Floatation advise - Nauticam A7RIII + 8-15 + 140mm dome port

Hi from Bangkok, Thailand.

I'm an ameteur underwater photographer (Beginner) but I frequently shoot landscape, panoramic photography and macro ( intraoral dental photographs). After research about housing, strobes and underwater photography technique , I bought my first full system (not include my old gopro4 and sony FDRx3000)

My gears:

A7Riii + metabones + 8-15 F4L

Nauticam housing + port adaptor + extension ring 30 + Nauticam 140 mm fisheye dome port

Sea & Sea YS-D3 + diffuser + mini flash trigger

Weefine 2300 focus light x1

I wish I will buy INON mega float M -650g x2 + INON float M -135g x2 

Total = -1570g

But I'm not sure it gonna work.

I see a lot photographers use Sony A7 with 8-15 and Nauticam 140 mm dome port. 

Please advise if you have any suggestions about buoyancy. 

Thanks

Namton

Seeing as how you have all of your gear - assemble it with camera and lens and weigh it hanging off a luggage scale in a tub of water - completely submerged.     Your YS-D3 is listed as -20g underwater (i.e positive bouyancy) and the Weefine light at 240gr  UW.  Add up all of the underwater weights paying attention to the signs and that is the amount of buoyancy you require.  You of course also need clamps etc. which add a little negative buoyancy.   I use a luggage scale - it's good enough just hang the housing off a rope or sling and let it settle and get the weight.  It's best in a tub of water that is deep enough to fully submerge.

Then select the float arms that add up to close to but not over the weight of your system - you do not want a positively buoyant rig - slightly negative is more stable.  You can use 4 float arms or two float and two regular arms.    INON provide a table of UW weight for all their equipment which may be helpful:  http://www.inon.jp/products/armsystem/weight_table.html

If I were to guess based upon my system I would say what you selected is too much buoyancy  - but don't guess weigh it and calculate.  It will be about 3% more buoyant in salt water - but that is normally within the margin of error of these calculations.

If you use the Mega float arms I would recommend long clamps for connecting it to your other arm otherwise they won't be able to fold them to get the two arms parallel and it will limit how close you can get the flash to your housing

15 minutes ago, ChrisRoss said:

Seeing as how you have all of your gear - assemble it with camera and lens and weigh it hanging off a luggage scale in a tub of water - completely submerged.     Your YS-D3 is listed as -20g underwater (i.e positive bouyancy) and the Weefine light at 240gr  UW.  Add up all of the underwater weights paying attention to the signs and that is the amount of buoyancy you require.  You of course also need clamps etc. which add a little negative buoyancy.   I use a luggage scale - it's good enough just hang the housing off a rope or sling and let it settle and get the weight.  It's best in a tub of water that is deep enough to fully submerge.

Then select the float arms that add up to close to but not over the weight of your system - you do not want a positively buoyant rig - slightly negative is more stable.  You can use 4 float arms or two float and two regular arms.    INON provide a table of UW weight for all their equipment which may be helpful:  http://www.inon.jp/products/armsystem/weight_table.html

If I were to guess based upon my system I would say what you selected is too much buoyancy  - but don't guess weigh it and calculate.  It will be about 3% more buoyant in salt water - but that is normally within the margin of error of these calculations.

If you use the Mega float arms I would recommend long clamps for connecting it to your other arm otherwise they won't be able to fold them to get the two arms parallel and it will limit how close you can get the flash to your housing

Thanks Mr.ChrisRoss for your good information.

I will try to weigh my system with luggage scale.

Many thanks.

Interesting buoyancy article of underwater photography equipment

BEST BUOYANCY SOLUTIONS FOR UNDERWATER CAMERAS
https://www.backscatter.com/reviews/post/Best-Buoyancy-Solutions-For-Underwater-Cameras

4 hours ago, turandot said:

Interesting buoyancy article of underwater photography equipment

BEST BUOYANCY SOLUTIONS FOR UNDERWATER CAMERAS
https://www.backscatter.com/reviews/post/Best-Buoyancy-Solutions-For-Underwater-Cameras

Thanks a lot.