Tetra Housing and Olympus C3030Z

2/27/00 - Preliminary posting. I'd appreciate feedback if anything I say is just the result of my own misunderstanding! --Dave Rossum

NOTE: In this review, I use color to indicate my ratings: BLUE indicates outstanding performance in an important feature, GREEN indicates a job well done, and RED indicates need for concern. Headings in BLACK indicate either that the feature is relatively unimportant or that it's undistinguished in execution. Text in orange indicates an important tip or caution. If my rating of the importance of certain features doesn't seem sensible to you, consider my write-up on thinking digitally.

Buoyancy - The Tetra is very close to neutral, slightly negative in salt water. With two SB-105's attached it's still a little negative. I've never had any fatigue while carrying it underwater.

Handle - The Tetra's neat hand strap feels good and provides a firm grip for carrying. But the housing adds enough bulk to the camera that I'm unable to easily work any of the controls one- handed. The shutter and zoom controls become very difficult to use. Often I feel I need a better grip to control the camera while shooting. I'm considering adding a "pistol grip" style handle to the left hand side for stability. I also wonder if the Tetra hand grip might be even more problematical for a leftie.

Attachment Mounts - The Tetra has three threaded holes on the housing bottom. Two 10-32 accessory mount holes are useful for attaching a tray, which nicely tightens against four rubber feet. A 1/4-20 hole is designed for tripod mount. Atop the lens extension is a pointer light mount which accommodates the smaller "infinity arm" nicely. Two optional wings at the top serve as strobe arm mounts. Everything is tightly and effectively positioned.

Strobe Ports - On top of the Tetra housing are two optional bulkhead ports which fit strobe connectors. The leftmost allows you to neatly string your strobe cable to the left side strobe arm. The right side port requires the cable to dangle over the shutter on its way to the right strobe arm, a little messy. The real problem is that the C3030 uses a proprietary method of TTL strobe control, so the camera's TTL features can't be used. In my opinion this is one of the major drawbacks of the Tetra/C3030 system. For more information, see my write-up on the Olympus TTL details and on thinking digitally.

Camera Mount - The Olympus camera is mounted in the Tetra housing in a simple "press in" mounting. A foam rubber ring around the C3030's lens acts to position the front of the camera against left-right and up-down motion. If you're careless, you can insert the camera into the housing pushing the foam ring in front of the lens, which prevents the camera from operating. I always check. Four plastic feet press against the front of the C3030 to position the lens area front-back. Foam around the view port presses the camera against these feet. The right hand side of the camera is positioned by the cup which mates with the mode dial. All this makes for simple assembly, but leaves some sloppy tolerances. For my first dozen dives, I noticed the shutter speed in manual mode would sometimes randomly increase. Then one dive the camera failed to operate properly because the top "jog dial" button was continuously pressed. I now carefully check the camera positioning each time I open the back to make sure the top jog dial button has enough free play so a little pressure won't engage it. Since adding this caution to my checklist I've experienced no further problems on dives.

Removable Back - The Tetra housing back has the same rotary latches and double O-ring seals as other Light and Motion products. It's simple, elegant and foolproof.

View Port - The view port is tight against the C3030's view screen, and gives a clear and full view.

LCD Display View - There isn't any. If you want to see whether or not you're in macro mode, what flash mode is set, and what resolution you're shooting, you need to press buttons to cause this info to appear on the rear view port. That's only slightly annoying.

Interchangeable Lens Ports - The Tetra housing supports three lenses: a flat port, a wide angle port, and an macro port. Changing the lenses is simple and foolproof. They're protected by double O-rings.

Markings - The Tetra mode dial is clearly marked with a durable plastic insert with an arrow, and a plastic sticker around the knob with labels indicating the positions and functions. The rear buttons are labeled with icons on the buttons, and these began to wear off during the first dive. It may be hard to remember the functions at 100 feet when the markings are illegible, which will be soon. Fortunately, you'll seldom need to remember much.

Shutter - The Tetra shutter might work if your hands are large and strong. Mine aren’t. When I first held the housing in the shop, the shutter button seemed stiff and awkward under my extended index finger (see photo at left). The problem was even more severe during the first dive. I was unable to fully depress the shutter without twisting the camera, altering the framing of the subject. It was virtually impossible to half-depress the shutter reliably, a skill that is vital to minimize the effects of autofocus lag.

