Hello everyone,

 

I have a Sony A7RV and Nauticam housing. I currently have a 90mm macro lens and Nauticam's corresponding port.

 

What non-dome port options do I have for attaching a wide or slightly wider angle lens? 

I'm considering a second port, so long as its not a dome because I am trying to keep budget on the lower side as I primarily take macro but would like a reasonable option for non-macro.

 

Thank you

Without a dome you can't really shoot wide due to increasing levels of pincushion distortion. If you want to stay with a flat port and keep things reasonably inexpensive, consider #37165 N100 Flat Port 45 and Sony 28-60mm f/4-5.6 lens. This will give you a reasonable zoom range to work with for stuff like fish portraits, and later on you can augment it with a WWL-1B for true wide-angle. You can also use it with wet diopters for macro.

2 hours ago, Barmaglot said:

Without a dome you can't really shoot wide due to increasing levels of pincushion distortion. If you want to stay with a flat port and keep things reasonably inexpensive, consider #37165 N100 Flat Port 45 and Sony 28-60mm f/4-5.6 lens. This will give you a reasonable zoom range to work with for stuff like fish portraits, and later on you can augment it with a WWL-1B for true wide-angle. You can also use it with wet diopters for macro.

 

That's a sensible approach.

 

I guess my question is, and you provided a suggestion, what is the widest angle I can use with a flat port before I reach limitations that will impact the image. 

15 minutes ago, hedonist222 said:

 

That's a sensible approach.

 

I guess my question is, and you provided a suggestion, what is the widest angle I can use with a flat port before I reach limitations that will impact the image. 

Depends on how fussy you are about image sharpness,  105mm is generally regarded as pretty good through a flat port and 60mm starts to show degradation towards the edges on full frame, but even the 105mm has some degradation which is part of the sales pitch for the new MFO to correct this.  Something like 35mm is probably OK.    In smaller formats a lot of people use 24-28mm equivalent lenses with flat ports, but would probably be pushing the limits of full frame.

 

It gets progressively worse as focal length reduces and as you go from centre of frame to the edges.  So there's no true line in the sand beyond which it suddenly becomes unacceptable.  It also depends on what you want to shoot, 28-40mm range is a bit of a no mans land UW not particularly good at anything except perhaps fish portraits, so could be disappointing potentially.  For not a lot more you could perhaps find a small dome and fisheye to do CFWA and wide angle macro shots, which may align better with your macro interests?

3 minutes ago, Chris Ross said:

Depends on how fussy you are about image sharpness,  105mm is generally regarded as pretty good through a flat port and 60mm starts to show degradation towards the edges on full frame, but even the 105mm has some degradation which is part of the sales pitch for the new MFO to correct this.  Something like 35mm is probably OK.    In smaller formats a lot of people use 24-28mm equivalent lenses with flat ports, but would probably be pushing the limits of full frame.

 

It gets progressively worse as focal length reduces and as you go from centre of frame to the edges.  So there's no true line in the sand beyond which it suddenly becomes unacceptable.  It also depends on what you want to shoot, 28-40mm range is a bit of a no mans land UW not particularly good at anything except perhaps fish portraits, so could be disappointing potentially.  For not a lot more you could perhaps find a small dome and fisheye to do CFWA and wide angle macro shots, which may align better with your macro interests?

 

What a great post. 

The latter indeed! 

For what it's worth, here's a series of comparison images taken in a pool. I was using a Sony A6300, so an APS-C sensor, but it should be broadly similar on FF if you adjust for the crop factor.

 

10mm (15mm-equivalent) behind flat port:

 

nullnull

 

Same behind dome:

 

 

16mm (24mm-equivalent) behind flat port:

 

null

 

Same behind dome:

 

null

 

18mm (27mm-equivalent) behind flat port:

 

 

Same behind dome:

 

null

 

30mm (45mm-equivalent) behind flat port:

 

 

Same behind dome:

 

null

 

You can see the loss of AoV, pincushion distortion, and loss of sharpness caused by a flat port at this medium-to-wide focal lengths. The 10mm and 18mm examples were shot with Sony 10-18mm f/4 lens, 16mm and 30mm were shot with Sony 16-50mm PZ kit lens; housing and ports were from SeaFrogs.

 

Regarding 8-15mm fisheye, it is obviously a very capable setup, but it is also quite expensive. You will need a $650 N100 to N120 adapter, a $650 extension ring, a $1476 dome, a $399 adapter, and a $1249 lens, plus maybe a zoom gear (you can print your own far cheaper than a brand-name one). If you will want to use it as a zoom lens, rather than switching between full circle at 8mm and diagonal coverage at 15mm, you will also need a teleconverter and another extension ring, so figure on spending an additional $1k or so. By comparison, flat port 45 is $518, and 28-60mm lens is $500. To get it shooting wide, a WWL-1B is $1546, and the required M67 to bayonet mount adapter is another $107, so we're talking about a ~$4500-5500 setup vs. a ~$2700 setup.

1 hour ago, Barmaglot said:

Regarding 8-15mm fisheye, it is obviously a very capable setup, but it is also quite expensive. You will need a $650 N100 to N120 adapter, a $650 extension ring, a $1476 dome, a $399 adapter, and a $1249 lens, plus maybe a zoom gear (you can print your own far cheaper than a brand-name one). If you will want to use it as a zoom lens, rather than switching between full circle at 8mm and diagonal coverage at 15mm, you will also need a teleconverter and another extension ring, so figure on spending an additional $1k or so. By comparison, flat port 45 is $518, and 28-60mm lens is $500. To get it shooting wide, a WWL-1B is $1546, and the required M67 to bayonet mount adapter is another $107, so we're talking about a ~$4500-5500 setup vs. a ~$2700 setup.

I keep forgetting the expense of doing anything with the N100 port system with the expensive adapters plus rings.  They really need an N100 small dome so you could use something like the sigma fisheye lens and the sigma adapter.  The flat port they offer is around the same price as a 4.33" N120 dome.  The only native N100 dome is the 180mm dome or you can get a N100 WACP.