Inon UWL-H100 for G7X MkIII Nauticam housing, need short port ?

Hello everyone, 

I want to buy a Inon UWL-H100 (maybe with a dome) for my Canon G7X MkIII on my Nauticam housing, after reading a lot on this subject I have seen that I need to change my port of my housing to fit with the lens. They said I need a short port. Is that right ? What will happend if I keep my standard port ? The dome on the Inon UWL-H100 is it worth it ? 

Thanks in advance guys ! 

The UWL H100 is designed for a 28mm equivalent lens and as a minimum you need to zoom into 28mm equivalent (from 24mm equivalent on the wide end of the G7X -III) .  With the standard port the lens is a long way from the port at this setting so it will vignette and you need to zoom in to compensate losing coverage angle so you need the short port to get back the wide view that you would lose otherwise.  The short port gets around this giving you the maximum field of view at the cost of zoom through not being available. 

INON actually recommends the UWL-S100 ZM80 for the G7X-II this gives a 100° field of view with the lens zoomed to 80mm equivalent focal length and it may be a better option allowing you to use the standard port.  It also has a dome unit.  You may lose a little of that field of view if you need to zoom in a little for vignetting.  I would suggest asking around for specific experience with this lens. 

The UW photo stores recommend a range of other lenses as well including Fantasea and Kraken lenses so i would suggest some research on experience with various wet wide lenses - they recommend these for use on other housings without the port options, so I expect they would work equally as well on the Nuaticam standard port.  The UWL-H100 will certainly work with the short port but you lose flexibility in this mode.

On 8/11/2020 at 9:29 PM, ChrisRoss said:

The UWL H100 is designed for a 28mm equivalent lens and as a minimum you need to zoom into 28mm equivalent (from 24mm equivalent on the wide end of the G7X -III) .  With the standard port the lens is a long way from the port at this setting so it will vignette and you need to zoom in to compensate losing coverage angle so you need the short port to get back the wide view that you would lose otherwise.  The short port gets around this giving you the maximum field of view at the cost of zoom through not being available. 

INON actually recommends the UWL-S100 ZM80 for the G7X-II this gives a 100° field of view with the lens zoomed to 80mm equivalent focal length and it may be a better option allowing you to use the standard port.  It also has a dome unit.  You may lose a little of that field of view if you need to zoom in a little for vignetting.  I would suggest asking around for specific experience with this lens. 

The UW photo stores recommend a range of other lenses as well including Fantasea and Kraken lenses so i would suggest some research on experience with various wet wide lenses - they recommend these for use on other housings without the port options, so I expect they would work equally as well on the Nuaticam standard port.  The UWL-H100 will certainly work with the short port but you lose flexibility in this mode.

Thanks a lot for your very good answer ! I'll do my research like a study student. The thing is my companion owns the UWL H100 so that's why I was asking with this specific lens but if I have to buy the short port and the dome it's start to be very expensive "just" for a wide angle. 

If you know someone with the lens you can test it for vignetting on land - just fit it and zoom in until the vignetting disappears and note the focal length.  from that you can work out what angle of view you get with the lens.  The INON lenses designed for 28mm are 0.64x lenses - multiply the focal length with no vignetting on your camera by 0.64 and that gives you the equivalent focal length you can expect if you use the INON lens UW. 

I'm not clear if you are proposing to just share the lens with your companion - which would be "free"- or buying the lens - the ZM80 lens I suggested is 320 Euro at one store I looked at and the INON UWL-H100 lens is 350 euro.  With the ZM80 lens that's all you have to buy to get a 100deg field of view, the equivalent of an 18mm lens.

I acually tried on the land with the UWL-H100 and the difference between the wide angle and the normal one is not very significant. Do I'll need a short port with the UWL-S100 ZM80 ? I'm a beginner sorry if this kind of questions are stupid ! 

What focal length did you get to prior to stop the vignetting?  the focal length for angle of view underwater is different but vignetting remains the same.

The ZM80 does not require the short port as it is designed to work when you zoom into around 80mm - you do need the right adapters though to attach it.