Saturday, 29 September 2007

Leak detector instructions

Here are step by step instructions for putting together your own leak detector.

This one fits in my Coolpix 5000 housing. Just needs minor reconfiguration to fit other housings.

Thursday, 27 September 2007

Sigma 15mm FE arrived today

The first thing needed was a comparison of angle of view. How wide is this lens with the DX sensor?
Being a fisheye lens the normal angle of view ratios dont apply. With a rectilinear lens you just multiply by the crop factor so a 15mm film rectilinear = 15 * 1.5 = 22.5mm on the D80. A 15mm fisheye is much wider than a 15mm rectilinear lens.

Nikon Coolpix 5000 with WC-E68 wide converter - TOP
Nikon D80 with Sigma 15mm FE - BOTTOM

The Coolpix wide setup gives the same angle of view as a 19mm lens on a full frame camera.
Calculation - 7.1mm Coolpix = 28mm film, multiplied by .68 (Wide adapter) = 19mm

D80 with Sigma 15mm FE gives a slightly wider horizontal view (maybe like an 18mm lens on film) and slightly less vertical view. So the equivalent would be about a 12mm rectilinear lens.
Calculation - 18mm divided by 1.5 (Crop factor for D80) = 12mm

Pay no attention to image quaity. Coolpix image cropped top and bottom from 4:3 to 3:2.

Sunday, 23 September 2007

Redesigned leak detector

This is a simpler design, actually just has shorter leads, positioning the bare wire ends directly below the buzzer. I figured the ends didn't need to be in the front corner and there would be less chance of the wire fouling o-rings. It would not be smart to increase the risk of floods with a device intended to reduce the consequences.

More photos here

If anyone knows where to get battery holders for 23A 12v batteries please let me know.

Leak detector

This is something I have been thinking about for a while. An audible alarm to detect the first few drops of water entering the housing would provide an extra safety factor against killing the camera.

A simple design by Glen Cowan in Sportdiving Issue 94 Oct/Nov 2002 provided the info.

The bare wire detector tips are in the corner that would collect water given the way my camera hangs most of the time and there was plenty of room between camera and housing on the left side. Let's hope it works but I will still be looking closely as the housing submerges.

Saturday, 22 September 2007

Blairgowrie marina 60mm macro

Jan, Trevor, Rich and I set off in the boat to Blairgowrie. It was a choppy trip over with 10kn easterly but conditions were great at the marina. This is probably the best pier dive in the bay. So many nudibranchs, gobies, blennies, crabs, cephalopods and abundant fixed life.

The 60mm macro was sensational here. 75 min and 100 shots passed too quickly. Here are the results.

We called in to Portsea Pier on the way back but recent pile works and annoying surge detracted from the dive. 2 dives at Blairgowrie in the future.

This was the first decent dive with the new rig. In a word.....awesome.
Now I feel like I am only limited by what I can find rather than whether the equipment can capture it.

Friday, 21 September 2007

18-55mm kit lens with 6" dome port

Aengus sent me two of his 6" domes to try which arrived yesterday. Many thanks Aengus, I owe you. So today was the day to test the kit lens behind the recommended dome.
St Leonards was the spot but vis was still rubbish at 2m. Closest focus was about 20cm from the dome, not ideal for bad vis but the results were surprising. I had selected Vivid in the camera settings, most other users do this I discovered, and the combination with the correct dome gave punchy saturation and contrast and sharpness. Could even back off a little.
Have a look.

18-55mm kit lens at Cottage, flat port.

16th Sept 07

Strong northerlies so St Leonards was out but tide was right for Cottage. This time I wanted to test the 18-55mm kit lens. All I had was the flat port for the 60mm macro but that would have to do. I was keen to try anything.

Once again the camera was a delight to use and I could see much more of the view with my old mask. The kit lens still focussed quickly and accurately even though a dome port is recommended. Again vis was not brilliant at 5m maybe.

Here are the images. Some nice bright and saturated images but some looked a little flat. Internal reflections became visible at 35mm when the lens was at it's shortest physical length.

First test in the ocean. 60mm macro

15th Sept 07
St Leonards Pier
Now for the real thing. The wind was in the right direction so the sea was flat but vis was bad, maybe 2m.
Most of the shots from the pool were underexposed so I darkened the review screen for this dive and of course most of the results turned out overexposed. I was checking the histogram occasionally but need to interpret it better next time.

