lehighjack Loc: somewhere in FL

A WA zoom allows more flexibility. Stitching a panorama is always feasible, but time consuming. Sigma 10-20 3.5, very sharp at 5.6 or even smaller apertures. Tripod, a gray/white/black card, bare bulb off camera flash and/or window light. Insure that all light fixtures are on and has LED or incandescent at daylight temp. Save your money, buy the Sigma and use the difference, from the Nikon, to buy a Venus 15 mm f/4 macro with shift about a 22 mm with your setup. These two lenses will handle most Real Estate photography for you.

Picture Taker Loc: Michigan Thumb

I would not go wider then 15 or 17 as you get distortion. I would also consider a Tilt Shift lens. Using HDR will allow you to pick up out side the windows as well as a great coverage of dark and light in the rooms.
HDR does not have to look strange. HDR can open your camera's light range.

penndragonn

I have an Tokina 20-35mm F2.8 that is fantastic. 77mm filter. Heavy beautifull piece of glass push/pull AF/MF Type.
Can be had for under $400 on the bay.

coolhanduke Loc: Redondo Beach, CA

My go to lens is the 24-120mm.

byjoe Loc: Stillwater, OK

I have used a Tokina 11-14mm 2.8 for about 4 years and my realtor has never complained. Use it on a Canon but they probably make it for Nikon. Was not that expensive compared to Canon’s comp lens.

GoofyNewfie Loc: Kansas City

Again, the OP is using a full-frame body.
This Tokina is for aps-c bodies.
Not the info he’s after.

MT Shooter Loc: Montana

Not gonna stop them Jim. People LOVE to post when they have not read the OPs statement. Or they just don't have a clue to begin with. Its really frustrating for those looking for real, dependable information.

GoofyNewfie Loc: Kansas City

kenArchi Loc: Seal Beach, CA

kenArchi Loc: Seal Beach, CA

There are many good choices.

Nikon: 14mm, 14-24mm, 16-35mm, 17-35mm, 18-35mm

Tamron: 15-30mm, 17-35mm

Tokina: 16-28mm, lowest prices

Rokinon/Samyang: 12mm, 14mm

Irix: 11mm

CatMarley Loc: North Carolina

Yes, I have the samyang 12mm for my fuji. The 14 is very similar. Very nice rectilinear lens. Just set it at hyperfocal distance and forget about focusing. For real estate, you don't need a zoom - you can walk indoor and outdoor property to get the distance you want. And they are relatively inexpensive too!

rcarol

This lens is for a crop sensor camera. The OP is looking for a wide angle lens for his FF Nikon camera.

Picture Taker Loc: Michigan Thumb

If you go much wider than 17-18mm Lens -FULL FRAME (That is about 12 or 13 mm not full frame) you start to get distortion.

Bobspez Loc: Southern NJ, USA

I got the Sigma 15-30mm D , EX Aspherical IF lens which sells on ebay used for about $200. It's a big piece of glass. Very good depth of field. Attached taken with FF Kodak DCS Pro 14-N with a Nikon mount, at 17mm, f11, 1/125 sec, ISO-80, hand held.

(Download)

amfoto1 Loc: San Jose, Calif. USA

First thing you have to decide is how much you want to spend. Some of the lenses suggested so far cost a few hundred dollars, while others cost several thousand. Your budget will really decide what you should be looking at, but there are some other generalities:

You don't need "fast" lenses for real estate photography. You should be using a tripod (and possibly supplemental lighting), which will allow even indoor shots to be taken using long exposures. In fact, you'll almost always need to stop down for sufficient depth of field, so it would mostly be a waste of money to go chasing f/1.8, f/2 or even f/2.8 lenses. "Slower" lenses are often less expensive, smaller and lighter. They also often offer better image quality (esp. corner sharpness) and lower distortion.

Primes are usually better corrected and can be sharper corner to corner than zooms. However, zooms are obviously a lot more convenient and versatile.

If you opt for a zoom, you'll have to decide if you can live with a variable aperture... where the lens' max aperture changes as it's zoomed. Since you are going to often be stopping down for adequate depth of field, a variable aperture might be no problem. They also are generally not a problem with modern dedicated flash that's metered through the lens and controlled by the camera. A non-variable aperture may be important, though, if using manual lighting such as studio strobes. It also may be a concern with multi-exposure panoramas. But, again, all this can be overcome by stopping the lens down a little, which you're very likely to be doing anyway.

You actually don't need autofocus for real estate photography. In fact, the tilt shift or perspective control lenses mentioned previously are all manual focus... and those might be considered the most ideal lenses of all for architecture. They are highly corrected for linearity and their movements that can be used to control plane of focus and perspective effects. Some of the other lenses mentioned are both manual focus AND manual aperture. Those can be fine, too, for real estate photography.

The wider the lens, the more it will exaggerate room size and the more difficult it will be for the manufacture to fully correct distortions. Some people opt to work with a less extreme lens and, when an ultrawide view is needed, take several shots and stitch them together in a panorama.

Edit: Several previous responses have suggested "crop only" lenses. Obviously those would be less than ideal for use on your full frame D750. You are probably aware that you need "FX" Nikkors and should avoid any labelled "DX". Tokina uses the same FX = full frame and DX = crop only designations with their lenses. Sigma calls their full frame lenses "DG" and their crop only lenses "DC". Tamron "Di" = full frame lenses "Di" and "Di II" = crop only. Other manufacturers may have their own designations for each type of lens. You'll have to be careful and investigate any candidates you're considering.