Canon 60D Optics
Canon EOS 60D Optics
As of this writing (mid December, 2010), the Canon EOS 60D digital SLR camera is available body-only, bundled with the Canon EF-S 18-135mm f/3.5-5.6 IS lens, or bundled with the EF-S 18-200mm f/3.5-5.6 IS lens.
The 18-135mm kit lens has a 7.5x zoom ratio, with a 35mm equivalent focal range of 29-216mm due to the 60D's 1.6x "focal length crop" (see below). The lens is constructed of 16 elements in 12 groups. Focusing is internal, and the 18-135mm uses a micro DC motor for autofocus instead of the ultra-sonic motor found on models with the USM designation. An AF/MF switch is provided. The lens features built-in image stabilization (IS) that is capable of up to four stops of correction. A Stabilizer On/Off switch is also provided. Other specifications include a 6-bladed (rounded) diaphragm, minimum aperture of f/22-f/38 (or f/36 if using 1/3 stop increments), maximum magnification ration of 0.21x (or 1:4.8) at 135mm, and 67mm filter thread. Dimensions are 101 long with a 75.4mm diameter (4.0 x 3.0 inches), and weight is 455g / 16.0 oz. The lens has a MSRP of US$499.99 if bought separately, but costs significantly less when purchased bundled with the camera. A lens hood and soft case are optional accessories. See below for our test results with this lens mounted on the Canon 60D, and see our full review of this lens on SLRgear.com.
The 18-200mm kit lens has an 11.1x zoom ratio, with a 35mm equivalent focal range of 29-320mm when the focal length crop is taken into account. This lens is also constructed of 16 elements in 12 groups, features internal focusing, and uses a micro DC autofocus motor which is enabled or disabled with an AF/MF switch. Again, the built-in image stabilization system is rated for up to four stops of correction, and is enabled or disabled with a provided switch. Other specifications include a 6-bladed (rounded) diaphragm, minimum aperture of f/22-f/38 (or f/36 if using 1/3 stop increments), maximum magnification ration of 0.24x (or 1:4.2) at 200mm, and 72mm filter thread. Dimensions are 102 x 78.6mm / 4.0 x 3.1 inches, and weight is 595g / 21.2 oz. This lens has a MSRP of US$699.99 if bought separately, and again costs significantly less when purchased bundled with the camera. As with the 18-135mm lens, both a lens hood and soft case are available as optional extras. See our full review of the 18-200mm lens on SLRgear.com.
The Canon EOS 60D will work with pretty much any EF-mount lens ever made, as well as with the special EF-S lenses designed for cameras with APS-C size sensors. Designed with a smaller image circle (the area covered by the image on the film/sensor plane), EF-S lenses tend to be smaller and lighter than full-frame models with the same focal length and maximum aperture. EF-S lenses can't be used on full-frame Canon cameras, nor on their models with 1.3x crop factors, like the current EOS-1D Mark III, but small-sensor cameras like the 60D can use any full-frame lenses in Canon's arsenal.
The sub-frame sensor on the Canon 60D means that it has a smaller angle of view (by a factor of 1/1.6x) than a full-frame camera with any given lens. While most properly called a "crop factor" or "focal length crop", the 1.6x ratio is most commonly referred to as the "focal length multiplier" since that's how it works in practice: Any lens used on the Canon 60D will have the same field of view as one with a 1.6x greater focal length will when attached to a 35mm camera. For example, a 100mm lens on the Canon 60D will show the same field of view as a 160mm lens on a camera with a 35mm frame size.
Lens Peripheral Illumination Correction
The Canon 60D provides what the company calls Lens Peripheral Illumination Correction, which corrects for lens shading (commonly called "vignetting"), producing more uniform exposure across the frame by compensating for the light falloff seen with some lenses in the corners of the frame. Lens Peripheral Illumination Correction first appeared in the 50D and has since featured in several of Canon's consumer and enthusiast DSLRs. Peripheral Illumination Correction works with over 85 different Canon lens models, in both RAW and JPEG workflows. For JPEG shooting, the correction is made at capture time, while RAW shooters can access the function in Canon's Digital Photo Professional software, although Canon shooters should note that the latter approach offers the highest degree of correction. In-camera correction of JPEGs operates with somewhat reduced strength, especially when shooting at higher ISO sensitivities, given that the correction can make image noise more pronounced. From the factory, the 60D body ships with correction data for about 25 lens models. Canon's EOS Utility software allows correction data for lenses (including models as-yet unreleased) to be uploaded to the Canon 60D, up to a maximum of 40 lenses.
