Dunadin

Depends a bit on the grease. Some are a mix of two or more components that can separate over time. That is usually an issue if you use grease to keep moisture out or for lubrication of machines. It is not a problem for O-rings since you only use a very small amount. If you leave the grease out in bright sunlight or areas with high ozone or other aggressive gases, you can degrade it to the extend that the products can degrade the O-rings. The most important part is that you use a grease that is formulated for the type of O-ring you have. The wrong grease will swell or embrittle the O-ring. The only other caution is to take the O-ring out of the groove if you don't use it for a while. All elastomers will set over time and provide less efficient sealing. That is a good time to inspect the O-ring for nicks or other damage.

As others have stated, the housing is only the beginning of the cost. You will need ports, strobes, arms and cables. The good news is that all of the later moves to a new housing of the same brand (strobes are more flexible even). As for the housing choice, I have always had my DSLRs in Ikelite housings and so far no problems. Some I even bought used here on wetpixel. Take proper care when assembling and cleaning it and all is well. That said, make sure you buy flood insurance. It brings a bit of peace of mind for the worst case and is not all that expensive. Now if you are not sure if you want a big DSLR under water or rather a more compact system. Check with local dive shops. Some might have systems you can borrow or take a underwater photo class with them they might let you play with their personal system.

Between the two, the 8" dome will give you less corner distortion. However, you will need the extensions that match the length of the lenses you plan to use. You might need two. Ikelite has a nice list of lenses and their recommended extension tubes. The 8" dome also saves some space if you have 2 or more lenses of different lengths. The only lenses I still have behind a small port are the macros (60 mm and 100 mm) with flat ports. Here is photo with a 17 mm lens behind the small dome https://flic.kr/p/7vijSQ and the large dome https://flic.kr/p/znL4t5. I think they are both uncropped, but I don't recall.

We've used Lembeh Resort twice and can highly recommend them. As others have noted, hire a private guide.

It is very important to use the proper lubricant for the type of o-ring you have. The wrong lubricant will swell or dry out the elastomer and the o-ring might not seal anymore. Swelling is not that bad usually, though it will weaken the material. Drying out the o-ring will make them brittle like an old rubber band.

I came across a couple invertebrates on the last dive to the oil rig Eureka (off Long Beach, CA) and I can't seem to find a source to ID them. Any pointers are greatly appreciated. Both were at about 50-70ft. Also does anybody know of a good ID book for "jellies" in the widest sense? Either there are a lot more in the water this year or I am just taking more interest to them lately. Either way, they are pretty cool and I'd like to be able to ID them. Thanks, Sergio

I'd throw the Tokina 12-24 into the mix. I've never used it for video, but I use it a lot for stills both u/w and topside and have been very happy with it. http://www.dpreview.com/lensreviews/tokina_12-24_4_n15

A couple days at room temp are no problem at all. You'll need to heat the o-rings to about 200-250F before compression set becomes a concern.

Thank you! Always a pleasure do learn something new.

It's a no-go for Ikelite as well. The Ike ports are ~85mm ID without the zoom ring and ~80mm with the zoom ring.

Yes, that's the solitary stage of Thetys vagina. The name becomes clear if you look at it from the front. They later go into a 'colony' form by cloning:

The last dive on San Miguel, CA resulted in two critters I could not ID. Any help and pointers are greatly appreciated. Thanks!

Just remembered an old post and found it again (www.carbonos.com/reports/usbconnect.htm). He had Ikelite install another sync port similar to the one used for the strobes in the back of the housing. That'll give you 5 pins in a proven feedthru. You might want to try something like that.

The Peace offers a guide for $125 (https://www.peacescubastore.com/ProductDeta...oductCode=GUIDE). Not sure about the other boats. If you get a guide through the local stores, it'll be a bit more since you'll have to cover the DM and the DM's trip cost. If you are comfortable diving and have done some cold water dives before, I suggest asking the DM on the boat to find a buddy for you during the briefing held before each dive. In my experience there are always a couple solo divers willing to pair up. If you've never done a cold water dive before, yes, get a DM at least for the first trip. Another option is to sign up for a class and you'll get an instructor in the water with you, you'll learn something new and the gear is sometimes included (depending on the shop). Good options would be Nitrox or dry suit diving. If you are staying past 9/29/12 (Lobster season opens), take a lobster hunting class and have dinner as well . There are a number of good dive shops in the area. I am partial to Malibu Divers (www.malibudivers.com) since I work for them . Lastly, you could do a guided beach check out dive and then go on the boat. As for dive sites. Like for other folks here, San Miguel is my favorite, but it is advanced diving and definitely on the cold side (40-50F). Not a lot of boats run out there since it is a 7 hr trip from Ventrua (one way). Anacapa has had marine protected areas for a long time and has a lot of great sites (Cathedral cove with lot so kelp, Underwater arch with lots of sea lions, Underwater island for a small wall to name some of my favorites). If you take a boat from San Pedro/Long Beach you can go to Catalina island, which often offers a little bit of better viz. And if you have time, take a road trip down to San Diego to dive the Yukon and Ruby E, two really nice wrecks.

There are 3 boats running out of Ventura (right next to Oxnard). The Peace (www.peaceboat.com) is the best IMHO. They run to all the northern islands, though mostly to Anacapa. Great food and a hot-tub on board. The Spectre (www.calboatdiving.com) only runs to Anacapa and sometimes to Santa Cruz. They run a lot of charters for Sports Chalet and have a lot of students. Both are great boats with very good crews. The last boat is the Rapture. It is a fairly small and fast boat, but serves no warm food. It is more of the type you would find in the Caribbean. Dive trips are typically 4 tanks and there is no DM in the water, i.e. bring your own buddy. You can "rent" a DM or simply ask on board during the briefing. There is usually no current around here and no drop-offs with a max depth of 60-80 ft on most sites. Also, all diving here is cold water diving. Temp on a warm day in summer is in the low 60s, more typically mid-50s. Viz is normally in the 20-30 ft range.