Experiences with a Compact Digital Camera System

At the January 5th Aqua Tutus meeting, Oliver Edwards gave a presentation on his new compact digital UW system and his experiences as a new UW photographer. This article, written in a “just the facts” style, amplifies upon that presentation.

System Description

My Background

I enjoyed land photography for over 25 years using a variety of cameras until, after having children, I found my 35mm SLR system too bulky to carry and too time consuming to use. The point-and-shoot camera I used next was good for family snapshots but the photographs lacked quality and the camera wasn’t satisfying artistically. About 5 years ago I learned UW photography in a great course given by Vaqueros Del Mar. At that time they allowed members to borrow the club’s manual Nikonos’. Over the next two years I shot about 15 rolls UW on a couple trips to Florida. The results were nice as “vacation pictures” but I was really looking for more. I found it took a lot of work to get good images with that system and the time lag to develop and review the pictures made it less fun and difficult to improve.

A Digital Family Camera

I bought my first digital camera about two years ago; A Canon S60 Powershot. I wanted a camera that was small enough to use as our family camera, had excellent picture quality, sufficient manual controls to be interesting to an avid photographer, and one that would work in an UW system. The S60 served those needs admirably. It’s qualities are:

  • 5 Mpixel
  • 28-100mm 3.6x optical zoom
  • Macro to within 1.6” at wide angle
  • an “enthusiast” camera offering manual as well as automatic controls.
  • excellent picture quality
  • small size, low weight 4.5” x 2.2” x 1.5”, 8 oz. fits in a pants pocket.
  • Moderate speed: 0.1 sec prefocused, 0.8 sec w autofocus & flash.

It cost $400 when I purchased it. Today you can purchase an S70 (7 Mpel) for the same price and an S80 (8 MPel) for a little more. The S70 appears compatible with UW system I describe below. The S80 requires a different UW housing.

An UW system

My goals for my UW system were:

  • Small, doesn’t dominate a dive. I didn’t want to “drive” the camera housing around during the dive. Like my family camera, I’d like to be able to take the system on a dive and not have to devote the entire dive to photography.
  • Uses family camera
  • High quality UW
  • Reasonable cost

To build the system, I needed the housing, flash, tray/arms, and I wanted a wide angle lens. It took a considerable amount of research on the web, emails, phone conversations, as well as one returned order to find a set of parts that worked together.

Housing

I used Canon’s WP-DC40 housing made especially for the S50/60/70. It’s qualities are:

  • camera manufacturer’s housing fits and works perfectly.
  • small, low volume, and low weight. Form fitting to camera.
  • Polycarbonate, clear
  • 130’
  • flash diffuser for camera flash
  • all buttons accessible
  • $150

Flash

It takes a special type of flash to work with a consumer digital camera. In addition to an optical sensor to trigger the external flash from the camera’s flash, the external flash has to deal with the camera’s preflash. (Digital consumer cameras flash twice – even with red-eye turned off – , once to gauge exposure and once to illuminate the scene.). I selected the Inon D-2000. It’s qualities are:

  • Specified to work with S60 camera.
  • STTL, auto, manual
  • GN 65 dry
  • 100 deg circular extended light source
  • Optically coupled
  • “clear photo” system cuts out almost all visible light from built-in camera strobe. This cuts backscatter.
  • Excellent construction.
  • $510+optical cables etc.
  • Compares to Ikelite DK125 = $700

In addition to being significantly less expensive the Ikelite’s “digital” flash, the Inon can operate in a TTL mode, using the camera’s flash metering system to control it’s exposure.

WA Lens

Based upon my experience using a Sea-n-Sea 17mm WA in Florida, I wanted to get a WA lens. I selected the Inon UWL 100-28AD. This bayonet mounts in front of the camera port. It’s designed specifically to work with cameras with a 28mm. You can zoom in to increase the focal length. It’s qualities are:

  • Specified to work with S60 in Canon housing.
  • 100 deg UW. Wider than a 15mm.
  • 179 deg air – vignettes a little.
  • Adding dome on top of lens gives 150 deg plus UW.
  • beautifully constructed

Tray and Arms

There were two plausible choices for the tray/arms: Ultralight and Inon. I chose ultralight because of it’s good rep. After one local retailer delivered a UL system with a tray that didn’t fit well, I found Marine camera distributors in San Diego. MCD had assembled the exact system I needed. (That’s the key – Don’t order from anyone unless they have actually held one of your systems in their hands. Note: Backscatter doesn’t sell much Inon gear or many Canon housings. They concentrate on Olympus, Sea and Sea, and Ikelite.) My arm system is:

  • “Small” kit from marine camera distributors
  • TR-D tray with TR-DH handle.
  • 1 DB-05 5” arm. Two adjustable brackets.
  • Inon strobe adapter
  • Tray is ok. The (custom) mounting to the Canon housing works but isn’t up to the quality of the rest.
  • Handle and arms are very nice.

