Pentax 645D vs K-1 II

The Pentax 645D and the Pentax K-1 II are two digital cameras that were revealed to the public, respectively, in March 2010 and February 2018. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a medium format (645D) and a full frame (K-1 II) sensor. The 645D has a resolution of 39.5 megapixels, whereas the K-1 II provides 36.2 MP.

Below is an overview of the main specs of the two cameras as a starting point for the comparison.

Headline Specifications

Pentax 645D		Pentax K-1 II
Digital single lens reflex		Digital single lens reflex
Pentax 645 mount lenses		Pentax K mount lenses
39.5 MP – Medium Format sensor		36.2 MP – Full Frame sensor
no Video		1080/60i Video
ISO 100-1,600		ISO 100-819,200
Optical viewfinder		Optical viewfinder
3.0" LCD – 921k dots		3.2" LCD – 1037k dots
Fixed screen (not touch-sensitive)		Fully flexible screen (no touchscreen)
1.1 shutter flaps per second		4.4 shutter flaps per second
Lens stabilization only		In-body stabilization
Weathersealed body		Weathersealed body
800 shots per battery charge		670 shots per battery charge
156 x 117 x 119 mm, 1480 g		137 x 110 x 86 mm, 1010 g

Check 645D offers at
ebay.com
Check K-1 II price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax 645D and the Pentax K-1 II? Which one should you buy? Read on to find out how these two cameras compare with respect to their body size, their imaging sensors, their shooting features, their input-output connections, and their reception by expert reviewers.

Body comparison

The side-by-side display below illustrates the physical size and weight of the Pentax 645D and the Pentax K-1 II. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All size dimensions are rounded to the nearest millimeter.

The K-1 II can be obtained in two different colors (black, silver), while the 645D is only available in black.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax K-1 II is notably smaller (17 percent) than the Pentax 645D. Moreover, the K-1 II is markedly lighter (32 percent) than the 645D. 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 and compare the specifications of available lenses in order to get the full picture of the size and weight of the two camera systems.

The adjacent table lists the principal physical characteristics of the two cameras alongside a wider set of alternatives. If you would like to visualize and compare a different camera combination, you can navigate to the CAM-parator app and make your selection from a broad list of cameras there.

Body Specifications

#		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price (USD)	Street Price
1.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	9,995	ebay.com
2.		Pentax K-1 II	137 mm	110 mm	86 mm	1010 g	670	Y	Feb 2018	1,999	amazon.com
3.		Canon 1D X Mark II	158 mm	168 mm	83 mm	1530 g	1210	Y	Feb 2016	5,999	ebay.com
4.		Canon 1D X	158 mm	168 mm	83 mm	1551 g	1120	Y	Oct 2011	6,799	ebay.com
5.		Canon 1D Mark IV	156 mm	157 mm	80 mm	1230 g	1500	Y	Oct 2009	4,999	ebay.com
6.		Leica S Typ 006	160 mm	120 mm	80 mm	1260 g	..	Y	Sep 2012	21,950	ebay.com
7.		Nikon D850	146 mm	124 mm	79 mm	1005 g	1840	Y	Jul 2017	3,299	amazon.com
8.		Nikon D5	160 mm	159 mm	92 mm	1415 g	3780	Y	Jan 2016	6,499	ebay.com
9.		Nikon D810	146 mm	123 mm	82 mm	980 g	1200	Y	Jun 2014	3,299	ebay.com
10.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	5,199	ebay.com
11.		Panasonic S1R	149 mm	110 mm	97 mm	1016 g	380	Y	Feb 2019	3,699	amazon.com
12.		Pentax K-1	137 mm	110 mm	86 mm	1010 g	760	Y	Feb 2016	1,799	ebay.com
13.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	8,499	ebay.com
14.		Sony A7R III	127 mm	96 mm	74 mm	650 g	650	Y	Oct 2017	3,199	ebay.com
15.		Sony A99 II	143 mm	104 mm	76 mm	849 g	490	Y	Sep 2016	3,199	ebay.com
16.		Sony A7R	127 mm	94 mm	48 mm	465 g	340	Y	Oct 2013	2,299	ebay.com
17.		Sony A850	156 mm	117 mm	82 mm	895 g	880	Y	Aug 2009	1,999	ebay.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
Convert to Imperial

Any camera decision will naturally be influenced heavily by the price. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The K-1 II was launched at a markedly lower price (by 80 percent) than the 645D, 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.

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. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixels in a sensor of the same technological generation. Further, a large sensor camera will give the photographer additional creative options when using shallow depth-of-field to isolate a subject from its background. On the downside, larger sensors are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Pentax 645D features a medium format sensor and the Pentax K-1 II a full frame sensor. The sensor area in the K-1 II is 41 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 0.79 and 1.0. The sensor in the 645D has a native 4:3 aspect ratio, while the one in the K-1 II offers a 3:2 aspect.