A hacksaw, a drill, a file and some 1/8” aluminum stock were all it took to kluge together a remedy (shown at left). The plate is shaped to screw onto the bottom of the left-hand flash mount and extend across the top of the camera just above the shutter button. A bend brings the tab at the plate’s right hand end into convenient thumb range. The squeezing pressure between the top of my index finger, which sits below the right hand flash mount in the handgrip, and my thumb, allows for precise shutter control, and makes it possible (but not easy) to gauge when the shutter is half-depressed. I may design a "Mark II" shutter modification to address this.

Zoom - Located in front of the shutter, the Tetra's zoom control is also virtually impossible to use effectively. The zoom on the C3030 itself is marginal. Rather than a pressure sensitive rate, the lever just runs the zoom motor at a constant and rather fast rate either in or out. Momentary pushes are possible when the camera isn't in the housing, but even then the results are inconsistent steps in zoom. The Tetra housing adds substantial resistance to the control, enough to completely eliminate it's spring return to center. This, combined with its awkward position, makes it almost impossible to seek a precise degree of zoom underwater. Additionally, if you ever fail to manually return the control to the center detent, some (but not all!) of the camera controls, including the shutter, cease to operate. There's no indication of the problem in the view port, so it can be very frustrating when this occurs.

Jog Dial - In vivid contrast to the zoom and shutter, the four jog dial buttons are wonderful! They're just separated enough that you don't press more than one at once, even with gloves in cold water.

Flash and Macro - These buttons are just a bit too close together. With my gloves on, I press them both when I plan to just hit one. In warm water they work fine.

OK, Monitor, and Menu - These buttons are large enough that they work just fine.

Note - There are other better reviews of the C3030 available elsewhere online, such as the one by Phil Askey in Digital Photography Review. My comments will focus primarily on the C3030 as it's used underwater in the Tetra housing. I'll make a few topside comments about the camera though, since most photographers will use the camera in this way as well.

Size and Shape - I like the basic feel of the C3030. It fits well in my hand, and without the bulk of the Tetra housing my fingers conveniently manipulate the shutter and zoom controls.

Media - Olympus digital cameras use "Smart Media," which in my opinion would be more aptly named "dumb media." (See my write up on SmartMedia vs. Compact Flash.) The big problem is that the C3030 is at present limited to 64MB of storage, which I see as a bare minimum. Delkin Devices, makers of the first shipping 128MB SmartMedia card, has told me that the C3030 will not work with 128MB cards. On the other hand, Olympus is now saying that it will! I should hear from a friend who's trying one by the end of the first week in March. While 81 "HQ" images may seem like a lot, it's not if you use my recommended u/w digital photo techniques.

Battery Life - The C3030's battery life seems entirely adequate for the longest (2 hour) dive. I exclusively use 1600+ mAh NiMH batteries. My battery life test yielded almost two hours of continuous focus power-on shooting and a 150 shots on a single charge with well used, 1500 mAH NiMHs. I recommend you replace both memory module and batteries between each dive.

Sleep Mode - After two minutes of idle time, the C3030 enters a "sleep mode." Pressing any button (I usually press the OK button) wakes it up and brings it back to its previous ready state. While this may extend the battery life, the feature is quite annoying underwater. On numerous occasions I've been ready to take a fine initial shot, only to have the camera sleep as I'm framing the subject. It takes about 3 seconds to wake up, just long enough for my subject to swim away. Since the batteries will last a full dive without sleep, the "feature" gives me no advantage. Contrast this with the Nikon CP950 and 990, which allow you to program the idle time to sleep mode to as long as 30 minutes.

The sleep mode seems to consume almost no power. Since the C3030 forgets its setting when powered off, it makes sense to set everything up topside, allow the camera to go into sleep mode, and wake it up after you're underwater.

Amnesia - Or I suppose you could call the C3030 the camera with Alzheimer's. The designers, in a poorly thought out attempt to save cost, did away with the back-up battery for the clock in the C3030. If you leave the camera without charged batteries for somewhere around an hour, it forgets everything! This can be extremely annoying, particularly when you don't realize that your settings are all screwed up until you're underwater.

Shutter Lag - This is a complex subject, so please read my full write-up on causes of shutter lag. To summarize, using half-depression of the shutter, you'll get about 300 msec of lag. Raw shutter depression will give you about a second. If you accidentally get into red-eye mode, you'll see 2.5 seconds. These aren't good, but they're typical of today's digital cameras.

