Ikelite 6" vs. 8" dome for Tokina 11-16?

I just ordered the Tokina 11-16, and will need to decide on the port for my Ikelite housing. The Ikelite chart indicates that one can use either the 6" 5503.50, or the 8" port and body combination (5510.45 + 5510.22) , which costs about $300 more than the 6".

It seems to me that every lens-port combination will differ as to how optimal (consistent) the distance is from lens surface to the port for a particular zoom point/angle of incidence, so some wide-angle lenses would perform better optically in a 6" than others, even if both "work".

How can I determine how much of a trade-off there is? I'm green as grass here, so even if "everybody knows" the 8" is always better for wide-angle lenses, don't assume I know that.

OK - you asked.

Go 8" - the 6" has some issues.

When using the Nikon 10.5 and the Tokina 10-17 at the wide end I had problems with reflections from the rim of the port and a tendency toward soft corners.

The six inch has no shade which complicates things somewhat when shooting anywhere where the sun may come near frame.

All in all the 8" is worth the extra dollars.

Paul C

tubino (and Paul,

All 6" Ikelite dome ports do indeed have shades........But any rectilinear (square i.e. not a fisheye lens) will show softer corners in a 6" port, especially at the widest setting.

After shooting numerous non-fisheye lenses (Canon 17-40L, 10-22mm EF-S lens and Nikon 12-24mm on a Nikon D100 ages ago) plus fisheye lenses including Canon 15mm, Sigma 15mm and of course the heralded Tokina 10-17mm FIsheye I saw noticeable improvement zooming in slightly from the widest end on all of these.

Many folks will use diopters to improve edge sharpness on even 8" dome ports. The sharpest corners with either a 6" or 8" will always be shot using a fisheye lens.

If you already have the Tokina 11-16mm I would go with the 8" and be prepared to:

1) Experiment with a mild +2 diopter and see if it improves edge sharpness.

2) Zoom in ever so slightly, maybe 13mm and see if improves with or without a diopter.

3) If you ever intend to shoot "over / under" shots the 8" dome will be required. A 6" will not cut it

Good luck!

dhaas

3) If you ever intend to shoot "over / under" shots the 8" dome will be required. A 6" will not cut it

I do intend to shoot some over/under shots, and it had never occurred to me to ask about this. What happens with the 6" in the air?

Looks like I'll be selling junk to fund the 8". Thanks for the wisdom, all, and keep it coming!

All 6" Ikelite dome ports do indeed have shades.......

Sorry to take issue - but that is not the case I have a 5503.15 for my Nikon 10.5 and it suffers a bit.

Not a big deal but you have to shoot with care.

From the Ike site :-

SUPER-WIDE 6" DOME PORT

For lenses with a 110 to 170 degrees angle of coverage. This port does not allow use of a port shade.

5503.15

Paul C

Paul (and Tubino)

Paul is correct on that ONE Ikelite #5503.15 port which is the shortest, super stubby for "old" film Nikon 16mm and now the Nikon 10.5mm digital Fisheye lens has no shade. It works well for those not wanting or needing an 8" port and since the 10.5mm Nikon lens is so wide depth of field is incredible.

Every other Ikelite 6" port from the short #5503 to longer models (like you would need IF you went with a 6" port for the Tokina 11-16mm) has a shade on it. I have to check if the new Tokina 11-16mm zoom is even physically usable in Ikelite's 6" ports since the Tokina 10-17mm Fisheye is much more popular. (??????)

Tubino, if you are referring to the 6" in air question, ANY port above water is simply a clear window. It's when you try and shoot over / under shots and the underwater portion created by the dome in water looks to be 12" image distance in front of your lens, and the above water part where the actual subject physically is farther away, when the 6" radius can't provide enough depth of field to keep both in focus.

Hope this makes sense.......

dhaas

I have to check if the new Tokina 11-16mm zoom is even physically usable in Ikelite's 6" ports since the Tokina 10-17mm Fisheye is much more popular. (??????)

Well, the Ikelite chart indicates that one can use the 6" 5503.50, but the chart also indicates that:

--------------------------------------------------------------------------------

(?*) This zoom lens will focus close enough that adding a + diopter close-up to the lens is NOT required, but some people feel a +2 close-up lens may enhance corner sharpness. Longer port may be required to stack filters or close-up lenses.

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and that plus your next comment (in addition to the previous comments!) make it look like poor economy to use a 6" dome on the 11-16.

Tubino, if you are referring to the 6" in air question, ANY port above water is simply a clear window. It's when you try and shoot over / under shots and the underwater portion created by the dome in water looks to be 12" image distance in front of your lens, and the above water part where the actual subject physically is farther away, when the 6" radius can't provide enough depth of field to keep both in focus.

 

Hope this makes sense.......

Yes, that makes sense with the under/over, AND reminds me of the focus advantage of the 8" dome over the 6" underwater too.

I see that a B&W +2 diopter for the 77mm lens size is something like $55 from Reef Photo, and that's barely a razor nick compared to the money hemorrhaging I've done lately with UW photography!

On a sort of related note, today I did a goofy thing. I put my 18-200mm Nikon lens on, and used some tape ( ) to fix it at around 38mm, the widest I could use with my one and only port without major vignetting. Then I took it to Maumee Bay on Lake Erie and tried some over/under shots, with f18 and up. I learned some things. I learned that the slight vertical difference of the eyepiece over the lens does NOT change the fact that you need a mask and snorkel to do this, esp. with waves breaking over you! I may learn something more significant once I look at the results on a screen.