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Digital Cameras - Canon PowerShot A70 Test Images

 

I've begun including links in our reviews to a Thumber-generated index page for the test shots. The Thumber data includes a host of information on the images, including shutter speed, ISO setting, compression setting, etc. Rather than clutter the page below with *all* that detail, we're posting the Thumber index so only those interested in the information need wade through it! (NOTE: Thumber apparently can't interpret the ISO information from the A70's EXIF headers properly, so all the photos show as having been shot at ISO 100. Refer to the information in the main Sample Pictures page (below) for the actual ISO settings used.)

 

Outdoor Portrait:

Excellent job, great resolution, detail, and color, excellent dynamic range.

The extreme tonal range of this image makes it a tough shot for many digicams, which is precisely why I set it up this way, and why I shoot it with no fill flash or reflector to open the shadows. The object is to hold both highlight and shadow detail without producing a "flat" picture with muddy colors, and the A70 performed very well.

The shot at right was taken with no exposure compensation adjustment, unusual among cameras I've tested. (Most require some positive exposure compensation on this shot, due to the relatively high overall brightness.) I chose the Daylight white balance as the most accurate overall, though the Auto setting also produced good results. The Manual setting was slightly warm.

Skin tones look good, but just slightly pinkish, and the blue flowers in the bouquet came out exactly right. (This is a very difficult blue for many digicams to get right, with most showing varying degrees of purple tints, but the A70 rendered them perfectly.) The red flowers are a bit oversaturated, but color throughout the rest of the frame is spot-on.

Resolution is high, with a lot of fine detail visible throughout the frame. Shadow detail is pretty good too, with low noise. Consistent with Canon's general philosophy of not over-sharpening images from their digicams, the images from the A70 tend to look a little softer than those from many competing models. The detail is all there though, coming out in fine shape in response to a little post-exposure sharpening in an imaging program like Adobe's Photoshop(tm).

To view the entire exposure series from zero to +1.0 EV, see files A70OUTDP0.HTM through A70OUTDP3.HTM on the thumbnail index page.


Photo Effect Series: The A70 offers a range of photo effects through its Function menu, which provides useful options for adjusting color saturation. The Sepia and Black and White options are fun creative effects as well.

Photo Effects
Normal
Neutral
(low saturation)
Vivid
(high saturation)
Sepia
Black and White



 

Closer Portrait:

Good resolution and detail.

Overall results are similar to the wider shot above, and the A70's 3x zoom lens helps prevent distortion of Marti's features. Detail is very nice, with a lot of fine detail visible in Marti's face and hair. Details are again slightly soft, but still well defined. The shot at right was taken at the default exposure setting, which produced a nicely balanced exposure with only the strongest highlights blown out. Shadow detail is moderate, with low noise.

To view the entire exposure series from -0.3 to +0.7 EV, see files A70FACDM1.HTM through A70FACDP2.HTM on the thumbnail index page.



 

Indoor Portrait, Flash:
Normal Flash
+0.3 EV
Slow-Sync
+0.7 EV

Good intensity and coverage with the built-in flash, good color as well.

The A70's built-in flash illuminated Marti very well here, requiring only a +0.3 EV exposure compensation adjustment. (Many cameras require as much as a +1.0 EV adjustment for this shot.) The default exposure was reasonably bright as well, with good color. The background incandescent lighting results in an orange cast on the back wall, but has only a minor effect on Marti's features. The Slow-Sync flash mode lets more ambient light into the image, which results in a more even exposure. The longer exposure results in a stronger orange cast as well. The shot at right required a +0.7 EV exposure compensation adjustment to brighten up Marti's features. (Click here for the default exposure.)



 

Indoor Portrait, No Flash:
Auto White Balance
Incandescent White Balance
Manual White Balance

Most accurate color with the Incandescent white balance option, but good results with Manual as well.

This shot is always a very tough test of a camera's white balance capability, given the strong, yellowish color cast of the household incandescent bulbs used for the lighting. The A70's Auto setting had a lot of trouble with the color cast, but its Incandescent and Manual options produced beautiful color, with the Incandescent looking slightly better to my eye. Marti's skin tone is pretty good here, although a little pinkish, and the blue flowers came out a little dark and purplish. (Probably to be expected, considering the light source.) There's also a magenta tint on the back wall, only at the top of the frame. The shots at right have a +0.7 EV exposure compensation adjustment, which delivers a nicely balanced exposure.