Shooting Rate - Digital cameras are limited in the rate at which you can shoot. The shot rate, in pictures per minute, depends both on the shutter lag (when severe) and the rate at which the camera can process and store pictures. For the C3030 I shot in continuous autofocus, flash off (external flash), manual exposure mode. I was able to achieve about 24 shots per minute.

Remaining Shots - In the lower right corner of the LCD, the memory remaining on the card, in shots, is displayed. With an empty 64MB card, you'll see 81 available if you shoot (as I do) in HQ mode. This is a somewhat pessimistic estimate; you'll get closer to 100 shots. There's no display of the actual shots taken, but there's no need to know this.

Buffer Indicator - A black bar in the lower left of the LCD viewfinder indicates in green how much information is awaiting transfer from the camera to the memory module. This is important only when you're shooting pictures at the maximum rate, and want to know how much longer you can keep it up before the camera's internal buffer fills and stops you from shooting. I've never come close to filling it.

Mode and Settings - Across the top of the LCD is the mode (I generally shoot in M for manual), the f-stop, the shutter speed, and the exposure value. In manual mode, you use the jog dial buttons to adjust f-stop and shutter speed, and the light meter tells you how many stops under or overexposed the natural light exposure will be. This works very well.

In shutter or aperture priority modes, the jog dial allows you to adjust the priority setting and an exposure compensation value in f-stops. The automatically adjusted setting is displayed. For example, in A (for aperture) mode, the jog dial adjusts the f-stop, and the camera decides and adjusts the shutter speed.

The only problem with this system is that it takes six button presses to change between modes.

Intermittently Displayed Items - The remaining items are shown for only a few seconds when certain buttons are pressed. The simplest way to get this display is to press the menu button twice.

Focus/Metering Mode Icons - About half way down the left side of the LCD, the focus and metering mode icons are briefly displayed. There are two independent modes, normal/macro range and normal/spot meter weighting. The macro mode is indicated by a flower, the spot metering mode by a square with a dot in the center. Lack of these icons indicates normal mode. All these modes can be useful underwater; I generally default to macro range and normal metering.

"Drive" Icon - About 1/4 of the way down the right hand side of the LCD, the "drive" icon is briefly displayed. There are five "drive" settings. A single rectangle indicates single shot mode. A stack of rectangles indicates "sequence" mode, and with an AF next to it "AF sequence" mode. A clock indicates timer/remote mode, and the letters BKT indicate automatic bracket mode. Single is the usual setting, but sequence and AF sequence are useful.

White Balance Icon - Just below the drive icon on the right hand side of the LCD, the white balance icon is briefly displayed. There are five white balance settings. No indicator is the default auto setting. The sun, cloud, and tungsten light bulb icons are easily recognized, the rectangle with extending lines is a fluorescent bulb. I generally leave the setting at "auto."

Remaining Battery Indication - While in "record mode" there's no LCD indication of a low battery. You can only see the battery status on the LCD by switching to "play" mode. This can be easily done by pressing the monitor button twice. The battery status icon is then briefly indicated at the upper left. A green full battery indicates the battery isn't dead yet. Unfortunately, you get almost no warning of low batteries when using NiMH cells.

I'll assume you're familiar enough with the C3030 that you understand the power/mode dial, the shutter and the zoom. The descriptions below tell how the various buttons work primarily in "Record Mode" (when you're taking pictures). I assume you're using the camera in "A/S/M" Record Mode, as the "P" Record Mode is pretty much useless in the Tetra.

Flash Mode Button - Indicated by a lightning bolt, this button cycles through the four flash modes (normal, red-eye, on, and off). In the Tetra, the only useful mode is "off". In play mode (reviewing photos) this button doubles as the delete function. Pressing it gives a choice of deleting (press OK) or not (press the flash mode button again).

Focus/Metering Mode Button - Indicated by a flower, this button cycles through the focus/metering modes. There are two independent modes, normal/macro range and normal/spot meter weighting, giving four combinations. Spot meter weighting causes the camera's exposure meter to evaluate the light only in the very center of the screen, which is useful when you want to light a particular subject properly. Macro mode enables a wide range of focus. It's worth noting that macro mode does not preclude distance shooting, though the auto-focus can get a little slower. I generally leave the camera in macro mode, normal weighting.

