Canon 70D Exposure
Canon 70D Image Quality
Saturation & Hue Accuracy
Typical saturation levels with excellent hue accuracy.
|In the diagram above, the squares show the original color, and the circles show the color that the camera captured. More saturated colors are located toward the periphery of the graph. Hue changes as you travel around the center. Thus, hue-accurate, highly saturated colors appear as lines radiating from the center. Mouse over the links above to compare ISOs, and click to load a larger version.|
Saturation. The Canon 70D produces images with fairly accurate saturation levels. Strong reds, oranges, dark greens and dark blues are pushed a little, while yellow and cyan are slightly muted. The mean saturation of 110.2% (10.2% oversaturated) at base ISO is typical, and saturation remains fairly consistent over the ISO range except at the highest ISOs where it increases, peaking at 113% at ISO 12,800. Most consumer digital cameras produce color that's more highly saturated (more intense) than found in the original subjects. This is simply because most people like their color a bit brighter than life.
Skin tones. The Canon 70D produced pleasing, natural-looking Caucasian skin tones in our tests when using manual white balance. Darker skin tones show a small nudge toward orange, but lighter tones are more pink. Very good results overall. Where oversaturation is most problematic is on Caucasian skin tones, as it's very easy for these "memory colors" to be seen as too bright, too pink, too yellow, etc.
Hue. As we've come to expect from Canon, the 70D's hue accuracy is excellent when manual white balance is used (as it is for these results), much better than average. There are the usual shifts in cyan toward blue (actually quite small), red toward orange, and orange toward yellow, but all are fairly minor. (The cyan to blue shift is very common among the digital cameras we test; we think it's a deliberate choice by camera engineers to produce better-looking sky colors.) Average "delta-C" color error at base ISO is only 3.63, which is first-rate, one of the best scores we've recorded to date. Delta-C color error increases with ISO, but remains better than average even at the highest ISOs. Hue is "what color" the
The Canon 70D offers a total of nine saturation settings, four above and four below the default saturation. This covers a very wide range of saturation levels, and as it should, the Canon 70D's saturation adjustment affects only saturation, leaving the contrast of images unaltered. (In some cameras, saturation tends to affect contrast, and vice versa.) The fine steps between settings mean you can program the camera to just the level of saturation you prefer. As usual for Canon, well done.
|Saturation Adjustment Examples|
The table above shows alternate settings including the default as well as the two extreme saturation settings. Click on any thumbnail above, then click again to see the full-sized image.
| See full set of test images
See thumbnails of all test and gallery images
Exposure and White Balance
Indoors, incandescent lighting
Auto and Incandescent settings both struggled with household incandescent lighting, though Manual and Kelvin temperature white balance worked well. Slightly higher than average exposure compensation required.
|Auto White Balance
|Incandescent White Balance
|Manual White Balance
|2,600K White Balance
Indoors, under incandescent lighting, the Canon 70D's Auto and Incandescent white balance settings struggled, both producing very warm red/orange color casts. Unfortunately, this is common among cameras we've tested, but disappointing nonetheless for a prosumer model. The Manual setting produced the most accurate results, though just slightly cool with a nudge towards green. The Kelvin temperature setting also performed well, with just a slightly cool bias towards blue. The Canon 70D required +0.7 EV exposure compensation for this shot, which is slightly higher than the +0.3 EV average among the cameras we've tested. (Our test lighting for this shot is a mixture of 60 and 100 watt household incandescent bulbs, a pretty yellow light source, but a very common one in typical home settings here in the U.S.)
