baddpix

I have had this problem several times and I think I've got it under control. Apart from dirty contacts, other possible causes are: wet contacts, caused by condensation in the housing. To avoid this, do the usual stuff - put some dessicant inside the housing. Assemble the housing in advance of the dive, so that the dessicant has time to work. Don't allow the camera to heat up in the sun. etc accidentally depressing the lens release. On the Ikelite SLR housings for Canon 20D and 350D etc, there is a small lever on the left side (below the large knob for the zoom gears) that is used to depress the `depth of field preview' button on the camera. The lever is also designed to be rotated through 180 degrees to engage with the lens release button on the camera body, so that you can change lenses after opening the front lens port. When you assemble the housing, make sure that the lever is not waving around inside the housing near the lens release button! Otherwise when you descend at the start of a dive, the increasing pressure may force the end of the lever to gently depress the lens release button, and hey presto, no communication with the lens. If you get Aperture 00 during a dive, or if the camera ceases to respond to everything except on/off switch, my suggestion is to try gently rotating the lever AWAY from the camera body. It's worked for me several times.

Thanks for all the comments - I seem to have touched a few raw nerves there B) Yes. I use TTL all the time with my single strobe. It works for me. I agree with dhaas that Canon eTTL2 is an outstanding system. Especially in the rough waters down here, TTL is fantastic for getting a correct flash exposure on a moving target. Ikelite's eTTL2 interface was one of the strong selling points of the Ikelite housing for me (especially the flash exposure compensation controls on the back of the housing). Yes, I realise that using a manual controller on the second strobe will effectively eliminate the TTL function of that strobe. That's why I asked how important it is, in practice, to have TTL working on the second strobe. As I understand it, none of the available systems includes a `ratio control' to tell the second strobe to put out (say) 1 stop less light than the primary strobe. So even if the second strobe is working on eTTL2, I would still have to adjust the lighting ratio manually, by moving the second strobe further away from the subject (as dhaas says) or ?? putting a diffuser on. Is this still much better than just having a manual power control on the second strobe? I guess it all depends on the type of picture. dmoss seems to be recommending TTL on twin strobes for macro, but manual for wide angle. Anyway thanks for the multiple votes in favor of the dual sync cord. I think I will go that way (and buy two!)

I want to add a second DS-125 strobe to my existing setup (Canon 20D, Ikelite housing and single DS-125 strobe with sync cord). Ikelite offer these options: A : dual sync cord B : manual controller with slave sensor C : wireless digital TTL slave sensor Any opinions/recommendations/experience about these? Ikelite's website says that C is not fast enough for TTL on current digital cameras. It also says that A is not necessarily more reliable than B. How useful/important is TTL on the second strobe? Any advice welcome.

For some reason that I can't quite explain, this humble shot is my favorite for the year. Ascidians competing for space at Rottnest Island, Western Australia Canon 20D, Canon 100 mm macro lens, Ikelite flat port 1/160 sec @ f/18 , ISO 400 (cropped)

Thanks for the advice, everyone. I selected the exposure manually (metering off the diver). Next time I'll bracket, and shoot in RAW. You've convinced me that these techniques could be worthwhile. The photo was taken at 45 metres (150 feet). Would a Magic Filter really help at this depth?

Crow's Nest, SS President Coolidge wreck, Vanuatu Canon 20 D, Ikelite housing Canon 10-22 mm lens, 8" dome port 1/80 sec at f/5 ISO 400 This image is straight out of the camera. I wanted to portray the wreck's huge size and the loneliness of the depths where it now rests. I am disappointed with the lack of detail in the foreground. Is the image underexposed?

It was just screwed into the front of the lens, and aligned so that the darkest part was at the top. So I could only take photos in landscape orientation (although I wish I had tried a few test shots in portrait orientation to evaluate the effect of the filter). Allegedly the front element of the lens doesn't rotate when it's zoomed. Just to be safe, I didn't change the zoom until I'd taken quite a few shots.

