Housing weight and buoyancy.

[Titanite]

Hello,

I am trying to get a rough calculation for how negative my camera set up will be and ways to offset this to help with arm strain.

Does anyone know how many pounds negative a Canon 7D Ikelite housing is? Im using a flat port for a 60mm macro lens. Says on the site that it weighs 7.15 LBS with out a port. Any help is greatly appreciated.

Thank you
T

[Ikelite Staff]

Every camera/housing and lens/port combination will be slightly different. My best guess for this combo would be 0.75-1.0lb negative.

Regards,
Jean / Ikelite
IKELITE Underwater Systems

[Titanite]

Hi Jean,
That would be with camera correct?
Thanks again

[ileiman]

Hello,
Does anyone know how many pounds negative a Canon 7D Ikelite housing is? Im using a flat port for a 60mm macro lens. Says on the site that it weighs 7.15 LBS with out a port.

I have done weight and buoyancy measurements with my rig at the pool (non-saline water).
Following are the results, weights in metric grams (g).
1 ounce (oz.) is 28.3 grams.
1 kg = 1000 g. 1 lb. = 16 oz.
For salt water, there will be 3...4% difference in buoyancy.

lens: Canon 60mm EF-S macro
port: Ikelite #5502 flat

• Canon 7D in Ikelite housing, Canon 60mm EF-S macro in port, no strobes, no arms:
  480 grams negative in water, 5210 grams surface weight
• add to that 2x DS161 stobes with SA-100 arms & sync cords:
  1390 grams negative in water, 8690 grams surface weight

lens: Tokina AT-X 107 DX, 10-17mm fisheye
port: Ikelite #5510.45 8" dome + #5510.11 superwide body

• Canon 7D in Ikelite housing, Tokina 10-17mm in port, no strobes, no arms:
  610 grams negative in water, 6360 grams surface weight
• add to that 2x DS161 stobes with SA-100 arms & sync cords:
  1520 grams negative in water, 9840 grams surface weight

The SA-100 arms used here are the #4086.61 sets with single 6" arms.
The sync cord is #4103.52 dual.
My #6871.07 housing is a modified version where the video lever has been replaced by a push button (by Ikelite per my request).

[ileiman]

For ideas how to get rid of arm strain, look at this thread at wetpixel:
Looking for longer strobe arms - Wetpixel :: Underwater Photography Forums

The Ikelite arms were too short for me with the wide fisheye lens, giving flare and backscatter, and the rig was too heavy to handle in water.
So I bought Stix float arms to replace them. They complement the Ikelite system very well, and fit nicely between the Ikelite housing and strobes.

For each two strobe I got two Stix SX-312 12" arm segments, which allow me to extend each strobe 70 cm to the side. The Stix arms come with floats, which you can add, remove and change by detaching the arm balls. The floats are made of very hard foam which does not compress in recreational diving depths. The 12" arms can have up to 5 floats on them, and there are 3 different sizes of floats.
I was able to fine tune the rig buoyancy and balance it perfectly with the floats, so that my rig is perfectly neutral in the water. Below is a picture of it with the 8" dome setup:

I could leave the rig to hang alone in mid-water, and it will stay there in same depth and position on its own. So this means it is very easy to handle in water.
In this picture you can see how far the arm can go:

The DS-161's are very powerful strobes, and can light up the entire reef, wreck, or a swimming pool, so for really wide-angle shots you really need the long arms.

You can detach the balls at the end of the arms, which allows you to remove, add and change the floats.

[rbarosa]

I have an Ikelite 6871.60 for my Canon Rebel T3i. I noticed that is positive (no flashes). Where and what kind of weight I can add to it? I could not find anywhere..

Thanks
Regi Barosa

[Ikelite Staff]

I have an Ikelite 6871.60 for my Canon Rebel T3i. I noticed that is positive (no flashes). Where and what kind of weight I can add to it? I could not find anywhere..

Thanks
Regi Barosa

Regi,

In an effort to streamline our DLSR housings, the newer style housing tray does not accommodate space for optional lead weights. Since most DLSR housing users attach underwater strobes, space for additional weight was not factored in the design change.

That said, I do have an option for you. We sell a NiMH Battery Pack Pouch that attaches to 1/4-20 female threads in the base of your DSLR housing tray. You could then fill the pouch as needed with lead diving weights (available at any dive shop). Also, the pouch is collapsible for easy storage and shipping.

You would need to order #1401.1 Single Battery Pouch ($25) and #1401.4 Ikelite Housing Mount Kit ($25). You can order from an Ikelite dealer or call Ikelite customer service direct with a Visa/MC at 317-923-4523.

Regards,

Brett Foster - Ikelite