Sea&Sea Compact Dome for Tokina 10-17

Is anyone using the compact dome with the SX extension ring with the Tokina 10-17 ? IF so is it working well, or would you recommend the fish eye dome ?

Also, is it possible to use the Tokina 12-24 with this combination ?

Thanks !

Sea&Sea recomends the Optical dome + SXER, which is basically a Compact one made of glass.

So it should work well on the Compact + SXER. The Nikon 12-24 also uses the same configuration.

If the Tokina is about the same size with the same close focus capability I would say it works well also.

The compact dome with the sx extension works well with the tokina 10-17

I wouldn't take much notice of Sea&Sea's recommendations.

There is no vignetting at any focal length with this combination.

You can, of course, use the other bigger domes but I find real advantage in the compact dome, particularly as it allows you to more easily light for close focus wide angle.

Well when I was buying my setup Yuzo (uwdigitalcamera.com) recommended me 40 mm NX extension ring and Optical Dome port, but I bought NX Fisheye Dome port (lack of money:) and all is working fine, in start I was using Sigma 10-20 with that port setup!

I wouldn't take much notice of Sea&Sea's recommendations.

Well, I wouldn't put it this way.

I know Sea&Sea does extensive tests and has an extremely high standard for image quality in it's previous tests before releasing an "official port configuration".

May I would say that due to market driven reasons the choice of ports/lenses can be improved upon with some tests... more politically correct.

One good parameter is the Athena compatibility table.

Their big dome can be compared to the NX Fisheye Dome, and the smaller one is about the same size as the Compact and Optical Dome Ports.

Other than that, the min. focus distance + lens length are the best parameters, but I would double check it in a pool with a couple of ERs.

Good luck.

I think Marcelo is spot-on in his last post.

Thanks for the replies - I spoke to my local Sea & Sea dealer this week-end, and he also confirmed that the compact dome port would work fine with the 10-17.

However he wasn't sure about the 12-24. Has anyone used this lens ?

Thanks for the replies - I spoke to my local Sea & Sea dealer this week-end, and he also confirmed that the compact dome port would work fine with the 10-17.

 

However he wasn't sure about the 12-24. Has anyone used this lens ?

The 12-24 seems to need a strong dioptre (plus4?) to get shrp focus across the frame. I use the optical glass dome (like the Athena) with the 10-17 and rarely use another lens. The curved field-of-focus is ideal behind a dome port.

http://www.divernet.com/cgi-bin/articles.p...c=1054&ac=d

Lenses

A smaller sensor allows the camera to be used with a shorter focal-length lens for the same angle of view. This gives a better depth of focus for a given lens opening (f/number) - an advantage when it comes to taking macro shots through a flat port of an underwater housing.

However, if you want to shoot wide-angle pictures, you'll need an optical dome port. This, as its name implies, becomes part of the optical system. The image focused on by the camera lens is actually a virtual image formed a short distance in front of the port, due to refraction where air and water meet.

One of the bigger challenges of taking wide-angle pictures through a curved dome port is in achieving a sharp image across the frame. Wide-angle lenses that have been designed to have a flat field of view, as one would need when using them in air, tend to be less able to focus on this curved virtual image across its width, and chromatic aberration (colour-fringing) is then evident.

Ironically, adding a strong dioptre supplementary close-up lens often adds the lens aberration and distortion needed to get it sharper, but a lot of wide-angle underwater pictures still have horribly smudged details at the extremities.

The bigger the sensor, the longer the focal length of the lens needed and the bigger the dome port required for a sharply focused picture of the virtual image so produced in water. Supplementary dioptre lenses also shorten the focal length of a given lens, allowing it to focus closer for a given lens-to-sensor distance.

So a bigger sensor means using a bigger dome port for the same quality of picture. A full-frame camera may need a housing with a 9in diameter dome port, whereas the cropped sensor DSLR will need only a 6in dome.

This is probably why medium-format cameras never became popular under water - they would need even bigger domes. It was just too difficult to get a satisfactorily sharp picture. So there's an optimum size of sensor, depending on the angle of view of the lens being used.

On the other hand, if you are shooting in low light conditions where the high ISO settings needed would produce too much digital noise on a cropped sensor, it might be worth trading off edge sharpness against the reduced grain of a bigger full-frame sensor.

With my previous set-up (Ikelite), I was using an 8 inch dome and found the 12-24 great to take sharks, mantas. Didn't have any problem with corner sharpness as corners were mainly blue (or green) water.