 

ISO Series:
Noise is low on the A70 at the ISO 50 sensitivity setting, increasing to a pretty high level at ISO 400. (Everyone's tolerance for image noise is different. Check the image links below to see how you feel about the amounts of noise present, particularly if you anticipate needing to shoot at high ISO frequently. - To my eye, the noise level at ISO 400 is objectionable, to the point that I'd avoid that setting unless I really needed a higher shutter speed. ISO 200 is marginal, ISO 100 is usable.)

ISO Series
ISO 50
ISO 100
ISO 200
ISO 400




 

House Shot:
Auto White Balance
Daylight White Balance
Manual White Balance

Very slight color casts, but good color overall, with nice detail.

The A70's Manual white balance setting produced the best overall color here, with the most accurate white value on the house trim (despite a cool cast). Both the Auto and Daylight white balances resulted in warmer images, with the strongest cast at the Auto setting. Resolution is high, as the tree limbs and shrubbery show a lot of fine detail. As in other shots, details are slightly soft, but with good definition.



 

Far-Field Test

Great resolution and detail, though dynamic range is a bit limited. Good color.

This image is shot at infinity to test far-field lens performance. NOTE that this image cannot be directly compared to the other "house" shot, which is a poster, shot in the studio. The rendering of detail in the poster will be very different than in this shot, and color values (and even the presence or absence of leaves on the trees!) will vary in this subject as the seasons progress. In general though, you can evaluate detail in the bricks, shingles and window detail, and in the tree branches against the sky. Compression artifacts are most likely to show in the trim along the edge of the roof, in the bricks, or in the relatively "flat" areas in the windows.

This is my ultimate "resolution shot," given the infinite range of detail in a natural scene like this, and the A70 does a nice job. The tree limbs over the roof and fine foliage in front of the house show strong detail, especially in the leaf patterns and tree bark. Details are slightly soft, but maintain good clarity from corner to corner. (Although there's some softness and lens flare evident in the lower left-hand corner.) The bright white paint surrounding the bay window is pretty much blown out, a trouble spot for many digicams. Detail is also only moderate in the shadow area above the front door, the combination showing a slightly limited dynamic range. Overall color looks good, although the image is just slightly overexposed overall. The table below shows a standard resolution and quality series, followed by ISO and effects series.

Resolution Series:
Here's a series of shots showing images snapped at each of the A70's resolution settings. Note that all three quality levels are available at all image sizes, but I've chosen to only show the higher compression samples for the largest image size, to save time and space.

 

Wide Angle "Fine"
JPEG
"Normal"
JPEG
"Economy"
JPEG
2,048 x 1,536
A70FAR2048F
A70FAR2048N
A70FAR2048E
1,600 x 1,200
A70FAR1600F
   
1,024 x 768
A70FAR1024F
   
640 x 480
A70FAR0640F
   



ISO Series:

ISO Series
ISO 50
ISO 100
ISO 200
ISO 400


Photo Effect Series:

Photo Effect Series
Normal
Vivid
Neutral
Sepia
Black and White
Low Sharpening



 

Lens Zoom Range

A typical 3x zoom range.

I routinely shoot this series of images to show the field of view for each camera, with the lens at full wide angle, at maximum telephoto (3x, in this case), and at full telephoto with the digital zoom enabled. The A70's lens is equivalent to a 35-105mm zoom on a 35mm camera. That corresponds to a standard wide angle to a moderate telephoto. Following are the results at each zoom setting. (I'm not sure why, but for some reason, the camera significantly overexposed these shots, even though it did a fine job on the main far-field images above.)

Wide Angle
3x Telephoto
Digital Telephoto



 

Musicians Poster
Auto White Balance
Daylight White Balance
Manual White Balance

Good color with the Daylight white balance, good detail as well.

This shot is often a tough test for digicams, as the abundance of blue in the composition frequently tricks white balance systems into producing a warm color balance. The A70's Daylight white balance setting did the best job here, with good skin tones and overall color. The Auto setting was indeed tricked by the preponderance of blue in the subject, responding with a warm cast, while the Manual setting came out a little cool. The blue robe looks nearly right, with only faint purplish tints in the shadow areas. Resolution is high, with great detail in the embroidery of the blue robe. (This original data file for this poster was only 20MB though, so cameras like the A70 are definitely capable of showing more detail than the poster has in it.)