Good color, though a tendency towards slightly cool color balance with somewhat high contrast under harsh lighting. Slightly below average exposure accuracy.
|Auto White Balance,
|Auto White Balance,
Outdoors, the Canon 70D tended toward a slightly cool color balance with Auto WB, though overall color is generally very good. The Canon 70D required +1.0 EV exposure compensation to keep the mannequin's face bright, a little more than the typical +0.7 EV we're accustomed to using for our "Sunlit" portrait shot. The Canon 70D's default contrast is a little high, producing some washed-out highlights and dark shadows under the deliberately harsh lighting of the shot above left, though the camera's contrast, Auto Lighting Optimizer and Highlight Tone Priority settings do help with high contrast scenes like these. See below for examples of this. The Far-field shot (above right) is also a bit cool, and exposure just a touch dim, though the camera did a very good job of avoiding blown highlights at default exposure. There are some deep shadows, however, which are somewhat noisy and posterized, though that shouldn't be an issue in properly exposed shots.
Very high resolution, ~ 2,400 to 2,500 lines of strong detail from JPEGs, about 2,500 to 2,600 from RAW.
|Strong detail to
2,500 lines horizontal
|Strong detail to
2,400 lines vertical
|Strong detail to
2,600 lines horizontal
ACR Converted RAW
|Strong detail to
2,500 lines vertical
ACR Converted RAW
Our laboratory resolution chart showed the Canon 70D's images with sharp, distinct line patterns down to about 2,500 lines per picture height horizontally and to about 2,400 lines vertically. Some may argue for higher numbers, but aliasing and sharpening artifacts start to interfere at this resolution. Extinction of the pattern occurred between 3,000 and 3,200 lines. An Adobe Camera Raw converted .CR2 file shows higher resolution than the in-camera JPEG, perhaps another 100 lines, though complete extinction of the pattern was extended to about 3,500 lines. While ACR was able to extract more detail, it also produced more moiré and false colors. Use these numbers to compare with other cameras of similar resolution, or use them to see just what higher resolution can mean in terms of potential detail.
Sharpness & Detail
Very good sharpness and excellent detail with a sharp lens. Minor to moderate detail loss due to noise reduction processing even at low ISOs.
Sharpness. The Canon 70D's 20-megapixel sensor captures excellent image detail when coupled with a good lens, though as is usually the case, the 70D's default sharpening setting generates visible edge-enhancement artifacts in the form of sharpening halos around high-contrast edges, as shown in the crop above left. (The above left crop shot was taken with Canon's very sharp 16-35mm f/2.8L II USM lens at f/8.) While JPEG images may look a bit oversharpened on screen at 100% (as do most in-camera JPEGs), they result in crisp prints. Edge enhancement creates the illusion of sharpness by enhancing colors and tones right at the edge of a rapid transition in color or tone.
Detail. The crop above right shows some detail loss due to noise suppression in darker areas and in areas with low contrast, perhaps just a little more than we're accustomed to seeing from a digital SLR. Still, good performance for a 20-megapixel APS-C model. (The image above right of the hair was taken with our very sharp Sigma 70mm f/2.8 reference lens.) Noise-suppression systems in digital cameras tend to flatten-out detail in areas of subtle contrast. The effects can often be seen in shots of human hair, where the individual strands are lost and an almost "watercolor" look appears.
Raw vs In-Camera JPEGs
As mentioned above, the Canon 70D does an excellent job of capturing sharp, detailed JPEGs when coupled with a sharp lens, but as is usually the case, additional detail can be extracted by carefully processing its RAW files.
In the table above, mousing over a link at the bottom will load the corresponding crop in the area above, and clicking on the link will load the full resolution file. Examples include in-camera Fine JPEG, the matching RAW file processed through Canon's Digital Photo Professional (DPP 3.13.20) software using default settings, and finally, the same RAW file processed through Adobe Camera Raw (ACR 8.1), then sharpened in Photoshop using 250% unsharp masking with an 0.5 pixel radius.
Canon's DPP software produced an image very similar to in-camera JPEG, perhaps with just slightly better detail and local contrast. The image processed through ACR show an improvement in fine detail compared to the DPP conversion (as well as less obvious sharpening halos, lower contrast and more neutral color), but also shows a bit more noise at default settings, which is not unusual. You may want to experiment with ACR's noise reduction settings to find the detail versus noise trade-off you're looking for. Regardless, the Canon 70D is clearly a camera that offers tons of detail in its RAW files.
