I am in need of a lens for my Canon 70D. Ultimately I would like a Sigma 10-20mm, but also in need of a general all purpose lens. I've also considered something like the Sigma 17-70mm so I can get F4 across that focal range. The only lens I have now is the Canon 50mm 1.8. Would the 17mm be adequate to at least get started? I don't have the money for both.
17mm will generally be enough for most rooms apart from very small bathrooms, etc where you can't "back up' enough, but it is dependant on the client. Generally there's two schools of thought the clients falls in to:
a) The photos should be as good as they possibly can be to wow the client and get them to view the property. This is generally for upper-end properties that have a good level of fit and finish, are nicely decorated/furnished, etc... These are the clients where your 17mm might not be acceptable as they want the super wide wow-factor to feel like the person viewing the photo is immersed in the room. The client being wowed by how nice the house looks books an appointment to view.
or
b) The photos are there just to give enough of an indication as to the general space and layout of the house to get the customer interested in viewing it in person, they don't want to give too much away, they'd rather the bad points be addressed in person by the agent who can steer the potential buyer away from the not so good aspects of the property and talk about the "potential".
So in short low-mid end vendors will generally be happy with 17mm shots high end might demand more.
You can always stitch images together though if push comes to shove.
