I posted the following review to steves-digicams underwater forum a couple of weeks ago. I hope it fits the bill for you:
Sea & Sea have recently released an adaptor for the Olympus PT-010 housing. This screws in to the filter thread on the front of the housing. Once there it provides a bayonet fixing for Sea & Sea’s range of lenses for the Motormarine Cameras.
The adaptor will attach all the Lenses available. The full range of which is as follows:
1:2 Macro
1:3 Macro
20mm Wide Angle
16mm ultra wide (weitwinkel) Angle
I have tried out all of the above lenses. However the two wide angle lenses are not recommended and I can see few times when they would be useful. This is because to avoid vignetting the zoom on the camera must be at the telephoto end of the range. When this is combined with the 16mm lens the resulting image has a smaller spread than using the wide angle end of the original camera lens. The one advantage is the ability to focus more closely than the original camera lens.
The adaptor is primarily designed for the two Macro lenses and it is these that I have tested. I have not had the opportunity to try out this rig in the ocean yet but have conducted tests in the bath. Roll on that holiday to the Maldives in February.
The adaptor screws on to the filter thread at the front of the housing. It is very important to apply a bit of silicon grease to this thread to prevent sticking of the adaptor. When unscrewing the adaptor the direction of turn is the same as that for the front ring of the housing. If the adaptor sticks it can loosen the front ring of the housing. This will cause the housing to flood. For this reason I would not recommend removing the adaptor ring underwater.
The additional lenses attach to the adaptor by means of a bayonet fitting. They must be turned to click into position. Both lenses have a plastic handle attached which is used to attach the framer. It is important to ensure that when the lens is in place the “handle” does not block the sensors to the left of the lens (when looking at the front) on the body of the camera.
The two macro lenses are designed for use with framers that are supplied with the lenses. One of the advantages of using these lenses with the Olympus housing is that the framers can be discarded. In fact the framers are not effective as the area that the lenses resolve is significantly smaller than the original framed area. This is a result of having to use the camera at full telephoto instead of 35mm, the lens that the Motormarine camera has.
Lens: 1:2 Framer Width: 9cm Ca.Size of Image: 2-3cm
Lens: 1:3 Framer Width: 14cm Ca.Size of Image: 4-6cm
In use the camera must be zoomed in to maximum telephoto to avoid vignetting of the picture. At any less than full zoom the picture will have fuzzy corners or indeed at wide angle have a circular border.
The following pictures show approximate size of image using a UK 1 pound coin which is 2.3cm across with the additional lenses compared with the standard Olmpus lens.
http://www.pbase.com/markyprior/sea__sea_macro_adaptor
The lenses are both wet lenses and must be attached underwater. This allows the space between the glass front of the housing and the back glass of the lens to flood. This is essential for correct focus.
The downside of these lenses is that the front of the lens must be reasonably close to the subject to obtain focus. This is coupled with a relatively small sweet spot of distance from subject outside of which it is difficult to obtain focus.
The 1:2 lens is in focus at approximately 4 cm from the target and the 1:3 lens at around 11cm.
If you already possess the macro lenses then the adaptor is an essential purchase although very over priced (at least in the UK).
I look forward to trying these out in the wild at the end of the month.
Mark