Sony A6400 metabones sea frogs housing

[mentosik83]

I am new in the underwater photography so please forgive me if I am trying to do something weird. I have Sony a6400 with stock 16-50mm and it is housed in Sea Frogs salted line housing with stock, flat port. I took my camera to my local quarry and while pictures are awesome and the camera has so much potential, I am thinking about something wider, like 10mm or so.

I am a surface canon shooter and have Canon 10-18mm and I have metabones converter. The lens with converter doesn't fit in stock flat port. I am thinking about 6" glass dome - right now it is priced as $380 which is not bad I think so I am about to pull the trigger but from the pictures I see on their page I am not sure if that dome can fit metabones with that lens. Lens with converter is 4.25". I am not concerned about zoom ring, I am fine with fixed 10mm.

Does anybody have something similar? Will it fit? Or should i get longer flat port? Or maybe flat port and wet dome?

 

[Barmaglot]

Definitely not flat port; this is the kind of distortion you'll get at 10mm shooting underwater through flat glass:

For the reference, the same shot taken through SeaFrogs 6-inch dome (Sony a6300, Sony 10-18mm @ 10mm):

As for the Canon 10-18mm, I don't have personal experience with it, but it should work okay-ish. Nauticam recommends a 60mm extension to use the Sony 10-18mm lens with their N85 housings and a 180mm wide angle dome, and a 40mm extension to use the Canon 10-18mm with Canon DSLRs and the same dome. Considering that for going between the mounts they recommend a 35.5mm adapter, this puts the total extension for Canon 10-18mm on Sony/Nauticam at 75.5mm - a 15mm difference. Putting the Canon 10-18mm lens on a shorter extension meant for the Sony one will give you some distortion (IIRC barrel rather than pincushion, but don't quote me on that), but not a whole lot, as well as somewhat softer corners.

Regarding glass vs acrylic domes, image quality is the same. Acrylic is lighter and floaty in the water, generally requiring trim weights to keep it from twisting the camera upward, whereas glass is heavier and tends to require extra floats on your rig. Acrylic is easier to scratch, but also easier to polish, while glass is more resistant to small scratches, but near-impossible to repair if you do get a major one.

Another option, if you already have an a6400 and a Metabones adapter, is the Tokina 10-17mm fisheye in EF mount. You can get a 2nd hand copy quite cheap, it fits the SeaFrogs domes made for Sony 10-18mm quite well, a zoom gear design for SeaFrogs Salted Line housings is available online, and it gives you 180 to 100 degree diagonal field of view zoom range, as opposed to the rectilinear 10-18mm which ranges between 109 and 76 degrees. See this thread for a comparison between fisheye zoom and a rectilinear ultrawide: The advantages of fisheye zooms!

 

[Nemrod]

I am new in the underwater photography so please forgive me if I am trying to do something weird. I have Sony a6400 with stock 16-50mm and it is housed in Sea Frogs salted line housing with stock, flat port. I took my camera to my local quarry and while pictures are awesome and the camera has so much potential, I am thinking about something wider, like 10mm or so.

I am a surface canon shooter and have Canon 10-18mm and I have metabones converter. The lens with converter doesn't fit in stock flat port. I am thinking about 6" glass dome - right now it is priced as $380 which is not bad I think so I am about to pull the trigger but from the pictures I see on their page I am not sure if that dome can fit metabones with that lens. Lens with converter is 4.25". I am not concerned about zoom ring, I am fine with fixed 10mm.

Does anybody have something similar? Will it fit? Or should i get longer flat port? Or maybe flat port and wet dome?

Does not SeaFrog have a lens and port chart for their equipment?

A wide angle wet lens might be easier to accomplish.

 

[Barmaglot]

Does not SeaFrog have a lens and port chart for their equipment?

Only a very basic one -

A wide angle wet lens might be easier to accomplish.

It would require a different flat port (Flat Short / Macro port for A6xxx / Rx1xx Salted Line with 67mm thread 40M/130FT) plus the lens itself would cost at least $600.

 

[Craine]

If I could make an alternate suggestion, I’d would say the Samyang AF 12mm in a 6” or 8” acrylic dome. I posted samples of the 6” combo in this other thread, and will dig up some samples of the 8” dome when I get home. You can get a “like new” copy of the lens on MPB for about $250 usually.

It ends up being pretty front floaty with the 8” dome, but I found the 12mm is a great focal length, and the image quality is good enough for me to print 20” x 30”.

 

[mentosik83]

Thanks for replies. I sent an email to Sea Frogs asking for their recommendation. I wonder if they reply.
Buying another lens is not rather an option, I have few lens from Canon EF-S already and I have that metabone converter.

Their website has 2 dome types - for sony A6XX series and A7. No idea what is the difference but in the section with extenders I don't see anything marked for A6XX series.

Does anyone know what is the difference between A7 and A6XX dome?

I am really puzzled, no idea what dome should I get. Glass 6", acrylic 6" or acrylic 8". I plan to use that stock 16-50mm and 10-18mm (or something like that if I cannot use converted canon lens).

 

[Barmaglot]

Does anyone know what is the difference between A7 and A6XX dome?

Mount diameter. The A6xxx housing and a few other older housings use a port mount with an 80mm internal diameter, whereas the A7/A9/A1 series housings, along with FX3/FX30 and A6600/A6700 use a port mount with a 100mm internal diameter. The extension rings are only available for the 100mm ports. There is no converter between mounts that I'm aware of. There is also a third mount, with 125mm internal diameter, that is used with their metal housings.

I am really puzzled, no idea what dome should I get. Glass 6", acrylic 6" or acrylic 8". I plan to use that stock 16-50mm and 10-18mm (or something like that if I cannot use converted canon lens).

The 8-inch dome is closer to 7 inches in actual sphere diameter. I have both 6-inch an 8-inch acrylic domes, and the 8-inch gives slightly better corner quality and is easier to do splits with.

 

[mentosik83]

ok, so I think I will take 6" acrylic. If my metabones with canon lens won't fit I will try to get some second market dedicated, well known lens.

Shipping fee kills those inexpensive pieces and I trying to figure out, what is the most popular affordable option for macro lens? SeaFrogs have macro ports, not sure which one should I take before knowing what lens I want to start for.

 

[Barmaglot]

Since you already have a Metabones adapter, you can get a 2nd hand Canon EF-S 60mm f/2.8 macro. It will fit in the flat long port made for Sony 90mm - the port is a bit long (there's a couple centimeters left between lens front element and port glass), but I haven't found that to be an issue.

 

[Craine]

Buying another lens is not rather an option, I have few lens from Canon EF-S already and I have that metabone converter.

Ah, I missed that you already had that in your OP, sorry!

I trying to figure out, what is the most popular affordable option for macro lens? SeaFrogs have macro ports, not sure which one should I take before knowing what lens I want to start for.

I have the Canon 60mm on the metabones adapter. I’d go with what @Barmaglot recommends for the port. I can tell you the combo does NOT fit into the “Flat short port with 67mm threads”. The combo is about 3-4mm too long for that port, so you cannot close the housing to get a seal. I’ve been using the 8” dome for it recently, and that works well enough while I looked at new housings to upgrade to.