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Canon 5D Mark III versus Sony A7S

The Canon EOS 5D Mark III and the Sony Alpha A7S are two professional cameras that were officially introduced, respectively, in March 2012 and April 2014. The 5D Mark III is a DSLR, while the A7S is a mirrorless interchangeable lens camera. Both cameras are equipped with a full frame sensor. The Canon has a resolution of 22.1 megapixel, whereas the Sony provides 12 MP.

Body comparison

An illustration of the physical size and weight of the Canon 5D Mark III and the Sony A7S is provided in the side-by-side display below. Three consecutive perspectives from the front, the top, and the back are presented. All size dimensions are rounded to the nearest millimeter. If you prefer, you can also use the toggle button to switch to a comparison in percentage terms (in this case, the camera on the left side – the 5D Mark III – represents the basis for the calculations across all the size and weight measures).

Canon 5D Mark III vs Sony A7S front
5D Mark III versus A7S top view
5D Mark III and A7S rear side
Body view (5D Mark III on the left)

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7S is notably smaller (32 percent) than the Canon 5D Mark III. Moreover, the A7S is substantially lighter (49 percent) than the 5D Mark III. In this context, it is worth noting that both cameras are splash and dust-proof and can, hence, be used in inclement weather conditions or harsh environments.

The above size and weight comparisons are to some extent incomplete since they do not consider the interchangeable lenses that both of these cameras require. Both cameras have similarly sized sensors, but DSLRs have a larger flange-to-focal plane distance than mirrorless cameras, which imposes contraints on the optical engineering process and generally leads to bigger and heavier lenses. You can find an overview of optics for the two cameras in the Canon EF Lens Catalog (5D Mark III) and the Sony FE Lens Catalog (A7S). Mirrorless cameras, such as the A7S, have moreover the advantage that they can use many lenses from other systems via adapters, as they have a relatively short flange to focal plane distance.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. If you want to switch the focus of the display and review another camera pair, just select a new right or left comparator from among the camera models in the table. Alternatively, you can also move across to the CAM-parator tool and choose from the broad selection of possible comparisons there.

Camera Body Specifications
Camera Camera
Width
Camera
Height
Camera
Depth
Camera
Weight
Battery
Life
(CIPA)
Weather
Sealing
(y/n)
Camera
Launch
(year)
Launch
Price
(USD)
Street
Price
(amazon)
Used
Price
(ebay)
Canon 5D Mark III (⇒ rgt) 152 mm 116 mm 76 mm 950 g 950 YES 2012 3,499discont. check
Sony A7S (⇒ lft) 127 mm 94 mm 48 mm 489 g 380 YES 2014 2,499discont. check
Canon 6D Mark II (⇒ lft | rgt) 144 mm 111 mm 75 mm 765 g 1200 YES 2017 1,999 latest check
Canon 5D Mark IV (⇒ lft | rgt) 151 mm 116 mm 76 mm 890 g 900 YES 2016 3,499 latest check
Canon 1D X Mark II (⇒ lft | rgt) 158 mm 168 mm 83 mm 1530 g 1210 YES 2016 5,999 latest check
Canon 5DS R (⇒ lft | rgt) 152 mm 116 mm 76 mm 930 g 700 YES 2015 3,699 latest check
Canon 5DS (⇒ lft | rgt) 152 mm 116 mm 76 mm 930 g 700 YES 2015 3,699 latest check
Canon 70D (⇒ lft | rgt) 139 mm 104 mm 79 mm 755 g 920 YES 2013 1,199discont. check
Canon 6D (⇒ lft | rgt) 145 mm 111 mm 71 mm 770 g 1090 YES 2012 2,099discont. check
Canon 1D X (⇒ lft | rgt) 158 mm 168 mm 83 mm 1551 g 1120 YES 2011 6,799discont. check
Canon 5D Mark II (⇒ lft | rgt) 152 mm 114 mm 75 mm 850 g 850 YES 2008 3,499discont. check
Canon 5D (⇒ lft | rgt) 152 mm 113 mm 75 mm 895 g 400 YES 2005 3,299discont. check
Nikon D750 (⇒ lft | rgt) 141 mm 113 mm 78 mm 750 g 1230 YES 2014 2,299 latest check
Nikon Df (⇒ lft | rgt) 144 mm 110 mm 67 mm 760 g 1400 YES 2013 2,749 latest check
Sony A7S II (⇒ lft | rgt) 127 mm 96 mm 60 mm 627 g 370 YES 2015 2,999 latest check
Sony A7 (⇒ lft | rgt) 127 mm 94 mm 48 mm 474 g 340 YES 2013 1,699discont. check
Sony A7R (⇒ lft | rgt) 127 mm 94 mm 48 mm 465 g 340 YES 2013 2,299discont. check

