When is a bigger dome a bad thing?

I am currently using the Olympus EPL10 with the Panasonic 8mm Fisheye inside the AOI housing with the 4" acrylic dome.

I am considering upgrading to an Olympus EM1-2 inside the AOI housing with the PEN-to-OMD adapter (the adapter is 35mm long) and 8" acrylic dome.  This upgrade would allow me to use the 12-40

My question is how would the using the adapter and 8" dome affect the image when I use the Pana 8mm Fisheye.  I understand there will be some vignette, I think I am okay with that especially if I can get the versatility of using both the 8mm fe and the 12-40.

depends on how it places the lens in relation to centre of curvature of the dome.  The vignette may be significant as the lens will be buried back in the extension quite likely.  You can measure that vignette on land and decide if it is too much.

I am currently using the Olympus EPL10 with the Panasonic 8mm Fisheye inside the AOI housing with the 4" acrylic dome.
I am considering upgrading to an Olympus EM1-2 inside the AOI housing with the PEN-to-OMD adapter (the adapter is 35mm long) and 8" acrylic dome.  This upgrade would allow me to use the 12-40
My question is how would the using the adapter and 8" dome affect the image when I use the Pana 8mm Fisheye.  I understand there will be some vignette, I think I am okay with that especially if I can get the versatility of using both the 8mm fe and the 12-40.

12 hours ago, Dann-Oh said:

I am currently using the Olympus EPL10 with the Panasonic 8mm Fisheye inside the AOI housing with the 4" acrylic dome.

I am considering upgrading to an Olympus EM1-2 inside the AOI housing with the PEN-to-OMD adapter (the adapter is 35mm long) and 8" acrylic dome.  This upgrade would allow me to use the 12-40

My question is how would the using the adapter and 8" dome affect the image when I use the Pana 8mm Fisheye.  I understand there will be some vignette, I think I am okay with that especially if I can get the versatility of using both the 8mm fe and the 12-40.

I cannot say anything about the 8" acryl dome, but I have the Zen DP170 WA port (6,7"; radius: 11 cm), Nauticam 140 fisheye (5,5", radius: 7cm) and Zen DP100 (3,9"; radius: 5cm), all from optical glass. Maybe you will get problems with buoyancy with the big acryl dome, but there are treads how to deal with this here...

I use the Zuiko12-40mm Pro behind the DP170, the performance is tack sharp. As Massimo says, WA and macro are the mostly used focal lengths in UW-photography and 12-40mm is rather seldom, but I personally find this range (and the outstanding IQ with DP170) wonderful, especially for fish portraits and also night dives. Especially the IQ with fishportraits often suffer from using a macro lens with long focal length and the accompanying long working distance. With the 12-40 (behind a domeport this is really 12-40 and not 1,33x) and depending on the shyness of the fish, one can start at 40mm (often not required) and zoom out up to 12mm, depending on the situation, what gives outstanding IQ. It is also my choice of lens for shy sharks, e.g. non-feeded hammerheads. In the Red Sea it is already difficult to come close enough with 12mm, extreme WA would be possible only on very rare exceptional occasions for these fish (not so with sharks that are less shy, e.g. longimanus)..

Regarding the Zuiko 8mm fisheye I can say that I have used it regularily behind the DP170 with outstanding IQ (no vignetting, since the positioning is not correct, but as recommended by Zen). I also have tested the adapted Canon 8-15mm behind DP70 and do not find any degradation in IQ (maybe it is even slightly better) compared to the Nauticam 140 dome (where positioning is correct). I know that correct positioning of the lens is impossible with the WA DP170 (while it is possible with the 140 domeport), but the larger radius of the DP170 obviously (more than) compensates for the wrong positioning. The 140 dome is just more convenient to use, since it is smaller, but does not further improve IQ...

Wolfgang

On 9/2/2022 at 1:54 AM, Interceptor121 said:

I don’t think this is a wise move personally as a lens like the 12-40mm is useful for video and shooting people but not much more.

On 9/2/2022 at 3:59 AM, Architeuthis said:

I use the Zuiko12-40mm Pro behind the DP170, the performance is tack sharp.

Interesting divergence of opinion.  Like Architeuthis, I have obtained what I consider very good results with the 12-40 Pro behind the DP170ii. While its integrated extension makes it impractical for the fisheyes (or at least, for the Panasonic fisheye I use), the little Nauticam 4" dome (Zen recommends its 5" dome for the Panasonic 8mm) affords closer shooting distance from the front of the lens to the inner of the dome, makes the rig easier to handle, and is hardly noticeable when packed.  Dann-O, is the only benefit you anticipate, from the configuration you're considering, not having to take the small dome with you?