ISO & Noise Performance
Very good high ISO performance, very similar to the 60D's despite slightly smaller photosites.
Default High ISO Noise Reduction
|ISO 100||ISO 200||ISO 400|
|ISO 800||ISO 1,600||ISO 3,200|
|ISO 6,400||ISO 12,800||ISO 25,600|
The Canon 70D's high ISO performance is pretty good and very similar to the Canon 60D's at the pixel level, though the 70D's increased resolution should help with prints. Images are quite clean at ISOs 100 through 400, with just a tiny amount of luminance noise seen in the shadows, as well as what looks to be chroma noise in the darker strands of hair. Some blurring of fine low-contrast detail is already visible at base ISO, though, as mentioned previously. Noise "grain" is slightly more evident at ISO 800, but detail remains very strong despite some minor blurring due to noise reduction. ISO 1,600 is of course noisier, but fine detail is still very good. At ISO 3,200 noise grain becomes coarser, blurring stronger and chroma noise more apparent, resulting in a more noticeable drop in detail. ISO 6,400 is quite grainy with obvious chroma noise, but there is still some fine detail left. Noise and the effects of noise reduction working hard to keep it under control really become apparent at ISO 12,800 and especially 25,600, with strong blurring and obvious chroma blotching, though we didn't see the same drop in saturation at high ISOs that we saw with the 60D.
See the Print Quality section below for our evaluation of maximum print sizes at each ISO setting.
A note about focus for this shot: We shoot this image at f/4, using one of three very sharp reference lenses (70mm Sigma f/2.8 macro for most cameras, 60mm f/2.8 Nikkor macro for Nikon bodies without a drive motor, and Olympus Zuiko 50mm f/2.0 for Four Thirds and Micro Four Thirds bodies). To insure that the hair detail we use for making critical judgements about camera noise processing and detail rendering is in sharp focus at the relatively wide aperture we're shooting at, the focus target at the center of the scene is on a movable stand. This lets us compensate for front- or back-focus by different camera bodies, even those that lack micro-focus adjustments. This does mean, though, that the focus target itself may appear soft or slightly out of focus for bodies that front- or back-focused with the reference lens. If you click to view the full-size image for one of these shots and notice that the focus target is fuzzy, you don't need to email and tell us about it; we already know it. :-) The focus target position will simply have been adjusted to insure that the rest of the scene is focused properly.
Extremes: Sunlit, dynamic range and low light tests
Very high resolution with strong overall detail, but somewhat high default contrast and unremarkable dynamic range. HTP, ALO and contrast adjustment options do a great job of dealing with tough lighting. Very good low-light performance.
|+0.3 EV||+0.7 EV||+1.0 EV|
The Canon 70D produced moderately high contrast with some washed-out highlights and deep shadows under the deliberately harsh lighting of the test above. The mannequin's face was too dim at the +0.3 EV and +0.7 EV settings, so we preferred the image with +1.0 EV exposure compensation. This resulted in more clipped highlights in the shirt and flowers than we're used to seeing from an APS-C sensor lately, indicating mediocre dynamic range compared to the best of recent competitors. Shadow detail was however pretty good, though very deep shadows are noisy and posterized. Bottom line: while dynamic range isn't bad, the Canon 70D didn't do as well with this difficult shot compared to some recent state-of-the-art peers.
Because digital cameras are more like slide film than negative film (in that they tend to have a more limited tonal range), we test them in the harshest situations to see how they handle scenes with bright highlights and dark shadows, as well as what kind of sensitivity they have in low light. The shot above is designed to mimic the very harsh, contrasty effect of direct noonday sunlight, a very tough challenge for most digital cameras. (You can read details of this test here. In actual shooting conditions, be sure to use fill flash in situations like the one shown here; it's better to shoot in open shade whenever possible.)
