Nikon D100 vs Pentax 645Z

The Nikon D100 and the Pentax 645Z are two digital cameras that were officially introduced, respectively, in February 2002 and April 2014. Both are DSLR (Digital Single Lens Reflex) cameras that are based on an APS-C (D100) and a medium format (645Z) sensor. The Nikon has a resolution of 6 megapixels, whereas the Pentax provides 51.1 MP.

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

Headline Specifications

Nikon D100		Pentax 645Z
Digital single lens reflex		Digital single lens reflex
Nikon F mount lenses		Pentax 645 mount lenses
6 MP – APS-C sensor		51.1 MP – Medium Format sensor
no Video		1080/60i Video
ISO 200-800 (200 - 1,600)		ISO 100-204,800
Optical viewfinder		Optical viewfinder
1.8" LCD – 118k dots		3.2" LCD – 1037k dots
Fixed screen (not touch-sensitive)		Tilting screen (no touchscreen)
3 shutter flaps per second		3 shutter flaps per second
not weather sealed		Weathersealed body
370 shots per battery charge		650 shots per battery charge
144 x 116 x 81 mm, 780 g		156 x 117 x 123 mm, 1550 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Nikon D100 and the Pentax 645Z? 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 Nikon D100 and the Pentax 645Z. The two cameras are presented according to their relative size. Three consecutive perspectives from the front, the top, and the back are available. All width, height and depth measures are rounded to the nearest millimeter.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax 645Z is notably larger (9 percent) than the Nikon D100. Moreover, the 645Z is substantially heavier (99 percent) than the D100. It is noteworthy in this context that the 645Z is splash and dust-proof, while the D100 does not feature any corresponding weather-sealing.

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.

Concerning battery life, the D100 gets 370 shots out of its Nikon EN-EL3 battery, while the 645Z can take 650 images on a single charge of its Pentax D-LI90 power pack.

The following table provides a synthesis of the main physical specifications of the two cameras and other similar ones. 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	Street Price
1.		Nikon D100	144 mm	116 mm	81 mm	780 g	370	n	Feb 2002	US$ 1 999	ebay.com
2.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	US$ 8 499	ebay.com
3.		Canon 5DS	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	US$ 3 699	ebay.com
4.		Canon 5DS R	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	US$ 3 699	ebay.com
5.		Canon 10D	150 mm	107 mm	75 mm	850 g	500	n	Feb 2003	US$ 1 999	ebay.com
6.		Hasselblad X1D	150 mm	98 mm	71 mm	725 g	..	Y	Jun 2016	US$ 8 995	ebay.com
7.		Leica SL	147 mm	104 mm	39 mm	847 g	400	Y	Oct 2015	US$ 7 449	ebay.com
8.		Nikon D40	124 mm	94 mm	64 mm	522 g	470	n	Nov 2006	US$ 499	ebay.com
9.		Nikon D70	140 mm	111 mm	78 mm	679 g	400	n	Jan 2004	US$ 999	ebay.com
10.		Nikon D70s	140 mm	111 mm	78 mm	679 g	500	n	Apr 2005	US$ 899	ebay.com
11.		Nikon D80	132 mm	103 mm	77 mm	668 g	600	n	Aug 2006	US$ 999	ebay.com
12.		Nikon D90	132 mm	103 mm	77 mm	703 g	850	n	Aug 2008	US$ 1 299	ebay.com
13.		Nikon D200	147 mm	113 mm	74 mm	920 g	400	Y	Nov 2005	US$ 1 699	ebay.com
14.		Nikon D300	147 mm	114 mm	74 mm	925 g	1000	Y	Aug 2007	US$ 1 799	ebay.com
15.		Nikon D300S	147 mm	115 mm	81 mm	938 g	950	Y	Jul 2009	US$ 1 799	ebay.com
16.		Nikon D500	147 mm	115 mm	81 mm	860 g	1240	Y	Jan 2016	US$ 1 999	ebay.com
17.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	US$ 9 995	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 obviously take relative prices into account. The manufacturer’s suggested retail prices give an idea on the placement of the camera in the maker’s lineup and the broader market. The D100 was launched at a markedly lower price (by 76 percent) than the 645Z, which puts it into a different market segment. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. 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 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. Moreover, a large sensor camera will give the photographer more control over depth-of-field in the image and, thus, the ability to better isolate a subject from the background. On the downside, larger sensors tend to be more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Nikon D100 features an APS-C sensor and the Pentax 645Z a medium format sensor. The sensor area in the 645Z is 288 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 0.79. The sensor in the D100 has a native 3:2 aspect ratio, while the one in the 645Z offers a 4:3 aspect.

