Hi folks,

it´s me again.

I am ready to oder Ikes housing for the digital rebel and get the #5503 domeport for the kit lens.

In addition I have the canon 50mm macro which would fit into the #5503.50 domeport. So far so good.

To make more out of my 50mm macro I bought the canon 1:1 lifesize converter which attaches to the macro lens. Can anybody (James?) tell me which port I need for that combination?

Might it be possible to get one port (dome or flat) to fit both the 50mm and the 50mm+lsc without vignetting?

Man those port choice are quite difficult....

I really hope that someone can help me and I can finish my order with B&H.


Thanks in advance!!!

Christian

..some technical infos (from the canon hp) on the lens dimensions:

life size converter
Max. Diameter x Length, Weight:
2.7" x 1.4", 5.6 oz. / 67.6 x 34.9mm, 160g

50mm macro lens
Max. Diameter x Length, Weight:
2.7" x 2.5", 9.9 oz. / 67.6 x 63.0mm, 280g

If I add the two lenghtes I get 97.8mm. That would theoreticly fit into the #5503.50 domeport (for lenses up to 101mm). But that is only 2.3mm space...
Can I savely move to the next larger port #5503.55 (for lenses up to 114mm) and will the 50mmmacro alone still work without vignetting?

Ok, hope someone can help?!

Christian

Monkeying around with lens position behind a dome port is not recommended. Remember, the dome/water acts as a lens and the position of the camera lens behind the dome is very important.

So for macro with the most flexibility, use a flat port.

Cheers
James

Well.... things aren´t getting easier...

I choose the domes because of the review and several posts Dave Haas wrote. Personally I am not decided because I have no real knowledge about the optical differences between dome- and flatports.

But the core question remains the same for my problem. If I choose the flatport route I could get the #5505.5 (up to 114mm) or the 50mm. Physically the lsz converter would also fit but will it work optical??? :-? Aaargh....


Anyone?

Christian,

The Ikelite #5503.50 port as you and James have calculated should work fine. The Canon 50mm macro lens with life size converter will be very close to the dome, but it should focus. Everyone forgets with the 1.6X magnification factor of the digital chips that the lenses "see" primarily a more central area. A flat port will vignette even more. Your 50mm X 1.6X = 80mm behind a dome port, will become an even longer macro telephoto (exactly how long, I'm not sure, approximately 25%?) Then this combination would equal a 100mm lens behind a flat port.

Years ago David Doubilet and other underwater photographers paid extra $$$$$ to put domes in their macro port barrels. Supposedly increased color saturation in addition to keeping your lens angle the same underwater. I've shot the 60mm Nikkor (equal to 90mm on a Nikon D100) behind the extended #5503.50 dome port and the results have been great. Even at 100-200% magnification reviewing the files. Having all dome ports, especially if Canon comes out with a wide angle zoom similar to the Nikon 12-24DX means only having to travel with 2 ports for 3 or more lenses......

Finally, the Canon 50mm macro lens once you add the life size converter locks you into shooting between 1:2 and 1:1 magnification. If this is what you want to conectrate on during a dive, great. But the less expensive Sigma 50mm macro lens can go continuously from inifinity to 1:1. A friend and I are trying it on our Canon Digital Rebel cameras after viewing Tim Rock's success with this same lens on his Nikon D100. Will report on the Canon mount lens sometime in the future.....

Hope this information helps.

David Haas
Haas Photography Inc.
dhaas@megsinet.net

http://www.pbase.com/dhaas

Hi Dave,

Using a dome port with a macro lens is usually pretty "uncomplicated" because the lens is designed to focus close. So no diopter is needed on the lens.

However, I feel it's still very important to tell people that when using a dome, it is NOT one size fits all. People should not be led to believe that they can put their lens behind a dome, then add a teleconverter to make it 1.5" longer and expect the same optical results.

The onus is on Ikelite as the manufacturer to recommend the proper dome or flat port for each lens. A summary table on Ike's website would be most useful.