Technology-wise, the K-1 II uses a more advanced image processing engine (PRIME IV) than the 645D (PRIME II), with benefits for noise reduction, color accuracy, and processing speed.

With 39.5MP, the 645D offers a slightly higher resolution than the K-1 II (36.2MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 4.88μm for the K-1 II) due to its larger sensor. However, the K-1 II is a much more recent model (by 7 years and 11 months) than the 645D, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixels. 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.

Unlike the 645D, the K-1 II has the capacity to capture high quality composite images by combining multiple shots after shifting its sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).

The Pentax 645D has a native sensitivity range from ISO 100 to ISO 1600. The corresponding ISO settings for the Pentax K-1 II are ISO 100 to ISO 819200 (no boost).

In terms of underlying technology, the 645D is build around a CCD sensor, while the K-1 II uses a CMOS imager. Both cameras use a Bayer filter for capturing RGB colors on a square grid of photosensors. This arrangement is found in most digital cameras.

Consistent information on actual sensor performance is available from DXO Mark for many cameras. 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"). The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.

Sensor Characteristics

#		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
2.		Pentax K-1 II	Full Frame	36.2	7360	4912	1080/60i	25.1	14.0	2698	93
3.		Canon 1D X Mark II	Full Frame	20.0	5472	3648	4K/60p	24.1	13.5	3207	88
4.		Canon 1D X	Full Frame	17.9	5184	3456	1080/30p	23.8	11.8	2786	82
5.		Canon 1D Mark IV	APS-H	16.0	4896	3264	1080/30p	22.8	12.0	1320	74
6.		Leica S Typ 006	Medium Format	37.5	7500	5000	none	23.9	12.2	824	76
7.		Nikon D850	Full Frame	45.4	8256	5504	4K/30p	26.4	14.8	2660	100
8.		Nikon D5	Full Frame	20.7	5588	3712	4K/30p	25.1	12.3	2343	88
9.		Nikon D810	Full Frame	36.2	7360	4912	1080/60p	25.7	14.8	2853	97
10.		Nikon D3S	Full Frame	12.1	4256	2832	720/24p	23.5	12.0	3253	82
11.		Panasonic S1R	Full Frame	46.7	8368	5584	4K/60p	26.4	14.1	3525	100
12.		Pentax K-1	Full Frame	36.2	7360	4912	1080/60i	25.4	14.6	3280	96
13.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101
14.		Sony A7R III	Full Frame	42.2	7952	5304	4K/30p	26.0	14.7	3523	100
15.		Sony A99 II	Full Frame	42.2	7952	5304	4K/30p	25.4	13.4	2317	92
16.		Sony A7R	Full Frame	36.2	7360	4912	1080/60p	25.6	14.1	2746	95
17.		Sony A850	Full Frame	24.4	6048	4032	none	23.8	12.2	1415	79
Note: DXO values in italics represent estimates based on sensor size and age.

Many modern cameras are not only capable of taking still images, but also of capturing video footage. The K-1 II indeed provides for movie recording, while the 645D does not. The highest resolution format that the K-1 II can use is 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. The 645D and the K-1 II 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 viewfinder in the K-1 II offers a wider field of view (100%) than the one in the 645D (98%), so that a larger proportion of the captured image is visible in the finder. On the other hand, the viewfinder of the 645D has a higher magnification (0.78x vs 0.70x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The table below summarizes some of the other core capabilities of the Pentax 645D and Pentax K-1 II in connection with corresponding information for a sample of similar cameras.

