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Pentax K-3 versus Nikon D7100

The Pentax K-3 and the Nikon D7100 are two enthusiast cameras that were announced, respectively, in October 2013 and February 2013. Both are DSLR (Digital Single Lens Reflex) cameras that are equipped with an APS-C sensor. The Pentax has a resolution of 24.1 megapixel, whereas the Nikon provides 24 MP.

Body comparison

The side-by-side display below illustrates the physical size and weight of the Pentax K-3 and the Nikon D7100. Three consecutive views from the front, the top, and the rear side are shown. All width, height and depth measures are rounded to the nearest millimeter. You can also use the toggle button to switch to a percentage comparison if you prefer that the measures are being expressed in relative terms (in this case, the camera on the left side – the K-3 – represents the basis for the calculations across all the size and weight measures).

Pentax K-3 vs Nikon D7100 front
K-3 versus D7100 top view
K-3 and D7100 rear side
Body view (K-3 on the left)

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Nikon D7100 is notably larger (11 percent) than the Pentax K-3. However, the D7100 is slightly lighter (4 percent) than the K-3. Cameras intended for semi-professional or professional use tend to be a bit bulkier in order to give them the necessary ruggedness. 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. Hence, you might want to study the specifications of available lenses in order to get the full picture of the size and weight of the two camera systems.

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)
Pentax K-3 (⇒ rgt) 131 mm 100 mm 77 mm 800 g 560 YES 2013 1,299discont. check
Nikon D7100 (⇒ lft) 136 mm 107 mm 76 mm 765 g 950 YES 2013 1,199discont. check
Canon 70D (⇒ lft | rgt) 139 mm 104 mm 79 mm 755 g 920 YES 2013 1,199discont. check
Nikon D7500 (⇒ lft | rgt) 136 mm 104 mm 73 mm 720 g 950 YES 2017 1,299 latest check
Nikon D7200 (⇒ lft | rgt) 136 mm 107 mm 76 mm 765 g 1110 YES 2015 1,199discont. check
Nikon D3300 (⇒ lft | rgt) 124 mm 98 mm 76 mm 430 g 700 no 2014 499discont. check
Nikon D7000 (⇒ lft | rgt) 132 mm 105 mm 77 mm 780 g 1050 YES 2010 1,499discont. check
Olympus E-M1 (⇒ lft | rgt) 130 mm 94 mm 63 mm 497 g 350 YES 2013 1,399discont. check
Olympus E-M5 (⇒ lft | rgt) 122 mm 89 mm 43 mm 425 g .. YES 2012 1,299discont. check
Panasonic GX8 (⇒ lft | rgt) 133 mm 78 mm 63 mm 487 g 330 YES 2015 1,199 latest check
Pentax K-3 II (⇒ lft | rgt) 131 mm 100 mm 77 mm 800 g 720 YES 2015 1,099 latest check
Sony A6500 (⇒ lft | rgt) 120 mm 67 mm 53 mm 453 g 350 YES 2016 1,399 latest check
Sony A7 II (⇒ lft | rgt) 127 mm 96 mm 60 mm 599 g 350 YES 2014 1,999 latest check
Sony A77 II (⇒ lft | rgt) 143 mm 104 mm 81 mm 647 g 480 YES 2014 1,199 latest check
Sony RX10 (⇒ lft | rgt) 129 mm 88 mm 102 mm 813 g 420 YES 2013 1,299discont. check

The listed prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The D7100 was somewhat cheaper (by 8 percent) than the K-3 at launch, but both cameras fall into the same price category. 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 size of the sensor inside a digital camera is one of the key determinants of image quality. A large sensor will generally have larger individual pixels that offer better low-light sensitivity, provide wider dynamic range, and have richer color depth than smaller pixels 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 are more costly to manufacture and tent to lead to bigger and heavier cameras and lenses.

Both cameras under consideration feature an APS-C sensor and have a format factor (sometimes also referred to as "crop factor") of 1.5. Within the spectrum of camera sensors, this places the review cameras among the medium-sized sensor cameras that aim to strike a balance between image quality and portability. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Pentax K-3 and Nikon D7100 sensor measures
Sensor size

While the two cameras under review share the same sensor size, the K-3 offers a higher resolution of 24.1 megapixel, compared with 24 MP of the D7100. This megapixel advantage translates into a 0 percent gain in linear resolution. On the other hand, these sensor specs imply that the K-3 has a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.91μm versus 3.92μm for the D7100). In this context, it should be noted, however, that the K-3 is a somewhat more recent model (by 7 months) than the D7100, and its sensor might have benefitted from technological advances during this time that at least partly compensate for the smaller pixel size. Coming back to sensor resolution, it should be mentioned that neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.

K-3 versus D7100 MP
Sensor resolution

Consistent information on actual sensor performance is available from DXO Mark for most cameras. This service assesses and scores the color depth ("DXO Portrait"), dynamic range ("DXO Landscape"), and low-light sensitivity ("DXO Sports") of camera sensors, and also publishes an overall camera score. The Overall DXO ratings for the two cameras under consideration are close, suggesting that they provide similar image quality. The following table provides an overview of the physical sensor characteristics, as well as the sensor quality measurements for a selection of comparators.

Sensor Characteristics
Camera Sensor
Class
Resolution
(Megapixel)
Horiz.
Pixels
Vert.
Pixels
Video
Format
DXO
Portrait
DXO
Landscape
DXO
Sports
DXO
Overall
Pentax K-3 (⇒ rgt) APS-C 24.1 6016 4000 1080/60i 23.7 13.4 1216 80
Nikon D7100 (⇒ lft) APS-C 24.0 6000 4000 1080/60p 24.2 13.7 1256 83
Canon 70D (⇒ lft | rgt) APS-C 20.0 5472 3648 1080/30p 22.5 11.6 926 68
Nikon D7500 (⇒ lft | rgt) APS-C 20.7 5568 3712 4K/30p 24.8 13.9 1192 86
Nikon D7200 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p 24.5 14.6 1333 87
Nikon D3300 (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p 24.3 12.8 1385 82
Nikon D7000 (⇒ lft | rgt) APS-C 16.1 4928 3264 10800/24p 23.5 13.9 1167 80
Olympus E-M1 (⇒ lft | rgt) Four Thirds 15.9 4608 3456 1080/30p 23.0 12.7 757 73
Olympus E-M5 (⇒ lft | rgt) Four Thirds 15.9 4608 3456 1080/60i 22.8 12.3 826 71
Panasonic GX8 (⇒ lft | rgt) Four Thirds 20.2 5184 3888 4K/30p 23.5 12.6 806 75
Pentax K-3 II (⇒ lft | rgt) APS-C 24.1 6016 4000 1080/60i 23.6 13.6 1106 80
Sony A6500 (⇒ lft | rgt) APS-C 24.0 6000 4000 4K/30p 24.5 13.7 1405 85
Sony A7 II (⇒ lft | rgt) Full Frame 24.0 6000 4000 1080/60p 24.9 13.6 2449 90
Sony A77 II (⇒ lft | rgt) APS-C 24.0 6000 4000 1080/60p - - - -
Sony RX10 (⇒ lft | rgt) 1-inch 20.0 5472 3648 1080/60p 22.9 12.6 474 69

Many modern cameras cannot only take still pictures, but also record videos. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, but the D7100 provides a faster frame rate than the K-3. It can shoot movie footage at 1080/60p, while the Pentax is limited to 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The K-3 and the D7100 are similar in the sense that both have an optical viewfinder. The latter is useful for getting a clear image for framing even in brightly lit environments. The adjacent table lists some of the other core features of the Pentax K-3 and Nikon D7100 along with similar information for a selection of comparators. If you need more detail on the specs, you can find comprehensive listings, 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
Pentax K-3 (⇒ rgt) optical YES 3.2 1037 fixed no 8000 8.3 13 YES
Nikon D7100 (⇒ lft) optical YES 3.2 1229 fixed no 8000 6.0 12 no
Canon 70D (⇒ lft | rgt) optical YES 3.0 1040 swivel YES 8000 7.0 12 no
Nikon D7500 (⇒ lft | rgt) optical YES 3.2 922 tilting YES 8000 8.0 12 no
Nikon D7200 (⇒ lft | rgt) optical YES 3.2 1229 fixed no 8000 6.0 12 no
Nikon D3300 (⇒ lft | rgt) optical no 3.0 921 fixed no 4000 5.0 12 no
Nikon D7000 (⇒ lft | rgt) optical YES 3.0 921 fixed no 8000 6.0 12 no
Olympus E-M1 (⇒ lft | rgt) 2360 no 3.0 1037 tilting YES 8000 10.0 no YES
Olympus E-M5 (⇒ lft | rgt) 1440 no 3.0 610 tilting YES 4000 9.0 no YES
Panasonic GX8 (⇒ lft | rgt) 2360 no 3.0 1040 swivel YES 8000 10.0 no YES
Pentax K-3 II (⇒ lft | rgt) optical YES 3.2 1037 fixed no 8000 8.3 no YES
Sony A6500 (⇒ lft | rgt) 2300 no 3.0 922 tilting YES 4000 11.0 6 YES
Sony A7 II (⇒ lft | rgt) 2400 no 3.0 1230 tilting no 8000 5.0 no YES
Sony A77 II (⇒ lft | rgt) 2359 YES 3.0 1229 full-flex no 8000 12.0 12 YES
Sony RX10 (⇒ lft | rgt) 1440 YES 3.0 1229 tilting no 3200 10.0 10.2 no

Both the K-3 and the D7100 have been discontinued, but can regularly be found used on ebay. The D7100 was replaced by the Nikon D7200, while the K-3 was followed by the Pentax K-3 II.

