14-42 mm & 9-18 mm in Olympus PT-EP10

[Interceptor121]

I just got myself a panasonic gx7 I have wet lenses I used for my compact. With the power zoom 14-42 and inon uwl-h100 and the nauticam macro port 35 I have very sharp images and am not planning to invest in the 9-18 mm lens
Generally 90-100 degrees is the limit for good corner sharpness and the lens is not really that sharp on the edges even on land. For what concerns loss of field of view a +2 diopter is white weak so this should not be massive but the only way to know is to do a test!!

---------- Post added January 22nd, 2015 at 07:41 PM ----------

I just got myself a panasonic gx7 I have wet lenses I used for my compact. With the power zoom 14-42 and inon uwl-h100 and the nauticam macro port 35 I have very sharp images and am not planning to invest in the 9-18 mm lens
Generally 90-100 degrees is the limit for good corner sharpness and the lens is not really that sharp on the edges even on land. For what concerns loss of field of view a +2 diopter is white weak so this should not be massive but the only way to know is to do a test!!

 

[nudibranco]

I have all the options and I tend to use the 4" port with the 60mm macro the 12-50 and the 9-18. Having the flip diopter makes the 12-50 more useful than behind the nauticam dedicated flat port. I also have the 8" with the 3.5 and 4.33" ports. I love the 8 when I can use it. And I love the 60mm although a bit extreme. Nonetheless the 2 zoom lenses are ok properly used. And a 10mm is a big difference to me than the 12mm. Too bad the 12-50 is not a 10-50! Behind the semidome Would do just about anything...

 

[Storker]

I also have the 8" with the 3.5 and 4.33" ports.

I know that Nauticam recommends the 4.33" port for the 8mm FE and warns about possible vignetting in the 3.5". OTOH, I've seen people claiming that the 3.5" allows for closer subjects, taking the CFWA even more CF. What's your opinion on 3.5" vs 4.33" for the 8mm FE?

---------- Post added January 22nd, 2015 at 09:55 PM ----------

the only way to know is to do a test!!

Quoted for truth

---------- Post added January 22nd, 2015 at 10:00 PM ----------

With the power zoom 14-42 and inon uwl-h100 and the nauticam macro port 35 I have very sharp images and am not planning to invest in the 9-18 mm lens

OTOH, the 9-18 works very well topside, too:



This is actually one of the reasons I decided to get the 9-18: It's a pretty decent WA zoom for topside use as well.

 

[Interceptor121]

I know that Nauticam recommends the 4.33" port for the 8mm FE and warns about possible vignetting in the 3.5". OTOH, I've seen people claiming that the 3.5" allows for closer subjects, taking the CFWA even more CF. What's your opinion on 3.5" vs 4.33" for the 8mm FE?

---------- Post added January 22nd, 2015 at 09:55 PM ----------


Quoted for truth

Based on theory you can get 6 cm closer with the smaller port however on some cameras (my GX7 for example) ou will have a tiny vignette in 4:3 aspect ratio
Am trying to determine if the 3.5" port is actually a cut out of the 4.33" dome itself which means the glass is actually closer on the 3.5" than it is on the 4.33 but not actually smaller
As corners are garbled anyway with a fisheye lens the difference performance is not visible
Will it make a difference to you a minimum distance of 10!cm instead of 16? Doesn't make a difference to strobe arm length but will allow you to get closer to a frogfish for example
Am waiting for some statements from nauticam on the glass or should say plastic used

 

[Storker]

Based on theory you can get 6 cm closer with the smaller port however on some cameras (my GX7 for example) ou will have a tiny vignette in 4:3 aspect ratio
[...]
Will it make a difference to you a minimum distance of 10!cm instead of 16?

Good question (again). Gotta think about that one. Luckily (?), it'll be a while before my budget allows me to buy the 8mm and the port, so I have some time to think

 

[Interceptor121]

I just got around it the glass on the 4.33" and the 3.5" port are exactly the same curvature, the 3.5 is just a slice of the other

Which means the lens with the 3.5" port is pushed 1 cm forward so theoretically more off centre so you can get close probably a tad (not the 6 cm I was talking maybe 1 or 2) but what is more important the lens is more flat which means there is magnification

So in the experiment of mr Mustard the duck looks bigger not because is closer but because at short range the dome is more linear

On this note am getting the 4.33 forget about the 3.5" port

 

[nudibranco]

Well I use the 4.33 much less because it is a lot bigger in my use and frankly compactness is why I went mirrorless in first place...the 3.5" focuses to glass and it gives less depth of field than the 4.33. It does not vignette on my setup at all. BTW it costs about 100
...less

 

[Interceptor121]

Well I use the 4.33 much less because it is a lot bigger in my use and frankly compactness is why I went mirrorless in first place...the 3.5" focuses to glass and it gives less depth of field than the 4.33. It does not vignette on my setup at all. BTW it costs about 100
...less

Am not sure about less depth of field? It is the same glass but closer which means flatter so edge sharpness is less of an issue however the image is actually lower quality overall
Quantifying exactly is not really possible as you have a fisheye lens

For a rectilinear lens the two ports are exactly the same however the 3.5" will need an extension as it is shorter otherwise field of view will be reduced due to the port being too flat

For close focus wide angle closing the aperture is not really a major issue and the port will maybe give you one stop benefit in the very best case as the glass is the same and is not anymore a 180 fisheye for what matters

The 4.33" sees to be 12 cm diameter the 3.5" is 9.5 cm is not like saying a 17 or 20 cm dome. The dome of my Inon wet lens for compact is 12 cm external radius itself and being acrylic it also lifts the housing a bit

 

[Storker]

the 3.5 is just a slice of the other

[...]

the lens is more flat which means there is magnification

Sorry, I just can't reconcile those two statements. Care to elaborate?

getting the 4.33 forget about the 3.5" port

Ok, that one was clear to me, at least

Right now, I'm sorta, kinda partial to the 4.33", since a larger dome is better for o/u split shots, and I'd love to experiment a bit with those.

--
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Typos are a feature, not a bug

 

[Interceptor121]

Sorry, I just can't reconcile those two statements. Care to elaborate?

Typos are a feature, not a bug

Imagine you have a glass dome and the lens is right in the centre you see a circle.

Now if you push the lens toward the glass surface the distance between the centre and the lens and the distance between the edges of the glass start to be different so the dome looks more flat

As the dome looks more flat the port becomes subject to magnification and the virtual image gets distorted

This is why in dome port theory you try to get the lens nodal point in the virtual centre of your dome, obviously this is all theoretical as you need to work out where the nodal point is by trial and error

In this example I assume that nauticam have found the correct nodal point and designed a port to fit it (otherwise it would not have panasonic fisheye in the description) so using something not designed for that lens means drifting away from that spec