Core Features

#		Camera Model	Viewfinder (Type or 000 dots)	Control Panel (yes/no)	LCD Specifications (inch/000 dots)	LCD Attach- ment	Touch Screen (yes/no)	Max Shutter Speed *	Max Shutter Flaps *	Built-in Flash (yes/no)	Built-in Image Stab
1.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
2.		Pentax K-1 II	optical	Y	3.2 / 1037	full-flex	n	1/8000s	4.4/s	n	Y
3.		Canon 1D X Mark II	optical	Y	3.2 / 1620	fixed	Y	1/8000s	16.0/s	n	n
4.		Canon 1D X	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
5.		Canon 1D Mark IV	optical	Y	3.0 / 920	fixed	n	1/8000s	10.0/s	n	n
6.		Leica S Typ 006	optical	Y	3.0 / 922	fixed	n	1/4000s	1.5/s	n	n
7.		Nikon D850	optical	Y	3.2 / 2359	tilting	Y	1/8000s	9.0/s	n	n
8.		Nikon D5	optical	Y	3.2 / 2359	fixed	Y	1/8000s	14.0/s	n	n
9.		Nikon D810	optical	Y	3.2 / 1229	fixed	n	1/8000s	5.0/s	Y	n
10.		Nikon D3S	optical	Y	3.0 / 921	fixed	n	1/8000s	11.0/s	n	n
11.		Panasonic S1R	5760	Y	3.2 / 2100	full-flex	Y	1/8000s	9.0/s	n	Y
12.		Pentax K-1	optical	Y	3.2 / 1037	full-flex	n	1/8000s	4.4/s	n	Y
13.		Pentax 645Z	optical	Y	3.2 / 1037	tilting	n	1/4000s	3.0/s	n	n
14.		Sony A7R III	3686	n	3.0 / 1440	tilting	Y	1/8000s	10.0/s	n	Y
15.		Sony A99 II	2400	Y	3.0 / 1229	full-flex	n	1/8000s	12.0/s	n	Y
16.		Sony A7R	2400	n	3.0 / 1230	tilting	n	1/8000s	4.0/s	n	n
17.		Sony A850	optical	Y	3.0 / 922	fixed	n	1/8000s	3.0/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the K-1 II and the 645D is in-body image stabilization (IBIS). The K-1 II reduces the risk of handshake-induced blur with all attached lenses, while the 645D offers no blur reduction with lenses that themselves do not provide optical image stabilization.

The Pentax 645D and the Pentax K-1 II both have an intervalometer built-in. This enables the photographer to capture time lapse sequences, such as flower blooming, a sunset or moon rise, without purchasing an external camera trigger and related software.

Concerning the storage of imaging data, both the 645D and the K-1 II write their files to SDXC cards. Both cameras feature dual card slots, which can be very useful in case a memory card fails. The K-1 II supports UHS-I cards (Ultra High Speed data transfer of up to 104 MB/s), while the 645D cannot take advantage of Ultra High Speed SD cards.

Connectivity comparison

For some imaging applications, the extent to which a camera can communicate with its environment can be an important aspect in the camera decision process. The table below provides an overview of the connectivity of the Pentax 645D and Pentax K-1 II and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.

Input-Output Connections

#		Camera Model	Hotshoe Port	Internal Mic / Speaker	Microphone Port	Headphone Port	HDMI Port	USB Port	WiFi Support	NFC Support	Bluetooth Support
1.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
2.		Pentax K-1 II	Y	stereo / mono	Y	Y	micro	2.0	Y	-	-
3.		Canon 1D X Mark II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
4.		Canon 1D X	Y	mono / -	Y	-	mini	2.0	-	-	-
5.		Canon 1D Mark IV	Y	stereo / -	Y	-	mini	2.0	-	-	-
6.		Leica S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
7.		Nikon D850	Y	stereo / mono	Y	Y	mini	3.0	Y	Y	Y
8.		Nikon D5	Y	stereo / mono	Y	Y	mini	3.0	-	-	-
9.		Nikon D810	Y	stereo / mono	Y	Y	mini	3.0	Y	-	-
10.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
11.		Panasonic S1R	Y	stereo / mono	Y	Y	full	3.1	Y	-	Y
12.		Pentax K-1	Y	stereo / mono	Y	Y	micro	2.0	Y	-	-
13.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-
14.		Sony A7R III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y
15.		Sony A99 II	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	Y
16.		Sony A7R	Y	stereo / mono	Y	Y	micro	2.0	Y	Y	-
17.		Sony A850	Y	- / -	-	-	mini	2.0	-	-	-

It is notable that the K-1 II offers wifi support, which can be a very convenient means to transfer image data to an off-camera location. In contrast, the 645D does not provide wifi capability.

Both cameras feature a PC Sync terminal to control professional strobe lights, which will be appreciated by studio photographers.

Travel and landscape photographers will find it useful that the K-1 II has an internal geolocalization sensor and can record GPS coordinates in its EXIF data.

The K-1 II is a recent model that features in the current product line-up of Pentax. In contrast, the 645D has been discontinued (but can be found pre-owned on ebay). As a replacement in the same line of cameras, the 645D was succeeded by the Pentax 645Z. Further information on the features and operation of the 645D and K-1 II can be found, respectively, in the Pentax 645D Manual (free pdf) or the online Pentax K-1 II Manual.

Review summary

So what conclusions can be drawn? Which of the two cameras – the Pentax 645D or the Pentax K-1 II – has the upper hand? Is one clearly better than the other? A synthesis of the relative strong points of each of the models is listed below.

Advantages of the Pentax 645D:

• Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.70x).
• Longer lasting: Can take more shots (800 versus 670) on a single battery charge.
• More heavily discounted: Has been available for much longer (launched in March 2010).

