I have not seem many "amateur user" reviews on this setup, so I thought I would post my experiences with the Oly PT-EP05L (the housing made for the relatively new E-PL3) FWIW. I recently bought this setup after losing my Nikon D5000 setup (with a Nimar housing, and my very much loved 105mm f/2.8 macro lens) to a flood ..a flood that I attribute at least in part to having to lug around too much oversize equipment (yes, not testing the seal after changing lens was my fault; but changing lens and lens ports on a full DSLR housing is such a hassle that in the 30 minute SI on a crowded boat I wonder how many of us always do the seal check?). Worse than losing my camera, lens and housing was the fact that I missed shots of an amazing encounter with a Gigantic Grouper and an Eagle Ray that swam within 20 feet of me on the next day's dive. Ugh. I actually bought another Nimar housing, camera and of course 105mm macro lens after the flood, but then discovered that Nimar changed the port mount so none of my very expensive ports for the "older" model (which carries the exact same model designation!?) would fit!! Bad Nimar, bad. Lost me as a customer for life over that issue alone (and as an aside, my brand new, unused Nimar housing, standard port and D5000 camera body are going up on ebay and in the classifieds this weekend).
Anyway, although I do plan to eventually buy the Subal setup for my even more loved D7000, cost and portability made that prohibitive for my most recent dive trip which I had to do as shore excursions from a major cruise ship (not something I would recommend to anyone serious about diving but that is another story). So, I decided to go with the very well-reviewed Oly E-PL3 and the matching housing the PT-EP05L.
As a spoiler, I loved it! This was the best experience I have ever had diving with photo equipment. I will probably love the Subal even more, but the ability to take a 12.3MP camera, that shoots in RAW mode (yes it does!), has an interchangeable and decent quality lens system (including several f/1.8 and f/2.3 lens options at the higher end), and which fit in my carry on bag along with all my other "essential" gear (including: my strobe (Sea & Sea YS-110a), strobe arms and tray, batteries, chargers, regulator, dive computer, laptop and charger, 2 days of clothing, and personal care stuff) was just amazing! On top of that, I was able to fit ALL of my gear (BC, camera+housing+strobe assembled, regulator, dive computer, skin, fins, mask) into an the large over the shoulder mesh bag from aqualung! No more lugging my pelican case around!
Those were the reasons I chose the system, here are some impressions after 4 dives:
1) The YS-110a worked great and connected very securely using a standard S&S optical cable. The PT-EP05L includes two optical ports. Once I setup the camera to use pre-flash sync. This is not the default setting on the E-PL3 so you need to go into the custom configuration menus (hidden by default) to set up the pre-flash. Also, the PT-EP05L comes with a small plastic mask to cover the internal flash when used with an external flash - don't forget to pack that small plastic piece like I did! Most of my shots were unaffected by the internal flash, but I lost a few due to the internal flash. I shot exclusively in TTL mode as I did not have enough dives to get comfortable with manual yet and I really wanted some good shots to start out with this system.
2) The E-PL3 supports Oly's RC controlled flash system which adjusts flash output and flash zoom automatically using TTL and infrared communication between the strobe and camera!!; but you need the Oly's UFL-2 (oly's new external strobe). I have ordered one from Walmart of all places (best price!?) but did not get it in time for the dive trip. More on that once I use it, but I can confirm that the E-PL3 has menu options for this feature. Very cool from such an inexpensive camera.
3) I shot exclusively with the 14-42mm f/3.5-5.6 II kit lens that came with the E-PL3. The PT-EP05L includes a standard lens port that is designed for this lens. I did also buy the "gear" so that I could adjust the zoom/focal length. Additional lens ports are available from Zen Underwater for this camera but I have not yet tried them (I am considering the flat low volume port for my Lumix f/1.8 45mm macro lens, as well as the dome port for wide angle). I don't love the 14-42mm lens, and in low light situations even with the S&S it was really not adequate (I had to boost ISO on nurse shark shot attached because I could not angle the strobe underneath the ledge; therefore there is an unacceptable amount of noise IMHO). However, the lens and gear fit like a glove and adjusting zoom was very easy. I used the 42mm to get the nurse shark, and backed it up to 14mm for most other shots. Having that flexibility was nice - I am thinking that with the addition of a second strobe and longer strobe arms I would probably be okay shooting with the 14-42mm lens. The autofocus worked without a hitch at all focal lengths between 14-42mm and was very fast (< .5 second except for a couple of close up shots where I had to back up a little to get AF to work). Further, I experimented with using the continuous target tracking AF and was very pleased - the stingray with "rider" was taken with continuous target based AF from about 20 feet away at full extension 42mm!
4) Camera speed was never an issue. On several occasions I shot 3 shots before I realized I had multiple exposures turned on (which is my standard setup above water) .. of course the strobe could not recharge that fast so the second and third pictures ended up too dark. But the point is that the camera had no trouble keeping up with me. It is not a D7000 to be sure, but it easily matches my now defunct D5000.
