I'm new to real estate photography. For now, I am doing condos/homes in the $250K to $500K range with $500K being the low end of our price range for homes on the Kona side. I am not ready for the higher end homes although I have shot one condo that was in the $650K range. Currently using a Nikon D7200 with a wide angle Sigma 10-20mm lens. I usually try and shoot at 12mm (with the crop sensor I am at around 18mm). I keep my camera level, using levels and use the live view grid to adjust my line angles.
I have plans to purchase the Nikon D810 full frame camera (for other reasons beyond RE photography) and I am considering a Rokinon TSL24M-N 24mm or the Nikon PC-E 24mm tilt shift version.
Would you try and use the lens in a small condo (i.e. 700sft) with low ceilings etc? Would you use the T/S lens to shoot a small bathroom? If shooting in a small space, where you could not back up to get more in the field of view, have you had agents object to a photo that was shot at 24mm?
Tilt-shift lenses are fantastic for shooting interiors! Many real estate photographers don't want to use anything else once they've tried one. However, you do lose some flexibility in small spaces and as we've discussed recently, many real estate agents want wider shots that 24 mm. I would recommend having a wide angle zoom like the 14-24 mm as well as of a tilt-shift 24mm if you are shooting a lot of small condos. Also, you could always use your D7200 with the Sigma 10-20mm when things get tight.
Read our review on the classic 24-70mm lens if you don't want to go for a tilt shift option. Or, read our review of the best wide angle lens for real estate photography.