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mexwell

port confusion

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Hello all!

 

The diving season in germany is (at least for me :D ) over and I am thinking of my equipment for next year. Especialy the port choice give me headaches...

 

I recently bought the Digital Rebel (300D) including the 18-55mm kit lens. From JamesW I got the 50mm macro with lifesize converter (thanks again!!!).

 

That leaves me with the following possibilites and lens lenghts:

- 18-55m -> appr. 7,6cm max.

- 50mm macro -> appr. 8,9cm max.

- 50mm + lsc -> appr. 12,4cm max.

 

Unfortunetly Ike can´t give me more specific information until the housing is available but I guess my questions are more generic and going the "How do ports work and what to have in mind buying one?" way.

 

Just reading the measures the easiest way would be buying one "#5505.45 Lens length less than 5.1" (13cm) flat port" that would fit all of my lenses.... but some logical thinking tells me that it can´t be that easy. Will for example the widest 18mm setting of the kit lense still work in a port that long or will I picture parts of the port instead? Same question für the 50mm macro....

 

What if I consider a dome port like the "#5503.80 Lens length less than 5" (12.7cm)"?

 

Or, my worst thought, do I need different ports and change same during trips? Can someone give me some thought how Ikelite housing handle the port change?

 

I hope you can give a converted "consumer cam" photograh some advise and help me to get the right ports with Ikes housing.

 

Thanks in advance

 

Christian

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Christian,

 

The Canon Digital 18-55mm "kit" lens works fine behind the standard #5503 Ikelite dome port. It focuses to less than 1 foot thus not requiring ANY diopter. See my photos under the review section when I tested the Canon Digital Rebel in Ikelite's pre-production canon Digital Rebel DSLR housing.

 

For the Canon 50mm macro and life size converter I believe you could use the #5503.50 extended dome port. I used this last week with a Nikon 60mm macro. It has plenty of room and since the Canon DSLR field of view is 1.6X the Canon 50mm (equaling approximately 80mm) lenses like the Nikon 60mm macro do not vignette. If using the life size adapter measure the total length extended and see if the #5503.50 port can accommodate this total length.

 

Going with dome ports is somewhat against the old theory of "macro lenses need flat ports" and "wide angle lenses need dome ports" specified for film SLRs. I've seen they work fine as you still have extra "critter hunting" room with an equivalent focal length of 80-90mm depending on the brand lens (Canon or Nikon.)

 

One final thought.....With the 1.6X FOV crop of the Digital Rebel I'm considering the Sigma 50mm macro which focuses continuously down to 1:1 without any convertor. Tim Rock posted some beautiful macro shots taken with his Nikon D100. While I confess to being a Nikon or Canon lens buyer in the past the sensors of DSLRs "see" the sharpest parts of after market lenses. These appear to work very well, and at less cost, too. I personally use a Sigma 15mm Fisheye with great results.

 

Good luck,

 

David Haas

Haas Photography Inc.

4596 Greenlawn Drive

Stow OH 44224

330-678-0591 Phone/Fax

330-329-5981 cell

dhaas@megsinet.net

 

http://www.pbase.com/dhaas

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Hello David,

 

thanks for your nice response!

 

As for the measurements. They are as I stated above (all fully extended) and only the "#5503.80 Lens length less than 5" (12.7cm)" dome would physicaly fit all lenses but I guess the optics won´t be right... How far away can a lens be away from the port glas, are there rules or stuff like this? If not, why not choose the bigest port and you can fit all lenses in it? I know it is stupid to ask but I like to (and need to) understand the function of those port systems...

 

Do you think I will need three ports in different dimensions to fit all lens combinations?

 

For the sigma, I think it would be a nice macro lens but I already have the cann ones and will stay with them for a while.

 

Best regards

 

Christian (still very confused)

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Oh oh it´s getting tricky...

 

After researching the offical specs for the canon lenses I own it seems like I measured the wrong dimensions...

 

On canon.com I found the following specs:

 

- 18-55m -> 6,62 cm max.

- 50mm macro -> 6,3cm max.

- 50mm + lsc -> 9,79cm max.

 

If these are the dimensions I use to find my ports I guess a "#5503.50 Lens length less than 4" (10.1cm)" would fit both of the 18-55 and the 50mm nicely.

 

David: Do you think the kit lens will work with this larger dome port? Will I need a diopter when not using the #5503 port you mentioned and used?

 

After all even the lzk+50 could work (with minimum distance to the glass) but my ambition now is to find one port for the 50mm and 18-55 to start it all. When I am more experienced to DSLR shooting I will give the lsk a try and might need another port for this.

 

I am very thankfull for any advice David or other can give me...

 

Best regards

 

Christian

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Christian,

 

You might be able to use the Canon "kit" 18-55mm EF-S lens behind the extended dome port #5503.50 but it also might vignette at the widest setting. This is an equivalnet focal length of only 29mm so it might just work.

 

I'll be housing this lens in the Ikelite housing and having both the short #5503 and extended dome port #5503.50 I'd have to try it before seeing if the lens is not too far back in the housing. I wil laways need teh shorter #5503 dome port for a Sigma 15mm wide angle, though.

 

It would be nice if for the two lenses you're starting with (Canon 18-55m plus Canon 50mm macro AND adding life size converter) could shoot through one port......Not sure, though......

 

I will ask Ikelite to check at the factory.

 

Best regards,

 

David Haas

www.pbase.com/dhaas

dhaas@megsinet.net

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One port for all lenses fits the definition for oxymoron. Edit: I did not mean for this post to be as smart aleck as it appears.............

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I thought Oxymoron was the name of the guy selling that bleach substitute on TV! :D

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Hello all!

 

One port to fit all would be to good to be true :-))

 

But perhabs the #5503.50 will fit the mentioned two without vignetting?!

 

If Ike can´t tell us anything about it right now, I guess we have to wait until the housing is available and find someone who is willing to try... David? :-)

 

 

Best regards

 

Christian

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