Batteries

It’s critical to have good batteries for the flash and camera. I use the following

  • For S60 NB-2LH generic lithium rechargeable 1200MaH pack. Look on Ebay. These cost ¼ the price of OEM and have 20% greater capacity.
  • For Inon Sanyo AA NiMH 2500MaH. Recommended by Inon and web sites that test actual battery capacity. Apparently many rechargables don’t deliver their rated capacity and/or have a short life.
  • LP4000N recharger. Fast – charges in 1 hour. It is also recommended by web sites that test actual battery capacity vs. charger. It’s very compact. Unfortunately, I find it often terminates the charge cycle prematurely – unplug and replug it and it continues. The manufacturer guarantees satisfaction – the story is still out. I might try the Maho C204w – also highly rated.

Storage

I use 512 MB compact flash cards. $20 on sale.

  • Kingston and PQI behave equivalently.
  • Holds 200+ high res jpeg (2.2 MB), 100+ raw
  • USB2 flash card reader
  • 32 MB that comes with camera isn’t useful.
  • Didn’t like an IBM disk based card. It got warm (so wastes energy) and has to be more fragile that flash.
  • Haven’t tried high speed 40x cards.

Cost

From my point of view, the UW system cost $1500; (I bought the camera and it’s accessories for land photography). You could do just fine without the WA lens, lowering the price to close to $1000.

  • Camera $400
  • UW housing $150
  • Flash $510
  • Optical cable + lens/cable adapter $150
  • UWL100-28AD lens + hood + pouch + holder $440
  • Ultralight Tray & arms $220
  • Batteries, charger, flash cards, card reader $140
  • Total ~$2000 (or ~$1500 after camera)

Slide Show

This is the point where you get to see the slide show if the presentation is live. Unfortunately it’s impractical to put the whole show here so I’ve included just a few samples.


Experience

Canon camera works well

  • Takes high quality UW photos.
  • 28mm fl very useful.
  • Exposure compensation w flash is quirky.

Canon housing works well

  • No fogging.
    • I load/unload inside an air-conditioned area.
  • Easy to operate.
  • Good screen visibility w sunshade
  • screen is small. Used to verify gross framing.
  • Hasn’t leaked!

It’s possible to take nice pictures w built-in flash

  • Autofocus needs light. Watch for the autofocus confirmation before shooting. Use a flashlight! But then you’ve got – Task loading!
  • The flash has a limited reach. Reset the camera for natural light if trying anything other than macro or close-up
  • Low flash output can require cutting down natural light to balance color. Get closer or DIVE DEEPER!
  • I’ve taken some nice UW shots in Monterey and Kauai with the setup.
  • Gives a $150, small UW system.

But, external flash works much better…

Settings

These are the settings I’ve been using for photography with the Inon flash.

Canon Settings:

  • Flash always fire.
  • Aperture priority (Av) mode. This allows you to control depth of field, flash reach, and natural light balance. But see flash sync speed section for advanced info below.
    • F6.3-F8 macro & close-up
    • F4 distance

    I don’t recommend automatic (A) because it prohibits many of the adjustments you have to make, or program (P) because it tends to set the aperture full open.

  • ISO 100 (200 distance)
  • Raw or Highest JPEG
  • Set camera overall exposure compensation and flash exposure compensation both to 0. See section on exposure compensation below.
  • Flash adjust auto.
  • Red eye off
  • Display intensity high
  • Display images with histogram

Inon Settings:

  • STTL-LOW
  • Exposure compensation 0 (B). Adjust to adjust exposure.