The Canon 60D's autofocus sensor is unchanged from that used in the previous 40D and 50D models. and features a 9-point diamond array, with nine cross-type f/5.6 autofocus points, meaning that they're all sensitive to vertical or horizontal lines. Nestled in the center is an additional precision dual-cross AF sensor that is arrayed diagonally and used when you mount a lens of f/2.8 or faster. All nine AF points can be selected automatically or manually, and the autofocus sensor has a working range of -0.5 to 18 EV (at 23°C / ISO 100). The Canon 60D includes the ability to detect the light source (including the color temperature and whether or not the light is pulsing), and then take these into account and microscopically shift the focus as necessary. Autofocus modes include One-shot, Predictive AI Servo AF, and AI Focus AF, which automatically selects between the One-shot and AI Servo modes. Of course, there is also a manual focus mode.
Unlike the 50D and 7D, the Canon 60D lacks a Lens AF Microadjustment custom function, which would allow you to tune the camera's autofocus system so as to compensate for lenses that back or front-focus. Not all lenses and bodies are tuned perfectly, but this tool can help make a lens / body pairing that yields slightly soft results a whole lot better. It's a disappointing omission, as its a feature available in some prominent models from competing manufacturers, at around the same price point.
In Live View mode, the Canon 60D offers three autofocus modes ,as per other recent Canon digital SLRs. The first of these is what Canon refers to as Live Mode AF, whereby the camera applies contrast detection algorithms to the data streaming from the image sensor. This allows focusing without interrupting the live view, but has the disadvantage that it is significantly slower to achieve a focus lock, which makes it less useful for handheld photography, or when shooting moving subjects. The second mode is Face Detection Live Mode. As you may expect, this mode detects and focuses on human faces. If more than one face is detected, the multi-controller can be used to select a different face. Alternatively, in what Canon refers to as Quick Mode AF, the mirror is briefly dropped to allow an autofocus operation using the camera's phase detection autofocus sensor. This mode offers quick autofocusing, but with the disadvantage that there is an interruption of the live view stream during the AF operation. Live View mode also offers a selectable 5x / 10x magnified view of the selected focusing point when the photographer elects to focus manually.
The Canon 60D uses the built-in flash head as its AF-assist illuminator, rather than a bright light built into the camera's body. (The small orange LED lamp on the front panel is used only for red-eye reduction, and as a self-timer indication.) In practice, this works well: the flash is quite bright, and probably has a longer range than an on-body illuminator bulb, being rated at 4 meters or 13.1 feet. If you attach a 550EX, 580EX or 580EX II external flash unit to the Canon 60D, its internal infrared AF-assist illuminator is used instead of the flash head itself, providing a useful working range of about 50 feet with a less obtrusive light source. For non-flash photography, Canon's ST-E2 wireless sync transmitter can also be used for AF assist. The ST-E2's AF-assist light has a useful range of about 25 feet.
Without an external strobe attached, and when in Creative Zone modes (Program, Priority, Manual, and Bulb), the internal strobe will fire its AF assist pulses if needed whenever the flash is raised. In the Basic Zone, AF Assist fires in all but Flash Off, Landscape or Sports scene modes. It never fires in Movie mode, even before capture starts. Using Custom Function III-4, AF assist can be disabled altogether, set to fire from the external flash only, or set to fire with external strobes including an IR assist beam only. You can also prevent the 60D from firing either the internal flash or external Speedlites altogether, by going into the Flash Control menu. This still allows the AF-assist pulses to fire; but without flash capability until you turn it back on.
Dust Reduction Technology
First introduced on the Canon Rebel XTi, Canon's system-wide approach to reducing the impact of dust on the image sensor is also included on the Canon 60D with a slight update to the anti-static coatings used.
A key feature of any SLR is the ability for the user to easily swap lenses. This expands creative options enormously, but every time the lens is removed, dust from the environment is free to enter the camera body. From there, it's only a matter of time before some of it makes its way to the surface of the sensor ,where it casts shadows that appear as dark blobs in your images. In truth, it's the anti-aliasing filter that collects dust, rather than the sensor itself, but common parlance refers to "sensor cleaning." For the sake of familiarity, we'll generally refer to sensor cleaning here, but will make mention of the anti-alias or low-pass filter as seems appropriate. Every DSLR ever sold has offered a sensor-cleaning mode, in which the mirror is locked up and the shutter opened to permit the sensor to be cleaned with compressed air, a solvent-carrying swab, or other means. As the market has matured and more DSLRs have found their way into the hands of novice users, it has become clear that some automated way of dealing with sensor cleaning is needed.
