Table of APS, C mount, and projection lenses covering FF online

Started 3 months ago | Discussions thread
petrochemist Senior Member • Posts: 2,891
Re: Crop circles

aidaho wrote:

For sure. I've noticed there isnt a reference "fisheye" projection, fisheyes can basically get away with anything not causing that much of a discomfort to viewer and manufacturers leveraged this advantage to the fullest extent.

I've seen references to five standard fisheye designs, which all give different FOV for a given sensor/focal length & different displacements from the centre of the image for a given subject angle. For comparison a rectilinear lens has displacement = f.tan (angle)

These are:

Equisolid displacement = 2f.sin (angle/2)
Apparently the Sigma 8mm f4 AF EX & convex mirrors show this sort of image.

Equidistant displacement = f. (angle in radians)
The Peleng 8mm f/3.5 was claimed to match this design

Orthogonal displacement= f. sin (angle)
Rarely used in photography no examples known

Stereographic displacement = 2f.tan (angle/2)
Rarely used in photography no examples known

Thoby displacement= A.f.sin(angle.B) (where A & B are constants in any one design)
The AF DX Nikkor 10.5mm f2.8 ED being given as an example.

Apparently most real world fisheyes often don't quite match any of these projections!

I've found some of the fisheye converters I have cramp a lot of the FOV into the edges of the image - which doesn't make for a pleasing image!

 petrochemist's gear list:petrochemist's gear list
Pentax K100D Sigma SD14 Pentax K-7 Panasonic Lumix DMC-GF2 Panasonic Lumix DMC-G5 +15 more
Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow