Newbie question about video housings

Hi:

This is my first post in this forum. I couldn´t introduce myself earlier because I was supposed to repply someone´s else topic before I could start a new one. So I hope this is the wright place for my introduction and a question.

I live in Argentina and with several years as video lighting cameraman I´m moving slowly to cinematography. During a sport show coverage I discovered diving. I have had a few dive experiences since then (I don´t live close to the sea) but I love it. I have had some experiences with video underwater too (covering a diving tv report in a lake and some short films in swiming pools) and have just finished an underwater still photography course. I think UW photography is so exciting!! It gives you endless possibilities. I have a Nikon D200 and my girlfriend has a D50. We would like to have housings for our cameras, but they are out of our possibilities by now. We´re thinking in a Canon G7 an a WP-DC 11 as a starting package.

I have some skills with tools too, so I don´t think is crazy to start with a film camera housing and modify it (¿a Nikon N90 housing?). I have a machinist friend who could help me.

I would like to build a video housing too (i.e. for a Z1/Z7, EX-1, HVX-200), so I´m in the research part. I´m very confused with the ports. In the UW photo course we learned that the dome ports keeps the angle of coverage underwater, while the flat ports "zooms" the image in ¿25%?.

So a dome port is just a rounded, clear piece of polycarbonate/glass with the size enough not to vignete. ¿wright?. I´ve read about using dipoter filters when using domes (not always) and I don´t know why.

And talking about video I could see there are more than simple domes. I could see price ranges from U$ 450 to U$ 3000. Is it because they´re not regular domes but wide angle converters? Is it because they´re specially made for underwater? because the expensive one lets you zoom all the range? What´s the difference using a wide angle converter in the camera and using a regular/std dome? Could I use just the lens of the camera and get good HD results UW with a standard dome?

Thank you!!! I hope my english is clear.

I think this community is great. Congratulations!

Best regards from Buenos Aires

Alejandro

Ok. I have done some search in the forums and I have updated my knowledge about domes. Anyway I have some doubts about video domes, i.e. if you could you use a regular dome in video (not a wide angle converter) and still have zoom through capabilities...

Thank you

Alejandro

Ale,

No matter what housing you use, and there are plenty of good quality housings on the market whether it be Light and Motion, Gates,

Amphibico ect, keep in mind, and especially for HD shooting, that the glass is of extreme importance. Both Gates and L & M offer Fathoms ports which, while expensive, offer superior quality which will result in considerably better imaging for you.

Steve

Ok. I have done some search in the forums and I have updated my knowledge about domes. Anyway I have some doubts about video domes, i.e. if you could you use a regular dome in video (not a wide angle converter) and still have zoom through capabilities...

Thank you

Alejandro

Alejandro,

The principles are still the same for stills and video. With a dome port you are focusing on a virtual image. Zooming in changes the minimum focus distance. For example that is why the Gates domeport doesn't offer full zoom for many of their HD 3xSensor cameras. Unfortunately with 10-20x zoom, you are going to have compromises.

Thank you!!

I don´t get totally yet the concept of focusing in a virtual image...so you´re really focusing in the inner plane of the dome?

About the glass...I think this is true when you are using a wide angle adaptor like the Fathoms, isn´t it?. But in the still photo course I did, the instructor had a Sea&Sea housing with an acrilic dome, not glass, and the photos looked great. I read that for a std port, acrilic is better than glass and cheaper. I´m thinking in this for a DIY housing for video...

Thanks again!

Alejandro

Thank you!!

I read that for a std port, acrilic is better than glass and cheaper.

Depends: Acrylic is cheaper, scratches heaps easier however the small scratches can be polished out with some ports. Glass is more expensive however is harder to scratch... but if you do you can't polish it.

As mentioned before zooming through dome ports isn't a great idea... you want to get closer to your subject and reduce the amount of water between you and the subject. Flat ports are much better for macro and can be zoomed through, you can also use diopters to get even closer.

As Steve mentioned the fathom super wide ports are amazing... both expensive and optically, they offer full zoom through and are around 120 degree at their widest.

Thanks a lot.

I will keep it mind.

Best regards

Depends: Acrylic is cheaper, scratches heaps easier however the small scratches can be polished out with some ports. Glass is more expensive however is harder to scratch... but if you do you can't polish it.

 

As mentioned before zooming through dome ports isn't a great idea... you want to get closer to your subject and reduce the amount of water between you and the subject. Flat ports are much better for macro and can be zoomed through, you can also use diopters to get even closer.

 

As Steve mentioned the fathom super wide ports are amazing... both expensive and optically, they offer full zoom through and are around 120 degree at their widest.