The principal approach other manufacturers have used to deal with dust has been to make the system self-cleaning, vibrating either the anti-aliasing filter itself or a protective cover glass lying above it, to shake loose adhering dust particles. Once dislodged, a strip of sticky material at the bottom of the sensor cavity or mirror box catches and holds them. This approach was pioneered by Olympus, but has since been adopted by Canon, Nikon, Pentax, Panasonic, and Sony, in various forms. Some cameras use a dedicated piezoelectric element to provide the vibration, while others perform double duty with the sensor shift mechanism used for their image stabilization, with widely varying vibration frequencies and efficacies. In addition, some manufacturers have adopted coatings on the low-pass filter intended to prevent dust particles from adhering in the first place.
Dust reduction. The Canon 60D includes Canon's EOS Integrated Cleaning System, first introduced on the EOS Rebel XTi camera. The camera's Self-Cleaning Sensor Unit uses a piezoelectric element to shake dust particles off of the low-pass filter in front of the sensor. The dust is then trapped by an adhesive strip along the base, preventing it from causing further nuisance. Cleaning is engaged each time the camera is powered up or shut down, or manually through the "clean now" function. The second part of the cleaning system involves post processing with a compatible personal computer and the supplied Digital Photo Professional software. Via a menu option, the camera maps any stubborn dust spots that remain on the sensor after cleaning, saving their locations as Dust Delete Data that can subsequently be used to subtract the spots during post-processing. A third option includes a manual sensor cleaning function which raises the mirror and allows users to clean dust that may have stuck to the low-pass filter.
No matter how good an automatic cleaning system, there are going to be some stubborn dust particles that it can't dislodge. To deal with these, the Canon 60D has the ability to shoot a dust reference photo, and then transfer that information to Canon's Digital Photo Professional software, which can use it to eliminate the shadows cast by dust particles on the images. Canon's "Dust Delete" processing works for both JPEG and RAW format files. The dust map ("Dust Delete data") that the software uses to perform its magic is stored in the headers of files created by the camera. There's thus no need to keep track of a separate dust image file, the information is always available in the file headers, assuming you've actually performed the dust-mapping process. You can update the Dust Delete data any time you think the camera might have been exposed to dust, or after you've manually cleaned the sensor. The latest dust map is automatically incorporated into the EXIF headers of all JPEG images, or the headers of any RAW files.
Located in Shooting Menu 3, the Dust Delete Data option displays a screen that shows when the last Dust Delete reference image was captured. Selecting OK on this screen initiates a cleaning cycle, after which the camera prompts you to take a picture of a blank white surface. (The camera automatically defocuses the lens and sets the aperture appropriately, to produce the best possible dust image.) The camera then processes this data, and reports whether it was successful or not. If the surface you used to capture the image wasn't sufficiently uniform, you'll get an error message, but if the image was good, you'll see a confirmation screen. The Dust Delete Data just generated will now be included in the headers of any JPEG or RAW images captured, until you decided to capture a new dust reference image.
Don't count on the anti-dust system to do everything, though.
Despite Canon's advanced anti-dust technology, we feel compelled to point out that we've thus far seen no anti-dust system that completely eliminates the need for sensor cleaning. Sooner or later, you're going to need to clean your sensor, so we strongly recommend purchasing a good-quality sensor cleaning kit right along with your DSLR. Automated anti-dust systems like Canon's will certainly help with some of the dust, typically the dust that the nylon brush-based cleaning systems can also handle. Inevitably, though, you'll encounter dust that sticks to the sensor's cover glass tenaciously; dust that only a wet/dry cleaning approach can remove. We ourselves use and recommend products from Copper Hill, which we've found to be both highly effective and among the most reasonably priced on the market.
Canon 60D Optical Test Results
Below are the results of our optical tests with the bundled 18-135mm kit lens.
