Since I have got some nice magnetic filters to play with for a bit, I thought it would be fun to do some long exposure, slowing down the shutter speed, capturing some motion of the flowing water. I was at KL Birk Park (yes, again) to test another product which will be mentioned on another blog entry, but it was just the perfect place to shoot the fake, man-made waterfall. Many people would be quick to point out that the OM System OM-1 that I was shooting with has built in Live ND filter, a computational trick to simulate the effects of neutral density filters, but the limit is at ND64, or 6 stops exposure. It was barely enough to achieve the silky smooth water effect, which required ND1000 (10 stops) or more, so I snapped on the 10 Stops ND on the Jetmag Pro magnetic filter kit, used it on my Olympus 12-40mm PRO, and took some 2 seconds hand-held images.
These images were shot hand-held at F4.5, ISO200 (for best dynamic range) and 2 seconds shutter speed, with the use of ND1000 Jetmag Pro magnetic filter kit. Supposedly I did not have the Jetmag Pro filter, and relied on the camera Live ND feature on the OM-1, I would have been stuck with ND64, which was about 4 stops less than the physical ND1000 I was shooting with. No matter how you play with the camera exposure settings, you just cannot get the same effect. Say I make some compromises - lower ISO200 to 100 to prevent overexposure, to gain one stop of exposure but to lose dynamic range in the process, and narrow down the aperture from F4.5 to F16, which gives another 2 stops but compromising on softer images with severe diffraction at F16. That adds up to 3 stops the most, still nowhere near what the ND1000 physical ND filter was offering, without having to compromise dynamic range or diffraction issues.
Whichever way you looked at it, the Live ND filter was almost useless in this case.
While I can see the potential of computational ND filter being more advanced and useful in the future, expanding it further with the increase of processing power, it is still very limiting in many situations. With physical ND filter, I can easily stack 2 or more filters for the added effects. Say 10 stops was not enough, I can stack on another 6 stops, creating a whooping 16 stops ND filter. Also, there are certain effects that the Live ND filter just cannot do - for example if you want to use a circular polarizer to either darken the sky, or cut reflection off glass or water surface. I used circular polarizer quite extensively recently shooting an art gallery, as the paintings were placed behind glass that was reflective. Furthermore, the Live ND feature cannot be used in video mode, and is only valid for stills photo, so videographers wanting to use ND filter to create the cinematic motion for their footage will find the Live ND filter quite useless.
Don't get me wrong, I am glad camera companies are pushing the boundaries of what the camera can do. Computational photography has come a long way. As for this specific case of ND filter, it still has quite a lot of way to go before it can be real useful in the field. Until then, physical ND filters will just have to suffice.
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No doubt that real ND filters are preferable and can provide greater flexibility than OM's computationally derived ND effect, assuming you remembered to pack your NDs. Also note that f4.5 to f16 is about 3 1/2 stops, not 2 stops. I am reluctant to shoot m43 much above f8.
ReplyDeleteThe Jetmag system seems very well thought out, though I didn't see any split grad ND's, which usually require square filters to implement. The 3 ND + CPL kit seems to cost $450 US (I believe) so one would really need its capability before buying.