Casio Exilim EX-G1 Performance, Timings, and Image Quality

PERFORMANCE
I had hoped to get into the ocean with the G1 and shoot some surfers close up, but between storm surf and some kind of flu on my part, the G1 never made it into any deeper water than the 8 feet in our backyard pool. Typically, cameras taken into or underwater have been purpose-built like the Nikonos 35mm film camera, or the G1. The other option is to enclose a terrestrial camera in a waterproof housing. Here are examples of both, the Nikonos V (which was rated to an official depth of 160 feet but routinely was taken to 200 ) and a present-day splash housing rated to 15 to 20 feet with its D200 and 50mm lens. You can see how small and compact the G1 is by comparison.

Besides staying in shallow, still water I also didn't drop-test our unit or expose it to sub-freezing temperatures: no G1 was harmed in the production of this review.

Shooting Performance
The G1 is not overly quick to power up, taking about 2.25 seconds to display an AF icon onscreen. Power on to first shot times ran about 2.75 seconds. Single shot-to-shot times (shoot, write, acquire focus and shoot) times ran about 3 seconds with both class 4 and 6 freshly formatted microSD cards. While the camera produced a 3.5 fps shooting rate for 8 images in the high speed continuous shooting mode in our studio, these images are at a much reduced 2 megapixel resolution. Write times for the class 4 card were about 2.5 seconds, with the class 6 coming in around 2 to 2.25 seconds. Using the normal speed continuous shooting mode the G1 rolled along at a leisurely 0.45 fps, but it will do that until the memory card is full - this rate was the same with either card. And while we're on the subject, after experiencing a dose of digital the microSD way, I'm just real glad all my cameras use CF memory.

Shutter Lag (press-to-capture, pre-focused)

AF Acquisition (press-to-capture, no pre-focus)

Continuous Shooting

* Note: Continuous shooting framerates are based on the camera's fastest full-resolution JPEG continuous shooting mode, using the fastest media type available (300x CF, SDHC, etc.). "Frames" notes the number of captures recorded per burst before the camera stops/slows to clear the buffer.

However, the camera puts on its track shoes when it comes to AF acquisition in good light, knocking down consistent 0.20 second times. It continues to do pretty well as light levels drop so long as some contrast is present, but struggles (as do most compacts) when things get real dark and contrast drops. Shutter lag was an excellent 0.01 seconds - no complaints from me about focus and shoot with the G1!

Flash range at auto ISO is a fairly close 9.4 feet at wide angle, and 4.3 feet at telephoto. Recycle times are listed as 4 seconds maximum by Casio and the G1 made this number consistently.

The G1 uses Casio's "anti shake" system of boosting ISO sensitivity to provide faster shutter speeds as a means to reduce image degradation due to camera movement. While a system using mechanical (sensor movement) or optical (lens element movement) would be preferable, Casio probably didn't have either option available given the shock-resistance they built into the camera - sensors or lens elements that move probably don't lend themselves to surviving impacts as well as fixed items that can be insulated more easily. Anti shake is disabled as a default, and is disabled automatically when shooting with flash.

Battery life is given as 300 shots at 73 degrees F, but performance will not approach that number in the 14 degree F range the camera is rated for. Recharging a depleted battery takes about 100 minutes.

Lens Performance
The G1's 3x optical zoom has fairly slow maximum apertures of f/3.9 and f/5.6 at the wide angle and telephoto ends respectively. Wide angle shows light falloff in the corners, along with some softness in the corners and edges. There is also wave ("moustache") distortion present - barrel distortion to the edges of the frame and pincushion to the corners.

Telephoto is better along the edges, but a little soft in the corners as well. Wave distortion is also present to a lesser degree than at wide angle. Here's a look at this distortion at both ends of the zoom, and in the real world, where straight lines like horizons near the edges of the frame are likely victims of the effect.

Wide angle
Telephoto

There is chromic aberration (purple fringing) present in some high-contrast boundary areas at both the wide and telephoto ends of the zoom, and sharp-eyed viewers might discern some defects at 100% enlargement. For more casual reviews this will probably not be an issue, particularly at smaller print sizes.

One nice feature of the lens is that with the digital zoom enabled (on by default), you can zoom to the maximum 3x optical setting, at which point zooming stops. You need to release the zoom button and then re-engage it to zoom into the digital range. Pretty hard to go digital by mistake.