With 51.1MP, the 645Z offers a higher resolution than the D100 (6MP), but the 645Z has smaller individual pixels (pixel pitch of 5.30μm versus 7.85μm for the D100). Yet, the 645Z is a much more recent model (by 12 years and 1 month) than the D100, and its sensor will have benefitted from technological advances during this time that enhance the light gathering capacity of its pixel-units. Coming back to sensor resolution, it should be mentioned that the 645Z has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The resolution advantage of the Pentax 645Z implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the 645Z for good quality output (200 dots per inch) amounts to 41.3 x 31 inches or 104.9 x 78.6 cm, for very good quality (250 dpi) 33 x 24.8 inches or 83.9 x 62.9 cm, and for excellent quality (300 dpi) 27.5 x 20.6 inches or 69.9 x 52.4 cm. The corresponding values for the Nikon D100 are 15 x 10 inches or 38.2 x 25.4 cm for good quality, 12 x 8 inches or 30.6 x 20.3 cm for very good quality, and 10 x 6.7 inches or 25.5 x 16.9 cm for excellent quality prints.

The Nikon D100 has a native sensitivity range from ISO 200 to ISO 800, which can be extended to ISO 200-1600. The corresponding ISO settings for the Pentax 645Z are ISO 100 to ISO 204800 (no boost).

In terms of underlying technology, the D100 is build around a CCD sensor, while the 645Z 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 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 table below summarizes the physical sensor characteristics and sensor quality findings and compares them across a set of similar cameras.

Sensor Characteristics

		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Nikon D100	APS-C	6.0	3008	2000	none	20.4	9.9	394	48
2.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101
3.		Canon 5DS	Full Frame	50.3	8688	5792	1080/30p	24.7	12.4	2381	87
4.		Canon 5DS R	Full Frame	50.3	8688	5792	1080/30p	24.6	12.4	2308	86
5.		Canon 10D	APS-C	6.3	3072	2048	none	21.1	10.9	571	57
6.		Hasselblad X1D	Medium Format	51.3	8272	6200	1080/25p	26.2	14.8	4489	102
7.		Leica SL	Full Frame	24.0	6000	4000	4K/30p	25.0	13.4	1821	88
8.		Nikon D40	APS-C	6.0	3008	2000	none	21.0	11.0	561	56
9.		Nikon D70	APS-C	6.0	3008	2000	none	20.4	10.3	529	50
10.		Nikon D70s	APS-C	6.0	3008	2000	none	20.4	10.3	529	50
11.		Nikon D80	APS-C	10.0	3872	2592	none	22.1	11.2	524	61
12.		Nikon D90	APS-C	12.2	4288	2848	720/24p	22.7	12.5	977	73
13.		Nikon D200	APS-C	10.0	3872	2592	none	22.3	11.5	583	64
14.		Nikon D300	APS-C	12.2	4288	2848	none	22.1	12.0	679	67
15.		Nikon D300S	APS-C	12.2	4288	2848	720/24p	22.5	12.2	787	70
16.		Nikon D500	APS-C	20.7	5568	3712	4K/30p	24.0	14.0	1324	83
17.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
Note: DXO values in italics represent estimates based on sensor size and age.

