Canon SX420 vs Pentax 645D

The Canon PowerShot SX420 IS and the Pentax 645D are two digital cameras that were officially introduced, respectively, in January 2016 and March 2010. The SX420 is a fixed lens compact, while the 645D is a DSLR. The cameras are based on a 1/2.3-inch (SX420) and a medium format (645D) sensor. The Canon has a resolution of 19.9 megapixels, whereas the Pentax provides 39.5 MP.

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

Headline Specifications

Canon SX420		Pentax 645D
Fixed lens compact camera		Digital single lens reflex
24-1008mm f/3.5-6.6		Pentax 645 mount lenses
19.9 MP – 1/2.3" sensor		39.5 MP – Medium Format sensor
720/25p Video		no Video
ISO 100-1,600		ISO 100-1,600
No viewfinder, LCD framing		Optical viewfinder
3.0" LCD – 230k dots		3.0" LCD – 921k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
0.5 shutter flaps per second		1.1 shutter flaps per second
not weather sealed		Weathersealed body
195 shots per battery charge		800 shots per battery charge
104 x 69 x 85 mm, 325 g		156 x 117 x 119 mm, 1480 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon PowerShot SX420 IS and the Pentax 645D? 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 Canon SX420 and the Pentax 645D. The two cameras are presented according to their relative size. 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.

The SX420 can be obtained in two different colors (black, red), 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 645D is considerably larger (154 percent) than the Canon SX420. It is noteworthy in this context that the 645D is splash and dust-proof, while the SX420 does not feature any corresponding weather-sealing.

The above size and weight comparisons are to some extent incomplete and possibly misleading, as the SX420 has a lens built in, whereas the 645D is an interchangeable lens camera that requires a separate lens. Attaching the latter will add extra weight and bulk to the setup.

Concerning battery life, the SX420 gets 195 shots out of its Canon NB-11LH battery, while the 645D can take 800 images on a single charge of its Pentax D-LI90 power pack.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. In case you want to display and compare another camera duo, you can use the CAM-parator app to select your camera combination among a large number of options.

Body Specifications

		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price	Street Price
1.		Canon SX420	104 mm	69 mm	85 mm	325 g	195	n	Jan 2016	US$ 299	ebay.com
2.		Pentax 645D	156 mm	117 mm	119 mm	1480 g	800	Y	Mar 2010	US$ 9 995	ebay.com
3.		Canon 1D Mark IV	156 mm	157 mm	80 mm	1230 g	1500	Y	Oct 2009	US$ 4 999	ebay.com
4.		Canon 1D X	158 mm	168 mm	83 mm	1551 g	1120	Y	Oct 2011	US$ 6 799	ebay.com
5.		Canon G5 X	112 mm	76 mm	44 mm	353 g	210	n	Oct 2015	US$ 799	ebay.com
6.		Canon G7 X Mark II	106 mm	61 mm	42 mm	319 g	265	n	Feb 2016	US$ 699	ebay.com
7.		Canon SX410	104 mm	69 mm	85 mm	325 g	185	n	Feb 2015	US$ 279	ebay.com
8.		Canon SX430	104 mm	69 mm	85 mm	323 g	195	n	Jan 2017	US$ 299	ebay.com
9.		Canon SX610	105 mm	61 mm	27 mm	191 g	270	n	Jan 2015	US$ 249	ebay.com
10.		Canon SX620	97 mm	57 mm	28 mm	182 g	295	n	May 2016	US$ 279	ebay.com
11.		Canon SX710	113 mm	66 mm	35 mm	269 g	230	n	Jan 2015	US$ 349	ebay.com
12.		Canon SX720	110 mm	64 mm	36 mm	270 g	250	n	Feb 2016	US$ 379	ebay.com
13.		Canon SX730	110 mm	64 mm	40 mm	300 g	250	n	Apr 2017	US$ 399	ebay.com
14.		Leica S Typ 006	160 mm	120 mm	80 mm	1260 g	..	Y	Sep 2012	US$ 21 949	ebay.com
15.		Nikon D3S	160 mm	157 mm	88 mm	1240 g	4200	Y	Oct 2009	US$ 5 199	ebay.com
16.		Panasonic ZS70	112 mm	67 mm	41 mm	322 g	380	n	Apr 2017	US$ 449	ebay.com
17.		Pentax 645Z	156 mm	117 mm	123 mm	1550 g	650	Y	Apr 2014	US$ 8 499	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 listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The SX420 was launched at a lower price than the 645D, despite having a lens built in. 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.