 

Macro Shot
Standard Macro Shot
Macro with Flash

A nice, small macro area, with great detail.

The A70 performed well in the macro category, capturing a minimum area of 2.98 x 2.23 inches (76 x 57 millimeters). Resolution is high, with strong detail in the dollar bill, coins, and brooch. There's more softness in the corners here though, visible in all four corners of the frame. (This is a very typical failing in digicam macro modes, caused by "curvature of field" in the lens system, when operating at macro focusing distances.) The camera's flash had trouble throttling down for the macro area, and overexposed the shot. - Plan on using external illumination for your macro shots with the A70.



 

"Davebox" Test Target
Auto White Balance
Daylight White Balance
Manual White Balance

Good exposure, color, and detail.

The Manual white balance produced the best color here, with the most accurate white value in the mini-resolution target and large, white color block. Color is just slightly cool and magenta, but still good. The Auto and Daylight settings were very nearly accurate, just slightly warm. Exposure looks about right, and the A70 has no trouble distinguishing the subtle tonal variations of the pastel blocks in the Q60 target. Colors are bright and vibrant in the large color blocks, although the additive primary colors (red, green, and blue) are slightly oversaturated. I also noticed a slight halo around the white areas, apparently caused by lens flare. (You can see this most clearly around the outside of the mini-resolution target in the middle right of the box.) The shadow area of the charcoal briquettes shows moderate detail, with moderate noise.



 

Low-Light Tests

Excellent low-light performance, with good color and low noise.

With a maximum shutter time of 15 seconds, and fully adjustable ISO settings, the A70 has great low-light shooting capabilities. Its autofocus-assist illuminator is a great help for focusing in dim shooting conditions as well. The camera produced clear, bright, usable images down to the 1/16 foot-candle (0.67 lux) limit of my test, with good color at all four ISO settings. The camera automatically employs a Noise Reduction system at longer exposure times, which did a great job of controlling image noise. Even at ISO 400, noise is high, but with a tight, fine grain. (Actually, the image noise in the long exposures below is much better than in the indoor portrait shot above, where the exposure time was too short for the special long-exposure noise reduction to kick in.) The table below shows the best exposure we were able to obtain for each of a range of illumination levels. Images in this table (like all of our sample photos) are untouched, exactly as they came from the camera.

 

  1fc
11lux
1/2fc
5.5lux
1/4fc
2.7lux
1/8fc
1.3lux
1/16fc
0.67lx
ISO
50
Click to see A70LL0503.JPG

2.5 secs
F2.8
ISO: 50

Click to see A70LL0504.JPG

6 secs
F2.8
ISO: 50

Click to see A70LL0505.JPG

13 secs
F2.8
ISO: 50

Click to see A70LL0506.JPG

15 secs
F2.8
ISO: 50

Click to see A70LL0507.JPG

15 secs
F2.8
ISO: 50

ISO
100
Click to see A70LL1003.JPG

1.3 secs
F2.8
ISO: 100

Click to see A70LL1004.JPG

3.2 secs
F2.8
ISO: 100

Click to see A70LL1005.JPG

6 secs
F2.8
ISO: 100

Click to see A70LL1006.JPG

13 secs
F2.8
ISO: 100

Click to see A70LL1007.JPG

15 secs
F2.8
ISO: 100

ISO
200
Click to see A70LL2003.JPG

1/ 2 secs
F2.8
ISO: 200

Click to see A70LL2004.JPG

1.6 secs
F2.8
ISO: 200

Click to see A70LL2005.JPG

3.2 secs
F2.8
ISO: 200

Click to see A70LL2006.JPG

5 secs
F2.8
ISO: 200

Click to see A70LL2007.JPG

10 secs
F2.8
ISO: 200

ISO
400
Click to see A70LL4003.JPG

1/ 3 secs
F2.8
ISO: 400

Click to see A70LL4004.JPG

1/ 1 secs
F2.8
ISO: 400

Click to see A70LL4005.JPG

1.6 secs
F2.8
ISO: 400

Click to see A70LL4006.JPG

3.2 secs
F2.8
ISO: 400

Click to see A70LL4007.JPG

5 secs
F2.8
ISO: 400



 

Flash Range Test

Excellent flash range, with only slight falloff at the 14 foot limit of my test, but a little "cheating" on the ISO to get there.