Canon S60 Flash Sync speed (shutter speed when using flash)

  • The S60 defaults to 1/60 flash sync speed in Av (and P) modes.
    • This relatively slow speed can blur shots due to movement when you’re in moderate to high ambient light environments. (This occurred in many shallow Monterey shots where there was a lot of surge. It also occasionally occurred in Chuuk. It’s not easy to hold an UW system steady if you’re staying off the reef.)
  • It is capable of flash sync speeds up to 1/250.
  • To get a high flash sync speeds and control the aperture, try the following:
    • Set Shutter priority mode (Tv).
    • Adjust the shutter speed to above 1/250 to stop down
      • At 1/250 the camera will set the aperture wide open.
      • For every halving of shutter speed, it selects an aperture one stop smaller! (It may not make sense but I believe that’s what the camera does.

Canon S60 Exposure Compensation – Don’t use it

  • When using the external Inon flash, the S60 overall exposure compensation doesn’t appear to have any effect.
  • When using the external Inon flash on STTL, the S60 flash exposure compensation does effect the Inon’s flash exposure, just as it should.
  • I took most of my UW photos with Canon overall exposure compensation set to -2/3 stop, Canon flash exposure compensation set to +2/3 stop and interestingly enough, Inon exposure compensation set to – 2/3 stop. However, I don’t recommend doing this. Why turn up flash exposure in the camera then dial it down in the Inon? Just set both to zero.
  • Use the Inon flash exposure compensation to adjust flash exposure.
  • Use camera shutter speed and aperture to adjust flash / ambient balance.

Inon D2000 STTL mode works well

  • STTL exposure is good for many scenes. You can predictably compensate for the exceptions.
    • Overexposes when very close: stop down
    • Underexposes when far away: open up
    • (I wonder if this is due to limitations in the canon flash autoexposure range?)
  • Distant shots easily come out too dark
    • Full diver, Large objects
    • Open up (you may have to zoom out. The camera only opens to it’s full f2.8 aperture at 28mm wide angle.
  • Close shots easily have blown out sections.
    • Sections can turn pure white. Can’t get them back in Photoshop.
  • Look for overall dark / light balance and for clipped pixels.
    • Set camera to display images w histogram. Examine each shot’s histogram after acquiring. Look for many 255 pixels (white areas) or overall balance too low (dark picture).

Inon Modeling light very good for auto-focusing and pointing strobe

  • Also works remarkably well as a flashlight inside ships or at night. (However safety demands you bring a separate flashlight whenever you are relying upon the light.)
    • I lock the modeling light so it stays on as long as the flash is turned on.

WA lens works well

  • Easy to get full diver shots
  • Increases sharpness by getting close to subject.
  • Great in boat interiors.
  • Limited vis on my dives so far hasn’t allowed “big” UW WA shots.
  • But Significant CA at frame edges
    • 4-6 pixels at bright to dark transitions on frame edge
    • I think this is in the camera! Consumer digital cameras don’t have as high quality optics as SLRs.

100 deg+ UW lens can be difficult to handle

  • it’s too close for macro – it’s easy to touch the front element
  • you scare small fish you’re so close
  • it’s easy to get distortion
  • I need to learn how to use it better.
    • You can zoom it in. I haven’t done tests to see if the quality holds up.

179 deg WA above water is a gas!

  • Great for wide panoramas
  • Great for indoor shots
  • Keeps full camera aperture.

Getting enough depth of field in Macro is tough

  • Stop down f6.3, f8.
  • Focus accurately – how?
    • Take lots of images.
    • Ensure modeling light is pointing at the point you want to focus.
    • Zoom all the way in on playback and look around the image (takes a lot of time)

28mm macro is usable but close

  • S60 only gives usable macro at 28-35mm. Higher focal lengths have a very limited macro focusing range.
  • This is too close (to the subject) for many shots.
  • Restricts perspective.
  • Probably will buy Inon macro tele. Gives 50-60mm macro range.

Auto-focus delay makes fish photography challenging (but possible)

  • 0.5 to 0.8 sec from first shutter push to taking image
  • You can reduce this to 0.1 sec by:
    • Pre focusing
    • Manual focusing
    • I haven’t experimented with either underwater.
  • I attempt to “track” fish movement when using autofocus.
  • Also anticipate and push release ahead of time.
  • This system isn’t really “real time”

1.8” Display works but not as nice as SLR

  • Can verify framing.
    • I match major elements near edge of the scene with their location in the display.
    • It’s too small to see all the pictures details.
  • Ability to zoom in on playback image is good to verify focus.
  • I found it easier to “picture” artistically with an SLR.
    • But I’ve only used the non-SLR digital for 2 years now and I’m learning.

