PREJUDICE AFFECTS US all in some way or another, and can put us at a disadvantage.
For example, I had always bought lenses made by the reputable manufacturers of the cameras I chose to use, and baulked at buying cheaper alternative brands.
I believed that I was paying the price to get a better product, one that would give me the best possible result.
I had to readjust my thinking when I discovered that the rather inexpensive Tokina 10-17mm zoom fish-eye lens performed miraculously well once installed behind the dome port of an underwater camera housing and immersed in water. That discovery didn’t stop me buying a Nikon Fisheye lens when I upgraded to a full-frame (FX) camera.
I was accustomed to the close-focusing abilities of the Tokina lens on DX cameras, and disappointed to find that, good as the Nikon lens was, it didn’t focus close enough for me once it was under water.
So I bit the bullet and lost money trading it in for a cheaper alternative that would do what I wanted. That lens is the Sigma 15mm Fisheye.
This lens gives the same angle-of-view on FX as the Tokina does on DX when set at 10mm – it has a field-of-view coverage of 180°, and fills the frame with image. Some older fisheye lenses gave a circular image within the frame.
The Sigma is a lens of seven elements arranged in six “groups”. It has a maximum lens opening of f/2.8, which is very useful for low-light viewing via the through-the-lens viewfinder of the camera, although it needs to be stopped down a little to f/8 or smaller to get perfect corner-to-corner sharpness.
FX cameras all have built-in focusing motors to give them auto-focus even with inexpensive lenses of other makes. This is not necessarily true with cheaper DX digital SLRs.
The depth of field is so massive with this lens that one is almost unaware of the focusing operation.
The minimum focusing distance is so short that the Sigma will focus on something stuck to the front of the housing’s dome port.
It has almost the same weight (370g) and dimensions as the 16mm Nikon Fisheye it replaced, so no adjustments were need to the camera positioning relative to my housing.
A filter mount at the back of the lens that takes gelatine filters cut to a rectangular shape accommodates those who want to shoot through a coloured filter. A little metal template is included with the lens to help you cut the gelatine accurately.
Underwater photography is all about getting close. The Sigma 15mm Fisheye lens allows me to get as close as is physically possible, while still getting everything in focus. That’ll do for me!

COMPARABLE LENSES TO CONSIDER:
Nikon 14mm f/2.8D, £1215
Nikon 16mm f/2.8D, £599

SPECS
PRICE £525
WEIGHT 370g
CONTACT www.sigma-imaging-uk.com
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