Here are the results which I thought looked low contrast and washed out unfortunately. Needed a fair bit more Photoshopping than I'm used to.

First test in the neighbours pool. 60mm macro

14th Sept 2007
Time to get wet!
I asked over the fence if I could jump in the pool (still unheated from winter - 13c, so donned the drysuit and scuba gear) and after checking the orings too many times took the first slow steps into the water.

I took a few colourful objects to photograph like Nuditor the test nudibranch and Fragmento the test great white shark.

Using the 60mm macro and flat port here are a few of the first shots.

First impressions
The very first thing I noticed was the restricted view through the viewfinder! I was not expecting this! With my Mares X vision mask, which slopes forward at the top, I could not get my eye close enough to see the full view. Note: Next dive try my older smaller mask. (This improved the view markedly but could still be better)

Once I accepted this issue I started to have fun with the lightning fast and accurate autofocus. It was like using a real camera again, just brilliant.

Nikon D80 arrived

13 Sept 07 pm - D80 arrived
Woo Hoo. The camera and lenses arrived. But of course the batteries needed charging before i could do anything. While waiting I attached the kit lens and peered through the viewfinder at an unfocussed and very grainy image. Even twisting the manual focus ring would not bring the image in to sharp focus. Ah, it's the eyepiece dioptre adjustment I thought, but that did not fix the issue either. Virg said "Just wait for the batteries to charge." She was right. I inserted the fully charged battery after an agonising 1.5 hrs and there it was, a bright, clear and sharp image in the eyepiece.

Housing leak test

13 Sept 07 am - housing leak test
Dunked the housing in water for the first time just to be sure. Needless to say there were no leaks.

Ordered the D80

2 Sept 07 - Nikon D80Ordered a Nikon D80 (+3yr warranty) with 18-55 kit lens and 60mm macro with spare battery and 2GB Sandisk Ultimate 3 SD card from on the Gold Coast. Very impressive service and communication and prices that can only be beaten by risky ebay imports from Hong Kong. Later ordered a Sigma 15mm fisheye as well.

The lenses I bought were: Nikon 18-55 kit lens - surprising good review from Ken Rockwell, Micro nikkor 60mm macro - It seemed like this macro lens is the most used of any lens underwater, Sigma 15mm fisheye for wideangle - I contemplated the Nikon 10.5 DX fisheye but it seemed way too wide for my needs and A$300. dearer.
The Sigma 15mm, equivalent to a 12mm rectilinear on a DX sensor, is a full frame lens as is the 60mm macro so both are "future proof".

Decisions about lenses and ports were helped/confused by this info at Wetpixel, Splashdown divers , Cameras Underwater,
and by talking to Bruce, Anthony, Aengus and Dave.

The beginning. D80 Ikelite housing

16 Aug 07 - Ikelite #6806.1 housing
Ordered the housing with #5502.41 flat port (Nikon 60mm macro lens) from in Cairns. Great people to deal with and the cheapest prices for Ikelite gear. They also ship straight to you rather than a dive shop. You could try importing from BHphoto but if you factor in GST then prices are comparable.
Here it is beside my Coolpix 5000 housing. It's a fair bit bigger and heavier.

Digital Diver gave me a very good quote just before the Aus dollar took a big dive. However they honoured the quote even though my payment deposit would not have cleared till a few days into the lower Aus dollar. The housing with flat port arrived safely 2 weeks later on 30th Aug.

Why did I decide to upgrade to a DSLR?
Well, I had gone as far as I could with the Coolpix 5000 underwater. It was and still is one of the best compact digitals for underwater featuring... Full manual exposure control and macro at all zoom settings as well as manual focus. The autofocus was not great but I developed a technique using macro framers and manual focus which helped greatly.

I chose the D80 over the Canon 400D for it's bigger brighter pentaprism vs pentamirror, Degrees Kelvin white balance, 3200 ISO max, more solid build. I also had a Nikon lens and flash. This info came from dpreview and Dave Harasti.
I chose the Ikelite housing because it fitted my budget, and I was very happy with the Ikelite Coolpix housing used for the last 3 yrs.