Hi guys -

Ok, you've convinced me to go with a housed DSLR setup, as opposed to a housed film SLR system (although that adds $2k to my spending budget).

I have decided to leave my current SLR system aside for top-side use, and get a separate kit for underwater use. I'll be getting a Canon 350D as my body and 2 lenses to go with it - 1 wide angle and 1 macro.

The housing setup is going to be all Ikelite and I plan to get 2 DS-125 strobes (although I may start with 1, as my wallet is KILLING me....)

My options are:
WA: Sigma 10-20 zoom
Macro: Canon 100/2.8 USM Macro (already own it) or Sigma 50mm macro

In terms of ports, I have 2 choices:
- get the 8" dome port, which will work with the Canon 100/2.8 and the the 10-20 (which would be the reason for getting the 100/2.8)
- get the smaller matching dome port for the 10-20, and a flat port for the macro lens, with some adapter thingummies

I dont see myself using too many filters underwater - I shoot RAW and can duplicate most filters in PS later.

My questions:

1/ Any potential problems with my selection of the wideangle lens? What is the optical performance of that extreme zoom with a normal dome port (5503.5)?

2/ Any recommendations on port choices? Having just a single port sounds appealing, but I am concerned that a super WA and a macro are pretty different beasts, and that a single big dome is too much of a compromise.

Any other comments and suggestions on the set-up welcomed.

Cheers and TIA,
Vandit

Hi,

Like Vandit. I am finalising my purchase of and Ikelite housing for the 350D + DS-125 strobe(s). I don't have any lenses, though am considering the following port-lens comabinations.

Wide Angle:

OptionA: 10-20mm(1) 1:4-5.6 EX DC HSM with port #5503.50
OptionB Sigma 15mm Fisheye with #5503

Standard:

18-55mm EF-S with with #5503 (Already owned)


My questions are:

1) What angle of coverage will I get with this combination. I've read articles suggesting that the Sigma 15mm Fisheye would be cut down from 180 degreess to ~100 degrees on a dslr. Am I to expect the same problem with the 10-20 on a 350D, or is it designed for a DLSR, thus providing the full range of coverage. I would like to at least get 100 degrees out of a wide angle lens, as I've been using an Epoque on my 5050 and I've loved the results after wreck diving in Truk.

2) If I do get a full range of coverage, will this type of lens be compatible with a 5D in future, should I choose to upgrade.

3) Is it worth getting a port for the 18-55mm lens that comes with the 350D?

4) Is there extra value in the 8" Dome port (5510.81) from Ike, or can I get away with the 6" Dome? Cost is an issues, as I've a limited budget to buy all the lenses, and I eventually would like to get a macro lens/port (suggestions welcome).

Thanks in advance,
Damien

should be fine, not as good as with the larger dome, but good enough for most people.



Optically, there is no compromise a large dome is ideal for all lenses, WA and telephoto. The reason why we generally use domes for WA and not for telephoto lenses is because WA lenses show the difference much more than a telephoto lens.

The problem here, big dome for macro, is that it will be very difficult to not scratch the dome when you are trying to get close for macro. You thought you were saving money sharing ports, but when you have to buy a second $400 port you will wish you had gotten the proper port for the macro lens to begin with.

You camera 350D has a 22mm sensor. Film cameras and expensive digital cameras use a 36 mm sensors. No lens ever made or ever will be made that will act the same on these two formats, it is just not possible. The same focal length will allways have less angle of view on the 22mm sensor than on a 36mm sensor.

Yes it is ture that the 15mm FE's are 180 degrees on a 36mm sensor so as i explained above, there is no way it can be 180 degrees on a 22mm sensor. If you want 180 degrees in an affordable digital camera, you have no choice but to switch to nikon who has a 10.5mm FE wich is 180 degrees on small sensors.

The same goes for the 10-20mm. It is designed for dSLR's but that does not mean it has the same angle of view as a 10mm lens would on a film camera. It is difficult to even guess what the angle of view would be of a 10mm lens on a film camera because no such lens has ever been made.

16mm is about as wide as lenses come for 35mm film or 35mm digital cameras.

Using diagonal angle of view with a FE lens makes things confusing. For comparison the 15FE on a 22mm sensor is similar in angle of view to a 12mm lens on a 22mm sensor.

On a 22mm sensor, the ultra wide angle zooms in the range 10- or 12- or the 15mm FE all are similar in angle of view to that 16mm on film. Thus any of them are wide enough. 10mm is the widest but the difference is not dramatic. In other words any of the ultra wide angle lenses 10-, 12- or 15FE will be wide enough.

Pros 15 FE

1. The 15FE will be considerably sharper. Not only because all primes are shaper than zooms, but the fisheye lenses loose very little behind a dome while the zoom will be effected no matter which dome you use.

2. Cost

Pros 10-20

1. slightly wider at 10mm.

2. the ability to zoom in when extreme WA is not needed. For example a shark or dolphin swim by.



The upgrade from a 22mm sensor to a 36mm sensor is very expensive. Much more than just the extra $2000 or more for the camera, but you must replace all of your lenses with more expensive lenses.

None of the lenses made for digital cameras will work on a 36mm sensored digital camera. That inclueds sigma 10-20 as well as canons your 18-55 and many other lenses. This is not a reason to not buy these lenses. If you want a WA lens on your 350D the only choice is to buy a lens that is made for small sensors.

The 15FE would work on a 35mm sensor, but it would be a very different lens.



Well, if you go with the 15FE, it uses the same port as the 18-55. But otherwise, yes, the 18-55 is a very usefull range.



Ike even admits on his website, that he has seen no evidence that the large port performs better. You are better off using the money you saved by getting the normal port torwards a macro lens.

As far as macro lens recomendations. For me the canon 60mm macro is the clear winner for a first macro lens. Second choice would be the sigma 50mm macro.

acroporas,

Thankyou very much for your help with my lense choice. It is much clearer now, and as such I will go with the following:

WA: Canon 10-22mm with #5503.50
Macro: Canon 60mm with $5502

I am heading to Palau later this year, so hopefully with this gear I can post some good shots in the near future.

ps. Do you happen to know if the Ikelite ports come with a neoprene cover? They're listed as replaced parts on Adorama, but nowhere does it say if they're included.

Many Thanks,
Damien

Yes, the ports come with the cover, 1 o-ring, and 1 tube of o-ring silicon.

That's interesting. I was under the impression that the dome diameter and focal point was linked to the lens being used, which is why I was thinking of 2 ports anyway. If the big dome is better, then I might as well get that instead - this way, if I ever want to use any other lens (say a standard zoom), then I will have the capability of doing so. And I'll buy a separate port for the macro.

At this point, my total is looking north of $5k so what's a couple of hundred more of less? I guess I am not getting away with buying this AND the 600/4L (had a hard enough time explaining to my wife why I needed a 500/4 as well as the 600/4 as it was...)

I assume that all I will need if I want to use a different lens in the 8" dome is the zoom/focus gears, and the spacer whatchamacallems (those jobbies that align the optical center of the dome with the lens). Zat correct?

Thanks for the clarification, William - appreciate the help.

Cheers,
Vandit

Yes, optically, the larger the dome the better for any lens.

And yes, as you hinted at, what is important is the placement of the dome. The center of the dome, sould be over the center point of the lens, or as close to this point as possible. Thus two lenses of very differnt dimensions would need different dome placement. I dont know if Ike offers different extension for his 8" dome but I believe that he plans to.