Jog/Shuttle Dial and Exposure Control - These four buttons are used for a variety of functions. In Record Mode, they are used to adjust the exposure. They can also be used for manual focus adjustment. In the Menu Mode, they navigate through the selections. In Play Mode, they skip through the stored photos, and serve to position the magnifier when zooming.

When the camera is in Manual (M) Record Mode, the left and right jog buttons increase and decrease the f-stop respectively. The top and bottom buttons increase and decrease the shutter speed. The 1/3 stop increments are just right. The range on the shutter speed is fine (down to 1/800 sec), but f-stop values beyond f/11 would be extremely useful.

In the Aperture Priority (A) Record Mode, the top and bottom buttons control the aperture, while the left and right control exposure value deviation from ideal. Similarly in Shutter Priority (S) Record Mode the top and bottom control shutter speed and left and right exposure value deviation. The only problem with this system is that it takes six button presses to change among the A, S, and M modes. I generally leave the camera in Manual Mode.

Manual Focus/OK Button - Indicated by the letters "OK," this button is used to confirm an operation in menu mode, and activates manual focus in Record Mode. When pressed during Record Mode, a distance display appears on the right side of the LCD viewfinder, along with the letters "AF" and "MF" at its bottom. The active mode, automatic (AF) or manual (MF) focus, is indicated in green, and can be toggled by either the left or right jog dial buttons. If manual focus is selected, the top and bottom jog dial buttons are used to adjust the focus distance. Pressing either activates a momentary magnification on the LCD viewfinder so the focus can be more accurately judged. The distance is displayed in two scales; one spans from infinity to 2.6 feet, the other from 31 inches to 8 inches. The scale automatically changes as the manual focus is adjusted. Pressing the OK button exits the distance display mode, leaving the letters "MF" displayed in red at the lower left if the camera remains in Manual Focus Mode. Photos can be taken while in the distance display mode, but the exposure cannot be adjusted.

It's worth noting that the distance display does not indicate the autofocus distance, nor is there any way to use autofocus to help determine the manual setting. However, the manual distance is remembered even while in autofocus, so you can quickly return to a previously set distance (unless the power is switched off). This is useful for macro shooting. It's also worth noting that you don't have to be in macro mode to focus as near as eight inches.

Monitor Button - Indicated by a rounded rectangle with vertical bars left and right, the monitor button turns on and off the LCD viewfinder. Since the viewfinder is the only indicator for the Tetra, you'll always want it on. Note that it takes about two seconds to turn it back on if you accidentally turn it off.

Pressing the monitor button twice in quick succession while in Record Mode transfers you quickly to Play Mode, so you can review your shots. It takes about two seconds before the most recent shot is displayed. Pressing the monitor button again, or pressing the shutter either halfway or entirely will return you to record mode in about 1.5 seconds. I generally wait to review my shots topside (or during my safety stop), but this feature can be quite useful if you want to critically examine a shot underwater.

Menu Button - A rounded rectangle containing three horizontal lines indicates the button that activates the programming menus of the C3030. Pressing the button a second time exits Menu Mode and cancels any changes you have made!

When you've pressed the menu button, a column of setting icons appears along the left side of the LCD viewfinder, with their corresponding value icons to their right. You navigate through the settings using the top and bottom jog dial buttons, and select a value using the right jog dial button. Once you've changed a value, you can take a picture using that setting immediately. You can also confirm the setting by pressing OK or the left jog dial button; either of these actions takes you back to the setting icon column. If you want the change you make to remain active when you exit menu mode, you must press OK. If instead you press the menu button, your selection will be deactivated. This can be confusing, so it's worthwhile playing with menus for a while to make sure you understand these rules.

DRIVE - There are five "drive" settings. A single rounded rectangle indicates single shot mode, in which you press the shutter and the camera takes a single picture. A stack of rectangles indicates "sequence" mode, and with an AF next to it "AF sequence" mode. In these modes, the camera takes up to five rapid-fire pictures if you hold down the shutter, and you can use your external flash if it's set to a low enough power setting. In the AF mode, the camera re-focuses between shots. A clock indicates timer/remote mode (pretty useless underwater), and the letters BKT indicate automatic bracket mode, which also has little underwater use.