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 more expensive and lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Canon SX420 features a 1/2.3-inch sensor and the Pentax 645D a medium format sensor. The sensor area in the 645D is 5086 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 5.6 and 0.79. Both cameras feature a native aspect ratio (sensor width to sensor height) of 4:3.

With 39.5MP, the 645D offers a higher resolution than the SX420 (19.9MP), but the 645D nevertheless has larger individual pixels (pixel pitch of 6.06μm versus 1.19μm for the SX420) due to its larger sensor. However, the SX420 is a much more recent model (by 5 years and 9 months) than the 645D, 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 neither of the two cameras has an anti-alias filter installed, so they are able to capture all the detail the sensor resolves.

The resolution advantage of the Pentax 645D implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the 645D for good quality output (200 dots per inch) amounts to 36.3 x 27.2 inches or 92.3 x 69.1 cm, for very good quality (250 dpi) 29.1 x 21.8 inches or 73.8 x 55.3 cm, and for excellent quality (300 dpi) 24.2 x 18.1 inches or 61.5 x 46.1 cm. The corresponding values for the Canon SX420 are 25.8 x 19.3 inches or 65.4 x 49.1 cm for good quality, 20.6 x 15.5 inches or 52.3 x 39.3 cm for very good quality, and 17.2 x 12.9 inches or 43.6 x 32.7 cm for excellent quality prints.

The Canon PowerShot SX420 IS has a native sensitivity range from ISO 100 to ISO 1600. The Pentax 645D offers exactly the same ISO settings.

