Ikelite 8" Dome
#1
Posted 08 March 2005 - 11:52 PM
anthonyplummer.com
"It's much better down there... It's a better place..." Enzo, Le Grand Bleu.
#3
Posted 09 March 2005 - 04:11 AM
Hopefully, I'll have some Hammerhead shots to post when we get back April 4
Karl
www.kdietz.com
#4
Posted 09 March 2005 - 04:24 AM
Can it be used with the 12-24 and the 18-70? That alone might make it worth the price of admission. Ummm, assuming I sell my other 2 ports.
http://www.redreefscuba.com/
#5
Posted 09 March 2005 - 04:41 AM
Sea & Sea strobes
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#6
Posted 09 March 2005 - 04:55 AM
It looks hot!
Can it be used with the 12-24 and the 18-70? That alone might make it worth the price of admission. Ummm, assuming I sell my other 2 ports.
Hi Jim....yes, the 18-70 w/+ 4 diopter works with the same dome.....the 10.5 does not work....massive vignetting
Karl
www.kdietz.com
#7
Posted 09 March 2005 - 04:58 AM
Sea & Sea strobes
www.underthecaribbean.com
#8
Posted 09 March 2005 - 05:22 AM
Karl
www.kdietz.com
#9
Posted 09 March 2005 - 05:40 AM
#10
Posted 09 March 2005 - 06:34 AM
I like having the right port for each lens. I think its is a benefit to have each port being optically correct for each lens.
I like not having to mess with extenders.
I like that the ports are light, sturdy and inexpensive too.
Someone mailed me the other week telling me they think maybe ikes polycarbonate willmake the picture "soft". Well, I say thats BS. I highly doubt that there is anyone who could tell the difference between a picture taken thru a glass vs a polycarbonate dome, especially in natural environment of ocean (salt) water, where the effects of natural elements (particulate matter in water, light absorption etc) far outweigh any supposed effects of the PC material.
I dare anyone to show some scientific proof that the differenece between glass and PC dome is significant to a level where the human eye can tell a difference in a image photographed uw thru one or the other... until such time I will be considering that type of comments "polycarbonate bashing" and "glass snobbery".
#11
Posted 09 March 2005 - 07:00 AM
Kasey comment indicates unfortunate perceived opinion. The existing Ikelite dome and port system have always been as optically superb as ANYTHING money can buy. The only limitation remains with a few isolated lens combinations and testing with these domes confirms this.
My comments were meant as a compliment. My knowledge of Ikelite dSLR systems is limited to briefly handling housings of people I've dived with. In some cases, the domes were sub-optimally matched to the ports. For example, a local instructor used the setup recommended by Ike for his digital rebel + kit lens, and the diopter recommended by Ike was scratching the dome as it hunted for focus. I don't see why a WA lens should ever be that close to the port optic.
Sea & Sea strobes
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#12
Posted 09 March 2005 - 07:17 AM
I highly doubt that there is anyone who could tell the difference between a picture taken thru a glass vs a polycarbonate dome, especially in natural environment of ocean (salt) water, where the effects of natural elements (particulate matter in water, light absorption etc) far outweigh any supposed effects of the PC material.
Regardless of material - just putting a diopter (especially a single element diopter) in front of a wide angle lens causes significant softening in the corners. This is VERY apparent on land and no less so underwater. For my purposes, I am MUCH happier with a big dome that doesn't need diopters. For some lenses this is more of a hassle than others - ie the Nikon 12-24.
As far as PC vs glass - Ask anyone that has put 100+ dives on a PC port which they prefer. Swirls and fogging on PC domes is a pain in the butt. Optically, a brand new PC dome may be indistinguishable from glass, but keeping them clean and scratch free is nearly impossible.
KC
Sea & Sea strobes
www.underthecaribbean.com
#13
Posted 09 March 2005 - 07:44 AM
I guarentee he was using the wrong port, much like if you use the 12-24 port with the 18-70mm kit lens, the diopter will touch the port.For example, a local instructor used the setup recommended by Ike for his digital rebel + kit lens, and the diopter recommended by Ike was scratching the dome as it hunted for focus.
A diopter on a wide angle lens does not cause corner softning so much as it causes light fall off. A big dome will not always cause you to not need a diopter, as is the case with the 18-70 Nikon. The 12-24 doesn't need a diopter in a big or small dome port. I personally don't know of any Nikon lens that needs a diopter with a small dome, but not a larger one. Although one may exist.Regardless of material - just putting a diopter (especially a single element diopter) in front of a wide angle lens causes significant softening in the corners. This is VERY apparent on land and no less so underwater. For my purposes, I am MUCH happier with a big dome that doesn't need diopters. For some lenses this is more of a hassle than others - ie the Nikon 12-24.
