Sigma fisheye 8mm f/4.0 EX Circular fisheye

[francesco]

Hi people,
I'm thinking to buy a circular fisheye lens to do VR works.
I'm focusing my attention on the sigma 8mm. The specs talk that it produce a circular image of 22mm over a 35mm film.
A circular image with a filed of view of 180° is what I need but
I'm afraid thet mounting this lens on the S2 Pro will cut part of the top and part o the bottom of the circulare image (due to the specs of di ccd sensor).

What do you think?

thanks.

[Tom V]

The S2 manual says the sensor is 23.0 x 15.5 mm, so a fisheye lens with a 22mm image circle will get cropped about 3.25mm top and bottom.

Anyone interested in seriously wrestling with perspective, especially in wide angles or fisheyes, should visit http://www.panoguide.com/software/reviews/panotools_v21.html

PanoTools is a plug in for Photoshop that corrects images in ways you probably never thought of.

PanoTools can convert fisheye images into rectilinear images. It can correct barrel and pincusion distortion. It can even take into account the slight mis-alignment between the optical center of the lens and the true center of your image. You can stitch images together, correct perspective and all sorts of other things that are difficult, very difficult, or impossible in Photoshop.

[StormChaser]

Did you get the lens already ? I was thinking of getting it too, but can't find any feedback or articles on it.

[francesco]

I found few comparative informations about this lens and other fish eye lenses. My final opinion is that is the best fisheye lens I can buy for my S2. There are other chepest solutions like Peleng fisheye but the quality of the image is very poor and it will be cutted on the edge. If you shoot in portrait mode the sigma (with his 22mm circle) will not cut the top and the bottom of the image, so if you do 4 shots you will be able to use PTGui (or PanoTools) to simply have a spherical image.

If you need more information just ask me. I already decided to buy this lens on the next days.

[StormChaser]

If you get it, post some sample shots, I would love to see them.

Thanks

[francesco]

I will post a shot for sure.
For the moment seem to be that the sigma 8mm is the best solution cause the peleng has a very poor quality at the edges and the Nikkor 8mm f2.8 AIS is optically better that the sigma but the cost is 6 times the cost od the sigma, and it's not so simple to find it.
That's why I will buy a sigma.

Francesco

[Tom V]

Originally posted by francesco
...If you shoot in portrait mode the sigma (with his 22mm circle) will not cut the top and the bottom of the image...

Even if you shoot in "portrait mode" (vertical camera position) your 22mm fisheye image circle will cut off. Any way you hold the camera, it will cut off a few mm on two sides.

In order to get the entire circle, you would have to shoot one image, rotate the camera 90 degrees on the lens axis, take a second shot, and combine the images in a graphic editing program such as Photoshop.