We really like it when a camera gives us the ability to adjust contrast and saturation to our liking. It's even better when those adjustments cover a useful range, in steps small enough to allow for precise tweaks. As was the case with its saturation adjustment, the Canon 70D's contrast setting meets both challenges very well.
|Contrast set to lowest,
|Contrast set to lowest,
At its lowest contrast setting, the Canon 70D did a good job of preserving highlight detail, maintaining fairly natural-looking skin tones, and holding nice detail in the shadows. Overall, very good results here when the contrast setting is adjusted.
|Contrast Adjustment Examples|
The Canon 70D's contrast-adjustment control offers a very broad range of control in usefully fine gradations, and does a good job of adjusting contrast without affecting color saturation in the process. (As noted earlier regarding saturation adjustment, something that not all cameras manage to do.)
Highlight Tone Priority
The Canon 70D's Highlight Tone Priority (HTP) option did an excellent job of preserving highlight detail, though shadows were also affected, as shown below. (Mouse over the Off and On links to load the corresponding thumbnail, histogram and crops.)
Highlight Tone Priority (+0.7EV)
to reveal noise.)
Both shots above were captured at the same exposure, the only difference being that HTP was enabled for the second shot which necessarily increases the ISO to 200; part of how HTP works. The result is evident in the histograms and thumbnails above, clearly showing the superior highlight preservation when HTP is enabled, though shadow brightness is also reduced somewhat. If you look closely at shadows (the levels in shadow crops above are heavily boosted to reveal noise that would be difficult to see otherwise), you'll notice an increase in noise is the price you pay when ISO is boosted from 100 to 200. Except in the very deepest shadows, though, overall noise is low enough at ISO 200 that this is really a negligible trade-off for all but the most critical applications.
Automatic Lighting Optimization
Like previous EOS models, the Canon 70D offers three selectable levels of Automatic Lighting Optimization (ALO), plus Off. In fully automatic and Creative Auto exposure modes, ALO is automatically enabled. Mouse over the links below to load the associated thumbnail and histogram, and click on the links to load full resolution images.
As you can see above, ALO has the effect of shifting shadows and mid-tones in the histograms to the right, brightening shadows and indeed most of the image without clipping too many additional highlights. ISO is not boosted for ALO so increased noise is not an issue, though it may be slightly more visible in shadows that have been boosted significantly.
Just like most point & shoot cameras these days, the Canon 70D has the ability to detect faces in Live View mode, and adjust exposure and focus accordingly.
Face Detect: Off
Face Detect: On
As you can see from the examples above, it works well, as the center image with face detection enabled is much better exposed for the face than the left image where face detection was not employed. Full Auto mode (right) was a slight improvement over Aperture Priority without face detection, selecting a larger aperture than we normally use for this shot (f/4 vs f/8), though the mannequin's face is still quite dim.
High Dynamic Range
The Canon 70D's HDR feature takes three continuous shots at different exposures and merges them together to create an image with wider tonal range than would be possible with a single exposure. There are three strength settings available (+/-1EV, +/-2EV,+/-3EV), plus Auto. The source images captured are not saved, and RAW mode is not supported. (Mouse over the links below to load the corresponding thumbnail.)
As you can see, the HDR shots have improved dynamic range with preserved highlights and shadows that have been opened up with lower noise. Do however note that a significant part of the image has been cropped away in the alignment process, and that the resulting images aren't quite as detailed overall, because the cropped image is resampled to full resolution. Also be aware that ghosting can occur when elements of the scene move during the sequence capture, as can be seen with the moving flag and person in some of these shots.
A key parameter in a digital camera is its Dynamic Range, the range of brightness that can be faithfully recorded. At the upper end of the tonal scale, dynamic range is dictated by the point at which the RGB data "saturates" at values of 255, 255, 255. At the lower end of the tonal scale, dynamic range is determined by the point at which there ceases to be any useful difference between adjacent tonal steps. Note the use of the qualifier "useful" in there: While it's tempting to evaluate dynamic range as the maximum number of tonal steps that can be discerned at all, that measure of dynamic range has very little relevance to real-world photography. What we care about as photographers is how much detail we can pull out of the shadows before image noise becomes too objectionable. This, of course, is a very subjective matter, and will vary with the application and even the subject matter in question. (Noise will be much more visible in subjects with large areas of flat tints and subtle shading than it would in subjects with strong, highly contrasting surface texture.)