5) I really liked being able to frame my shot on the LCD screen. This is a huge luxury that you will only appreciate when you try it! The large LCD was easily visible and camera settings were easy to adjust underwater due to the LCD. Unlike the Nikon, the E-PL3 was designed to use the LCD only, so it does not suck battery life like live mode on a Nikon does. There is no viewfinder of course this being a mirrorless camera (there is one actually as an accessory but it won't work underwater).
6) I set white balance for underwater use (which is an option on this camera). However, I had to make some major adjustments to white balance on all my shots. Luckily Lightroom easily corrected white balance in almost every case. I suspect this is due to the raw format not using the auto white balance? but I don't know because I have never had an "underwater" option on my white balance before!?
7) Ergonomics were very good. I could easily enter the water with this camera in one hand, and except for actually taking pictures, I mostly carried the camera in one hand during the dives. This made it much easier to deal with my regular scuba gear!! ALL of the functionality of the camera was accessible, and buttons were clearly labelled consistent with the labels on the corresponding buttons on the camera itself. I would strongly recommend getting familiar with the camera top side, though, as oly's menu structure and button layout were foreign to me as a dedicated long time Nikon user. Luckily I had taken this on a few birdwatching trips with the 150mm lens and already was over the learning curve mostly.
8) You will need a tray and arms. Oly makes these, but I could not find the Oly tray and arms anywhere in the U.S. So, I got the generic compact "S" tray and arm set (with 8" arms) from Optical Ocean. The S tray is very compact was a great match for the Oly. You do need to make sure to line up the tray's ridge with the back ridge of the camera to prevent the camera from rotating, as the provided thumbscrew is not tight enough to prevent rotation, and there is not any left/right mounting screw holes on the housing to provide a more stable rotation free setup. Not sure if that was how the tray ridge was supposed to be used, but it worked. Additionally, with this tray, the camera would only work in one orientation - if you "flip" the camera around the shutter trigger was essentially blocked by the right arm.
9) Given the size of the camera's sensor and lower speed lenses (versus my Nikon anyway), I really think it is necessary to get 2 strobes and longer (2 piece) extension arms to be able to better position the strobes behind the very short snout of the camera lens. You will see backscatter on my shots because I had a lot of trouble positioning and moving the strobe on the short single 8" arm. My next trip I will use the UFL-2 with the YS-110a hooked up as slave, each on a two piece 12" arm. That should improve results re backscatter and lighting generally and may also make the 14-42mm lens adequate.
10) Did I mention RAW mode! I hate shooting in JPEG which is why I have always avoided the point and shoot uw camera. Having a usable raw mode on such a small camera is great! A number of shots were saved by Photoshop due to raw mode.
11) Battery life on the camera was outstanding. I changed the battery after the third dive; 2 dives day 1, 2 dives day 3 with lots of "tourist" topside pictures in between. I probably could have finished the 4th dive but I didn't want to risk it (and I had 4 charged batteries with me in any case).
12) The housing has 67mm threads for wet lens mounting. I bought the Oly macro lens but I did not use it because I had no good place to put the lens! I really need to come up with a solution to where to put the wet lenses so ideas are appreciated. I would probably buy some stacking macros for super macro use but without knowing where to put them when not in use, I am a little hesitant to shell out more $$.
13) Oring seal and locking mechanism was excellent. The Oring is extremely secure in the well designed oring grove (single oring fwiw). The locking mechanism is simplicity itself - you turn a large round knob/clasp that locks the back to the main housing. It is very very easy to close and there is a satisfying "click" when properly closed... and almost impossible to open accidentally. To open, you must push in on a lock release so accidental unlocking is very unlikely. The housing has a moisture alarm too if you install the batteries for that feature (also, batteries power macro target lights on the front of the housing, but I did not really get enough macro work in to notice if these are useful).
My only experience with compact setups was the old Sealife DC800 and that did not come close. The DC800 was nice when I starting out with UW photography, but the Oly is at a whole different level. It easily matches the performance and features of my much larger Nikon D5000 setup (now defunct) at a fraction of the size and cost and in a size package that is only slightly larger than the DC1000 was. Even once I buy my Subal setup, I expect to take the Oly with me as a backup and alternate camera for dives with difficult water conditions where I might not want to risk or handle a more expensive and cumbersome camera. I would take this setup over my old Nimar/D5000 any day or night.
Finally, cost wise .. this setup is a great deal and not much more expensive than a point and shoot which would be far inferior. Here is my tally (not including many extra lenses I got for topside use that may eventually make it into my bag for UW use with the Zen ports)...
Camera and lens kit with 14-42mm lens: $649
PT-EP05L housing: $799
Sea & Sea YS-110a: $0 (already had, but expect to pay $700 I think for a new one or $550 for the UFL-2)
S Tray and arm kit: $200
PPZR-EP02 Zoom Ring: $45
Total: about $1,700
An example photo is attached... I think I need to resize my photos so i can post some more which I will do later, sorry!