Quality architectural photography is more than just snapping a bunch of pictures and handing the client a CD.  It is a multi-step process that, especially in low light  photography, results in a quality image. This applies to both interior and exterior photography.

Sun Angle
We never go to a site for an exterior daytime shoot without knowing the lighting ahead of time.  Photographing the front of a building with eastern exposure in the afternoon may  result in significant shade, which is not desirable. We use an online program called SunCalc, which uses Google Maps to plot the direction of sunlight on the subject at a specific time of day and day of year. This is not as critical in dusk and dawn photography, but can still have an impact.

Polarizing Filter
Don’t leave home without it.  In daytime photography, the polarizer minimizes glare, resulting in richer colors, especially in a blue sky.  In interior photography, it minimizes reflections on floors, countertops, etc.  Note that the polarizing filter only works on non-metallic surfaces.

Low Light Photography (dawn and dusk)

Shooting ‘Raw’
As discussed in another blog post, shooting raw images gives more control over the final image than shooting jpeg.  This is because the file is written to the memory card with little or no in-camera processing.  We do the processing later with special software.  This provides maximum flexibility.

Bracketing for HDRI
Because of the limited dynamic range of digital sensors, image quality falls off rapidly in areas of the image that are not exposed correctly.  Therefore just one exposure in low light situations will generally not yield a well exposed image. We capture three images of each scene, one exposed correctly for the overall scene, one under-exposed and one over-exposed.  This gives us more shadow detail and avoids severe over-exposure of bright areas, such as lights.  Because of the long exposures required and the fact that the three images must line up exactly, a tripod and remote release must be used. HDRI is also discussed in another blog post.

Raw Image Adjustment
The image files are brought into a program which  processes them in the same way the camera does when creating jpg files, but here we can have some control. The two most common adjustments made are exposure and white balance. Exposure correction generally does a better job when applied to the raw file than when using ‘lighten’ or ‘darken’ in Photoshop.  It should not have to be adjusted much, but the capability is there.

White balance is very important.  It is what makes incandescent lights look yellow and fluorescent lights look green.  The camera can be set to ‘Auto White Balance’, which tries to calculate how the scene should look, as long as we are shooting raw.  This is because the raw controls allow us to set the white balance to achieve the overall color balance we desire. We can make the scene ‘warmer’ or ‘cooler’ with the white balance adjustment.  When shooting HDRI, ie three images of each scene, it is important to set the white balance adjustment the same on each one.  Raw files provide many more adjustments, even lens distortion correction, if required.

HDRI Processing
Now it is time to merge the three images into one image with the HDRI software (or HDRI plugin in Photoshop).  The three images are selected and merged by the software.  There are many different adjustments in the HDRI processing software depending upon the desired ‘look’.  When satisfied with the image, the HDRI software will write a single file, which is merged from the original three.

Perspective Correction
Also discussed in another blog post, it is common, especially when using super wide angle lenses pointed up at a building, to have the building appear that it is falling onto itself.  This is not natural looking and is usually undesirable.  There are special lenses to correct this, but it is more common to correct it in Photoshop. There is some degredation of the image, but it is imperceptible.  This does force cropping of the final image, so we generally shoot wider than is necessary.

Final Crop
This determines the final composition of the scene.  The image is cropped to the desired composition and aspect ratio.

Additional Post Processing
The final step is to perform any other type of processing that is required, such as cutting out and editing a specific element, fixing blemishes, making light poles disappear, etc.

Conclusion
Of course, not every situation follows the above steps exactly.  Some may require more, some less.  But it is important to understand that quality architectural photography doesn’t happen by accident.  It is a result of thorough planning and execution, as well as the right knowledge and tools.