Camera Battery life is acceptable. Flash battery life excellent

  • Flash often lasts the entire day (3+ dives) (2500 MaH Sanyo batteries)
    • Even with modeling light locked on.
  • Camera battery lasts 1 dive if you’re doing a lot of photography, 2 if you’re not
  • Generic higher capacity (1200mah) batteries help
  • Reviewing, zooming, adjusting burns battery.
  • Battery warning light may flash early in the dive when in cold water. Less capacity but it still works.
  • Make sure batteries are fully charged before diving!
    • Lithium rechargeables self-discharge; Significant capacity gone in a month.
  • Have to have two (or more) camera batteries.
  • Nice to have two sets of flash batteries but not required.

512MB compact flash cards good size

  • Sometimes can shoot entire day on one card.
  • I save at highest resolution JPEG ~2MB or RAW ~5MB
  • Make sure you erase the images off the card after downloading them to your PC.
    • Otherwise you’ll spend dive time erasing images UW.
  • Nice to have two cards – they’re cheap now.
  • Get an external USB 2.0 compact flash card reader.
    • PQI is one of the smallest.

Stuff

  • Photoshop Elements 4.0 is a great program and worth the price ($50 or lower) just for the photo organizer. Elements user interface is excellent and makes using the program easy and fun.
    • I am using “Photoshop Elements 4 one-on-one” to learn elements ($23 from Amazon) and find it’s enjoyable to read as well as informative.
  • B&W filters Photoclear lens cleaning cloth and lens cleaner both work very well. B&H photo stocks them.

How I try to avoid flooding

  • ONLY prepare the camera when not in a hurry.
  • NEVER prepare the camera just before you dive.
  • Prepare the camera inside the boat or at home.
  • Skip shooting rather than take a chance.
  • “Test” dunk the housing in the photo rinse bucket after sealing. You could see water entering the clear housing.

The Inon seals with a single round O-ring. The seal looks very reliable. The Canon housing has the usual extended O-ring seal around the back. This one looks like it deserves TLC. It (like the Inon’s) is made of a nice supple yellow rubber. You can see both of them through the clear housings. The Canon housing also has a large number of captive O-rings around the buttons. When I asked Backscatter how they could be maintained their response was basically: use it for a few years (until it wears out) then throw it away. At $150 it can be considered a consumable item.

Summing up – UW picture quality can be excellent

Major picture quality issues are:

  • autofocus
  • autofocus
  • where did my subject go during the autofocus?
  • exposure
  • Blurring from slow flash sync
  • chromatic aberration at edges of especially WA
  • Canon default raw processing makes image more vivid – good for some images, bad for some “busy” already saturated UW images.

Recommendations

  • Digital UW is the way to go.
    • immediate feedback helps a beginner tremendously
    • it’s fun to shoot a lot UW. Film costs lots of $s and even if you’re rich limits you to 36 exp per dive. (I’ll often take >100 images in a dive.) Plus, digital is easier to organize and present (especially with a program like photoshop elements).
  • Compact UW system is perfect for a “part-time” photographer.
  • Manufacturers housing is great (Canon, Olympus).
  • New “digital” flashes work well with consumer cameras.
  • 100 deg UW lens is useful but not general purpose

What I’d do differently or I plan to do next

  • Try using shutter priority to control the flash sync speed along with the aperture
  • Set both the camera’s overall exposure compensation and flash compensation to 0.
  • Use the flash diffuser.
  • Set the flash to STTL rather than STTL-LOW
  • Get a second 5” arm. The flash is too close to the camera for medium to long distance work. It’s also difficult to twist it into the positions you’d desire for close macro shots.
  • Try the Inon 1.6x tele macro adapter.
  • Use Adobe Photoshop to “develop” raw images in cases where the Canon raw processing is too vivid.

Sources

Camera, Housing: Canon USA

Inon Flash, Lenses: Inon

Ultralight: Ultralight Control Systems

Retail outlet, system integrator, good advice (sells everything except camera): Marine Camera Distributors, San Diego

Retail Camera Internet: B&H Foto

© 2006 Oliver Edwards