ISO - You can select ISO speeds of 100, 200 or 400. The slower the speed, the less noisy the CCD image. Generally you'll want to shoot at 100, but you may sometimes find conditions where the added speed is worth the noise of higher settings. A setting of AUTO which chooses an ISO setting based on lighting conditions is only available in the P Record Mode, hence not useful underwater.

TTL Flash Exposure Compensation - A rectangle containing a lightning flash and +/- indicates the TTL flash exposure compensation setting. Since TTL flash doesn't work with the Tetra, you can ignore this one.

Slow Shutter with Flash - The lightning bolt icon next to the word SLOW indicates the slow shutter speed flash setting. A setting of OFF prevents the shutter speed from going below 1/30 second, SLOW 1 causes the flash to fire at the beginning of a slow shutter speed, and SLOW 2 causes it to flash at the end. OFF is the only useful setting underwater.

Flash Int/Ext Mode - The word FLASH indicates the flash internal/external mode setting. Either my camera is broken, or this setting doesn't do anything useful. The only way I get what you want for the Tetra housing, which is internal flash OFF, external flash firing, is to use the flash mode button to set the flash mode to OFF. The setting of this internal/external mode doesn't seem to matter. In particular, even when I select external only (picture of external flash unit) the internal flash still fires.

Digital Zoom Enable - The words DIGITAL ZOOM indicates the digital zoom enable setting. In my opinion, there's no point to digital zoom since you can crop the photo using Photoshop under better conditions. I leave this set to OFF.

Image Processing Functions - The word FUNCTION indicates the image processing function setting. OFF indicates no special processing. BLACK & WHITE causes the image to be captured in black and white. SEPIA gives a monochrome picture with a sepia tone. WHITE BOARD and BLACK BOARD are high contrast settings useful for capturing black on white or white on black text respectively. OFF is the only useful setting; black and white or sepia effects are easily achieved from a color image in Photoshop.

Record Enable - A picture of a microphone indicates the record enable setting. When ON, about four seconds of sound are recorded with each picture. Not useful underwater.

Memory Card Format - The words CARD SETUP indicate the memory card format operation. Selecting this operation, then pressing OK twice causes the memory card to be re-formatted. This is the easy way to erase all images on the card. Be careful, unlike many cameras you can erase everything just by pressing OK with no other buttons.

MS - Initial Settings - The words ALL RESET indicate the initial settings menu, which can be set to OFF, ON, or CUSTOM. ON causes the camera to reset the settings listed below to their default values, which is generally annoying. OFF causes the camera to remember these settings when you cycle power, which is more useful. CUSTOM allows you to define the power-up status, which I find most useful. The settings are:

Setting	Default	I Recommend	Comment
FLASH MODE	Auto	OFF	Any other setting causes internal flash to fire
Focus/Metering	OFF	Macro/Normal	Gives full focus range at cost of slower autofocus
Zoom	32mm	Your choice	Starting point for zoom
F-Number	F/2.8	F8.0	Or chose your most common setting
Shutter Speed	1/4 sec	1/100	Or chose your most common setting
Exposure Comp	Zero	Zero
Focus	Autofocus	Autofocus
LCD in P mode	OFF	OFF	So I can tell if I'm accidentally in P mode
"Drive"	Single	Single
White Balance	Auto	Auto
ISO	Auto	100	Optimum quality
Flash Expos'r Cmp	Zero	Zero	Doesn't matter since TTL doesn't work
Flash Slow Mode	OFF	OFF
FLASH	INT+EXT	EXT ONLY	Doesn't seem to work, but this is what you want
Digital Zoom	OFF	OFF	Use Photoshop instead
Function	OFF	OFF
Record Audio	OFF	OFF
Still Quality	HQ	HQ	Optimum compromise btwn memory and quality
A/S/M Mode	A	M	Full manual allows both shutter and aperture control
Movie Quality	HQ	HQ	Don't care, not useful underwater

MS - Image Sharpening - A circle solid on top and dotted on the bottom indicate the image sharpening setting, which can be HARD, NORMAL, or SOFT. It's not clear from what Olympus says whether SOFT gives a blurred image or just zero sharpening. In general, I believe in doing all the image processing on my computer, but I opt for NORMAL here in the absence of an explicit "NONE" setting.