Interesting divergence of opinion.  Like Architeuthis, I have obtained what I consider very good results with the 12-40 Pro behind the DP170ii. While its integrated extension makes it impractical for the fisheyes (or at least, for the Panasonic fisheye I use), the little Nauticam 4" dome (Zen recommends its 5" dome for the Panasonic 8mm) affords closer shooting distance from the front of the lens to the inner of the dome, makes the rig easier to handle, and is hardly noticeable when packed.  Dann-O, is the only benefit you anticipate, from the configuration you're considering, not having to take the small dome with you?

Somewhat reverting from the specific to the generic...

When is a bigger dome port a bad thing?

Optically...never. Vignettes can be largely fixed by correct lens position, although in some instances, it may need the removal of dome shades. However, at some point, dome size increase will have such a marginal effect on quality, that these advantages may well be moot and offset by water quality, light and all the other factors that complicate image quality underwater.

Practically...smaller domes make it easier to get physically closer to subjects and as importantly, to light subjects that are close to the front of the dome.  

Of course, bigger domes are also more expensive, harder to travel with and physically more difficult to move through the water.


 

Adam pre-empted my own thought: when is bigger dome port a bad thing? When you have to travel with it. Especially if you have a European airline baggage allowance.

The 12-40 is easily my most used lens underwater; If I can expect viz over 50' I may switch to the Panasonic 8-18, and for truly spectacular viz or situations where I want a smaller form factor I'll use the Olympus 8mm.  I used all three lenses in the same Inon 170mm dome port (plus the Oly 7-14 when I had it) without issue.  I have recently made the switch from my M1mkI / Oly housing to the M1mkIII / AOI housing- I haven't had a chance to dive with the 12-40 in that combo yet, but testing it with the AOI PEN/OMD port adapter shows that it works fine without vignetting.  Here's what you'll need:

Inon dome port intended for the old 4/3 system:  http://www.divervision.com/inon-dome-port-olympus-with-protector-ii-set-for-zuiko-digital-ed-8mm-f3.5-fisheye-456212143338.html  note- this port is glass, not acrylic.  Buy once, cry once, but really it's pretty reasonable for such a big glass dome.

PAD-EP08 adapter to go from 4/3 to OMD:  https://www.bhphotovideo.com/c/product/917611-REG/olympus_v6360360w000_pad_ep08_port_adapter.html

1" Olympus extension to go between the adapter and the port:  https://www.amazon.com/Olympus-260506-PORT-UW-PER-E01/dp/B000B8VTQU

From there, use the PEN / OMD adapter and you're all set- about a thousand bucks, maybe less if you can find stuff on e-bay or through classifieds.  That said- I believe the guy I was dealing with at Backscatter mentioned that AOI was working on a dome for use with Pro lenses in PEN housings, but for now we have to cobble things together.

To your other question- while it's possible you could use the Oly 8mm in my combination by removing the 1" extension, the Panasonic 8mm is probably too short to do so without vignetting (on the OMD housing, removing the 2" extension worked perfectly with the Oly 8mm- you'll end up with an inch of extension with the AOI housing because of the port adapter).  Changing the extension ring is a bit of a pain in the ass, too- get out the oil filter wrenches.  I found a good deal on an open box small dome for the Oly 8m in PEN housings so I just went with that.

On 9/3/2022 at 3:49 PM, rickmorgan said:

Dann-O, is the only benefit you anticipate, from the configuration you're considering, not having to take the small dome with you?

@rickmorgan Honestly, it seems when I am packing up for a day of shooting I pick either macro or wide angle (lets say wide angle for this conversation). I pack my camera bag on Wednesday  night and pack my diving bag on Thursday night. Friday night I drive down to the boat for a day of diving on Saturday.  I do not bring extra stuff, like the Oly 30 or 60mm macro lenses and the flat port with extension rings and macro strobes. Since I'm geared up for wide angle Ill have my Pana 8mm Fisheye and Inon Z330s (Thanks @adamhanlon :-)). I can guarantee that I will only see small stuff less than 3" long (about 8cm long), this happens nearly EVERY time.  I don't want to sound like a millennial but I'm getting tired of always having the wrong camera gear once on out on a day of diving.  Its getting to a point that I haven't taken my camera in the water the last few days of fun boat diving.

Also, when talking about dive site visibility its not uncommon for our local areas (from Los Angels to San Diego, Southern California, USA) to have 2ft to 80ft (0.5m to 24m) vis.  I have been on dives when we started with 50ft (15m) and it dropped to 3ft (1m) in about 45sec but generally we have 30-45ft (9-12m) viz.

I think my goal would be to use the 12-40 so that I could be prepared for anything (within reason) that I might come across on my dives. I understand there is a large size range here but these are the things I see. and I think the 12-40 would help with getting photos. 

Frequent sightings include: California sheephead, garibaldi, kelp bass, kelp snail, kellets welk, chest nut crowie, spanish shawls, sea stars, bat stars, red sea hares, spiny lobsters, sea cucumbers.

Every once in a while sightings: hopkins rose, three lined aeolid, sheep crabs, smaller crabs, wreck fish (giant black sea bass), jelly fish, pyrosomes, salps

I hope this helps out.

I use the 12-40 like you outline around Sydney where we have similar vis issues.  It works quite fine my purposes.  With the 170mm Zen dome I can shoot subjects down to about 2-3" fairly readily as it focuses quite close.  At the wide end it usable for sharks up to about 2m long and certainly does garibaldi fish readily.  Heres' some pics from a day's diving I did in California (Catalina Island) a few years back:

https://www.aus-natural.com/Underwater/California/index.html

The image below shows the limitations for larger subjects, in this case Grey Nurse sharks at an aggregation site south of Sydney.   I was tracking the background shark when the foreground shark appeared in the viewfinder, It's about 2m long and too close for the 12-40 at 12mm:

I'm wondering if there's a way to adapt the Zen 170mm dome?  It will work with the 12-40 and also with the Olympus 8mm fisheye as I recall.

9 hours ago, ChrisRoss said:

I use the 12-40 like you outline around Sydney where we have similar vis issues.  It works quite fine my purposes.  With the 170mm Zen dome I can shoot subjects down to about 2-3" fairly readily as it focuses quite close.  At the wide end it usable for sharks up to about 2m long and certainly does garibaldi fish readily.  Heres' some pics from a day's diving I did in California (Catalina Island) a few years back:

https://www.aus-natural.com/Underwater/California/index.html

 

I'm wondering if there's a way to adapt the Zen 170mm dome?  It will work with the 12-40 and also with the Olympus 8mm fisheye as I recall.

Hi Chris,

I am using the DP-170 (N120 version without any extension):  N85/N120 34,7mm adapter for Zuiko 8mm (but now I use practically exclusively the Canon 8-15mm with Metabones 1x for WA fisheye) and N85/N120 60mm adapter for Zuiko 12-40, Pana 7-14 and Zuiko 9-18. I use the 60mm N85/N120 adapter because I have it since ever and bought the 34,7mm adapter later:

=> An even better solution would be to use just the (universal) 34,7mm N85/N120 together with a 25mm N120 extension for the non-fisheye lenses. Then one does not need to buy the expensive N85/N120 60mm adapter.

=> Probably Wapiti knows whether it is possible and how to adapt this combo to the AOI housing.

MAYBE one could test out the 30mm extension with the two WA lenses, in case they would not vignette, 30mm extension will be presumably better for IQ (positioning of the entrance pupil) than 25mm...

Wolfgang

Regarding benefit/drawback of large domeport, I would say:

Benefit of large domeport:

#1.: IQ (in my personal experience using the small MFT sensor, fisheye lenses did not require a real fisheye domeport, but large WA port also gave very good results).

#2.: Good for split shots.

Drawback of large domeport:

#1.: Transportation when travelling with airoplane, as already mentioned (I personally think this is a little bit overrated, since travelling with a system camera means carrying around a hughe amount of sensitive extra lugagge anyhow).

#2.: Strenious, when swimming againgst current.

#3.: In the way when one wants to get close to an object.

Wolfgang

Benefit of big dome port: A feeling of safety when it is between you and a moray eel.

Big domes are impossible where it is too shallow for them. In this stream I have struggled to use micro domes and other small ports. This year I used the Nauticam EMWL with the 100 degree objective. Even so it was challenge to submerge the port housing the 105mm lens.

The location is in the upper inter-tidal. Seawater reaches the base of the sedges growing at the edge at the higher of the two high tides that occur each day during spring tides. These are Pink Salmon, now an invasive species in northern Europe. They have a two-year life cycle so are the "rabbits" of the Salmonidae. This location is about 2km from where I am sitting right now

pd-16-dome-port-aquatech-imaging-solutions-2_300x.webp

Now this is a dome, does anyone have experience with a dome this big?

PD-16" Dome Lens Port | AquaTech - AquaTech Imaging Solutions