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

[nudibranco]

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

yes ... that is correct... and i just checked the 2 ports side by side with the 3.5" dome at least 1cm closer to the 8mm lens ... This makes it for reaching the subject closer (I scratched by getting too close) and probably a bit of the "flatter" perspective to the nodal point of the lens will distort as well. However in practical terms the FE lens will be super sharp in corners anyway. I see a bit of chromatic distortion that is easily fixed. In practical terms to me this is a summary of the 2:
3.5" cheaper, smaller, and better CFWA
4.33" easier O/U, very slight less chromatic distortions on far edges...

---------- Post added January 22nd, 2015 at 04:09 PM ----------

here is a typical red star with the 8mm and 3.5" port last Sunday:

https://www.flickr.com/photos/77146796@N07/16339682405/in/photostream/lightbox/

and here a CFWA:

https://www.flickr.com/photos/77146796@N07/16339753045/in/photostream/lightbox/

 

[Interceptor121]

The point is that this dome can also be used with lenses with minimum focus distance such as the nikkor 10mm. If you wanted something only for the 8mm fisheye you could have got away with a 3:5" real dome that would have been 2 cm shorter and even more close focus wide angle however this product would then not been an option for rectilinear lenses

 

[Storker]

The point is that this dome can also be used with lenses with minimum focus distance such as the nikkor 10mm.

...or the Olympus 12mm f/2

 

[Interceptor121]

...or the Olympus 12mm f/2

Yes most likely you will need a +2 diopter to get sharp corners
I have seen tests even with a +5 but the loss of field of view was apparent and also worse in the centre
I can also use this dome with my panasonic 12-32 in the 12-20mm range again a +2 diopter will make it better

 

[StefanKruse]

That's a pretty darned good question

I'd like to try the 8mm Panasonic FE to go even wider, but I don't know if it's really worth the cost for me. Right now I definitely don't have the budget for it (and the extra port). I also like having a little bit of zoom to shoot critters that won't let me get as close as I'd want to at 9mm. There's also the thing about lugging an extra lens and an extra port when I'm traveling and the fact that there's a learning curve to get good shots with a FE (topside, I'm more of a telephoto guy, so I've been through a learning process to get half-decent shots with a WA perspective).

Thanks, with all the techny talk I sometime struggle to keep up

I completely get the urge to go even wider and the FE lens does look appealing. However it is a bit of a novelty lens and topside use seems limited plus the learning curve issue (which I thik could be a real showstopper for me as the number of dives I am able to squeeze in every year is limited). It does however look fun, but at the end of the day I think it is just not that useful. Why not consider the pana 7-14 or even better the new Oly 7-14mm (when it comes out and if they make a domeport for it). Its obviously along way from 180 degrees FOV, but for topside use and with the added bonus of Zoom it might be a better value proposition in the long run?

 

[Divezilla]

Nudibrancho mentioned adapting a macro adapter to the Zen WA100 port.
Curious how that would work with the WA100's curved surface.
Does anyone have a reference/link showing how this can be done or bought ?

 

[smoore]

Nudibrancho mentioned adapting a macro adapter to the Zen WA100 port.
Curious how that would work with the WA100's curved surface.
Does anyone have a reference/link showing how this can be done or bought ?

See post 4 in this thread: http://www.scubaboard.com/forums/the-olympus-outlet/504968-zen-wa100-dome-subsee-5-a.html. I have not yet tried this in the water. However, I have tried it on land and it seems to work. You simply place the Oly macro adaptor over the Zen port. The author of post 4 suggests attaching Velcro to the outside of the flange of the Zen port and then friction will hold the Oly macro adaptor onto the Zen port. I think this may be a good solution. I intend to try this in the pool later this year and then I may go back to Reefnet and see if I can convince them to make me a flip adaptor for the Zen port.

 

[Divezilla]

Thanks!

 

[jgnu]

I spent quite some time deciding on whether or not to buy the 9-18 or a zen dome port or both a few months ago. The pictures posted in this thread helped my out quite a bit in getting a feel for what sort of results the 9-18 would give me with the standard flat port.

I ended up getting the 9-18, but stayed with my flat port for now. I almost immediately brought it on a week-long liveaboard in the red sea to try it out.

My conclusion is that the corners are a bit too smudged for my liking at the far 9 mm end, but I also found that at 10-11mm it is better. Still, having the option to go 9mm when there is nothing important in the corners was nice.

For me, getting the 9-18 without the dome was probably the right call since I don't dive much more than one or two trips per year. I also considered getting the dome port only, and use it with the 14-42, but that seemed silly since I'd get a lot of use out of the 9-18 on land as well.

Below are two albums with examples; one with pictures at 9mm, and another with shots at 10-11mm. The shots are not cropped, but all have had my my usual lightroom treatment for uw photos applied to them (white balance, contrast, maybe raised shadows, automatic ca-correction. Pretty standard.)

My gear consists of an epl-5 in pt-ep10, standard flat port, single sea&sea YS01 strobe.

9mm:
9-18mm @9mm. Red Sea, June 2015 - Album on Imgur

10-11mm:
9-18mm @11mm. Red Sea, June 2015 - Album on Imgur

Maybe this can help someone else who is struggling to decide

 

[Interceptor121]

I don't think the corners are soft. What you see it's pincushion distortion that pulls the pixels at the corners. This is due to the fact you are using a flat port and can't really be corrected easily. You can try lens distortion correction but then the centre of the image will get soft. On the other hand the wide port will give you filed of view and no distortion but also soft corners....