Fisheye vs ultra-wide angle

[StreetShooter]

What is exactly the difference between a fisheye lens and an ultra-wide angle lens?

I understand that a fisheye gives you a 180 degree view, but with vignetting ie your field of view is round instead of rectangular. An ultrawide angle lens, on the other hand, gives you a rectangular field of view.

What puzzles me is why there is a 15mm fisheye lens, and a 14mm ultrawide angle lens. Which would give a wider field of view? If the 15mm fisheye gives you a 180 degree field of view, does that mean the 14mm gives you a field of view greater than 180 degrees?

Would much appreciate some clarification on this, or links to a site that may help.

 

[zapp!]

I think the 14mm will give a lesser field of view due to rectilinear correction...

Wait for the technical experts to answer this...

 

[Simon]

Originally posted by zapp!
I think the 14mm will give a lesser field of view due to rectilinear correction...

Wait for the technical experts to answer this...

I have a Sigma 14mm f/2.8 Prime, anyone wanna try it out?

 

[ckiang]

If I am not wrong, there are 2 types of fisheye lenses - the one which gives severely distorted images covering 180° or more angle of view, giving you a circular image, and the rectilinear one which is more or less an ultrawide angle.

So, a 15mm fisheye can actually have more angle of view than a 14mm rectilinear lens, which has less distortion.

Regards
CK

 

[StreetShooter]

So basically angle of view does not always correspond to focal length?

 

[Red Dawn]

Hi

slightly off topic:

i have read on dpreview (and they have shown samples) that with a fisheye lens on a digital SLR, the 1.6x multiplier does not crop the FOV 1.6 times. in fact, u will get a focal length very close to the lens' 35mm focal length (eg u can get near 15mm for a 15mm fisheye on a D30)

in other words, if not for the intended distortion of a fisheye lens, u can achieve very wide angles with a digital SLR and a fisheye lens....

 

[ckiang]

Originally posted by StreetShooter
So basically angle of view does not always correspond to focal length?

99% of the time, it does. Except when it comes to non-rectilinear fisheye lenses. I was confused initially too. ;p

Regards
CK

 

[zapp!]

Originally posted by Simon


I have a Sigma 14mm f/2.8 Prime, anyone wanna try it out?

How much was the Sigma 14?

 

[siron]

Originally posted by StreetShooter
What is exactly the difference between a fisheye lens and an ultra-wide angle lens?

I understand that a fisheye gives you a 180 degree view, but with vignetting ie your field of view is round instead of rectangular. An ultrawide angle lens, on the other hand, gives you a rectangular field of view.

What puzzles me is why there is a 15mm fisheye lens, and a 14mm ultrawide angle lens. Which would give a wider field of view? If the 15mm fisheye gives you a 180 degree field of view, does that mean the 14mm gives you a field of view greater than 180 degrees?

Would much appreciate some clarification on this, or links to a site that may help.

I read a book saying fisheye gives up to 220degree!! How true is that?