Many modern cameras cannot only take still pictures, but also record videos. The 645Z indeed provides for movie recording, while the D100 does not. The highest resolution format that the 645Z can use is 1080/60i.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The D100 and the 645Z 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 645Z offers a wider field of view (98%) than the one in the D100 (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the 645Z has a higher magnification (0.78x vs 0.53x), 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 Nikon D100 and Pentax 645Z 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.		Nikon D100	optical	Y	1.8 / 118	fixed	n	1/4000s	3.0/s	Y	n
2.		Pentax 645Z	optical	Y	3.2 / 1037	tilting	n	1/4000s	3.0/s	n	n
3.		Canon 5DS	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
4.		Canon 5DS R	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
5.		Canon 10D	optical	Y	1.8 / 118	fixed	n	1/4000s	3.0/s	Y	n
6.		Hasselblad X1D	2360	n	3.0 / 920	fixed	Y	1/2000s	2.3/s	n	n
7.		Leica SL	4400	Y	3.0 / 1040	fixed	Y	1/8000s	11.0/s	n	n
8.		Nikon D40	optical	n	2.5 / 230	fixed	n	1/4000s	2.5/s	Y	n
9.		Nikon D70	optical	n	1.8 / 130	fixed	n	1/8000s	3.0/s	Y	n
10.		Nikon D70s	optical	n	2.0 / 130	fixed	n	1/8000s	3.0/s	Y	n
11.		Nikon D80	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
12.		Nikon D90	optical	Y	3.0 / 920	fixed	n	1/4000s	4.5/s	Y	n
13.		Nikon D200	optical	Y	2.5 / 230	fixed	n	1/8000s	5.0/s	Y	n
14.		Nikon D300	optical	Y	3.0 / 922	fixed	n	1/8000s	6.0/s	Y	n
15.		Nikon D300S	optical	Y	3.0 / 920	fixed	n	1/8000s	7.0/s	Y	n
16.		Nikon D500	optical	Y	3.2 / 2359	tilting	Y	1/8000s	10.0/s	n	n
17.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One difference between the cameras concerns the presence of an on-board flash. The D100 has one, while the 645Z does not. While the built-in flash of the D100 is not very powerful, it can at times be useful as a fill-in light.

The Pentax 645Z has 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.

The D100 writes its imaging data to Compact Flash cards, while the 645Z uses SDXC cards. The 645Z features dual card slots, which can be very useful in case a memory card fails. In contrast, the D100 only has one slot.

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 Nikon D100 and Pentax 645Z 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.		Nikon D100	Y	- / -	-	-	-	1.1	-	-	-
2.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-
3.		Canon 5DS	Y	mono / mono	Y	-	mini	3.0	-	-	-
4.		Canon 5DS R	Y	mono / mono	Y	-	mini	3.0	-	-	-
5.		Canon 10D	Y	- / -	-	-	-	1.1	-	-	-
6.		Hasselblad X1D	Y	stereo / mono	Y	Y	mini	3.0	Y	-	-
7.		Leica SL	Y	stereo / mono	Y	Y	full	3.0	Y	-	-
8.		Nikon D40	Y	- / -	-	-	-	2.0	-	-	-
9.		Nikon D70	Y	- / -	-	-	-	1.0	-	-	-
10.		Nikon D70s	Y	- / -	-	-	-	2.0	-	-	-
11.		Nikon D80	Y	- / -	-	-	-	2.0	-	-	-
12.		Nikon D90	Y	mono / mono	-	-	mini	2.0	-	-	-
13.		Nikon D200	Y	- / -	-	-	-	2.0	-	-	-
14.		Nikon D300	Y	- / -	-	-	mini	2.0	-	-	-
15.		Nikon D300S	Y	stereo / mono	Y	-	mini	2.0	-	-	-
16.		Nikon D500	Y	stereo / mono	Y	Y	mini	3.0	Y	Y	Y
17.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-

Studio photographers will appreciate that the Pentax 645Z (unlike the D100) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the D100 and the 645Z have been discontinued, but can regularly be found used on ebay. The D100 was replaced by the Nikon D200, while the 645Z does not have a direct successor. Further information on the features and operation of the D100 and 645Z can be found, respectively, in the Nikon D100 Manual (free pdf) or the online Pentax 645Z Manual.