The listed prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The A7S was launched at a markedly lower price (by 29 percent) than the 5D Mark III, which puts it into a different market segment. Usually, retail prices stay at first close to the launch price, but after several months, discounts become available. Later in the product cycle and, in particular, when the replacement model is about to appear, further discounting and stock clearance sales often push the camera price considerably down. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.

Sensor comparison

The imaging sensor is at the core of digital cameras and its size is one of the main determining factors of image quality. A large sensor will tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color depth than smaller pixel-units in a sensor of the same technological generation. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to isolate a subject from the background. On the downside, larger sensors tend to be associated with larger, more expensive camera bodies and lenses.

Both cameras under consideration feature a full frame sensor, but their sensors differ slightly in size. The sensor area in the A7S is 1 percent smaller. They nevertheless have the same format factor of 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Canon 5D Mark III and Sony A7S sensor measures
Sensor size

With 22.1MP, the 5D Mark III offers a higher resolution than the A7S (12MP), but the 5D Mark III has smaller individual pixels (pixel pitch of 6.25μm versus 8.45μm for the A7S). Moreover, the A7S is a somewhat more recent model (by 2 years and 1 month) than the 5D Mark III, and its sensor might have benefitted from technological advances during this time that enhance the light gathering capacity of its pixels.

5D Mark III versus A7S MP
Sensor resolution

For most cameras, data on sensor performance has been reported by DXO Mark. This service determines an overall sensor rating, as well as sub-scores for low-light sensitivity ("DXO Sports"), dynamic range ("DXO Landscape"), and color depth ("DXO Portrait"). Of the two cameras under consideration, the A7S has a markedly higher DXO score than the 5D Mark III (overall score 6 points higher), which will translate into better image quality. The advantage is based on 0.1 bits lower color depth, 1.5 EV in additional dynamic range, and 0.7 stops in additional low light sensitivity. The table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar cameras.

Sensor Characteristics
Camera Sensor
Class
Resolution
(Megapixel)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Canon 5D Mark III (⇒ rgt) Full Frame 22.1 5760 3840 1080/30p 24 11.7 2293 81
Sony A7S (⇒ lft) Full Frame 12.0 4240 2832 1080/60p 23.9 13.2 3702 87
Canon 6D Mark II (⇒ lft | rgt) Full Frame 26.0 6240 4160 1080/60p 24.4 11.9 2862 85
Canon 5D Mark IV (⇒ lft | rgt) Full Frame 30.1 6720 4480 4K/30p 24.8 13.6 2995 91
Canon 1D X Mark II (⇒ lft | rgt) Full Frame 20.0 5472 3648 4K/60p 24.1 13.5 3207 88
Canon 5DS R (⇒ lft | rgt) Full Frame 50.3 8688 5792 1080/60p 24.6 12.4 2308 86
Canon 5DS (⇒ lft | rgt) Full Frame 50.3 8688 5792 1080/60p 24.7 12.4 2381 87
Canon 70D (⇒ lft | rgt) APS-C 20.0 5472 3648 1080/30p 22.5 11.6 926 68
Canon 6D (⇒ lft | rgt) Full Frame 20.0 5472 3648 1080/30p 23.8 12.1 2340 82
Canon 1D X (⇒ lft | rgt) Full Frame 17.9 5184 3456 1080/30p 23.8 11.8 2786 82
Canon 5D Mark II (⇒ lft | rgt) Full Frame 21.0 5616 3744 1080/30p 23.7 11.9 1815 79
Canon 5D (⇒ lft | rgt) Full Frame 12.7 4368 2912 no 22.9 11.1 1368 71
Nikon D750 (⇒ lft | rgt) Full Frame 24.2 6016 4016 1080/60p 24.8 14.5 2956 93
Nikon Df (⇒ lft | rgt) Full Frame 16.2 4928 3280 no 24.6 13.1 3279 89
Sony A7S II (⇒ lft | rgt) Full Frame 12.0 4240 2832 4K/30p 23.6 13.3 2993 85
Sony A7 (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 24.8 14.2 2248 90
Sony A7R (⇒ lft | rgt) Full Frame 36.2 7360 4912 1080/60p 25.6 14.1 2746 95

Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration are equipped with sensors that have a sufficiently high read-out speed for moving images, but the A7S provides a faster frame rate than the 5D Mark III. It can shoot movie footage at 1080/60p, while the Canon is limited to 1080/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. For example, the A7S has an electronic viewfinder (2400k dots), while the 5D Mark III has an optical one. Both systems have their advantages, with the electronic viewfinder making it possible to project supplementary shooting information into the framing view, whereas the optical viewfinder offers lag-free viewing and a very clear framing image. The adjacent table lists some of the other core features of the Canon 5D Mark III and Sony A7S along with similar information for a selection of comparators. The full specs-sheets can be found in the camera manual or, for example, in the dpreview camera hub.

Core Features
Camera Viewfinder
(Type or
'000 dots)
Control
Panel
(Y/n)
LCD
Size
(inch)
LCD
Resolution
('000 dots)
LCD
Attach-
ment
Touch
Screen
(Y/n)
Shutter
speed
(1/sec)
Shutter
flaps
(1/sec))
Build-in
Flash
(GN)
Build-in
Image
Stab
Canon 5D Mark III (⇒ rgt) optical YES 3.2 1040 fixed no 8000 6.0 no no
Sony A7S (⇒ lft) 2400 no 3.0 921 tilting no 8000 5.0 no no
Canon 6D Mark II (⇒ lft | rgt) optical YES 3.0 1040 swivel YES 4000 6.5 no no
Canon 5D Mark IV (⇒ lft | rgt) optical YES 3.2 1620 fixed YES 8000 7.0 no no
Canon 1D X Mark II (⇒ lft | rgt) optical YES 3.2 1620 fixed YES 8000 16.0 no no
Canon 5DS R (⇒ lft | rgt) optical YES 3.2 1040 fixed no 8000 5.0 no no
Canon 5DS (⇒ lft | rgt) optical YES 3.2 1040 fixed no 8000 5.0 no no
Canon 70D (⇒ lft | rgt) optical YES 3.0 1040 swivel YES 8000 7.0 12 no
Canon 6D (⇒ lft | rgt) optical YES 3.0 1040 fixed no 4000 4.5 no no
Canon 1D X (⇒ lft | rgt) optical YES 3.2 1040 fixed no 8000 14.0 no no
Canon 5D Mark II (⇒ lft | rgt) optical YES 3.0 920 fixed no 8000 3.9 no no
Canon 5D (⇒ lft | rgt) optical YES 2.5 230 fixed no 8000 3.0 no no
Nikon D750 (⇒ lft | rgt) optical YES 3.2 1229 tilting no 4000 6.0 12 no
Nikon Df (⇒ lft | rgt) optical YES 3.2 921 fixed no 4000 5.5 no no
Sony A7S II (⇒ lft | rgt) 2400 no 3.0 1229 tilting no 8000 5.0 no YES
Sony A7 (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 5.0 no no
Sony A7R (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 4.0 no no

Both the 5D Mark III and the A7S have been discontinued, but can regularly be found used on ebay. The 5D Mark III was replaced by the Canon 5D Mark IV, while the A7S was followed by the Sony A7S II.

Summary

So what is the bottom line? Is the Canon 5D Mark III better than the Sony A7S or vice versa? Below is a summary of the relative strengths of each of the two contestants.


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Arguments in favor of the Canon EOS 5D Mark III:

  • More detail: Offers more megapixels (22.1 vs 12MP) with a 36% higher linear resolution.
  • Brighter framing: Features an optical viewfinder for clear, lag-free composition.
  • Easier setting verification: Has an LCD display on top to control shooting parameters.
  • Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
  • More detailed LCD: Has a higher resolution rear screen (1040k vs 921k dots).
  • Faster burst: Shoots at higher frequency (6 vs 5 flaps/sec) to capture the decisive moment.
  • Longer lasting: Can take more shots (950 versus 380) on a single battery charge.
  • More heavily discounted: Has been available for much longer (launched in March 2012).

