priority mode

9 tips to make this year’s Christmas photos better than last year’s

Marius Waldal — Fri, 11 Dec 2009 13:40:01 +0000

Once again, Christmas is just a few days off. Grown-ups are fuzzing around to get everything done and kids get more and more butterflies in their bellies. And even though it may not seem that way just yet, everything will be ready and the calm Christmas mood will be upon you. You’ll have a great time with friends and family, and of course you will want to capture it all with your camera. Take heed to these tips, and your Christmas photos will be even more interesting than those you shot last year!

Christmas Shopping HBW, by Photocillin on Flickr

Watch the background

Christmas time is decoration time. Often loads of it. This is of course an important part of creating the right Christmas mood (good), but it can also generate very fuzzy backgrounds for your photos (bad). Be sure to take your background into account when shooting, to avoid elements in your background that takes too much attention from your subject.

Move closer to your subjects

If the background is fuzzy, consider moving closer to your subject. More often than not, a photo will improve by removing the surroundings and filling the frame with your subject(s).

Christmas-time is bokeh-time

Day 4, by Phil Peck on Flickr

In no other time of year is your home so filled with various light-sources. Candles, the Christmas tree, stars in the windows etc. And why is this great for photographers? Because this is great for bokeh!. Being aware of your background will enable you to use these lights to best effect creating great bokeh in your Christmas photos.

Don’t take only posed photos

When you look at Christmas photos, they often include people looking straight into the camera (“Say cheeeeeeese!”). In gatherings like these, I usually prefer that people are not posing, as this often looks unnatural. I want my photos to capture the mood as it was, not how it was staged. Candid shots are great. Capture the intense glee the kids show, instead of the unreal calmness when they are posing.

Use a tele for kids

Speaking of kids. They have an uncanny ability to notice that someone is taking their picture (“Can I see, can I?”), so why not try and make it more difficult for them? If there is sufficient light, try using a tele lens so that you can get more distance to the kids and perhaps get some really nice shots of them playing.

Get down on children-level

Let’s not leave the kids just yet (after all; they are the most important part of Christmas, right?). Too many photos of kids are taken downwards. Get down to their level. This perspective is a lot more pleasant and interesting. Or even better; get lower! Photos of kids taken from below creates an unusual perspective that will add an interesting twist to your photos.

Cross-process some of your photos

Unique, by pixelprints on Flickr

While this isn’t really a tip that will help you take better Christmas photos, it will make your Christmas album even more interesting if you choose to cross-process some of your photos. Cross-processing adds an interesting “old style” feel to your photos.

Try to avoid flash

If you own one (or can borrow), go for a fast lens like a 50mm 1.4 or 1.8. This will enable you to take a lot of your photos without flash. If you use the built-in flash, most photos will have hard shadows and unnatural lighting. And a quality flash won’t help you much if it isn’t used right. To capture the warm, cosy Christmas mood, it is better to shoot without a flash. A fast lens (and a little higher ISO) is your friend!

Capture the details

As I said earlier, Christmas is very much about decoration. Which means details details details. Many of these details can be interesting subjects if you use your creative vision. Photos of details will add a nice touch to your Christmas photo album (you do print some of your photos, right? They don’t all just stay on your hard drive…?). Well, they look great in digital albums as well, of course

I hope these tips will help you take better photos this year! Do you have some tips on your own? Please share them with us! And if you’ve taken Christmas photos that you are particularly satisfied with, do share them in the comments section.

I wish you all a wonderful Christmas!

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Using bokeh actively in photographic composition

Marius Waldal — Fri, 30 Oct 2009 13:13:10 +0000

Many photographers are hooked up on focus, getting razor sharp rendering of their main subject. And many know the effectiveness of rendering the other parts of the photo out of focus to emphasize and draw even more attention to the main subject. But with just a little extra thought and awareness, these “other parts” can greatly enhance a photo. In this article, I will show you how.

Chained by Marius Waldal

What is bokeh?

Bokeh, derived from the japanese word boke, meaning blur or haze, has become an increasingly popular effect in the photographic world. The technique is not new, of course, although the term is relatively new.

When talking about bokeh, people often mean the circular shapes created by out-of-focus light-sources, as in the photo above. Indeed, for many, this is the most important aspect of bokeh. This is close to my personal preference as well, but it is important to point out that there is much more to bokeh. In fact, everything out-of-focus might be called bokeh, but in common use we usually don’t use the term for “almost-in-focus” areas.

Short DOF for bokeh

Using a short depth-of-field (DOF) is a common technique if you can’t control your background. If your subject is placed in front of a messy background, using a large aperture will then effectively remove so much detail in the background that it doesn’t compete with your subject for attention.

But using the same technique when you can control your background is a great way of getting the background to work with you rather than just not being a disturbance. Why? Because you can then “paint” a beautiful soft background for your subject.

Painting with bokeh

Holding on by Marius Waldal

In this photo, I wanted a colorful background since the subject in itself takes up so little space in the photo. The background I had to work with was the rest of the bush this twig belonged to. But I found it to be too dark and monotone. What I did was bend some branches and twigs away and then I crouched down to get a lower point of view so that I got a glimpse of the sky through the bush, and also some green leaves from another bush. This enabled me to “paint” more colors into my background, resulting in a photo with more life.

Bokeh as your main attraction

Ground level by kpriceWicked on Flickr

Above, I used bokeh to achieve a more pleasing background for my subject, but the background was still subordinate to my real subject. But sometimes, bokeh in itself can be the main attraction. You can do this by not including a main subject, or you can choose a main subject that in itself is less interesting than the bokeh.

Not including a main subject can be risky. This probably means that your photo is lacking something that the viewer’s eyes may rest upon. Our brains like sharp focus. This is a result of the fact that our eyes focus on subjects to “rest” on them. If they cannot find focus, they will keep on searching until we get dizzy and close our eyes. (If you’ve ever tried on a pair of glasses that are not adjusted to your eyes, you will know the feeling.)

For this reason, it is generally wise to include something in your photo that the eyes may rest upon. This does not have to be large, and preferably not very interesting. The mere presence of something in-focus creates a more harmonious sensation.

Different bokeh with different lenses

Twilight ballads by Astrid Tvedt on Flickr

How different lenses render bokeh vary greatly. You should try out all your lenses and see which of them creates the most pleasing bokeh. This is especially obvious when dealing with the kind of bokeh created by light-sources. Some lenses will create perfectly round bokeh circles, while others create octagons (this also depends on how large the aperture is).

Whether one is more beautiful than the other is of course a matter of taste, but it seems most people prefer round shapes. Learn the specifics of your lenses.

How to achieve bokeh

It has been mentioned already, but bokeh is most easily achieved using large apertures, combined with focusing on something relatively close. The larger the aperture, the more of the background is out of focus, and the more bokeh you will achieve. The aperture size will probably also affect the appearance of your bokeh circles.

Competing circles, by Marius Waldal

If you focus on something that is far away, you will not get much bokeh. At least not in the background. But with a little creativity, you can create foreground bokeh instead!

There’s no trick to achieving bokeh, as you can see. The trick is planning and using it right, resulting in bokehlishious photos!

In an upcoming article, I will take a more hands-on approach to bokeh, doing a case-study. So stay tuned!

If you have bokeh-tips you want to share with us, we would love to hear them! Also, if you have Flickr-photos etc where you’ve accomplished wonderful bokeh, please include a link in the comments.