8 replies to this topic

[Nico]

Hi all!

Just received my Nexus D100 housing and i can hardly wait to try it out! I also got an Athena 170mm glass dome port which I intend to use with a Sigma 15mm fisheye and flat ports for Nikon's 60mm and 105mm macro lenses. However, I feel that with the 1.5x cropping factor, the 60mm now becomes a bit too long for general fish photography. For this, I am thinking of getting one of the following:

20mm/f2.8D
24mm/f2.8D
28mm/f2.8D
35mm/f2D

All the above lenses have a min. focusing distance of 0.25m except for the 24mm which has a min. focusing disance of 0.3m. Right now, I am leaning towards the 35mm as it will still allow me obtain about 1:3 when in a pinch. What do you guys think?

Also, can you guys/gals recommend any diopters and/or filters that might be useful for my setup?

TIA

- Nico

[james]

Have you considered a short zoom lens like the 24-85AFS G?

Cheers
James

[Alex_Mustard]

I am a big fan of Sigma's 28-70 f2.8mm. Excellent for the fishies.

[craig]

The 20mm and 24mm work behind the dome without diopters. I don't know about the 28mm and 35mm. The 60mm works great behind the WP-4 small dome and the multiport base. Doing so makes the 60mm effectively 90mm, only 10% longer than it would be with a flat port and a film camera. No diopter is needed to do this.

By contrast, a 35mm with the D100 and a flat port would be effectively 70mm. I believe the 60/dome would be optically more desirable. The short zoom choices will be limited to what you can get gears for . The Nikon 24-85 f/2.8 does not have gears but I hope to get some made. If you have the time, that might be a nice choice. Don't know about the Sigma, but's probably the same issue. Call MCD.

[Cybergoldfish]

A good all around value for money lens is the Sigma 24mm, it's as sharp as a pin. In a dome this gives the equivellent of a 20mm Nikonos lens which I use for 80% of my work.

In theory the 24mm would be an equiv (20 x 1.6 =) 32mm - Perfect for fish and sharks. Good DOF and close focus ability.

[underwatercolours]

For fish pictures I almost always use a 60 or 105 for juveniles and fish faces. Now that I've gone digital I find the 60 even more useful because it ends up somewhere in between (and the 105 only useful if I can park myself in one spot and stick to macro and tiny, tiny fish. This depends also on where I'm diving and how much time I've got to hang around one spot or if I'll be cruising with a current and required to keep up with a group. I would like to pick up a zoom lens, but also don't want to give up the macro option either. Whether this is right for you might depend on your composition and style.

[Nico]

Thank you everyone for your suggestions!

I have also considered using either Nikon's 18-35 or Sigma's 28-70 zoom lens but Nexus does not currently offer any zoom gears for these two lenses. I will prolly just wait for Nikon's 12-24 zoom and have an extension ring and zoom gear custom made for it. For the meantime I think that I will just get a 24mm prime and use it with a domeport.

Cybergoldfish, the Sigma catalog only lists the 24mm/f1.8 Macro lens and is more expensive than Nikon's 24mm/f2.8D lens (about U$341 vs. U$308) here in Japan. In fact it is a couple of U$ more expensive than Nikon's 20mm/f2.8 (U$333 ). One thing I like with the Sigma is that the Sigma can focus much closer than the Nikon (0.18m vs. 0.35m) and it can obtain about 1:2 magnification albeit with a very small working distance. Knowing that the virtual image of a subject at infinity appears at twice the dome diameter (0.17m x 2 = 0.34m in this case) measured from the dome center, and knowing the minimum focusing distance of the Sigma and Nikon 24mm lenses, is it safe to assume that the Sigma will work with my 170mm dome without a diopter while the Nikon needs to be fitted with a diopter to work with the 170mm dome? If diopters are needed, how does one decide which diopter to use?

- Nico

[Cybergoldfish]

Hi Nico,

Check the price of the Sigma 24mm at Cathay Camera in Singapore, I'm pretty sure it will be less. This is a lens I need to purchase myself as my original was stolen along with 41 others! I doubt either of us would be disappointed.

I would opt for the Sigma over the others as you are shooting through sharper, prime fixed optics and as you say there will be no need to buy an expensive ($80 - $100) secondary optic.

You should also check out the Sigma 15 - 30 mm lens, expensive in relation but very flexible, with a narrower barrel than the 17 - 35mm giving more port options (small dome with an extention collar).

[craig]

The 15-30 will work with the small dome and extension like Bob said. I just tested it. You still need to find a zoom ring and the right extension length, probably 60mm.