Summary

So what is the bottom line? Which of the two cameras – the Pentax K-3 or the Nikon D7100 – has the upper hand? The listing below highlights the relative strengths of the two models.


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Advantages of the Pentax K-3:

  • Faster burst: Shoots at higher frequency (8.3 vs 6 flaps/sec) to capture the decisive moment.
  • More compact: Is smaller (131x100mm vs 136x107mm) and thus needs less room in the bag.
  • Sharper images: Has hand-shake reducing image stabilization build-in.
  • More modern: Is somewhat more recent (announced 7 months after the D7100).

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Arguments in favor of the Nikon D7100:

  • Better video: Provides higher movie framerates (1080/60i vs 1080/60p).
  • More detailed LCD: Has a higher resolution rear screen (1229k vs 1037k dots).
  • Longer lasting: Gets more shots (950 versus 560) out of a single battery charge.
  • More heavily discounted: Has been on the market for longer (launched in October 2013).

If the count of individual advantages (bullet points above) is taken as a guide, the match-up finishes in a tie (4 points each). However, the relevance of individual strengths will vary across photographers, so that you might want to apply your own weighing scheme to the summary points.

K-3 04:04 D7100

In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it says nothing about, for example, the handling, responsiveness, and overall imaging quality of the K-3 and the D7100 in practical situations. At times, user reviews, such as those published at amazon, address these issues in a useful manner, but such feedback is on many occasions incomplete, inconsistent, and unreliable. This is why hands-on reviews by experts 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)
Pentax K-3 (⇒ rgt) - 83/100 Gold 5/5 4.5/5 5/5 2013 1,299discont. check
Nikon D7100 (⇒ lft) HiRec 85/100 Gold 4.5/5 5/5 4.5/5 2013 1,199discont. check
Canon 70D (⇒ lft | rgt) HiRec 83/100 Gold 4.5/5 4.5/5 5/5 2013 1,199discont. check
Nikon D7500 (⇒ lft | rgt) HiRec 86/100 Silver 5/5 4.5/5 4.5/5 2017 1,299 latest check
Nikon D7200 (⇒ lft | rgt) HiRec 84/100 Silver 4.5/5 4/5 4.5/5 2015 1,199discont. check
Nikon D3300 (⇒ lft | rgt) Rec 77/100 Silver 4.5/5 4.5/5 4.5/5 2014 499discont. check
Nikon D7000 (⇒ lft | rgt) - 80/100 Silver 4.5/5 5/5 4.5/5 2010 1,499discont. check
Olympus E-M1 (⇒ lft | rgt) HiRec 84/100 Gold 4.5/5 4.5/5 4.5/5 2013 1,399discont. check
Olympus E-M5 (⇒ lft | rgt) HiRec 80/100 Gold 4.5/5 5/5 5/5 2012 1,299discont. check
Panasonic GX8 (⇒ lft | rgt) Rec 82/100 Silver 4.5/5 5/5 4.5/5 2015 1,199 latest check
Pentax K-3 II (⇒ lft | rgt) - - 5/5 4.5/5 5/5 2015 1,099 latest check
Sony A6500 (⇒ lft | rgt) HiRec 85/100 Silver 4.5/5 5/5 4.5/5 2016 1,399 latest check
Sony A7 II (⇒ lft | rgt) Rec 82/100 Silver 4.5/5 5/5 5/5 2014 1,999 latest check
Sony A77 II (⇒ lft | rgt) - 80/100 Silver 4.5/5 4/5 5/5 2014 1,199 latest check
Sony RX10 (⇒ lft | rgt) Rec 80/100 Gold 4.5/5 4.5/5 4.5/5 2013 1,299discont. check

The review scores listed above should be treated with care, though. The assessments were made in relation to similar cameras of the same technological generation. Thus, a score needs to be put into the context of the launch date and the launch price of the camera, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

Other comparisons

In case you would like to check on the differences and similarities of other camera models, just use the search menu 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 cannot find the camera you are interested in, kindly get in touch, and I will try to update the database with the necessary infos.

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