Olympus C-3040 ZoomOlympus updates its top-of-the-line 3-megapixel model with a "faster" lens and increased movie capabilities.<<Viewfinder :(Previous) | (Next): Exposure & Flash>> Page 5:OpticsReview First Posted: 4/14/2001 |
OpticsThe Olympus C-3040 Zoom provides an all-glass, aspheric lens design, with 10 elements in seven groups. The 3x, 7.1-21.3mm lens provides a focal range equivalent to a 35-105mm zoom on a 35mm film SLR. We were very pleased by the speed of the lens (measured by its maximum apertures), which was an impressive f/1.8 at the wide angle setting, and f/2.6 at telephoto. This doubtless contributed to the excellent low-light performance we experienced with the C-3040.
Focusing distances range from 2.6 feet (0.8 meters) to infinity in Normal mode, and 7.9 to 31.5 inches (0.2 to 0.8 meters) in Macro mode. The macro focusing produces a minimum capture area of 3.21 x 2.41 inches (81.5 x 61.1 mm), about average among top-end digital cameras we've tested. Autofocus is determined through the lens, using a contrast detection method. This means that the autofocus will work properly with auxiliary lenses. The green LED next to the optical viewfinder glows solid as soon as the subject is in focus (flashing means there's a problem focusing and you may need to switch to Manual Focus or Macro mode).
The C-3040 Zoom's Manual Focus mode is activated through the Still Shooting and Movie (Record) menus. Once selected, a distance scale readout pops up on the LCD monitor to help you gauge focus in difficult focusing situations. The distance readout is especially helpful when shooting in Macro mode, which can often be a little tricky to focus. Though the C-3040 doesn't feature an automatic focus lock, you can manually lock it by centering the target portion of the subject in the frame, pressing the shutter button halfway, and then recomposing the image while continuing to hold the shutter button halfway.
You can opt to keep the camera in continuous focus by activating the Full-Time AF mode in the Record menu. Full-Time AF means that the autofocus is constantly engaged as you move the camera from subject to subject, instead of waiting for the shutter button to be depressed halfway. This is useful for action photography like fast-paced sports or children playing, but it is an additional drain on the battery because the focusing mechanism is constantly at work. You can also designate whether the camera determines focus from the center of the image or the entire image area, by choosing the appropriate AF Mode option in the Record menu.
The C-3040 Zoom's outer lens barrel incorporates 41mm filter accessory threads that couple to Olympus' lens adapter tube, the CLA-1. This optional adapter extends the threads outward (and increases their diameter to 43mm), so they are flush with the front of the lens when it's fully extended. It's important to note though, that this adapter is made to work with Olympus' own accessory lenses, all of which use an additional adapter ring to step up the threads to the diameter needed by the auxiliary lenses. The consequence of this is that the CLA-1 design requires another threaded adapter ring, because it doesn't extend far enough for 43mm filters to clear the lens barrel. The 43mm filters will interfere with proper lens operation, and could damage the lens mechanism itself! Therefore, if you buy a CLA-1 adapter unit, be sure to also buy a step-up ring to whatever filter size you use, just to give you the extra millimeter or two necessary for the lenses to clear the front of the lens barrel.
While the C-3040 Zoom's lens provides up to 3x optical zoom, the camera's Digital Zoom can increase that magnification to a maximum 15x (albeit with noticeable quality degradations in the resulting image). Digital zoom is activated through the Record menu and controlled by the Zoom Lever on top of the camera. The image resolution determines the amount of digital zoom available. For example, 2,048 x 1,536-pixel images can be enlarged digitally to 2.5x. The 1,600 x 1,200-pixel size can be enlarged up to 3.2x, while 1,280 x 960-pixel images can be enlarged to 4.0x. Finally, the 1,024 x 768 and 640 x 480-pixel resolutions offer a maximum 5x digital zoom. Note that the Digital Zoom must be turned on in the Record menu; it cannot be used with the uncompressed TIFF mode; and it is only accessible when the LCD monitor is engaged. When the LCD is turned off, the digital zoom returns to the 1x setting.
Unfortunately, one consequence of the unusually "fast" lens design is that optical distortion on the C-3040 is rather high at the wide-angle end, where we measured approximately 1.0 percent barrel distortion. The telephoto end fared much better, where we found approximately 0.2 percent pincushion distortion. Corner sharpness also suffers a bit at wide angle, and chromatic aberration is a little higher than average. All forms of distortion improve markedly toward the telephoto end of the lens' range. Center resolution is very high, easily extending to 800 lines per picture height in both horizontal and vertical directions, and with strong detail visible all the way out to 1,000 lines on our resolution target.
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