What makes most sense then, is to specify useful dynamic range in terms of the point at which image noise reaches some agreed-upon threshold. To this end, Imatest computes a number of different dynamic range measurements, based on a variety of image noise thresholds. The noise thresholds are specified in terms of f-stops of equivalent luminance variation in the final image file, and dynamic range is computed for noise thresholds of 1.0 (low image quality), 0.5 (medium image quality), 0.25 (medium-high image quality) and 0.1 (high image quality). For most photographers and most applications, the noise thresholds of 0.5 and 0.25 f-stops are probably the most relevant to the production of acceptable-quality finished images, but many noise-sensitive shooters will insist on the 0.1 f-stop limit for their most critical work.
JPEG. The graph at right (click for a larger version) was generated using Imatest's dynamic range analysis for an in-camera Canon 70D JPEG file with a nominally-exposed density step target (Stouffer 4110). At default camera settings and base ISO, the graph shows 11.9 f-stops of total dynamic range, with 7.61 f-stops at the "High" Quality level. These are decent numbers for a JPEG, though somewhat lower than some recent competitors. Compared to the Canon 60D, the 70D scored essentially the same at the High Quality level (7.61 vs 7.46 f-stops), but significantly higher in total dynamic range (11.9 vs 10.5 f-stops), likely due to improved JPEG processing, though as mentioned above, the total dynamic range number is not terribly useful. Note though that this measurement has a margin of error of about 1/3 f-stop, so differences of less than 0.33 can be ignored.
RAW. The graph at right is from the same Stouffer 4110 stepchart image captured as a RAW (.CR2) file, processed with Adobe Camera Raw using the Auto setting, then manually tweaked from there. The Canon 70D's RAW file scored 1.1 f-stops more in total dynamic range (13 vs 11.9 f-stops) but the score at the highest quality level increased only 0.7 f-stops from 7.61 to 8.31, which isn't much of an improvement over the JPEG and below average these days. Like all recent Canon SLRs, the higher quality scores are somewhat below average for a modern sensor. For example, the Nikon D7100 managed 10.1 f-stops at the highest quality level, almost 2 stops better. As always, it's worth noting here is that ACR's default noise reduction settings reduced overall noise somewhat (see the plot in the lower left-hand corner) relative to the levels in the in-camera JPEG, which would tend to boost the dynamic range numbers for the High Quality threshold, but notice that pixel noise in darker midtones and shadows is actually higher than the JPEG. Also, the extreme highlight recovery being performed by ACR here would likely produce color errors in strong highlights of natural subjects.
Low Light. The Canon 70D performed well in our low-light tests, capturing bright images at the lowest light level (1/16 foot-candle), even with the lowest sensitivity setting (ISO 100). As expected, noise increases as ISO goes up and light levels go down, but luminance noise remains fairly low up to ISO 1,600, and image quality is still quite good up to ISO 6,400. Some chroma noise in the form of subtle color blotching in the shadows and dark areas is visible at low to moderate ISOs at lower light levels, though it's effectively suppressed by default noise reduction at higher ISOs. Noise is quite high at the extreme ISOs of 12,800 and 25,600, particularly when noise reduction is minimized (extreme right column in the table above), though that's to be expected.
We noticed a few hot pixels here and there particularly when long exposure noise reduction was turned off (where they can be expected), but that's not unusual. And we didn't see any significant banding (pattern noise) or heat bloom issues.
Color balance was pretty neutral with Canon 70D's Auto white balance setting (just a touch cool), even at high ISOs, though white balance took on a warm, slightly red or magenta tint at lower light levels.
