Micro 4/3 wide angle options

Lots of good comments in this thread.

I have been experimenting with wide angle shots using my E-M1. Some of what I have learned below.

The FT 7-14 is often available used (ebay) or reconditioned. Works fine (if a bit slow focusing) on mFT.  Lovely lens (if large, especially with the adapter).

Microsoft ICE used to be limited in processing wide angel lens panoramas. Not yet tested the new version, but the earlier one quit at about 12mm mFT equivalent. However, when it works, it is far faster, easier and often better at building a panorama than the alternatives I have tried. I think Photoshop may have the same issue building panoramas from extreme wide angles and fisheyes, but I have not tried in a while.

Shooting a 2 frame panorama with the Rokinon 7.5 lens and feeding it to PTGui or Hugin or Panavue will generate a fully "de-fished" shot in way less than a minute if shot with a tripod. A cylindrical or spherical projection, especially if cropped a bit generates the straight lines you require.

A very light-weight and low cost single row panorama head can be built with an L bracket (mine is from RRS, but there are others), and a nodal slide clamped to a leveling, panning (above the leveler) ball-head or equivalent.

A kit is available that allows a normal ball head to be reversed so the panning rotation is on the top and you level it using the ball. Flip Kit to Invert Tripod Head for about $20 from Amazon. I just leave mine on the tripod inverted as it works fine for regular tripod use when inverted. You need a shortened nodal slide (you will need to cut one down to keep the end of the slide out of the frame) to use the Rokinon, but the FT 7-14 and 12-40 pro both need a 180 nodal slide to drop into the ball head clamp. PTGui will build panorama shots (with HDR if desired) so you may be able to get window views and interior without adding lights.

360 perspective of a Yurt shot with OMD E-M1 and 7.5 mm Rokinon Full Frame fisheye

I am not a pro, and the shot above was an experiment using PTGui to stitch and do HDR. PTGui can produce web page browse-able output directly that allows the normal pan and zoom you would expect in an on-line real estate presentation. The sticks bending at the top are not a lens distortion, they all meet at the top of the rounded ceiling. The Yurt was lighted though the windows and the 6' glass circle in the top--it was pretty dark inside.

With a higher budget, the same trick the $20 Flip kit performs is also available in a very robust "Ball Head with Gimbal Feature, Panoramic Head...." from Arcatech. Finally, you can use a leveling base with panning clamp to get an efficient single-purpose way to mount the modal clamps described above.

I have tried using multi-row panorama hardware, a leveling base with panning clamp and nodal slide, and the flipped ball head with nodal slide. I prefer the flexibility of the flipped ball head approach, but if I was doing a lot of real estate interiors, the leveling base with panning head is really easy to set up and use--and both weigh well under a pound.

Once you have put the kit together and calibrated the entry pupils for your lenses, the time to set up and shoot a single row panorama is not much longer than the time to shoot one shot.