What is the benefit of hiring a professional photographer to photograph interiors?
To make your project shine and be able to present your work to the world in its best light. Since most homes are private, it is very difficult for prospective clients and others to view all the hard work of interior design. Photos are the key to getting your work seen and noticed by others. Photos have the benefit of highlighting the best areas/details of the project and with the right point of view, masking any flaws or unhappy choices.
A professional interior photographer knows how to light the space and/or use natural light to showcase your work. They know how to find the best angles and interesting compositions to bring the space to live.
What should an interior designer look for when hiring a photographer?
Find a style of photography that you like and hire a photographer that shoots in that style. Make sure the work the photographer is currently doing is what you like and will match your style. Shooting interiors is a very niche area of photography and is very technical. Just because someone is an amazing wedding photographer does not mean they have the knowledge to shoot an interior space. A vertical wall must be vertical.
Current professional camera equipment is a must.
How can an interior designer prepare the space for photoshoot day?
Simple and fresh styling is best. Everything looks different from the camera's angle, so be flexible to allow to arrange things according to the camera's point of view. Flowers (always fresh, never fake) are nice and objects of various sizes/textures work great for styling. Keep styling natural and casual, work with what you have. Remove personal clutter. Layer to create a story. Less is more. Let the homeowner know ahead of time that it will get messy during the shoot, but not to worry, it will all get put back into place.