When using the optical viewfinder and dedicated phase-detect AF, the Canon 70D's autofocus system was able to focus on the subject down to just below the 1/8 foot-candle light level unassisted with our Sigma f/2.8 lens. That's good, though not great for a prosumer model, but the camera was able to focus in complete darkness with AF assist enabled. In Live View mode using Hybrid AF, the Canon 70D was able to focus down to just below the 1/4 foot-candle light level, which is fair for a DSLR in Live View mode with an f/2.8 lens.
As always, keep in mind that the longer shutter speeds here demand the use of a tripod to prevent any blurring from camera movement. (A useful trick is to just prop the camera on a convenient surface, and use its self-timer to release the shutter. This avoids any jiggling from your finger pressing the shutter button, and can work quite well when you don't have a tripod handy.)
How bright is this? The one foot-candle light level that this test begins at roughly corresponds to the brightness of typical city street-lighting at night. Cameras performing well at that level should be able to snap good-looking photos of street-lit scenes.
NOTE: This low light test is conducted with a stationary subject, and the camera mounted on a sturdy tripod. Most digital cameras will fail miserably when faced with a moving subject in dim lighting. (For example, a child's ballet recital or a holiday pageant in a gymnasium.) Digital SLRs like the Canon 70D do much better than point & shoots, but you still shouldn't expect a quick autofocus lock with moving subjects.
Very nice 30 x 40 inch prints at ISO 100; a good 11 x 14 at ISO 3200; and even prints a reasonable 4 x 6 at its highest ISO of 25,600.
ISO 200 prints are excellent at 24 x 36 inches, with sharp detail, and again are suitable for wall display purposes up to 36 x 48 inches.
ISO 400 also looks nice at 24 x 36 inches, with only mild softening in areas of fine detail. Prints here are super-crisp at 20 x 30 inches.
ISO 800 yields a nice 20 x 30 inch print. There is a hint of noise in some shadowy areas of our test target, imparting a subtle "film grain" look, but still a very nice print. The noise is mostly non-apparent at 16 x 20 inches.
ISO 1,600 produces a very good 13 x 19, which is quite a respectable print size for this ISO, retaining nice, accurate colors throughout.
ISO 3,200 holds up well at 11 x 14 inches, which is yet again a nice size for so far up the ISO scale.
ISO 6,400 prints still pop nicely at 8 x 10 inches, with accurate color renditioning and only minor noise apparent in some areas.
ISO 12,800 prints a good 5 x 7 for this ISO, and colors still come through quite well.
ISO 25,600 prints at 4 x 6 just pass our standard for "good", which is no small feat considering that not many APS-C sensor cameras can make that claim.
The Canon 70D more than holds its own in the print quality department, delivering sharp, worthwhile images at sizes comparable to its competition all the way up the ISO scale. It is worth noting here that one of its primary competitors, the Nikon D7100, does print one size larger at base ISO due in large part to higher resolution and the lack of a low pass filter, but the 70D stays in step for most of the remaining ISOs, and even bests the D7100 at ISO 25,600. The D7100 does better at resolving detail in our difficult red fabric swatch, while the 70D does a better job controlling noise in shadowy areas as ISO rises, so a definite trade-off one direction or another. But for the most part these two challengers deliver comparable image quality other than the difference we mentioned at base ISO.
Testing hundreds of digital cameras, we've found that you can only tell just so much about a camera's image quality by viewing its images on-screen. Ultimately, there's no substitute for printing a lot of images and examining them closely. For this reason, we now routinely print sample images from the cameras we test on our Canon Pro9000 Mark II studio printer, and on the Canon Pixma MP610 here in the office. (See the Canon Pixma Pro9000 Mark II review for details on that model.)
The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Canon EOS 70D Photo Gallery .
Not sure which camera to buy? Let your eyes be the ultimate judge! Visit our Comparometer(tm) to compare images from the Canon EOS 70D with those from other cameras you may be considering. The proof is in the pictures, so let your own eyes decide which you like best!
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