Difference in Ikelite 6" dome ports?

[RonFrank]

I 'm curious, what is the difference between the Ikelite 6" Dome ports.

So I have a Tokina 12-24mm f4, and it takes a 5503.51 dome port. I have a Nikon 60mm macro, and it takes a 5503.50 dome port. I have a 17-35mm f2.8, and it takes a 5503.55 dome port. I'm assuming that I can use the same port for all three lenses. So what is the difference? I'm assuming it has something to do with the zoom and focus ring position, but there is nothing on Ikelites webpage about why these have different part number desingations, nor about purchasing whatever would be necessary to convert the ports.

One thing that is both interesting, and a bit troublesome is that all the 8" dome ports have the same part number which makes me wonder why the 6" dome ports do not. I'll certainly purchase an 8" port even at twice the cost if I can't use the same 6" dome port for all lenses I want to use.

 

[sharkbaitDAN]

#5503.... Lens length less than 3" (7.6cm)
#5503.50 Lens length less than 4" (10.1cm)
#5503.55 Lens length less than 4.5" (11.4cm)
#5503.80 Lens length less than 5" (12.7cm)
#5503.85 Lens length less than 6" (15.2cm)

This is from Ikelite's website. The difference is the lenght of lens that can be accomodated. I would think that using the wrong length with some lenses would cause vingetting. It probably has no effect on other lenses. I think the 8" dome is wide enough in diameter that there is no problem when using lenses with different lengths.
For the macro lens, a flat port would probably be better, at least that is what I have been told.

 

[RonFrank]

#5503.... Lens length less than 3" (7.6cm)
#5503.50 Lens length less than 4" (10.1cm)
#5503.55 Lens length less than 4.5" (11.4cm)
#5503.80 Lens length less than 5" (12.7cm)
#5503.85 Lens length less than 6" (15.2cm)

This is from Ikelite's website. The difference is the lenght of lens that can be accomodated. I would think that using the wrong length with some lenses would cause vingetting. It probably has no effect on other lenses. I think the 8" dome is wide enough in diameter that there is no problem when using lenses with different lengths.
For the macro lens, a flat port would probably be better, at least that is what I have been told.

I this is the reason why, this is very bad news.

I still however don't understand the difference between the 5503.50, and the 5503.51. I can not imagine carrying around two different huge dome ports for my two lenses. Maybe this is where the $400 8inch dome port makes sense.... .sigh.. this just get's more expensive, and more equipment intensive all the time.

 

[Cacia]

yea. I am having to buy the 400+ 8" dome port for my new 10.5 fish eye and unfortunately, I already have three other dome ports so the fact that the new pricey
8" works for them all doesn't really help soften the blow of the price. I wish I could see images from the 6" next to the 8" with the 10.5 to see the edges and the amount of distortion. Everyone is telling me there is no comparison for doing split images with the 8 VS the 6, so guess I will bite the bullet after 15th. I love split images so...

I hear exposure under/over is tricky. Ron, I need you to figure all this out, so I can ask you!

 

[Jamdiver]

yea. I am having to buy the 400+ 8" dome port for my new 10.5 fish eye and unfortunately, I already have three other dome ports so the fact that the new pricey
8" works for them all doesn't really help soften the blow of the price. I wish I could see images from the 6" next to the 8" with the 10.5 to see the edges and the amount of distortion. Everyone is telling me there is no comparison for doing split images with the 8 VS the 6, so guess I will bite the bullet after 15th. I love split images so...

I hear exposure under/over is tricky. Ron, I need you to figure all this out, so I can ask you!

I'd love to see your attempts Catherine.., re over/under shots with the dome port...
I've tried a few with my little p&s but obviously they've all turned out horribly.

 

[Diver Dennis]

It's not only the O/U shots Catherine. The *' does a much better job on wide angle, eliminating the softness around the edges that I have with my 6". Ron, check the Ike website because the 8" can be modified with different collars to fit different lenses. Another problem is the focus distance of the lenses. They might end up just being able to focus on the dome itself if they are not close enough to the end.

 

[Rooster]

One thing that is both interesting, and a bit troublesome is that all the 8" dome ports have the same part number which makes me wonder why the 6" dome ports do not. I'll certainly purchase an 8" port even at twice the cost if I can't use the same 6" dome port for all lenses I want to use.

Actually there are three different 8" dome combinations with three different part #s. There is the #5510.81 which covers most length wide angle and zoom lenses. The #5510.82 is for super wide lenses like the Nikon 10.5 or Sigma 15 Fish Eye. The #5510.83 is for extra long Zoom lenses. All three of these “assemblies" use the same Dome, part #5510.40. But each uses a different “Body”. So you could buy the one Dome assemblies and a different body to cover most applications. However the cost will be mort than “Twice the cost” of a 6 dome. Either way you go I would not use a dome port for the 60mm. Get the flat port for it, Part #5502.41. Using a Macro lens behind a dome port is a compromise you won’t be happy with. A few other things you might want to consider about the 8” vs. 6” dome ports. Though I can get away with using one 8” dome to cover my Sigma 10-20mm and Nikon 18-70mm zooms. The 8” is much bigger and will be harder to pack. Also the 8” does not come with a shade, and at this time, I don’t think one is even available. The 6” domes come with a shade. The shade does not just help prevent flare, but also helps protect the dome from bumps and scratches. I paid less for the two 6” domes, and the flat port for my 60mm, than the cost of the 8” dome. The 8” tends to make the housing want to rotate dome up. I don’t have this problem with the 6” domes. All this being said I’m waiting on the delivery of an 8” dome. Hope it gets here before my trip to Palau. I want to do some over under shots, the 8” dome will be much better for this. Hope this helps.

 

[Diver Dennis]

You're right about the shade Rooster, and Ike has no plans to make one at this time. I have a problem with the 6" dome being light in the front and expect the 8" to be even more so but I have some wheel weights to rectify that problem.

 

[Rooster]

When I get mine, I’ll check it against my Aquatica 8” dome. Maybe the Aquatica will fit or can be modified to fit. I see the Aquatica shades on Ebay all the time. Too bad I don’t have access to a machine shop, like I used to, or I’d just make one. An aluminum shade just might help to keep the nose down.

 

[Diver Dennis]

Hey, that's a great idea Rooster. I'll look into that.