Casio Point and Shoot
Home >
Digital Camera Reviews >
Casio Digital Cameras >
Casio Point and Shoot
Casio Exilim EX-Z700 Digital Camera Review
by Emily Raymond
Published on November 22, 2006
Color (7.97)
Our round of testing begins with photographs of the GretagMacbeth color chart, which is widely known as the standard for color in the imaging industry. The chart is made up of 24 square tiles each with a different color. We photographed the chart with the Casio Exilim EX-Z700, and uploaded the images to Imatest software. The program compared the original colors of the chart to those produced by the Z700. The following is a chart modified by the program to show the ideal colors (vertical rectangles), Z700’s colors (outer squares), and ideal colors corrected for exposure (inner squares) all on one chart.
Because it is sometimes difficult to see the difference between all these colors, the software quantified the information and put it into a graph below. The circles represent the Casio Z700’s colors, and the squares represent what they should be.
These results actually look quite similar to the Casio Z850’s color testing results. Many of the colors are slightly off, and most are undersaturated. In fact, the entire image was saturated 93.6 percent. This is a bit surprising, as most digital cameras tend to oversaturate images by about 10 percent to fake more flattering skin tones. Indeed, even the Z850 oversaturated by 14 percent.
The good news is that the camera metered the scene and white balance almost exactly right. For its performance, the Casio Exilim EX-Z700 received a 7.97 overall color score and 7.65 mean color error.
Still Life Scene
We photograph the same awesome still life scene of the colorful markers, doll, ring, and other such items with every digital camera we test. This photo is taken by the Casio Z700. A full-resolution file can be viewed by clicking on the image below.
Resolution (3.01)
Casio’s Z700 comes with a 1/2.5-inch CCD loaded with 7.41 total megapixels, 7.2 of which are effective in imaging. The advertised pixel counts don’t always add up though, especially when paired with less than amazing lenses and processors and such. To test this, we photographed an industry standard resolution chart using various focal lengths and apertures to get the absolute sharpest shot. Our best picture came from using a focal length of 15.3mm and an aperture of f/4.6. Below is the resolution chart; clicking on it will show a full-resolution shot.
Click on the chart above to view the full resolution file.
Fringing is evident in the picture, and it gets worse closer to the edges of the frame. The image isn’t blurry everywhere but it isn’t crystal clear either. We uploaded the image to Imatest, which quantified how sharp the picture is in units of line widths per picture height (lw/ph). This measurement describes how many black-and-white alternating lines of equal width could theoretically fit across the frame horizontally and vertically without blurring.
The Casio Exilim EX-Z700 resolved 1367 lw/ph horizontally, but did so with 1.07 percent undersharpening. Vertically, the camera resolved 1356 lw/ph with 9.54 percent undersharpening. These results are very similar to the Casio Z850’s resolution results, despite the Z850 advertising another megapixel on its sensor. Overall, the 7.2-megapixel Casio Z700 doesn’t perform as well as it should.
Noise – Auto ISO (0.49)
When we tested the noise output of the camera using the automatic ISO setting, a new record was set. Most compact models meter the scene, choose the lowest ISO available, and produce just a tiny amount of noise in our brightly lit studio. The Casio Z700 metered the scene and selected an ISO around 200, and produced a ton of noise. The ISO 200 setting on this Exilim produces about the same amount of noise as competing models’ ISO 800 or even 1600 settings. The Casio Exilim EX-Z700 set a new low for this test with a 0.49 overall score. It doesn’t get much lower than that.
Noise – Manual ISO (2.07)
Despite other compact digital cameras offering higher sensitivity these days, this Exilim still only has four basic manual ISO settings: 50, 100, 200, and 400. We tested the noise output of each of these while shooting in a brightly lit studio. The chart below shows the ISO settings on the horizontal axis and the resultant noise on the vertical axis.
There is a lot of noise at the lowest ISO 50 setting, and it only gets worse from there. To determine the overall score, we used the noise output results from each setting and generated a regression analysis. The Casio Z700 turned out a disappointing overall manual ISO noise score of 2.07. This is unfortunate, as these pictures were taken in bright light but will hardly be usable.
Low Light (1.0)
While all other testing is done in a brightly lit studio, this is done at light levels of 60, 30, 15, and 5 lux. The two brightest tests are fairly common lighting situations found in dimly lit restaurants and bars. The darkest two tests are uncommon for photography, but help us determine any limitations the image sensor may have. For this test, we photograph the color chart in the diminishing light so readers can compare it with the brightly lit version. Imatest has altered the pictures below to show the ideal colors (vertical rectangles), camera’s produced colors (outer squares), and camera’s colors corrected for luminance (inner squares) just like the color test.
|
Low Light Tests
|
 |
 |
|
60 Lux
|
30 Lux
|
 |
|
|
15 Lux
|
5 Lux
|
This test was not easy to perform. First of all, it was difficult to straighten the camera because of its physical imbalance; it had a hard time sitting straight on a tripod even when screwed onto the plate. The second problem was the inaccurate metering in low light. The metering system seemed to perform just fine in optimal lighting, but it has trouble finding much when the lights are low. The other problems include increasing color inaccuracy and an exorbitant amount of noise. There was already a ton of noise in bright light, but it only gets worse as the lights dim. Check out the chart below to see just how much worse it gets. The horizontal axis shows the exposure time and the vertical axis shows the amount of noise produced at that shutter speed.
Surprisingly, the Z700 produces less long-exposure noise than the Casio Z850 – perhaps due to the camera’s noise reduction system. However, this is still a substantial amount of noise and makes shooting in low light virtually impossible when combined with the terrible metering and aversion to the tripod.
Speed / Timing
Startup to First Shot (8.28)
It took the Casio EX-Z700 1.72 seconds to start up and take a first image. That’s quick for a compact camera. Still, users ought to be sure to turn the camera on before they get into a situation where a spontaneous shot might come up. Two seconds is a long time when it comes to a candid moment.
Shot-to-Shot (9.71)The Casio EX-Z700 offers three burst modes. In its Unlimited mode, it will shoot a little faster than 1 shot every two seconds – our math says 0.57 frames per second – but it will keep going at that rate until the memory card fills up. Its High mode shoots 3 frames in slightly less than a second. The Z700 will also shoot 3 flash shots in less than a second, which is an unusual and useful option. It’s possible to find compact cameras that shoot more than 3 frames in a burst. For portraits and some candids, it’s sometimes more useful to have more shots.
Shutter to Shot (8.65)
The perfect camera would take the picture the instant its shutter was pressed. The Z700 isn’t perfect, but with a delay of only 0.18 of a second, it’s very quick, and outstanding among compact cameras. It’s speed will be helpful to users who want to catch action and candid shots.
