Nauticam 180mm Glass Dome Port and Sigma 15mm f2.8 DG Fisheye

I’m planning to start shooting WA with my D800 (mounted in Nauticam Housing). After a thorough tough I’m planning to use a diagonal fisheye and in particular the Sigma 15mm f2.6.

I was wondering if anyone has experience of using this lens with Nauticam 180mm Glass dome port on FX camera, I have gone thru the lens chart provided by Nauticam and this dome is not recommended for this lens while is for Standard wide angle lenses like te 16-35 f4, I wonder if this is due to vignetting or soft corners or other reasons.

Further I was wondering if anyone has experience on shooting WA with Video lights as fill and smaller strobes Like the Inon S2000, my idea would be to use 2 video light of 10,000 Lumens each with a beam angle of 110° + 2 INON S2000.

Any contribution/suggestion will be highly appreciated.

The 180mm dome is a segment from a larger dome and not a full 180° hemisphere, so that means you can either place the dome in the right spot to prevent vignetting or place the the entrance pupil at the centre of the radius of curvature, but not both.   You need to have the lens well forward of the centre of curvature of the dome so that the lens can see out to the side.    The segment is chosen so that about a 114° field of view is available/visible from the base of the dome (about a 14mm lens field of view), but the fisheye needs 180°

The recommended 140mm dome is a 180° hemisphere so you can have the lens placed correctly at the centre of curvature and not vignette.

Regarding the flash, the penalty of the full frame is you need to stop down to get enough depth of field probably f11 so you need a lot of light.  Video lights won't cut it, see for example this post: 

View archived post in: Using Video Lights for Still Photography?

And this: 

View archived post in: Strobe VS LED light

The little S2000 would need to be on full power and would probably also struggle a little bit, fisheye wide angle is the most demanding for lighting, even the little S-2000 will put out significantly more light than your video lights will, so using them to assist the strobes doesn't help as there is just not enough light. 

Thank you Chris for your contribution, your explanation confirm my “fear”. 

It seems that I will switch to the original plan of getting a Zen-170mm dome port, I have read very good reviews. 

For the lighting, one day I will decide to invest in a pair of Z-330, they have a GN33 and should be able to illuminate correctly the 180deg of the diagonal FE.

Thank you Chris for your contribution, your explanation confirm my “fear”. 
It seems that I will switch to the original plan of getting a Zen-170mm dome port, I have read very good reviews. 
 
For the lighting, one day I will decide to invest in a pair of Z-330, they have a GN33 and should be able to illuminate correctly the 180deg of the diagonal FE.

No doubt sea cam are among the best strobes, and very expensive, for what concern retra from the compare below seems that in terms of output power the Z-330 is performing better, beam angle is comparable, light temperature is warmer in retra (Here is a matter of taste).

https://wetpixel.com/articles/strobe-tests-inon-z330-retra-flash-and-symbiosis-ss2/P5

24 minutes ago, italypeppe said:

No doubt sea cam are among the best strobes, and very expensive, for what concern retra from the compare below seems that in terms of output power the Z-330 is performing better, beam angle is comparable, light temperature is warmer in retra (Here is a matter of taste).

 

https://wetpixel.com/articles/strobe-tests-inon-z330-retra-flash-and-symbiosis-ss2/P5

 

The Retra tested in that article is their old model with a straight bulb, which is out of production now. The Retra that Interceptor121 is referring to is the new model, featuring a circular bulb, announced last year and supposed to ship in October.

I would regard the Zen 170mm dome and the Nauticam 180mm dome as more or less interchangable.  It looks like Zen consider the compromise of using the 170mm dome acceptable while Nauticam do not for their 180mm dome.  They are both more or less the same spherical segment.  You will note that Nauticam recommend the 140mm dome as the optimum. 

Any particular reason you would like to use the bigger dome?, the 140mm dome is more compact and probably better for CFWA work and getting in close.  With smaller formats you could argue that you could use the dome for other wide lenses but it is probably a bit small for the 14-16mm rectilinear wide lenses.

The Retra tested in that article is their old model with a straight bulb, which is out of production now. The Retra that Interceptor121 is referring to is the new model, featuring a circular bulb, announced last year and supposed to ship in October.

I would regard the Zen 170mm dome and the Nauticam 180mm dome as more or less interchangable.  It looks like Zen consider the compromise of using the 170mm dome acceptable while Nauticam do not for their 180mm dome.  They are both more or less the same spherical segment.  You will note that Nauticam recommend the 140mm dome as the optimum. 
Any particular reason you would like to use the bigger dome?, the 140mm dome is more compact and probably better for CFWA work and getting in close.  With smaller formats you could argue that you could use the dome for other wide lenses but it is probably a bit small for the 14-16mm rectilinear wide lenses.