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Advantages of the Sony Alpha A7S:

  • Better image quality: Scores markedly higher (6 points) in the DXO overall evaluation.
  • More dynamic range: Captures a broader range of light and dark details (1.5 EV of extra DR).
  • Better low-light sensitivity: Can shoot in dim conditions (0.7 stops ISO advantage).
  • Better video: Provides higher movie framerates (1080/60p vs 1080/30p).
  • More framing info: Has an electronic viewfinder that displays shooting data.
  • More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
  • More compact: Is smaller (127x94mm vs 152x116mm) and will fit more readily into a bag.
  • Less heavy: Has a lower weight (by 461g or 49 percent) and is thus easier to take along.
  • More legacy lens friendly: Can use many non-native lenses via adapters.
  • More affordable: Was introduced into a lower priced category (29 percent cheaper at launch).
  • More modern: Reflects 2 years and 1 month of technical progress since the 5D Mark III launch.

If the number of relative strengths (bullet points above) is taken as a guide, the A7S emerges as the winner of the match-up (11 : 8 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features.

5D Mark III 08:11 A7S

In any case, while the specs-based evaluation of cameras is instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the 5D Mark III or the A7S handle or perform in practice. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased. This is why expert reviews are important. The table below summarizes the assessments of some of the best known camera review sites. You can find the full text of the reviews, respectively, at cameralabs.com, dpreview.com, ephotozine.com, imaging-resource.com, and photographyblog.com.

Review scores
Camera camera
labs
dp
review
ephoto
zine
imaging
resource
photography
blog
Camera
Launch
(year)
Launch
Price
(USD)
Street
Price
(amazon)
Used
Price
(ebay)
Canon 5D Mark III (⇒ rgt) HiRec 82/100 Gold 4.5/5 5/5 4.5/5 2012 3,499discont. check
Sony A7S (⇒ lft) - 86/100 Gold 4.5/5 4.5/5 5/5 2014 2,499discont. check
Canon 6D Mark II (⇒ lft | rgt) Rec 80/100 4.5/5 4/5 4/5 2017 1,999 latest check
Canon 5D Mark IV (⇒ lft | rgt) HiRec 87/100 Gold 4.5/5 5/5 4.5/5 2016 3,499 latest check
Canon 1D X Mark II (⇒ lft | rgt) - 89/100 Gold 4.5/5 5/5 4.5/5 2016 5,999 latest check
Canon 5DS R (⇒ lft | rgt) Rec 83/100 Silver 5/5 5/5 4.5/5 2015 3,699 latest check
Canon 5DS (⇒ lft | rgt) Rec 83/100 Silver 4.5/5 5/5 4.5/5 2015 3,699 latest check
Canon 70D (⇒ lft | rgt) HiRec 83/100 Gold 4.5/5 4.5/5 5/5 2013 1,199discont. check
Canon 6D (⇒ lft | rgt) HiRec 83/100 Silver 4.5/5 4.5/5 4.5/5 2012 2,099discont. check
Canon 1D X (⇒ lft | rgt) - - 4.5/5 4.5/5 4.5/5 2011 6,799discont. check
Canon 5D Mark II (⇒ lft | rgt) 91/100 79/100 HiRec 4/5 5/5 - 2008 3,499discont. check
Canon 5D (⇒ lft | rgt) 88/100 HiRec reviewed reviewed - 2005 3,299discont. check
Nikon D750 (⇒ lft | rgt) HiRec 90/100 Gold 4.5/5 5/5 4.5/5 2014 2,299 latest check
Nikon Df (⇒ lft | rgt) - 81/100 4/5 4/5 4/5 2013 2,749 latest check
Sony A7S II (⇒ lft | rgt) Rec - 4.5/5 5/5 5/5 2015 2,999 latest check
Sony A7 (⇒ lft | rgt) HiRec 80/100 Silver 5/5 4.5/5 5/5 2013 1,699discont. check
Sony A7R (⇒ lft | rgt) HiRec 82/100 Gold 4.5/5 5/5 5/5 2013 2,299discont. check

The review scores listed above should be treated with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, and comparing ratings of very distinct cameras or ones that are far apart in terms of their release date have little meaning. Also, please note that some of the review sites have changed their methodology and reporting over time.

Other comparisons

If you would like to see a different side-by-side camera review, just make a corresponding selection in the search boxes below. An an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool. If you do not see the camera that you are looking for, please send me an email, and I will try to locate and add the respective data to the application.

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