Here's a series of images taken at Million Dollar Point in Vanuatu, with and without a Magic Filter. Without Magic ... Dive 732 With Magic ... Dive 738

Vanuatu is well worth a trip. Wonderful friendly people, lush green tropical jungle, great weather, interesting history, WW II relics, caves, freshwater pools. All I can tell you about is the reefs in the neighbourhood of the Coolidge, near Luganville on the island of Espiritu Santo. The reefs are nothing special. Large variety of coral species but the visibility is often poor. This is in a tidal channel with rainwater runoff. Plenty of food for corals and anemones, but not great for photography. There are too many storms to allow big gorgonians to grow (this also applies to the Coolidge except in sheltered corners). Million Dollar Point is a fantastic photographic opportunity. There are hundreds of large vehicles and a few wrecked boats all piled up on a slope from 9 to 40 metres. Wide-angle paradise. I didn't see any pelagics at all. There is reputed to be a single whitetip reef shark on the Coolidge.

Here are a couple of images from my first try with a Magic Filter, at Million Dollar Point in Vanuatu. The visibility was mediocre but the sun was fairly strong. Canon 10-22 mm lens at 10 mm. These images have not been post-processed at all. depth = 15 metres 1/100 sec f/8 ISO 400 depth = 10 metres 1/125 sec f/9 ISO 400

I have a problem with internal reflections in my dome port. This is a clean, new Ikelite 8 inch dome port (for Canon 10-22 mm lens). I took some shots in a crystal clear freshwater pool: some half-in-half-out shots and some very close to the surface. In many of the photos you can clearly see an image of the lens itself (the concentric rings of the lens front elements, or even the lettering on the lens). It's presumably caused by internal reflections in the dome port. Is this a well known problem, and are there tricks to avoid it?? In these pictures there was a graduated 2 stop neutral density filter on the lens. Could that be part of the problem? Any advice welcome

It depends whether you want the background to be visible or not. There are two sources of light - the available sunlight, and the strobe. The strobe light can only reach a very short distance through the water. So there is a distinct `foreground' range (where the strobe will provide the dominant source of light) and `background' range (where only the dim sunlight is present). If you meter the background (pointing the camera at the background and half-pressing the shutter button) the camera displays what it thinks are the right exposure settings to make the background come out adequately bright (like an average scene on land). These settings would be appropriate, for example, if you are pointing the camera upwards at a fan with open water behind it and you want the background water to come out as a sky blue. To get richer deeper blues, adjust these metered settings to a darker exposure. If the main subject of interest is not within the strobe's range, as in your first two photographs, then effectively you are just taking a photograph in available light. Then there may not be enough contrast in brightness or colour to allow the subject to stand out, and I guess this is the main comment on your first two photos. The first two photos are probably exposed OK, it's just that at that distance from the subject there is insufficient contrast to isolate the subject from the background. Your third photo has a nice subject that is (marginally) within range of the strobe. Using TTL the camera will control the amount of light put out by the strobe and usually make a pretty good job of adjusting the brightness of the subject. In your third photo the TTL has done a reasonable job, stopping the flash at the point where the coral is starting to look too white. But the background is also visible, which weakens the contrast and the separation between foreground and background. The background is just sand which is not so interesting. It would be have been better in this case if you had severely under-exposed the background, so that it came out much darker. That could have been done by metering the background, then setting an exposure that was 3-4 stops darker. In the third photo the foreground subject is roughly correctly exposed, but the colour is rather too washed out. Getting the camera closer to the subject would have retained more of the saturated reds and greens that otherwise get absorbed as the light travels between the strobe and the subject. But hawkfish *are* pretty hard to approach. I would recommend Skerry and Hall, Successful Underwater Photography HTH

There is a nice side-by-side comparison of wide-angle lenses for digital cameras at photo.net

Please ignore the second question. None of the Cokin holders is wide enough for this wide-angle lens. Only the screw-in 77 mm filters can be used. I'd still like to know if anyone uses Cokin graduated colour filters

Does anyone have experience in using the Cokin range of gel filters? Cokin webpage I'm paticularly interested in graduated colour filters. I have a Canon 20 D, Canon 10-22 mm lens, Ikelite housing and Ikelite 8 inch dome port. Does anyone know whether a Cokin P series filter holder will fit inside this port?