- Banned
- #1,141
Pawel Achtel
Banned
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- Oct 12, 2007
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- Location
- Tasmania
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You can not compare Nikonos 15 to Nikon 14-24: one has been designed for underwater and one for land. It is like comparing a sports car with a spead boat in an ocean race. How relevant do you think it is that the sports car is newer make than the boat?...The Nikonos 15 is DEFINITELY an antiquated lens, regardless of how good, and I agree it produces outstanding images, it is even by today's standards. But, it was built using technology, methodology and materials that have been since, far surpassed in quality. Several generations of lens making have come and gone since. That is definition of antiquated. Just as a sports car built in the 1970's is still fun to drive and fast, when you compared it to the technologies available today, you realize what antiquated and modern means. Thus, the quality, precision and coatings of the glass used on the Nikon 14-24 is far superior to those employed in the Nikonos 15, as are the precision of the methods used for its fabrication. Fact.
To my knowledge there is no wide underwater lens or any optical system that would perform better than the Nikonos 15mm. The Nikonos 15 features modern (and expensive) retrofocus design, very solid build and is the only underwater optics worthy of 4k and 5k sensors. What generations, or more precisely, features have "come and gone"? To my knowledge there is nothing that comes close in underwater optics. There never was.
Yes, this answer is very simple. It is also entirely incorrect. Where do you get all this nonesense from? :frown2:...But, how then does the Nikonos lens still look much better than most, if not all, water corrected lenses behind a dome? The simple answer as you pointed out is that it is a system built from the ground up to compensate for, or eliminate, the problems the underwater medium presents. But in so building this system, Nikon simply took a 20 mm air corrected lens and built around it to eliminate the aberrations that water introduces....
...The solutions to this problem, though ingenious, are simple:
- use a dome that will precisely align with the lens' entrance pupil, so that nodal point is equidistant from dome center and sides. This will produce a a properly aligned image, though with softer edges since the image projected by the dome is still curved.
- Build the dome with variable thickness glass, such that thicker edges provide a magnifying effect and help render the softer corners sharper so they match the center. To that effect, the center of the dome is much thinner.
- Introduce corrective elements in the lens design that will further correct the aberrations and curvature of image so that final result is rectilinear and sharp from edge to edge.
That's it, is not rocket science...
Indeed, it is not rocket science and there is no evidence that it would produce the desired outcome. However, there is good evidence to the contrary. In fact, placing positive diopters or/and making front element positive has been known for donkeys years and it has proved to produce rather poor results: it introduces severe chromatic aberrations, causes additional distortions, it makes the edges soft and does not overcome image plane curvature produced by the dome.
Please post the images that can be somehow evaluated.
I think 14-24 is a relatively poor lens for land cinematography as it has been designed as a still lens: flimsy build for cine use, inaccurate focus ring, breathing, flare, etc.... There are much better cinema lenses for this purpose. But, having the 14-24mm produce satisfactory results in water may be as challenging as making a Ferrari sail across the Pacific. Horses for courses....I was merely trying to share my excitement for something I've seen that seems to solve the main problem underwater encountered by a lens, the 14-24, that on land is possibly the very best rectilinear wide angle ever made. I know I am enthused with the images I'm seeing, as would be many other people on this forum that, like me, go more on feeling than on numbers.
Cheers,