Week 4 - Project Research Notes

Camera Techniques and Settings for Architectural Photography

Since I wanted to test the idea of incorporating architectural photography into my project's theme of symmetry, I thought it would be a good idea acquire more knowledge about how to manipulate a DSLR camera and its settings to improve my techniques before I went out on another architecture-themed shoot. 

I sourced and made notes from Nic Granleese's blog for architectural photographers which has given me a better understanding of why to use certain settings for capturing architecture, the value of perspective in my images and has also given me comfort in manipulating a DSLR and reinforced my knowledge in camera operation and logistics. This will be beneficial to my project as it develops my practical and compositional skills and means I can spend more time focusing on the composition of my shots when on location than toying around with the settings.

Here are the notes I made from the article: http://blog.nicgranleese.com/

Perspective Control

Figure 1

In figure 1, the building on the left has vertical lines that are parallel (Perspective correct), while the building on the right has vertical lines that are converging (Falling away). The general orthodoxy of architectural photography is that an image should be perspective correct. That is the type of image that magazines typically require and photographers spend a lot of money on specific cameras and lenses to ensure they can achieve this. 

How to create this basic perspective correct images is to do with the angle of the actual camera. All you need to do is make sure your camera is perfectly level. You can do this by using a level that sits in your flash mount; via the spirit level built-in to your tripod; use the leveling tools provided in new model cameras. 
Once the camera is perfectly level, it’s view plane will be parallel with rectilinear buildings and this will produce perspective correct images, as you can see in figure 2.

Figure 2

Warning:
If you tilt your camera, (which is typical when you’re trying to fit a large building like a skyscraper into your frame) then you end up with the camera’s view plane being skewed to the building and this results in the building falling backward in the photo.

This is because when you tilt your camera up, the distance between the top of the camera’s view plane and the bottom is no longer equal. The distance at the top is larger and therefore the top of the building becomes smaller in the photo. Even a very small angle change in the level of a camera will result in an image not being perspective correct. Check figure 3 for a visual interpretation of this issue.

Figure 3

Potential Problem when Shooting:

When you are composing shot and trying to make the camera perfectly level, a large proportion of your photo will be taken up by the ground. But you now have a perspective correct image, but you cannot see the top of the building. 

- This is where tilt shift lenses come in because they allow you to keep your camera level, but they also allow you to mechanical move the lens so you can fit the top of the building in.

- You can use Photoshop in the post-production phase to correct the perspective by distorting the image.

- Crop down the image

- Use a wide angle lens (35mm focal length or less)

- Move away from your subject and maybe to higher ground, but now you may need to use a telephoto lens

Results

By abiding by some of these rules, you'll end up with far more content in the frame than you wanted, but you can get rid of this by cropping down the image so the focus is on the building. THE MAIN ISSUE WITH THIS METHOD IS YOU COMPROMISE THE QUALITY FOR PERSPECTIVE SO CHOSE WHICH IS MORE IMPORTANT.

Horizontal, Parallel Importance

When you look at architectural photographs, particularly of buildings, horizontal lines converge just like vertical lines, but often this is just part of the natural perspective of the building getting smaller in the distance towards what is known as the vanishing point. 

To get both the horizontal and vertical lines of your shot parallel within you shot, you need to deal with them both separately. However, to save time, you can:

1) Use Live View
By using live view, you can via the settings put on a more detailed grid overlay than the viewfinder. The grid will give you a reference as to whether the lines of the subject are parallel, or converging. If they’re not, then rotate the camera left, or right until the lines become parallel. Obviously, this method requires the camera to be mounted to a tripod and a geared three-way head is recommended for fine movements. What you’ll find is that even very subtle adjustments will effect the horizontal lines.

Architectural Photography During the Daylight Hours

Twilight is a favourite time of day for many architectural photographers, but due to time constraints, I may choose to shoot during the middle of the day. Nic Granlesse came to the conclusion that "twilight is not the be all and end all of architectural photography and that strong daylight is a valuable tool for particular scenarios."

Why Not During the Day?
A typical problem in architectural photography is that there are different elements in your frame that will expose differently. Some will be very dark and some will be very bright. Your camera can’t capture the extreme differences, even if you're using high dynamic range settings (HDR). Thus, you are then forced to expose for either the really bright objects (like clouds or metal) and have murky dark areas (like the shadows under a tree) or visa versa, expose for the dark areas and have blown-out bright areas, loss of colour saturation and glare.