People like yourself who help do the testing required to make these recommendations should - in my opinion - be very careful to back up these recommendations with test results. When I tested the 12-24DX I provided sample shots and shooting info to show soft corners and improper extension rings. Robert Delfs and others have also helped tremendously with pool tests of test-rigs designed specifically for this purpose. People are making purchasing decisions based on posts here at Wetpixel so I feel a certain personal responsibility to verify that the information posted here is correct, and stated in a way that consumers can understand.

Cheers
James

James and Christian,

I DO agree on accurate information as you state. And yes, I only have shot certain lens combinations.... Here's Ike's own web site showing the #5503.50 specified for the Canon 50mm macro lens. Maybe this is strictly for the lens alone (???)

http://www.ikelite.com/web_pages/port_chart.html

The length of this lens plus the life size converter does make the whole arrangement longer at 3.9" which is still within the maximum limits specified by Ikelite's port chart. The macro lens will still "see" an apparent image on the dome, especially with the 1.6X magnification factor from the Canon 300D camera chip. Since we're talking about the lens being so close with the life size adapter, maybe the slightly longer #5503.80 dome port would be a better choice. I would bet $10.00 (I'm cheap that even this long a dome port won't vignette with a macro lens's narrow angle of view. AND I'll bet that same dome port would deliver just as sharp if not better performance than a flat port........Best bet would be to email Ike and ask if the Canon 50mm EF and life size adapter being this close will cause a problem.

My intention in exploring and recommending dome versus flat ports was to provide MAX flexibility depending on specific lens choices. A flat port, especially a long one will certainly increase your effective magnification as I previously stated. If an equivalnet focal length 100mm macro lens that only will focus between 1:2 and 1:1 for a whole dive is Christian's goal, so be it. The only other thing that bothers me is the "holy mantra" that macro lenses HAVE to be shot behind flat ports. As far as I've seen this is pure BS since we got 1.5X and 1.6X chip magnification in dSLR cameras. At least from my experience using the Nikon 60mm macro behind the same #5503.50 dome port I've used with the 12-24DX and no diopter. One port usable with a wide angle zoom and a macro lens.....Easy to travel with, too......

One last thing is all the posts obsessing about corner sharpness.... I simply don't understand.... Are the corners of everyone's images the most important affecting the impact of one's photograph? Not sure about you guys but I crop out anything I don't like

Hope none of my comments were too harsh. I enjoy a spirited discussion as much as the next guy....

Best regards,

David Haas
dhaas@megsinet.net
www.pbase.com/dhaas

Hello Dave,

I agree with James about the need for accuracy, but I also agree with you that a macro lens behind a dome port is a viable option. In fact, via a tip from David Doubilet, I even use a mini-dome (curved piece of acrylic) in my flat port at times. However, I would not encourage wholesale changes without some experimentation in a pool or a relatively inexpensive open water spot. Below is an image that was captured with the mini-dome and a 60mm lens:



Scott

Hello again,

thanks to all of you and aspecially James and David for your input!!!

Because nobody could guarantee me an solution for my needs I decided to get a bit risky... I ordered the #5505.45 flat port which physically fits my macro combo (50mm plus lifesize converter) but seems to long for the 50mm alone.

Yesterday my housing arrived and really love it. Ike surpassed himself!

I did some quick testing (only on land so far) and both the combo and the 50mm worked without vignetting. Please find a picture enclosed.

I hope this will not change once I am underwater...

I will get into the pool as early as possible to test everything in more detail and will let you know of the results!

Best wishes

Christian
(who is a ery happy person right now )

Hello Christian

You will be happy with the flat port.

Yes a dome port will work and produce excellent results, BUT Macro lenses are designed to produce a sharp image edge to edge similar to a enlarging lens. A dome port because the port creates a curved image, therefore the outer edges may be a little soft ,although at minimum apertures this may not be much of a issue.

In regard to increasing saturation, I consider that this is not a major issue with digital, where software plays a major part in color adjustment.

Another advantage of the flat port is it will increase the magnification 25%. Also the smaller diameter of the flat port will aid in getting close to the subject as well as make lighting subjects that are at your minimum focus distance easier.

Also remember that Ike will make custom ports. I have many such ports, and have been able to shoot up to 7:1 macro using these.

kindest regards

Chris