Buoyancy of the WP-DC30 with A75 in it?

[ScubaTexas]

What is the buoyancy characteristic of the WP-DC30 housing with the A75 in it: positive, negative or neutral? If positive, what do you do to combat that; add weight inside the housing?

 

[hdtran]

Positive buoyancy.

You generally add weights to the housing on the outside tripod mount (yes, there's a 1/4-20 tripod mount on the outside of the housing). You can either use the Canon-brand weights, or roll-your-own.

Most accurate method is to measure the housing displacement & measure the housing weight; second most accurate is to use the manual information on displacement & weight. Third is to just use the Canon recommendation.

The link here http://consumer.usa.canon.com/ir/co...yAct&fcategoryid=113&keycode=underwater_photo shows you approximately how much.

 

[ScubaTexas]

Positive buoyancy.

You generally add weights to the housing on the outside tripod mount (yes, there's a 1/4-20 tripod mount on the outside of the housing). You can either use the Canon-brand weights, or roll-your-own.

Most accurate method is to measure the housing displacement & measure the housing weight; second most accurate is to use the manual information on displacement & weight. Third is to just use the Canon recommendation.

The link here http://consumer.usa.canon.com/ir/co...yAct&fcategoryid=113&keycode=underwater_photo shows you approximately how much.

Thanks. That is very helpful information. A quick search showed the Canon branded weights run about $30 (+/- $2), which seems like a bit much for some pre fabbed lead. Is it easy to make your own or is it better to just suck it up and pay the $30?

 

[hdtran]

Thanks. That is very helpful information. A quick search showed the Canon branded weights run about $30 (+/- $2), which seems like a bit much for some pre fabbed lead. Is it easy to make your own or is it better to just suck it up and pay the $30?

Pre-fab'ed stainless steel, not lead. Gently aged in Japanese wood barrels

Seriously, I'm sure DYI works just fine. Get some stainless steel or perhaps brass shims; snip; drill a 1/4 or 17/64" hole (if 1/4, use a file to enlarge it slightly), and get a 1/4-20 stainless steel screw. Snip your shims to get about 20-40 grams of weight total (you probably want to retain a little bit of positive buoyancy). Brass will corrode a bit more than stainless, but is much easier to work. You can get brass tubing or shims at hobby shops (it's frequently used by model railroaders). For stainless steel sheets, you need to make friends with a local metal supply house. Stainless is something of a pain to work with. As an alternative, you can haunt Lowe's, Home Depot, Sears, etc. Go find some stainless steel (not plated, but stainless steel) washers for 1/4-20, and a 1/4-20 stainless screw. Get sufficient weight to make about 1 to 1.5 ounces (30-45 grams). That's your weight!