divegypsy

Hi Paul,  

As a seacam dealer you probably know more that I do about their products.  I thought that I had read somewhere that Seacam had made a version of their superdome that was more of the full hemisphere.  Maybe it was only the "deepwater" superdome that others on Wetpixel have referred to.  My superdomes were purchased about 1999 or 2000.  If all superdomes are the same portion of the full hemisphere, my good results using 80mm of extension tube with the 16-35mm lens would also be applicable for all seacam users and their superdomes.  

One thing different on my superdomes is that they do not have the original seacam dome port shade of that era because it did not allow you to turn the housing on its nose to change film without the glass hitting the table or bench.  So I made paira of concentric "nesting" shades for my superdomes.  The inner shade is for use with a fisheye lens and does allow you to set the housing on its nose without bumping the glass. The second outer shade protrudes a bit farther and was cut to match the coverage of a 14mm lens.  This shade is what I use slightly narrower angle coverage 17-35mm f2.8 and 16-35mm f4 lenses. The "larger" shade provided far better prevention of flare, particularly with the early versions of Sigma's 14mm lens which was all Nikon users had available prior to the introduction of the Nikon 14mm several years later.  The outer shade can be easily removed when using the fisheye. Having them "nest" was the best way I could think of to travel with two shades.  I also made pairs of nesting shades for my seacam wideports.  The wider shade to use with the 17-35mm when I didn't want the size and bulk of the superdome and the outer shade cut for use with the Nikon 24-85mm.  

Fred

As an afterthought - Harald Hordosch could answer this question about superdomes in a moment, and from what Stephen Frink has told me, he does watch for online comments about seacam products. But for some reason, he refuses to help in these discussions.

It is my understanding that Seacam has two variations of their Superdome, one of which is more of the full hemisphere.  My Superdome is the older, less of a hemisphere, variation.  I have been reasonably pleased with the results I've gotten using my Superdome with 80mm of extension tubes when shooting with Nikon's 16-35mm f4 lens.

Fred

I just looked up the photozone test report.  This is one paragraph from their "VERDICT" of the lens.    http://www.photozone...-tokina162828ff

"Unfortunately there may be a hair spoiling the (optical) soup here - quality control. As mentioned we purchased three lens samples for testing, two in Nikon and on in Canon mount, and all three showed some centering issues. The initial Nikon variant was so poor that we had to cancel the testing procedure. The second sample, used for this review, was better, but still suffered from slight decentering at the long end."

Fred

Concerning the Tokina 16-28mm lens.  If you buy one, pray that its a good one.  When www.photozone.de tested this lens the first one they bought had de-centering of lens element(s) and as a result they had to obtain a second one for testing.

Fred

Lens test reports that I find much more useful than those on DxO can be found at www.photozone.de.  What I really like is that they give a "standard" MTF result for lenses at a range of apertures.  They also give very specific distortion and chromatic aberration numbers at the various f-stops all of which helps you decide what may be the best apertures to use for your needs.  

What no regular lens tests seem to evaluate is the performance of the various wide-angle lenses at the close focusing distances which is what we utilize when we use a wide-angle behind a dome port.  Lenses typically are designed for best performance at infinity and near infinity distances. Close focus performance is lower.  How much lower we usually have to find out by personal experience.  

But unless the technical performance of a lens is really bad, image content - what you choose to shoot and how well you frame it and light it is far more important.

One thing you usually get from the major manufacturers, like Nikon and Canon, is consistency in construction quality.  At www.photozone.de they gave the Tokina 16-28mm a good review optically, but said that there was significant decentering of elements in the first sample they bought and tested, and that their results were based on that second lens.  Some of us here on Wetpixel have seen the same thing with Sigma lenses - that sometimes one is quite good and another example of the same lens type is not very good.

You pay for what you get.  But you don't always get what you pay for.

Fred