51 minutes ago, italypeppe said:

 

Mainly two reason, first retain the possibility to use the dome with rectilinear WA lenses (like 16-35) in the future and second the opportunity to buy a 180mm dome pre-owned at competitive price so save some bucks to invest in strobes for instances.

On the other hand I do not want to end up with a solution that is neither fish nor fowl, unfortunately I have no possibility to test different solutions first.

I have no experience with FX, I have a much smaller sensor (MFT, Oly EM1II). But even on the small sensor the performance of rectilinear WA (7-14mm, equivalent to 14-28mm on FF) with the Zen-DP170 is not the optimum, because the domeport is too small for correct positioning of the lens. It was shown in WP here, that 7-14mm WA performs best with the Zen DP200 (that is, unfortunately, not produced any more).

If I had FX, I would not go for the DP170. It probably may work reasonable with the fisheye, but certainly very suboptimal for rectilinear WA. Instead I would go for the 140mm Nauticam for the fisheye lens (=optimum solution) and for a really big dome for rectilinear WA (the latter will also work with the fisheye, but is not handsome). Why invest so much in one of the very best camera systems and then destroying IQ by using inappropriate domeports?

Wolfgang

Have to agree with Wolfgang - also the 140mm domes do come up second hand occasionally, there's one from a month back in the classifieds : 

View archived post in: Nauticam 140mm Glass Fisheye Dome for FX and DX (18810 N120)

The 170mm dome is too small for a 16mm lens on full frame, if budget is a concern you could buy the 8.5" acrylic dome if and when you get something like a 16-35mm.  Dome size scales with sensor size and focal length.   If on the other hand you wanted to use something like a 24-70 the 180 dome would be fine. 

In the end I went for the 140mm dome, can’t wait to test it in water.
By your experience will I have to mount some weight to balance it in the water?
Will the vacuum system affect the buoyancy? As it should reduce the quantity of air trapped in it.

Hi Italypeppe,

The vacuum will not have any noticeable effect on buoyancy (air weights approx 1.2 kg/m3 at 1 bar).

Regarding the rig, you need floats pretty shure. I have smaller housing and camera (EM1II and NA-EM1II) and have to use floats. If not using floats, your wrists will be overstressed. Exact buoyancy force required can only said by someone using identical rig or probably requested at Nauticam US (They have very good customers consultation).

Wolfgang

Hi Wolfgang,

Perhaps my question was not well posed, I’m sure I will need float, I have for my macro setup and is a good suggestion to ask Nauticam so I won’t have to wait till I have parts and make a weight in water.

My point was if by your experience I would need some weight to be stick under the dome port, I know that even if the rig is neutrally buoyant it can tilt if one part is more buoyant in comparison to the others in this case the dome vs the housing + camera.

Hope to have clarified my point.

Giuseppe

Hey Giuseppe

It's hard to give a definitive answer to this. To an extent it depends on what additional buoyancy you use and the angles of the strobe arms (assuming that's where the additional buoyancy is located).

Domeports can have a tendency to twist upwards. But it isn't a given. Weight of the lens and the air space around it are other factors.

I'd suggest trying it all out before buying additional domeport weights. It could be that the problem is negligible or no-existent.

On 9/8/2019 at 6:44 PM, italypeppe said:

Hi Wolfgang,

Perhaps my question was not well posed, I’m sure I will need float, I have for my macro setup and is a good suggestion to ask Nauticam so I won’t have to wait till I have parts and make a weight in water.

My point was if by your experience I would need some weight to be stick under the dome port, I know that even if the rig is neutrally buoyant it can tilt if one part is more buoyant in comparison to the others in this case the dome vs the housing + camera.

Hope to have clarified my point.

Giuseppe

Probably not, the glass domes are less buoyant than the acrylic ones and the volume of the 140mm dome is small- buoyancy varies with displaced water volume and the weight of the item - a small dome has less buoyancy than a large one and glass domes are heavier.  I certainly don't notice anything with my 170mm dome or 100mm fisheye dome, while I know people with a 7" acrylic Nauticam dome on the same rig and that has noticeable buoyancy (tends to twist up) as it is lighter and large in volume being a full 180° dome. 

I just wanted to add an important factor.  The Nauticam 180mm glass dome (18809) is not compatible with the Sigma 15mm f/2.8 fisheye lens as it has roughly 30mm of extension built into the plate which causes improper placement and vignetting with this lens.  The Zen DP-170-N120 has no built in extension and is compatible with the Sigma 15mm f/2.8 fisheye.