Review summary

So how do things add up? Is there a clear favorite between the Nikon D100 and the Pentax 645Z? Which camera is better? A synthesis of the relative strong points of each of the models is listed below.

Reasons to prefer the Nikon D100:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Less heavy: Is lighter (by 770g or 50 percent) and hence easier to carry around.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• More affordable: Was introduced into a lower priced category (76 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in February 2002).

Advantages of the Pentax 645Z:

• More detail: Has more megapixels (51.1 vs 6MP), which boosts linear resolution by 186%.
• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• Better image quality: Is equipped with a larger and more technologically advanced sensor.
• Richer colors: The sensor size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger sensor captures a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger sensor produces good images even in poorly lit environments.
• 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 (98% vs 95%).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.53x).
• Larger screen: Has a bigger rear LCD (3.2" vs 1.8") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (1037k vs 118k dots).
• More flexible LCD: Has a tilting screen for odd-angle shots in landscape orientation.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• Longer lasting: Gets more shots (650 versus 370) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Faster data transfer: Supports a more advanced USB protocol (3.0 vs 1.1).
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• More modern: Reflects 12 years and 1 month of technical progress since the D100 launch.

If the number of relative strengths (bullet points above) is taken as a guide, the 645Z is the clear winner of the contest (19 : 5 points). 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 when reflecting and deciding on a new camera. 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 Nikon D100 and the Pentax 645Z 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 remains incomplete and does no justice, for example, to the way the D100 or the 645Z perform in practice. 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.

Expert reviews

This is where reviews by experts come in. The table below provides a synthesis of the camera assessments of some of the best known photo-gear 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	Street Price
1.		Nikon D100	..	..	..	+ +	o	..	Feb 2002	US$ 1 999	ebay.com
2.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	US$ 8 499	ebay.com
3.		Canon 5DS	..	+	..	83/100	4.5/5	4.5/5	Feb 2015	US$ 3 699	ebay.com
4.		Canon 5DS R	5/5	+	..	83/100	5/5	4.5/5	Feb 2015	US$ 3 699	ebay.com
5.		Canon 10D	..	..	..	+ +	..	..	Feb 2003	US$ 1 999	ebay.com
6.		Hasselblad X1D	..	o	..	81/100	..	4/5	Jun 2016	US$ 8 995	ebay.com
7.		Leica SL	4/5	..	4/5	84/100	4.5/5	4/5	Oct 2015	US$ 7 449	ebay.com
8.		Nikon D40	..	81/100	..	+ +	o	4.5/5	Nov 2006	US$ 499	ebay.com
9.		Nikon D70	..	..	..	+ +	..	..	Jan 2004	US$ 999	ebay.com
10.		Nikon D70s	..	..	..	..	..	5/5	Apr 2005	US$ 899	ebay.com
11.		Nikon D80	..	+	..	+ +	o	4.5/5	Aug 2006	US$ 999	ebay.com
12.		Nikon D90	..	+ +	..	+ +	4/5	4.5/5	Aug 2008	US$ 1 299	ebay.com
13.		Nikon D200	..	+ +	..	+ +	o	..	Nov 2005	US$ 1 699	ebay.com
14.		Nikon D300	..	+ +	..	+ +	5/5	4.5/5	Aug 2007	US$ 1 799	ebay.com
15.		Nikon D300S	5/5	+ +	..	82/100	4/5	4.5/5	Jul 2009	US$ 1 799	ebay.com
16.		Nikon D500	5/5	+ +	4.7/5	91/100	4.5/5	5/5	Jan 2016	US$ 1 999	ebay.com
17.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	US$ 9 995	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

Care should be taken when interpreting the review scores above, though. The assessments were made in relation to similar cameras of the same technological generation. A score, therefore, has to be seen in close connection to the price and market introduction time 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.

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Other camera comparisons

Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just use the search menu below. As an alternative, you can also directly jump to any one of the listed comparisons that were previously generated by the CAM-parator tool.

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