For an expensive camera, there are a couple of MUST HAVES (in my opinion) for an underwater housing.
1. Positive lock ports. That is, once the port is locked in place, it would take a sledge hammer to remove it.
2. A vacuum valve. You seal the housing, turn the VV on and apply a vacuum (usually supplied hand pump). When the light goes green and stays green, you dive.
Not all older housings have #1. There is one housing that had little click-tabs to hold the ports on. My buddy lost a Canon D30 many years ago because the port got bumped as he was getting into the water. I think all modern housings, and especially the aluminum ones, have a really solid locking port mechanism. I certainly love the locking mechanism on my Nauticam housing (for a Canon 7D Mark 1).
Likewise, the vacuum port is (to me) a real layer of security. You not only seal the thing with a vacuum (all o-rings seated etc.) but you have visual confirmation (blinking green light) that it's working. I love mine (leak sentinel V4 on the above Nauticam housing).
Otherwise it's just some common sense and following guidelines that have been around for some time (i.e. don't just dump the system in a rinse bucket and walk away for a while)...
There was a 7DMk2 housing for sale just this past week. You should be able to find an excellent housing used for a good price.
1. Positive lock ports. That is, once the port is locked in place, it would take a sledge hammer to remove it.
2. A vacuum valve. You seal the housing, turn the VV on and apply a vacuum (usually supplied hand pump). When the light goes green and stays green, you dive.
Not all older housings have #1. There is one housing that had little click-tabs to hold the ports on. My buddy lost a Canon D30 many years ago because the port got bumped as he was getting into the water. I think all modern housings, and especially the aluminum ones, have a really solid locking port mechanism. I certainly love the locking mechanism on my Nauticam housing (for a Canon 7D Mark 1).
Likewise, the vacuum port is (to me) a real layer of security. You not only seal the thing with a vacuum (all o-rings seated etc.) but you have visual confirmation (blinking green light) that it's working. I love mine (leak sentinel V4 on the above Nauticam housing).
Otherwise it's just some common sense and following guidelines that have been around for some time (i.e. don't just dump the system in a rinse bucket and walk away for a while)...
There was a 7DMk2 housing for sale just this past week. You should be able to find an excellent housing used for a good price.