Test Pictures: Oly versus Pana 8mm
Top-side pictures 1 and 2 compare performances of the new Olympus 8mm 1.8 F and the Panasonic 8mm 3.5 F. Both lenses were mounted on an Olympus EPL-5 body (the Oly 8mm with extension ring). Same distance to object, ISO 200, 3.5 F, 1/100, s AF. No flash. My first impression is that the quality is almost identical.
Top side pictures 3-12 show Oly 8mm shots with various apertures and shutter speeds. Focusing on medium distance objects. Pay attention to the corners. Details do not seem to differ much between the widest aperture f1.8 and narrower apertures. Picture 10: 100% crop of the right upper corner of picture 9 (non cropped) at 1/30, ISO 800 and f1.8. Depth of field and the crop look pretty good. Pictures 11 and 12 are close ups of a small box 5 cm in front of the FE lense. Nr 12 with the wide aperture f1.8 shows more blur of the background than nr 11 with aperture f4.
Pictures 13 and 14 with the plastic bottle and shells are taken in a little plastic container filled with water with the Olympus F1.8 on the EPL-5 in a PEN housing (PT-EP 10) and dome (4 inch Precision). I used a Zen 2.5 cm extension ring between the dome and the housing. Aperture settings F1.8 and F 7.1 respectively. Background slightly blurred at @ 1.8
On the basis of these preliminary tests I feel that the specific merits of the new Oly lense will be in natural light UW settings, when the maximal aperture (1.8) can be helpful to absorb all available light. Im thinking of shots in caverns or of fast moving objects like dolphins when ultra fast shutter speeds (>500) are required, and you want to keep the ISO within limits. Even with a filter, normal ISO (200) and shutter speed (1/125) it should give reasonably good sharpness and lighting of larger objects. With close up shots and strobe light the lens will have to be stopped down, and the difference with its cheaper 'rival' the Panasonic 8mm could be negligible. Since the new lense is longer it will need an extension on the housing, that will bring the mini dome in a more forward position relative to to the housing. Compared with the shorter Panasonic this means less risk of glare from the strobes entering the corners of your picture. Especially when shooting CFWA with your strobes positioned close and a litte backward relative to the housing.