MS - TIFF Resolution - The word TIFF indicates the TIFF resolution setting, which has five choices. I recommend you don't use TIFF format.

MS - SQ1 Resolution - The word SQ1 indicates the SQ1 resolution setting, which has a three choices. I recommend you don't use SQ format.

MS - SQ2 Resolution - The word SQ2 indicates the SQ2 resolution setting, which has a three choices. I recommend you don't use SQ format.

MS - Beep Volume - A speaker radiating sound waves indicates the beep volume setting, which can be HIGH, LOW, or OFF. While you don't hear the beep underwater, I recommend the LOW setting so you can hear the button acknowledgement when the camera is out of the housing.

MS - Continuous Autofocus - The words FULL-TIME AF indicates the continuous autofocus enable, which I recommend you enable by choosing ON.

MS - Record View - The words REC VIEW indicates the record view enable, which has three settings, OFF, ON, and CHECK. CHECK requires you to confirm storage of every picture, OFF means you need to go to play mode to review your shot. I recommend ON, which causes the shot to appear on the screen for about 2.5 seconds after shooting, just long enough to make sure it's correctly composed and focused.

MS - File Naming - The words FILE NAME indicate the file naming convention setting, which can be either RESET or AUTO. The Olympus uses a nice system for naming files. The name looks like PMDDNNNN.jpg, where M is a character representing the month of the year (1 to 9, then A, B, and C), DD are two digits representing the day, and NNNN is a four digit sequential number. Now you can see why it's important that the clock be correctly set. RESET causes the camera to reset the sequential numbering system each time you format the memory card (or insert a blank card). If you use RESET, you can easily get two different pictures of the same name on your laptop. I recommend using AUTO, wherein the sequential number never resets, thereby guaranteeing unique file names for all the pictures in a given year.

MS - LCD Brightness - A rounded rectangle with a vertical line on each side, and a set of growing vertical bars below indicates the LCD brightness setting. I have found the default setting just about right. A brighter setting is more visible in bright light, but consumes more battery power and wears the display light out faster.

MS - Date and Time - A picture of a clock dial indicates the date and time setting. Be sure this is properly set or your filenames will be messed up. You may want to check it each time you dive to ensure that amnesia hasn't occurred.

MS - Metric/English - The words m/ft indicates the focus units setting, which can be either feet or meters depending on which century you were born.

This ends the discussion of the MODE SETUP menu.

Resolution - A solid triangle changing on the right into dots indicates the picture resolution setting. Your choices are TIFF, SHQ, HQ, SQ1, and SQ2. I recommend HQ as the optimum tradeoff between memory size and quality. To my eye, the compression artifacts at HQ are barely visible if at all, particularly on any real underwater subject. In a 64MB card, HQ allows close to 100 pictures, which is barely adequate. Going up to SHQ reduces this picture count to around 40, not much better than a roll of 35mm film. Some would argue that this should be enough because you can delete your bad shots, but while you're messing with that, I'll be out taking more pictures! You can only get about six TIFF images on a 64MB card, clearly too few.

Lens Ports - There will be three optional lens ports available for the Tetra. The standard flat port does not modify the optics of the C3030 lens. There will also be a wide angle port and an macro port. I was able to briefly test a loaner unit of the wide angle port (which is currently in production) and a prototype of the macro port.

With the Flat Port - The flat port gives a 35mm equivalent focal length of 32mm to 96mm over the 3x zoom range. The lens speed is F/2.8, and this value is maintained throughout the zoom range.

I find the 32mm wide angle setting usable for distance shots, though of course I'd prefer a MUCH wider angle lens. The modest telephoto settings are useful for fish pictures; the extreme telephoto end of the zoom range isn't terribly useful underwater.

In macro mode, the closest you can focus is about 6" with the zoom at 32mm (wide angle). This gives a 35mm equivalent frame to film ratio of 2.8 : 1, or in other words a frame of about 4" x 3". Zoomed to 96mm (full telephoto), you can focus as close as 12", giving a 1.75 : 1 ratio or a frame of 2.5" x 1.6". The optimum zoom setting for maximum magnification seems to be about 85mm, where a 9" focus can be achieved giving a ratio of 1.6 : 1 which is a frame of 2.25" x 1.5". While it's no where near as fabulous as the Coolpix for macro work, it's still quite usable.