In my testing, the A70's flash illuminated the test target all the way out to 14 feet, without any significant decrease in intensity. But, there's at least a minor catch: The A70 gets such good flash range by boosting its ISO rating, which makes flash pictures shot with it much noisier than normal shots. My utilities can't read the ISO information from the A70's file headers though, so I can't tell just how high the camera boosted it in the flash shots here. Below is the flash range series, with distances from eight to 14 feet from the target.

 

8 ft 9 ft 10 ft 11 ft 12 ft 13 ft 14 ft
Click to see A70FL08.JPG

1/60 secs
F4.8
ISO: ?

Click to see A70FL09.JPG

1/60 secs
F4.8
ISO: ?

Click to see A70FL10.JPG

1/60 secs
F4.8
ISO: ?

Click to see A70FL11.JPG

1/60 secs
F4.8
ISO: ?

Click to see A70FL12.JPG

1/60 secs
F4.8
ISO: ?

Click to see A70FL13.JPG

1/60 secs
F4.8
ISO: ?

Click to see A70FL14.JPG

1/60 secs
F4.8
ISO: ?




 

ISO-12233 (WG-18) Resolution Test

High resolution, ~1,100 lines of "strong detail." (See notes below though.) Average barrel distortion.

The A70 performed quite well on the "laboratory" resolution test chart. It started showing artifacts in the test patterns at resolutions as low as 700 lines per picture height vertically, and around 600 lines horizontally. I found "strong detail" out to nearly 1,200 lines horizontally, although severe artifacts crept in as low as around 950 lines vertically. Picking a single number, I'd call it at around 1,100 lines, but feel compelled to note that it isn't actually that high for vertical detail. "Extinction" of the target patterns didn't occur until about 1,300 lines.

Optical distortion on the A70 is slightly better than average at the wide-angle end, where I measured an approximate 0.7 percent barrel distortion. (This is close to the 0.8% average I've found among cameras I've tested, but I'd really like to see much less geometric distortion in digicam images than that.) The telephoto end fared better, as I measured only two pixels of barrel distortion, corresponding to about 0.1% distortion. Chromatic aberration is very low, showing only about two or three pixels of coloration on either side of the target lines. (This distortion is visible as a very slight colored fringe around the objects at the edges of the field of view on the resolution target.) The most evident shortcoming I noticed in the A70's lens design is higher-than-average flare, particularly in the corners of its images, but present to a lesser extent across the frame as well.

Resolution Series, Wide Angle
Here's a series of shots showing images snapped at each of the A70's resolution settings. Note that all three quality levels are available at all image sizes, but I've chosen to only show the higher compression samples for the largest image size, to save time and space.
Wide Angle "Fine"
JPEG
"Normal"
JPEG
"Economy"
JPEG
2,048 x 1,536
A70RESWLF
A70RESWLN
A70RESWLE
1,600 x 1,200
A70RESWMF
   
1,024 x 768
A70RESWSF
   
640 x 480
A70RESWTF
   

 

Resolution Test, Telephoto
2,048 x 1,536
(Fine, Tele)
A70RESTLF



 

Viewfinder Accuracy/Flash Uniformity

A tight optical viewfinder, and loose LCD monitor.

The A70's optical viewfinder is pretty tight, showing only 81 percent of the frame at wide angle, and 79 percent at telephoto. The CCD in the production model I tested also appeared to be rotated slightly, as images framed with the optical viewfinder were slanted. The LCD monitor actually proved to be just slightly loose, since my standard lines of measurement were just out of frame in the final images. Given that I like LCD monitors to be as close to 100 percent accuracy as possible, the A70's LCD monitor did quite well, but I really wish that its optical finder was more accurate. Flash distribution is a bit uneven at wide angle, with a little falloff at the corners and edges of the frame. At telephoto, flash distribution is more uniform.

 


Wide Angle, Optical

Telephoto, Optical

Wide Angle, LCD

Telephoto, LCD


 

A70 Review
A70 Test Images
A70 Specifications
A70 "Picky Details"
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