Ikelite N90 modified to fit 7D
Posted 16 June 2011 - 07:45 PM
My interest in underwater cinematography, my girlfriend interest in underwater still photography, and the fact that todays DSLR´s are broadly used in the professional field, inclined our choice to the Canon EOS 7D 18Mp cámera as a UW video/photo camera.
I made some early tests to make an aluminium housing. Aluminium could be easier to work with (I thought) and cheaper than acrylic (at least in Argentina). I tried to bend two “U” of 6mm aluiminium to weld them and add a cover. An acrylic back-cover would give a transparent view to the LCD screen and a base for the main controls
After a couple of test (the aluminium just broke during the bending. Anyway now i found the right aluminium to be bended...for the next housing) then suddenly an Ikelite for N90 appeared (not that cheap, but was the only housing that was in mercadolibre, latin american version of ebay, that had appeared there in months (or years). The used market for undewater here is really small...or none at all.
So then I started to modify this housing for the 7D
First of all I had to make a new back cover. The original was very narrow to accomodate the 7D plus controls. And it was black, so I couldn´t see the LCD screen either. I took the original one to an acrylic shop, so they could copy the outer shape in order to fit in the housing, but made it in transparent 20mm acrylic (in fact, 50mm, but they “shaved” 30mm with a milling machine to give enough room for the 7D and controls).
I added some controls there: the main buttons , and the scroll wheel.
I had some controls made by a machinist.
Made them this way because I wanted them modular. So in case I change the camera, just need to re-arrage the position of these same controls only drilling new 10mm holes.
I could use most of the original Ike controls. Just made some modifications to acces the controls in the 7D. In most of them I had to cut the original 1/8 shaft and drill the ¼ shaft with a 3mm drill, glue a 3mm hard wire (the one that allows you to bend it) and use the original rubber end caps.
I had to make a new base plate. The original was too thick, and the 7D was just off center with the port. I had to make a 2mm plate (the original was close to 6mm). I made it in aluminium and it´s a little bit weak. I´m planning in a new stainless steel 2mm plate.
I bought an Ikelite port in advance (5503), without knowing wich lens I was going to use. I choosed that because it was the shortest, and I could add a spacer when I knew the real dimensions of the lens. I ended buying a Tokina 11-16 2.8, mainly because it´s a very popular lens here for surface photography (so I thought in a double use). I had made an aluminium extensor by a machinist to make the dome work: I measured the distance lens mount-housing mount, I found the Tokina entrance pupil distance (in some panoramic photography website. I will try to find it to give them a credit!) and calculated the extensor lenght so the dome center of radius coincide with the entrance pupil of the lens. The front lens it´s just at the base of the dome! It slightly vignetes in this position, but it is the theoretical best place to be...
I think I can get rid off the vigneting using the lens in 11,25mm. The other problem is the sunshade. I can see it. In the tests I had to use the lens in 13mm to not see the sunshade. I could only see the sides, so I will cut them. I need to check the sunshade with wider settings...The 11-16 NEEDS a dipoter. The focus ring was mostly in its closest settings. 30cm. And objects very close to the dome were out of focus.
I made some test in a pool and, and sure that everything was OK, I made a trip to Perú for a norwegian tv documentary for the first job. It was an easy dive in Paracas, south to Lima. Cool waters (16C aprox) and 10-11m deep. The results are very good. It handled OK and I got some good footage. It was not a touristic or nature doc, but ecological. Although the water conditions were not optimal, the images are powerfull and right for the doc (the last ones are from a Gopro as a “backstage” camera. My partner and guide: Stefan Austermuhle).
I would like to thank this website, forum, and all the people that helped. Thank you!
Posted 20 July 2011 - 08:40 AM
Did you have to add any weight to the rig to get it down?
Great to see,
Canon 5D Mk III, 7D & 40D, 60mm, 100mm, 17-40L, Tokina 10-17, Nauticam 7D, Sea & Sea MDX-40D YS-250's ULCS arms, Lightroom
Posted 03 August 2011 - 01:06 PM
The housing is just slightly positive, front light. But it handled very well.
I added an Ikelite tungsten light to the housing, and was just a little bit negative. Again handled very good. May be I need to fine tune with some little weight (I´m planning in 2x housed LED lights), but the results are great for me.
Best regards from Buenos Aires.