The Tokina zoom 10-17 mm fisheye and the Canon EOS 5D

Shown here with a Nikon mount...

Dave Albright at 360Texas.com has shot sets of photographic images with a Canon EOS 350D and a Canon EOS 5D that were fitted with the new Tokina 10-17mm Zoom Fisheye - Canon mount - on behalf of Rodrigo Alarcon-Cielock, the lens owner).

Canon EOS 350D /Tokina 10-17
Canon EOS 5D /Tokina 10-17
Canon EOS 1DsII /Nikkor 10.5 mm (shaved) Canon EOS 1DsII / Sigma 8mm
Focal length @ 10mm
Focal length @ 11mm

Above, on the left part, is a comparison of two typical photos (thumnails resized to the same dimensions) from two different Camera/Sensor size. Note the effect of the sun shield of the Tokina Zoom lens on the larger 5D sensor coverage.

On the right, I have put two other typical (unrelated to the other pair) images from photographs on a fulframe 24x36mm sensor. This is just to give an idea of the different coverage area by three different lenses on a sensor of same size (EOS 5D and EOS 1DsMark II respectively).

It is rather obvious that the image distortion mapping of the Tokina (& Pentax) designed lens is very different and may be much more of a standard equisolid projection type than the Nikkor lens: the circle of the "freed from sun shield" picture shall be much larger than on the Nikkor case.

What about the Angle of view of the Tokina zoom on a FF (24x36mm) sensor?

I have used the photographs from the second camera (EOS 5D).

I then have first slightly rotated these 7 images by 1 degree CCW. (It seems that the lens sun shield is slightly wrongly rotated in the Canon mount reference frame).

I have also rotated the zenith shot by 90 degrees to have it in portrait mode as were already the other six images.

I have inputted all seven pictures in PTGui 6 on the Mac and cropped all of them in PTGui to described them as Fulframe fisheye images.

After optimization those images looked typically as follows in the Crop Tab Window of PTGui:

1) One of the six images of the sides (this one facing toward the sun with typical flare for this type of fisheye):

2) and this is the Zenith shot:

I ran again PTGui, optimized the panorama and finally PTGui outputted a PSD multi-layered equirectangular image.

Here it is shown (reduced and flattened):

And at last, one could look carefully at the Zenith side layer of the equirectangular image:

One can see clearly that the four corners of (the top side) rectangular cropped original rectangle are at an angular distance of about 97 degrees from the zenith

and the sun shield is not yet sawed-off....

Conclusions:

1) This zoom lens can be mounted on the EOS 5D to safely shoot beautiful and apparently crisp images. Thanks to Dave Albright at 360Texas.com for having shown this important fact and to Rodrigo Alarcon to make me aware of this. BTW: Rodrigo had used this zoom lens for the making of its latest WWP contribution.

2) The automatic operations of the lens are not crippled at all: it's a fully compatible Canon mount made by Tokina.

3) As for the Nikon 10,5 mm f/2.8, the sun shield of the lens "vignettes" the picture only to compel the user to use only APS-c camera and not venture to mount the lens on a fulframe camera such as Canon EOS 5D or EOS 1Ds or 1DS markII etc.

4) Fortunately, this sun shield doesn't completely hide most of the diagonal of the covered field on a full frame 24 x 36 mm sensor camera.

5) The usable angle of view of the potential circular fisheye (at 10 mm focal length) is found to be probably much more than 180 degrees. It may be as high as 194 degrees! (Some tests should be done to check if this marvelous discovery is not a mirage though).

6) The angle of view of this Tokina-Pentax zoom fisheye lens on the diagonal of an APS-C DSLR sensor (e.g. EOS 350D) is claimed by the manufacturer to be 180-100 degrees. This has to be confirmed: I could not concur fully with this statement. Here is my own experimental result.

Hence this lens is potentially another candidate for a free shave!!

Panorama Image quality:

I was not provided with Nadir pictures to make a complete cubic QTVR from the EOS 5D only. For the fun, I have fed PTGui with the set of seven 5D photographs mixed with the two Nadir shots from the EOS 350D

Apparently the zoom setting for shooting with the EOS 5D was 11mm and 10mm with the EOS 350D. The shootings with the two different combos were done four hours apart, hence the sun and shadows had moved a bit in the mean time...

The resulting panorama is here (1.6 MB QTVR)

Note: The aperture was set at f/14 for the shootings and this small opening may emphasize the flare effect on one of the 5D picture (as this happens also on the Nikon 10,5mm f/2,8).

Michel Thoby

Rev: 15 January 2007