You normally overcome this by shooting at twilight when the light is softer and the difference between the bright areas and the dark areas is more balanced. What you don’t normally get at twilight though is strong direct sunlight that can provide reflectance to things like glass and metal and it’s also difficult to give materials with strong colours their punch because the twilight is balancing everything out.

If you do decide to shoot architecture during the day, Nic Granlesse recommends shooting things such as:
- Shiny material such as glass or metal
- Materials with strong colours like red, green and blue
- Rusty materials as the daylight will bring out the highlights better

3 Tips for Shooting Architecture During Midday

1) Photograph during perfectly clear days
This avoids white clouds which are typically too bright compared to your building. What you’re left with is a blue sky which acts like a blue screen in the movies. This allows you to expose for your building (which will typically leave the sky too dark) and then adjust the sky in Lightroom or similar software afterwards. Since the sky is now one simple colour, this adjustment is super easy, it’s just one slider (discussed in another one of Nic's blogs). The other problem with clouds is that they diffuse the light which can take away from this technique.

2) Keep the sun behind you so there is direct sunlight on your subject
This will mean that your building is bright which will bring out colours, details and shiny materials. It will also balance the brightness exposure of the building with the already bright sky.

3) Isolate your subject and focus on details
The challenge with architectural photography during daylight hours isn’t that it’s too bright, it’s that the range between bright things and dark things is too high, so you often end up with one thing that is exposed well and a lot of other stuff that is too dark or too bright. By isolating your subject you simplify the number of light intensities your camera is trying to deal with.

Getting Off Auto

With architectural photography, your subject tends to always be static. Therefore, a lot of architectural photographers use the 'Aperture Priority' mode when taking shots as this allows them to control the depth of field of the photo, but leave the shutter speed for the camera to figure out. 

Fine Tuning Aperture Priority Mode

There are two other things that you’ll want to learn more about if you plan to use aperture priority mode. The first is metering modes, which controls how a camera measures light in a scene to calculate a shutter speed. The second is exposure compensation which allows you make shots taken in aperture priority mode lighter or darker.

- Metering Modes - https://www.youtube.com/watch?v=BK9cKMXG_Gs

- Exposure Compensation - https://www.youtube.com/watch?v=2sWIqzcSs4s

Focal Length and Architectural Photography

From the diagram on the right, it makes you question why wouldn't you always use a wide angle lens for architectural photography?

Well all lenses have compromises. What a wide angle lens does is cram a lot more of a building into a single frame. This affects the proportion of your shot. As a general rule, try and use a 24mm lens, which is a sweet spot for many architectural photographers.

Focal length affects more than just field of view. Magnification, image sharpness and bokeh (Background blur) are also factors to consider. 

Depth of Field and Architectural Photography

3 Things That Affect the Depth of Field

1) Aperture

Aperture is a prime control of depth of field. A large aperture (small number) results in a shallow depth of field (good for details) while a small aperture (large number) results in a larger depth of field (good for almost all other types of architectural photography). However, aperture is not as effective in controlling the depth of field in architectural photography as it is in other types of photography. 

2) Focal Length

The smaller the focal length of the lens the larger the depth of field. So using a wide angle lens will increase depth of field while a zoom lens will reduce it.

3) Distance

As the distance from the camera to the subject increases so does the depth of field. This is why it is difficult to achieve background blur with large subjects like architecture.

Why Depth of Field is Different in Architectural Photography

Architectural photography often involves large distances and wide angle lens a large depth of field is almost always achieved no matter what aperture you select. You can test this concept by using an online depth of field calculator. Enter some typical details for architectural photography like a distance of 50m and a 24mm lens. Now adjust the aperture. You’ll see that the far plane is fixed at infinity and changing the aperture only affects the near plane. What this means in a practical sense is that the concept of DOF and adjusting the aperture in architectural photography is more about deciding how much of the foreground is in focus.

F.11 as a Rule of Thumb in Architectural Photography

Aperture 11 is the rule of thumb for architectural photographers as its a good balance between depth of field, shutter-speed and image quality. 

Once you go beyond an aperture of 11, the change to the depth of field is minimal and you have to contend with other issues because smaller apertures let in less light and increase exposure times. You also move away from the lens’s sweet spot when it comes to sharpness.