I was somewhat surprised to find no macro mode in the Best Shot library, but there is a macro AF mode that can be accessed via the REC menu in the auto shooting mode. Whether you'd want to use it is questionable - it limits AF range to 3.9 inches to 19.7 inches instead of 3.9 inches to infinity in normal AF. The G1 won't focus in any mode closer than 3.9 inches which explains why no macro mode per se - so why bother with the macro AF setting? Here are two "macro" shots made in plain old auto mode with normal AF. Just don't get any closer than 3.9 inches.

Video Quality
Video quality is OK at the highest resolution 848x480 captures, but no one will mistake it for HD. The G1 microphone is quite adept at capturing video related sound. The lens will zoom during video capture and refocus upon completing the zoom. Maximum movie size is 4 gigabytes for the 848x480, 640x480 and 320x240 formats; the YouTube 640x480 format is limited to 10 minutes.

Image Quality
Probably the first thing folks want to know is how the G1 does underwater - and the answer is not bad. Here are shots of the pool cleaner in about 4 feet of water made in auto and underwater modes respectively; ISO was manually set at 100 in each case. For comparison, a shot from the housed D200 in a bit shallower water at 100 ISO, and finally a shot of the Nikonos in a couple feet of water.

Casio Exilim G1, auto mode	Casio Exilim G1, underwater mode
Nikon D200, ISO 100

Looking at some of the first images out of the G1 for the first impressions article it seemed the shots were a bit soft at default settings. By the end of the shooting for first impressions I was changing my view a bit, and now I think Casio did a pretty good job of establishing default settings for color and sharpness. Trying a few of the Best Shot scene modes didn't produce a lot of difference in the overall image to my eye - here are auto mode (the default) and scenery, pet and flower Best Shot modes.

Default	Scenery
Pet	Flower

If the camera doesn't produce images to your liking at the default settings, you have a host of inputs available in auto mode (which happily is the default shooting mode - good call, Casio!), and some, if not all in many of the Best Shot scenes. I have one nagging reservation about the G1 images overall, and it's not a major concern, but at 100% enlargements the G1 shots seem to have just a bit more artifacts than a lot of other compacts I've reviewed.

At less than 100% the images look good, and they're not bad at 100%, but just not quite as clean to my eye. Personally, I'd shoot this camera in auto mode at 64 or 100 ISO for almost everything, possibly with one extra notch of sharpening. Here are the default, +1 and +2 sharpening settings:

Default

Sharpened +1

Sharpened +2

There are color filter options that allow you to shoot in black and white, sepia, and a number of other hues.
Auto white balance worked well in the field and did a good job with the incandescent light in the studio. The G1 provides daylight, overcast, shade, day white and daylight fluorescent, tungsten, and manual white balance options.

Auto White Balance, 3200k incandescent light

Multi-pattern exposure metering is the G1 default and was used for all images produced by the G1 for this review. Center-weighted and spot metering options are available, but multi-pattern proved quite accurate for all but some high contrast scenes, where it would lose some highlights on occasion - a not unusual occurrence for this class of camera.

ISO noise performance would probably have to be termed average at best for a 1/2.3 inch sensor packing 12.1 megapixels of resolution. The ISO 64 sensitivity did not appear quite as clean as many other compacts I've reviewed, and I found it lacking in detail with regard to the inscription in the pen case - the fine print is usually legible at the base ISO for every compact I can ever recall. This may speak more to the overall image quality from the lens - the top of the pen case shows a bit of the wave distortion we discussed earlier, as does the base of the display - rather than ISO alone. 100 ISO showed slight but definite deterioration, with 200 exhibiting a like amount.

ISO 64	ISO 64, 100% crop
ISO 100	ISO 100, 100% crop
ISO 200	ISO 200, 100% crop
ISO 400	ISO 400, 100% crop
ISO 800	ISO 800, 100% crop
ISO 1600	ISO 1600, 100% crop
ISO 3200	ISO 3200, 100% crop

ISO 400 dropped off a bit more and there was a large jump in image degradation between 400 and 800. ISO1600 dropped off a significant amount over 800, and 3200 was a clear drop from 1600.

Additional Sample Images