How to calculate WA 35mm equivelent?

Hi all,

Can anyone explain how to calculate the 35mm equivelent for add on WA lens? For example when starting with a 35mm standard digital lens and adding the Inon AD165 how can this be expressed as a lens mm quivelent (15mm, 18mm, etc) and how is this calculated.

Whats the equivelent when you start with a 28mm lens, or 24mm lens?

Any advise welcome to assist my limited knowledge

Hi all,

 

Can anyone explain how to calculate the 35mm equivelent for add on WA lens? For example when starting with a 35mm standard digital lens and adding the Inon AD165 how can this be expressed as a lens mm quivelent (15mm, 18mm, etc) and how is this calculated.

 

Whats the equivelent when you start with a 28mm lens, or 24mm lens?

 

Any advise welcome to assist my limited knowledge

It does not work that so easy.

http://www.bobatkins.com/photography/techn...ld_of_view.html

The Inon 165AD fisheye lens is just that --a fisheye. It cannot be compared directly to a rectilinear lens like most 18-28mm lenses. The FOV of the Inon 165AD is 165 degrees diagonal. It is not a rectilinear lens. BTW, I have both the Inon 100WAL with dome and the Inon 165AD fisheye and use both on my Canon A570IS and Ikelite housing.

IMO the 165AD has a FOV equivalent roughly equal to the Tokina 10-16 zoom fisheye lens @ about 12mm. Additionally the 35mm film camera has a 3:2 aspect ratio and the typical digicam has a 4:3 aspect ratio.

Photo above taken by pro with dSLR, photo below taken by me with Canon 570IS: