Wet dome or dry dome ?

[Pyndle]

Hi,

For years I've been shooting with a wet dome.
I have a Sony A6500 with a 16-50mm lens, the old Meikon/Sea Frogs housings and a Meikon 6inch wet dome.

I like this setup because I also have a +6 Inon diopter, and a kit of magnets. Which means that on any dive, I can shoot wide at 16m + dome, or change in a few seconds and be at 50mm + diopter for macro.

I sold all my gear except the Camera (I knew I woudn't dive for the last year and a half, and thought I'd upgrade to an A7R IV but I didn't and will not for now).

Now going diving again, I'm gonna get the new Sea Frogs housing, but not sure whether I should get the normal port and a wet dome, or a dry dome?

The benefit of the dry dome is that I can use my 10-18mm lens in it so my shots would be much wider and I can get closer to my subjects (always better for lighting with strobes). But I don't realize if it does it make a significant/noticeable difference in quality (aside from lighting), just from the fact that there is less water between you and the subject. Is it really significant?

Drawback is obviously losing the ability to take off the dome and shot at 50m if I see a cool nudi/shrimp etc.

Also, is there a big difference between a 6inch and 8inch dome? (please don't say "yes, 2 inches" )

Any info/tips welcomed!

Thanks

 

[Barmaglot]

Also, is there a big difference between a 6inch and 8inch dome? (please don't say "yes, 2 inches" )

I've done some testing of 6-inch vs 8-inch SeaFrogs domes, you can see the results here.

As for wet vs dry dome, 10-18mm in a dome is going to be considerably wider than 16-50mm with a wet dome attachment, but if you get a real wet lens (Nauticam WWL-C, Kraken/Weefine KRL-01/WFL-01, Fantasea/AOI UWL-09) then you can use it with 16-50mm and a short flat port and get a field of view similar to that of 10-18mm, albeit with some fisheye distortion, while maintaining flexibility.

 

[OTF]

what about for over/under shots? are dry domes the only way to go?

 

[Barmaglot]

what about for over/under shots? are dry domes the only way to go?

In general, you want really big domes for those, and wet lens front elements are just too small. Meikon used to have an 8-inch wet dome, but I don't see it listed anymore. Another thing with wet lenses and domes is that they require the space between port glass and rear element to be filled with water, and when you take the camera halfway out of the water, it may drain out, especially if you're using an adapter rather than screwing it in.

 

[Pyndle]

I've done some testing of 6-inch vs 8-inch SeaFrogs domes, you can see the results here.

As for wet vs dry dome, 10-18mm in a dome is going to be considerably wider than 16-50mm with a wet dome attachment, but if you get a real wet lens (Nauticam WWL-C, Kraken/Weefine KRL-01/WFL-01, Fantasea/AOI UWL-09) then you can use it with 16-50mm and a short flat port and get a field of view similar to that of 10-18mm, albeit with some fisheye distortion, while maintaining flexibility.

Hey Barmaglot! Long time no speak (I kind of disappeared of scubaboard for a bit, not much diving going on over the last 2 years). I hope you're well

Thanks for the super helpful comparison! And damn, those 8inch wet domes are expensive !!

Just a few questions:

In your test you only have dry domes, right? Out of curiosity, why did you buy all theses domes? I mean if you have an 8inch dome what would you do with a 6/4inch dome?

It's funny, there's barely any difference between the 6 and 8 inch domes at 18mm. However the difference is massive at 10mm - Is that normal? It doesn't feel proportional.

The reason I ask is because it looks like the 16mm@6inch is equivalent to the 18mm@8inch. So I'm wondering if upgrading the 16mm@6inch to a 16mm@8inch will have a big impact (like it does at 10mm on the 10-18) or no impact at all (like it does on the 10-18 at 18mm). Have you not tried that 16mm in the 8inch dome?

Also, do you have a wet dome? Curious to know what kind of differences there are between a wet and dry one for a given lens (let's say the 16-50), feels hard to quantify and I have no idea how it works.

Thanks!

 

[Barmaglot]

In your test you only have dry domes, right? Out of curiosity, why did you buy all theses domes? I mean if you have an 8inch dome what would you do with a 6/4inch dome?

I got the bundle of housing + 6-inch dome initially, but some time after that, Meikon released the 8-inch dome, and there was a sale of some kind (black friday? I don't remember) and I got it as an upgrade. The 6-inch dome has been gathering dust on the shelf ever since. The 4-inch dome is for use with the fisheye lens (7Artisans 7.5mm in my case).

It's funny, there's barely any difference between the 6 and 8 inch domes at 18mm. However the difference is massive at 10mm - Is that normal? It doesn't feel proportional.

Wider FoVs are proportionally more affected by the dome size. The dome projects a curved virtual image into the lens, and as you go wider, you need this image to be bigger and further away to stay within the lenses depth of field.

The reason I ask is because it looks like the 16mm@6inch is equivalent to the 18mm@8inch. So I'm wondering if upgrading the 16mm@6inch to a 16mm@8inch will have a big impact (like it does at 10mm on the 10-18) or no impact at all (like it does on the 10-18 at 18mm). Have you not tried that 16mm in the 8inch dome?

I haven't run a direct comparison, no. I've used the 16-50mm in the 8-inch dome a lot on my last trip, and it worked very well, but I can't really compare it with the 6-inch dome in the same circumstances. Probably not a lot of difference, as 16mm isn't very wide.

Also, do you have a wet dome? Curious to know what kind of differences there are between a wet and dry one for a given lens (let's say the 16-50), feels hard to quantify and I have no idea how it works.

No, I used to have the 4-inch one with the old fixed-port housing, but sold them both.

 

[Pyndle]

Thanks!
Why would you use the 16-50mm in the 8inch dome rather than the 10-18mm? You can still get good close-ups/portraits at 50mm with the dome?

 

[Barmaglot]

Flexibility. Provided very clear water and lots of strobe power (I use a pair of Retra Pros), it can range from reefscapes, to fish portrait/behavior shots taken from a reasonable distance, to close-ups on smaller subjects like GPFs or larger nudis. Short flat port + WWL-C + diopter would work better, but I don't have those.

These were taken on the same dive, using A6300 + 16-50mm, in a SeaFrogs housing with 8-inch dome and Retra Pro strobes:

It even works for blackwater, although a 30mm macro would've been better there.

Not to say that 10-18mm doesn't give great results

But it's frustrating to encounter something really cool and having it come out as a little speck somewhere in the middle of the image.

 

[Pyndle]

Flexibility. Provided very clear water and lots of strobe power (I use a pair of Retra Pros), it can range from reefscapes, to fish portrait/behavior shots taken from a reasonable distance, to close-ups on smaller subjects like GPFs or larger nudis. Short flat port + WWL-C + diopter would work better, but I don't have those.

These were taken on the same dive, using A6300 + 16-50mm, in a SeaFrogs housing with 8-inch dome and Retra Pro strobes:

View attachment 660583

View attachment 660584

View attachment 660585

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It even works for blackwater, although a 30mm macro would've been better there.

View attachment 660589

Not to say that 10-18mm doesn't give great results

View attachment 660590

But it's frustrating to encounter something really cool and having it come out as a little speck somewhere in the middle of the image.

Wow, thanks for the cool pics! I was not expecting to be able to get such closeups with an 8inch dome!

But I think I agree with with your last sentence. I'll probably just get the cheapest seafrogs case with the flat port (it can take the 10-18 and 16-50). And add a wet dome to it (6inch or 8inch if I manage to find the old ones). So I keep that flexibility while diving.


Just wished someone had sample pictures between a wet and a dry dome, if anyone reads this and has it, please feel free to post

 

[Pyndle]

**** of course it was too good to be true. Just realized the standard port from Sea Frogs has this in the description:

"Please note, that a standard port that comes with this unit doesn't have a 67mm thread, so it is not possible to attach 67mm accessories such as filters or lenses."

So no wet domes