What are the ultra-wide-angle options for the NEX?

Started Jul 28, 2013 | Discussions thread
OP DWMurf Senior Member • Posts: 1,203
Re: De-fishing the Rokinon fisheye

ProfHankD wrote:

DWMurf wrote:

Does it make sense to go with just a fisheye lens and make corrections according to the results desired like I did here? Or do I need to buy both a fisheye and rectilinear ultra-wide-angle zoom for the best results?

De-fishing (projection transformations in general) do not change perspective (relative sizes of near and far objects), so a de-fished lens at beast is equivalent to a fixed-focal-length ultrawide. Further, it is very difficult to visualize the precise rectilinear image when looking at the fisheye view in the viewfinder/LCD, and NEX doesn't support de-fishing of the live view (something I've had students play with on CHDK PowerShots).

In sum, zooming is exceptionally useful for ultrawides because of the control of perspective it allows, so I have both ultrawide zoom and fisheye lenses. Unfortunately, ultrawide zooms are optically challenging, so they are not cheap -- in fact, the two most expensive lenses I own are the Sigma 8-16mm and Sigma 10-20mm I bought before there was an 8-16mm....

So much can be done with images in post processing, but there seems to be limits to what can be done for the time being, at least until the next breakthrough in imaging technology. I guess once 3D objects are projected onto the 2D surface of the sensor there is only so much that can be done, so that it would be difficult to change the relative size of near and far objects even with Photoshop.

There are perspective correction tools that can be used in post process so that one can bring the leaning walls in a building photo back to vertical, like an architectural photographer would traditionally do in the first place with his camera. I am sure that you are aware of all this, I'm just expounding on what I think you are referring to.

After many years in the architectural profession, I'm very familiar with constructing perspectives mechanically on a drawing board in the past and now with computer aided drawing and 3D modeling software, but I am on unfamiliar ground with extreme wide angle views and the spherical projection of images in fisheye lenses. There is more to learn for me now, but the traditions of what looks right, by keeping the perspective within the normal angle of vision and keeping vertical buildings looking vertical still seem to be valid in most architect's eyes.

Unlike drawing, there are often real life restraints that limit the viewing point for buildings both on the exterior and interior, so it seems that there is the need to do things photographically to make up for that. It would be great if the perspective in the photos could be manipulated as if one had stood back far enough for the photo, or had removed a wall to see inside, to avoid an ultra-wide angle view that stretches buildings and spaces unrealistically. Although it seems that some real estate brokers like that sort of exaggeration of the size of the buildings and spaces.

That CHDK PowerShots sounds like fun, I'll have to try that on my Canon some time.

In my film camera days, ultra-wide and fisheye lenses were not available as they are now. An 18mm lens was considered extreme and not normally used it seems to me. There is more for me to learn now days.

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