Kit Lens Test Results
The Canon EF-S 18-135mm IS (Image Stabilized) kit lens offers better-than-average zoom ratio, with pretty good performance.
|18mm @ f/8||135mm @ f/8|
The Canon 60D is offered with an EF-S 18-135mm f/3.5-5.6 IS kit lens, with a generous (for an SLR kit lens) optical zoom range of ~7.5x. The 35mm equivalent range is about 29-216mm, because of the 60D's 1.6x "crop factor". Sharpness is very good across most of the frame at 18mm, though there's moderately high chromatic aberration and some coma distortion visible in the corners. Corners are just a touch soft as well. Sharpness at full telephoto is quite good too, with excellent detail across the frame, though chromatic aberration is still a bit high. All in all, this is a pretty sharp optic for a kit lens especially considering the zoom range, and the built-in image stabilization will come in handy for low-light or telephoto shooting. While chromatic aberration is a bit high, it is easily corrected with some post-processing. Here's an example of the wide-angle shot above with most of the chromatic aberration removed in Adobe Camera Raw. You can also correct it with Canon's bundled DPP software.
A fairly large macro area with soft detail. Flash throttled down well.
18-135mm IS Kit Lens
|Macro with Flash|
The Canon 60D's macro performance will of course depend entirely on the lens in use. With the 18-135mm IS kit lens set to 135mm, the Canon 60D captured a fairly large (even for an SLR lens) minimum area measuring just 3.92 x 2.62 inches (100 x 67 millimeters). Details were pretty soft in the center, and softer still in the corners. (Most lenses have some softening in the corners at macro distances.) Some noticeable vignetting (corner shading) was also present. Both the softness and vignetting would likely improve by stopping down to f/8, though. (The above macro shots were taken at f/5.6.) The Canon 60D's flash throttled down for the macro area very well. There was no detectable shadow from the lens barrel, resulting in a good exposure with the flash.
Higher than average barrel distortion at wide-angle and moderate pincushion distortion at telephoto with the 18-135mm IS kit lens.
|Barrel distortion at 18mm is 1.2 percent|
|Pincushion distortion at 135mm is 0.4 percent|
The Canon EF-S 18-135mm IS lens produced about 1.2 percent barrel distortion at wide-angle, which is higher than average and noticeable in some of its images. At the telephoto end, there was about 0.4% pincushion distortion, which is also higher than average though not quite as noticeable. The Canon 60D does not appear to be correcting for any geometric distortion in its JPEGs, as uncorrected RAW files have identical amounts. Geometric Distortion is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide-angle) or inward (like a pincushion -- usually at telephoto).
Chromatic Aberration and Corner Sharpness
Moderately high chromatic aberration at wide-angle and telephoto with the 18-135mm IS kit lens. Only slight softening in the corners.
|Wide: Upper right
C.A.: Moderately high and bright
Softness: Slightly soft
|Tele: Upper right
C.A.: Moderately high and bright
Softness: Slightly soft
C.A.: Very low
Chromatic Aberration. Chromatic aberration in the corners with the Canon 60D's 18-135mm kit lens is moderately high at both wide-angle (18mm) and telephoto (135mm) settings. The amount and intensity of the color fringing reduces as you move toward the center of the image, but is still slightly evident in the center at wide-angle. C.A. is negligible in the center at full telephoto. The Canon 60D does not appear to be correcting for C.A. in its JPEGs, as uncorrected RAW files exhibit similar amounts.
Corner Softness. The Canon 60D's 18-135mm IS kit lens produced some slightly soft corners in a few shots. At full wide-angle, corners on the right side of our test targets were somewhat softer than the center, but the blurring didn't extended very far into the frame. The left side, however, showed less softening in the corners. The center of the image was quite sharp. At full telephoto, all four corners were only slightly soft with the top right being the softest. The image was pretty sharp in the center. There is also some corner shading or "vignetting" wide-open, as evident by the darker corner crops above.
Overall, a pretty good performance for a kit lens here, especially one with a 7.5x zoom ratio. Also keep in mind the above lab target shots are taken with the lens "wide-open" and sharpness and corner shading generally improve when a lens is "stopped-down" a couple of f-stops from full aperture. The main optical issues with this lens are chromatic aberration, corner-shading and geometric distortion, all of which can be corrected for or reduced in most advanced image editing software. As mentioned previously, the Canon 60D has the capability of reducing corner shading automatically in-camera by enabling Peripheral Illumination Correction.
The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Canon EOS 60D Photo Gallery .
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