Macro Port - Light and Motion's "achromatic" macro port modifies the optics to achieve about twice the magnification available with the flat port. I measured the ratio at 1 : 1.15, giving a frame size of 1.25" x 0.8". This is achieved with the zoom at 96mm (telephoto), and the nearest focus distance of 7".

The problem with the macro port, of course, is that you can't change back during a dive. When the zoom is at the telephoto end, you can only focus out to about 11" away, and the frame size is still less than 2" x 1.3". As you zoom towards wide angle, the lens starts to vignette, but you can push things to about a 6" x 4" frame at 15" distance. This gives you considerably more flexibility than with a Nikonos framer, but nowhere near as nifty as the Coolpix.

Wide Angle Port - Light and Motion's Wide Angle port for the Tetra modifies the optics to optimize for distance shots. I'd estimate the wide angle port gives the 35mm equivalent of about an 18mm lens, and this is a substantial improvement over the limits of the 32mm unmodified optics. Unfortunately, like the macro port, use of the wide angle port limits your flexibility. Even in macro mode, the closest you can focus is about 15", and at the telephoto setting this is a 6" x 4" frame. So you lose any macro capability with this port.

Chromatic Aberration - The C3030 lens system suffers from a significant optical aberration. It results is colored fringes near edges of high contrast, which are worst near the edges of the picture. I'm told that this is not the result of poor lens crafting, in fact Olympus has worked very hard to manufacture particularly good lenses to minimize the problem. Instead, it's apparently the consequence of the camera's high resolution using a physically small (and thus inexpensive) CCD chip.

I've created a simple setup to demonstrate the problem, and I've concluded that the problem exists to about the same degree whether underwater or in air, and with all the various Tetra ports. The section below shows the test photos and explains what you're seeing and my conclusions.

A full frame photo of my demonstration setup. It's a sheet of dark gray construction paper with holes punched around the edges, placed over a sheet of plain white paper. Not shown in this case is a business card I place in the center to give the auto-focus processor some data. The light source is the internal camera strobe.

The idea is that the very sharp edges of the holes should produce either black, white, or (in the case where the edge crosses a pixel) pure gray pixels. There should be no color in the image at all. Of course, the white balance could be off, so an overall cast won't indicate any problem. But, as we'll see, if there's chromatic aberration, the white light will refract slightly and tend to create a purple fringe on one side of the hole and a green fringe on the opposite side.

Zooming in on the upper left hole (chosen because it's the farthest from the center of the image), you can see the limits of the camera's definition. In this case, the camera is my Fuji S-1, which has a very large (1" wide) CCD with 3.3M pixels. The lens is a Sigma 28-300mm ultrazoom, so we're not looking through particularly high quality optics. Note in this case that the image is still purely gray, with no hint of colors.

Here's a 360 x 270 pixel portion of the original test image from the C3030 test performed in air, outside the Tetra housing. This test is at nominal zoom, F11, but my experience is that neither the F-stop nor the focal length have substantial effect on the magnitude of the phenomenon.

You can clearly see the purple and green fringes on the opposite sides of the hole.

Is this effect something to be concerned about? I'm afraid I have to say yes. At left is a photo I took in the Caymans. Even at this size, you can see a bit of purple on the bubbles near the top.

I should note that this is the only photo I've taken where the chromatic aberration has been anywhere near this obvious. But you need to watch for it whenever there is a sharp, high contrast edge near the side of the image.

Well, I've said all I have to say about the Tetra and the Olympus 3030 underwater. Of course the final test is the photos you can take. Below are a handful of pictures I shot in my first two months owning my Tetra. All were shot using the flat port. Locations are Carmel, Monterey, and Grand Cayman. Click on the photo to get the full resolution (2048x1535) version. All have been touched up by Photoshop, but I've done nothing gross. I think (and I hope you'll agree) that in conclusion, even though there are a number of shortcomings, one can still take some pretty fine pictures with the Tetra/C3030 system.


"Above and Below" shot at Grand Cayman 11/30/00	"In the Anemone Forest" shot at Grand Cayman 11/29/00	"Sea Lion Shadow-Play" shot in Monterey 12/21/00

"Knights" shot at Grand Cayman 11/30/00	"Jelly" shot in Monterey 12/27/00	"Eye of the Stingray" shot in Grand Cayman 12/1/00

	"Nesting" shot in Monterey 12/21/00