As far as PC vs glass - Ask anyone that has put 100+ dives on a PC port which they prefer. Swirls and fogging on PC domes is a pain in the butt. Optically, a brand new PC dome may be indistinguishable from glass, but keeping them clean and scratch free is nearly impossible.
KC
I also disagree with you about PC vs Glass. Try buffing a light scratch out of a PC dome, then try doing the same thing on glass.
http://www.redreefscuba.com/
#14
Posted 09 March 2005 - 08:02 AM
I'd love to hear from someone that switched from glass to PC and prefers PC!
Sea & Sea strobes
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#15
Posted 09 March 2005 - 08:05 AM
Per the Aquatica Port Chart, their 8" port requires a "+3/+4" diopter lens for the 18-70.
http://www.aquatica.ca/catalog.htm#
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#16
Posted 09 March 2005 - 08:15 AM
I guarentee he was using the wrong port, much like if you use the 12-24 port with the 18-70mm kit lens, the diopter will touch the port.
A big dome will not always cause you to not need a diopter, as is the case with the 18-70 Nikon. The 12-24 doesn't need a diopter in a big or small dome port. I personally don't know of any Nikon lens that needs a diopter with a small dome, but not a larger one. Although one may exist.
The port was the one recommended by Ikelite. I believe Marjo had the same experience.
The nikon 17-35 needs a diopter with a small dome but not with the 8"Aquatica or Seacam SD. The Nikon 12-24 doesn't work well with diopters, so manufacturers have revised their recommendations. Initially, based on the MFD of the lens, diopters were recommended when used with small ports. In fact, diopter/MFD issues resulted in initial problems with the use of that lens underwater. One of the reasons I bought Aquatica over Subal was that Subal recommended a diopter in front of the 12-24, but the Aquatica dome was big enough not to need it. Subal has since changed its recommendation for housing that lens. Others would be more informed as to what those recommendations are at this time.
KC
Sea & Sea strobes
www.underthecaribbean.com
#17
Posted 09 March 2005 - 08:18 AM
How does the port system work with multiple lenses? Do you use extension rings on top of the port adapter?
What will I need to use the 12-24mm 15mm FE (sigma) and the 60mm behind this port?
I already own ports for all of these so the next biggest justification would be less ports to travel with and split level shots.
Total newbie to diving and UW photography.
Nikon D70: 60 mm, 12-24mm, 105mm, 15mm, 10.5mm, 18-200mm
Ikelite iTTL Housing, dual Ikelite DS125
Canon Digital Elph Canon Housing, S&S 15mm and 2x lenses
#18
Posted 09 March 2005 - 09:59 AM
Based on information given by Ike earlier in this board the smaller Ikelite dome glass provides radius just a bit less than the new 8“ dome assuming ~ 4” as the effective outer radius (roughly a hemisphere with 8” glass diameter?).
Assuming the smaller dome glass is positioned according optical requirements the difference would be small for lenses with smaller field of view because the radius is not that different. Also a possible dioptre requirement would not be influenced (again: if the small dome is setup correctly). In other words: only a small part of the 8” dome curvature would be used with a lens with less field of view.
This would require:
- small dome is setup correctly and not to close
- the lens field of view is equal or smaller than the Ikelite small dome glass’ field of view
Based on information in this board the second item has not been the case with extremely wide lenses and/or fisheyes. In order to avoid vignetting (as the dome curvature doesn’t cover the lens’ field of view) the small dome glass is placed closer to the lens different to an optical correct setup. While covering the complete filed of view the dome is positioned too close, degrading close focus ability and corner performance. I see the 8” dome addressing this issue for very wide and fisheye lenses.
That’s why I would prefer to accept Kasey’s compliment. The greater curvature provides the opportunity to house super wideangles and fisheyes properly. I would not reduce the 8” dome usefulness to split level work only.
Julian
#19
Posted 09 March 2005 - 11:00 AM
I don't agree with your statement.
Pool tests I conducted a while back indicate very good performance with the Nikkor 10.5mm lens behind the Ikelite #5503.15 port.
http://www.peterpete...tests/index.htm
And calculations I did indicate that the center of the radius of curvature of the #5503.15 port is at the entrance pupil of the lens.
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#20
Posted 09 March 2005 - 11:25 AM
Pool tests I conducted a while back indicate very good performance with the Nikkor 10.5mm lens behind the Ikelite #5503.15 port.
http://www.peterpete...tests/index.htm
I would have considered the corner in your closeup example very soft - look at the N compared to the O.
Difficult to say without it being side - by -side with another combo. I would hardly call those corners sharp.
Just measurebating I guess, but remember that the 10.5 should be less affected by a small dome than a zoom,.
KC
Sea & Sea strobes
www.underthecaribbean.com
