TheQ

I saw a comment about April in forum as well, which would be about right based on Canon's annoucement to availability track record. From similar, sometimes not so reliable sources, the US price should be around $1400-$1450.

Assuming the lens diagrams on Canon Museum web page are to scale (a big assumption perhaps), the EP for the 17-40 is ~74mm and the EP for the 16-35 is ~80mm. I have no idea at what focal length the elements in the diagrams are set to so there is no way of knowing what focal length (if any) the element positions represent. 162.6-74=88.6 > port entension = 46mm 162.6-80=82.6 > port extension = 52mm A 49mm extention could be better for both lenses. I'm going to work on getting the camera underwater with the longer extension.

I am running into the same issue with blurred edges with the 5D with the 16-35. It is not a DOF issue... even at F4 the DOF in that image should be around 10ft, which should be more than enough to have held detail in most of the blurred areas. I posted a sample in this thread. I have tested with +2 and +4 diopters and while helping, they don't fix the problem. Ferg's results seem suprisingly good to me. The right edge of his image is very close to the camera. Perhaps the problems starts when the subject is further away? Ferg, do you have any other samples you could post? Ike, do you have any suggestions? Getting good UWA results with the 5D is a problem that has me stumped. I'm either doing something wrong or there is some other variable causing the issue.

I have tested the 16-35 behind the Ike 8" dome and the diopters help corner sharpness a bit... but not enough. I'm still looking for ways to improve my results. I have not had a chance to test the 17-40. It would be interesting to see in water results with it. Scubastu seems to be getting better results with 16-35 behind the Subal 8" dome in his enclosure (is the Subal dome glass?). I find the one-shot AF mode works best for macro. Once One-shot AF gets me close, I move the camera back and forth to fine tune the DOF range where I want it. I am very happy with the 5D/Ike viewfinder combo.

The 16-35 does produce good edge to edge results on land. Underwater, I'm seeing refraction blurring at the edges. It is not DOF blurring. The +4 on the 6" does produce the sharpest results, but I didn't like the barrelling it added. Admittedly, barrelling isn't much of an issue underwater. This picture is an example of the blurring that I'm referring to (16mm, f/5.6, 8" dome w/+2 diopter):

After extensive testing with the 16-35 on the 5D with various combinations of both the 6" and 8" domes with +2 and +4 diopters, I have concluded the following: Optically, the 6" and 8" are similar, with the 6" causing more barrelling. Also, adding a +2 diopter helps a bit on both ports. The 8" is great for over-under shots. I have found the 16-35 to be a very difficult lens to house. Even at it's best, the outer 10-20% on the long edges are blurred. Has anyone found a way to get sharp edges with the 16-35 on a full frame camera (with any housing/port)? I'm not certain if it's worth housing it... I am seriously considering trying a 17-40 as I have heard people get better results underwater with that lens. Another item which is high on my 'must get' list is a 15FE which I have also heard produces excellent results. (A quick note for 1.5 crop camera users, the crop will resolve the blur issue.)

I think part of the problem with Ikelite DS-125 and 200 strobes may be related to usage. The back half of the strobe is attached to the front half by a pin in the middle. The 200s are probably more prone to the below problem due to their larger diameter. It's very tempting to grab the back half to postition the strobe. That may cause the o-ring to lose it's seal if you crank too hard on it, particularly at the surface where there is no pressure holding the two halves together. I make a point to use the strobe arms to move the strobes at the surface when adjusting them. Once I descend and get the arms tensioned, I usually adjust them by grabbing the back and gently moving them... even then I'm careful to not apply too much pressure.

I would go Belize if you are going primarily for diving. I would also recommend that you head further out from shore and dive Lighthouse reef. The vis on Lighthouse is dramatically better. This January, almost every day on Lighthouse was 100'+ with deep blue water. I only dove on a few sites on Turneffe so I don't know if we were simply in a bad area, of it was at a bad time. Turneffe(East side) averaged ~20-40 with green tinted water. Topside, if you go on a liveaboard to Lighthouse reef, there will prbably be a stopover on Halfmoon Caye, which is a bird sanctuary. You can also catch tours to the jungle and local Mayan ruins. out of Belize city before and after the cruise. Hawaii is great for topside sights, but aside from the indemic fish species (which are great), therei is not a lot to be seen on Hawaiian reefs.

I believe so. The shutterspeed is the only way for a camera to control the ratio between ambient light and strobe light (once the strobe is at full power). Aperature and ISO affect both ambient and strobe light at the same time. Of course, you can always bring more strobes or get more powerful strobes. I suspect that conditions play a bigger part though.

What dome was used with the 14mm? It looks like you have a fair amount of blurring at the edges with the 14mm, similar to what I am getting with the 16-35 behind the 6" dome.

I don't know why people who write these programs continue to be mired in one dimensional thought. For years I have wished for a slideshow utility that has a TRUE storyboard model (think video and audio editing). I would like to have complete, independant control of each image and it's transitions. Proshow Producers' Layers concept is a poor attempt at accomodating independant control over mutiple images. I wanted to pull my hair out in frustration trying to use it. Combine that with it's hardware key copy protection and it's a no sale for me. It's truly sad to say that Proshow Producer is the best on the market at this time. The only way I have found to create the type of slideshows I want is with video editing tools, but then you are restricted to video resolutions.

I have the #5510.16 and the #5510.10 stalks... if the 16-35 fits in both I'll expand the test to include it.

I expect that the 8" will prove to be a benefit on the 5D. I had mixed results with the 6" w/the 16-35 and no diopter... the problems ocurred outside the 1.5 crop area so I doubt there would be any problem with the 350D behind the 6". I plan on testing the following combinations with the 16-35/5D: 6" 6" with a +2 diopter 6" with a +4 diopter 8" 8" with a +2 diopter If anyone has any requests or suggestions for what I should test, let me know.

Adustability and color filters are good arguments for a separate aiming light. I have not found many creatues on carribean reefs that are noticably disturbed by bright lights.... most are attracted to it. Octopi are an exectption to that though (athough, I think they are attracted to light out of curiosity). I don't like taking pictures of them with the way the flinch when the strobe goes off. Trying to take more than one picture usually ends up with a very red, very angry octopus. I also give sleeping fish a wide berth.

The Ikelite DS-125 modeling light does a great job. A pair of them put out nearly as much light as my UK800R 25W light. I have trouble getting my head around buying a Fisheye when it and a spare battery is nearly the cost of another DS-125. Be sure to get a pair of fast chargers. Having two will allow you to fully recharge both strobes during your surface interval.