I've just done my own pool trial with the Nikon 12-24 in my new Subal housing. I've never been a fan of zooms underwater and was ready to hate it.

I know that it has been done already, but the configuration available to me was SWB port, 33mm extension and a plus 4 dioptre. I was about 1.2 to 1.4 metres from the pool wall.

I was pleasantly surprised with the results. There is noticable pincushion distortion at 12mm with much less at 24mm. I don't find this distortion unacceptable and in fact it is not really noticeable at when you're not photographing a grid pattern.

What i was very happy with was the corner sharpness which was good throughout the f stop range from f4 to f22. There was not really chromatic "breakup" which I did used to get with my 20mm lens and the small DP54B.

The thing will focus down to about 6" from the dome at 24mm and probably 3" at 12mm!

I'm sort of pleased that I'm happy so far with the 12-24 because I have sold my fisheye (geez that was dumb) and I don't happen to have a spare OZ$2K for an FE2 port.

I'm off to Mount Gambier in South Australia on New Year's day to do some cave and sinkhole diving. I'll be taking the new toy! See http://www.users.bigpond.net.au/harry_online/Cave diving sites 1.htm (sorry I can't get the URL thingie to work, you'll have to cut and paste but it is worth it) for some shots of the places I'm going, especially Picaninnee Ponds and Kilsby's Sinkhole, both of which have visibility in the range of 60 to 100 metres.

I'll have access to a 16mm fisheye with the old 6" Subal FEB fisheye dome so I hope to do some comparative shots there too. i may also try the 12-24 with the FEB, but my understanding that as it's the same radius as the SWB I'll probably not see much difference.

Was there a question here?

If so, then answer is FE2 port with EXR-50 extension and +2 diopter (although some feel the diopter is not necessary).

Regards,

Yeah sorry I sort of got carried away.

The questions are:

1. For the extra OZ$1K is there any appreciable difference with the FE2?

2. Can anyone direct me to test(s) that show the differences between the SWB and the FE2?

3. Am I correct in my assumption that since the FEB (old fisheye) and the SWB have the same curvature that I will get the same results with these ports?

Andrew,

This may be what you're looking for.

The very negative MarineCamera.com tests which showed unacceptable pincushion distortion with the 12-24 and a diopter with the SWB port is located here. Their conclusion was that "any glass added to the [12-24] lens causd optical distortion" and that the 12-24 lens was unacceptable for underwater use.

Craig posted the reference to this test in a discussion in this thread in September and some of his own tests with the 12-24 and the SWB port.

The second page of that thread contains two posts iwth some test shots of mine with the 12-24 lens and the FE2 port that show what I consider quite minimal distortion.

For me, it seems pretty clear that the problems reported in the MarineCamera.com tests were primarily related to the inappropriate choise of the SWB port. As far as I'm concerned, the FE2 (used with a 50 mm extension ring and a +2 diopter) is clearly superior to the SWB for use with the 12-24. This also seems to be Subal's position - they do not recommend use of the 12-24 or any other hyperwide lenses with the SWB port.

Robert Delfs

Many thanks Robert.

I've been using the 12-24 behind the FE2 port with a 50mm extension ring, no diopter. According to Arnold Stepanek, the diopter is necessary only if you want to match the near focus of the lens out of water. For most wide angle applications that's not necessary.

The great white shark photos on my website were all done with this setup, mostly at the 24mm end. Check them out at www.ehanauer.com.

Eric

Nice! All natural light? Your sun-rays look very good.

Cheers
James

All of my white shark shots from Shark fest 2003 ( on my website) were taken with the FE2 dome and the 50 mm ext. ring. No dioptor. More shots were taken at the 24 mm end on the zoom but most of the good ones were at or near the 12 mm end.

James,

All were shot with soft strobe fill, two Ike DS125's at 1/4 and 1/8 power with diffuser.

Eric

You know it's fascinating how different people can use the same equipment is what seems to be the same way and get such different results.

With my D10 housing and Nikkor 12 -24 I used the SWB, a 33mm extension and a +4 dioptre. This is what SeaOptics told me to do.

I've done some pool tests with this and now shot some natural light W/A, W/A with one strobe and a little CFWA.

As far as I can tell this combination is sharp as a tack. It's good at f4 and it's good at f22. Better even than my old 20mm.

I dunno what the other guys were doing but I won't be buying an FE2 in a hurry.