Reasons to prefer the Pentax K-1 II:

• High quality composites: Can combine several shots after pixel-shifting its sensor.
• Better jpgs: Has a more modern image processing engine (PRIME IV vs PRIME II).
• Broader imaging potential: Can capture not only stills but also 1080/60i video.
• More complete view: Has a viewfinder with a larger field of view (100% vs 98%).
• 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 (1037k vs 921k dots).
• More flexible LCD: Has a full-flex screen for odd-angle shots in portrait or landscape orientation.
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (4.4 vs 1.1 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (137x110mm vs 156x117mm) and will fit more readily into a bag.
• Less heavy: Has a lower weight (by 470g or 32 percent) and is thus easier to take along.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• Easier geotagging: Features an internal GPS sensor to log localization data.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Faster buffer clearing: Has an SD card interface that supports the UHS-I standard.
• More affordable: Was introduced into a lower priced category (80 percent cheaper at launch).
• More modern: Reflects 7 years and 11 months of technical progress since the 645D launch.

If the number of relative strengths (bullet points above) is taken as a guide, the K-1 II is the clear winner of the contest (17 : 3 points). However, the pertinence of the various camera strengths will differ across photographers, so that you might want to weigh individual camera traits according to their importance for your own imaging needs before making a camera decision. A professional wedding photographer will view the differences between cameras in a way that diverges from the perspective of a travel photog, and a person interested in cityscapes has distinct needs from a macro shooter. Hence, the decision which camera is best and worth buying is often a very personal one.

How about other alternatives? Do the specifications of the Pentax 645D and the Pentax K-1 II place the cameras among the top in their class? Find out in the latest Best DSLR Camera listing whether the two cameras rank among the cream of the crop.

In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it says little about, for example, the shooting experience and imaging performance of the 645D and the K-1 II in practical situations. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate.

Expert reviews

This is where reviews by experts come in. The adjacent summary-table relays the overall verdicts of several of the most popular camera review sites (amateurphotographer [AP], cameralabs [CL], digitalcameraworld [DCW], dpreview [DPR], ephotozine [EPZ], photographyblog [PB]). As can be seen, the professional reviewers agree in many cases on the quality of different cameras, but sometimes their assessments diverge, reinforcing the earlier point that a camera decision is often a very personal choice.

Expert Camera Reviews

#		Camera   Model	AP   score	CL   score	DCW   score	DPR   score	EPZ   score	PB   score	Camera Launch	Launch Price (USD)	Street Price
1.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	9,995	ebay.com
2.		Pentax K-1 II	..	..	4.5/5	79/100	4.5/5	4.5/5	Feb 2018	1,999	amazon.com
3.		Canon 1D X Mark II	..	..	4.5/5	89/100	4.5/5	4.5/5	Feb 2016	5,999	ebay.com
4.		Canon 1D X	5/5	..	..	..	4.5/5	4.5/5	Oct 2011	6,799	ebay.com
5.		Canon 1D Mark IV	5/5	..	..	89/100	..	..	Oct 2009	4,999	ebay.com
6.		Leica S Typ 006	..	..	..	..	..	..	Sep 2012	21,950	ebay.com
7.		Nikon D850	4.5/5	+ +	5/5	89/100	4.5/5	5/5	Jul 2017	3,299	amazon.com
8.		Nikon D5	..	..	4/5	89/100	4.5/5	5/5	Jan 2016	6,499	ebay.com
9.		Nikon D810	5/5	..	5/5	86/100	5/5	4.5/5	Jun 2014	3,299	ebay.com
10.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	5,199	ebay.com
11.		Panasonic S1R	4.5/5	..	4.6/5	89/100	4.5/5	4.5/5	Feb 2019	3,699	amazon.com
12.		Pentax K-1	5/5	..	..	84/100	5/5	5/5	Feb 2016	1,799	ebay.com
13.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	8,499	ebay.com
14.		Sony A7R III	..	+ +	4/5	90/100	4.5/5	5/5	Oct 2017	3,199	ebay.com
15.		Sony A99 II	..	..	4.5/5	85/100	4.5/5	4.5/5	Sep 2016	3,199	ebay.com
16.		Sony A7R	5/5	+ +	..	82/100	4.5/5	5/5	Oct 2013	2,299	ebay.com
17.		Sony A850	3/5	..	..	75/100	..	4.5/5	Aug 2009	1,999	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The ratings are only valid when referring to cameras in the same category and of the same age. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, and comparisons of ratings among very different cameras or across long time periods have little meaning. Also, kindly note that some of the listed sites have over time developped their review approaches and their reporting style.

Check 645D offers at
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Check K-1 II price at
amazon.com

Other camera comparisons

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