Technology-wise, both cameras are equipped with CCD (Charged Coupled Device) sensors. 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 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.		Canon SX420	1/2.3	19.9	5152	3864	720/25p	20.3	11.7	806	48
2.		Pentax 645D	Medium Format	39.5	7264	5440	none	24.6	12.6	1262	82
3.		Canon 1D Mark IV	APS-H	16.0	4896	3264	1080/30p	22.8	12.0	1320	74
4.		Canon 1D X	Full Frame	17.9	5184	3456	1080/30p	23.8	11.8	2786	82
5.		Canon G5 X	1-inch	20.0	5472	3648	1080/60p	21.4	12.3	471	62
6.		Canon G7 X Mark II	1-inch	20.0	5472	3648	1080/60p	21.8	11.9	260	62
7.		Canon SX410	1/2.3	19.9	5152	3864	720/30p	20.2	11.6	720	47
8.		Canon SX430	1/2.3	19.9	5152	3864	720/25p	20.5	11.9	900	49
9.		Canon SX610	1/2.3	20.2	5184	3888	1080/30p	20.2	11.6	712	47
10.		Canon SX620	1/2.3	20.2	5184	3888	1080/30p	20.4	11.8	838	49
11.		Canon SX710	1/2.3	20.2	5184	3888	1080/60p	20.2	11.6	712	47
12.		Canon SX720	1/2.3	20.2	5184	3888	1080/60p	20.3	11.8	817	48
13.		Canon SX730	1/2.3	20.2	5184	3888	1080/60p	20.5	11.9	924	50
14.		Leica S Typ 006	Medium Format	37.5	7500	5000	none	23.9	12.2	824	76
15.		Nikon D3S	Full Frame	12.1	4256	2832	720/24p	23.5	12.0	3253	82
16.		Panasonic ZS70	1/2.3	20.2	5184	3888	4K/30p	19.1	10.6	106	36
17.		Pentax 645Z	Medium Format	51.1	8256	6192	1080/60i	26.0	14.7	4505	101
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 SX420 indeed provides movie recording capabilities, while the 645D does not. The highest resolution format that the SX420 can use is 720/25p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. For example, the 645D has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the SX420 relies on live view and the rear LCD for framing. The following table reports on some other key feature differences and similarities of the Canon SX420, the Pentax 645D, and comparable 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.		Canon SX420	none	n	3.0 / 230	fixed	n	1/4000s	0.5/s	Y	Y
2.		Pentax 645D	optical	Y	3.0 / 921	fixed	n	1/4000s	1.1/s	n	n
3.		Canon 1D Mark IV	optical	Y	3.0 / 920	fixed	n	1/8000s	10.0/s	n	n
4.		Canon 1D X	optical	Y	3.2 / 1040	fixed	n	1/8000s	14.0/s	n	n
5.		Canon G5 X	2360	n	3.0 / 1040	swivel	Y	1/2000s	5.9/s	Y	Y
6.		Canon G7 X Mark II	none	n	3.0 / 1040	tilting	Y	1/2000s	8.0/s	Y	Y
7.		Canon SX410	none	n	3.0 / 230	fixed	n	1/4000s	0.5/s	Y	Y
8.		Canon SX430	none	n	3.0 / 230	fixed	n	1/4000s	0.5/s	Y	Y
9.		Canon SX610	none	n	3.0 / 922	fixed	n	1/2000s	2.5/s	Y	Y
10.		Canon SX620	none	n	3.0 / 922	fixed	n	1/2000s	2.5/s	Y	Y
11.		Canon SX710	none	n	3.0 / 922	fixed	n	1/3200s	6.0/s	Y	Y
12.		Canon SX720	none	n	3.0 / 922	fixed	n	1/3200s	5.9/s	Y	Y
13.		Canon SX730	none	n	3.0 / 922	tilting	n	1/3200s	5.9/s	Y	Y
14.		Leica S Typ 006	optical	Y	3.0 / 922	fixed	n	1/4000s	1.5/s	n	n
15.		Nikon D3S	optical	Y	3.0 / 921	fixed	n	1/8000s	11.0/s	n	n
16.		Panasonic ZS70	1166	n	3.0 / 1040	tilting	Y	1/2000s	10.0/s	Y	Y
17.		Pentax 645Z	optical	Y	3.2 / 1037	tilting	n	1/4000s	3.0/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 SX420 has one, while the 645D does not. While the built-in flash of the SX420 is not very powerful, it can at times be useful as a fill-in light.

The Pentax 645D 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.

Concerning the storage of imaging data, both the SX420 and the 645D write their files to SDXC cards. The 645D features dual card slots, which can be very useful in case a memory card fails. In contrast, the SX420 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 Canon PowerShot SX420 IS and Pentax 645D 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.		Canon SX420	-	mono / mono	-	-	-	2.0	Y	Y	-
2.		Pentax 645D	Y	stereo / -	-	-	-	2.0	-	-	-
3.		Canon 1D Mark IV	Y	stereo / -	Y	-	mini	2.0	-	-	-
4.		Canon 1D X	Y	mono / -	Y	-	mini	2.0	-	-	-
5.		Canon G5 X	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
6.		Canon G7 X Mark II	-	stereo / mono	-	-	micro	2.0	Y	Y	-
7.		Canon SX410	-	stereo / mono	-	-	-	2.0	-	-	-
8.		Canon SX430	-	mono / mono	-	-	-	2.0	Y	Y	-
9.		Canon SX610	-	- / -	-	-	micro	2.0	Y	Y	-
10.		Canon SX620	-	mono / mono	-	-	micro	2.0	Y	Y	-
11.		Canon SX710	-	stereo / mono	-	-	micro	2.0	Y	Y	-
12.		Canon SX720	-	stereo / mono	-	-	micro	2.0	Y	Y	-
13.		Canon SX730	-	stereo / mono	-	-	micro	2.0	Y	Y	Y
14.		Leica S Typ 006	Y	- / -	-	-	mini	2.0	-	-	-
15.		Nikon D3S	Y	stereo / -	-	-	mini	2.0	-	-	-
16.		Panasonic ZS70	-	stereo / mono	-	-	micro	2.0	Y	-	-
17.		Pentax 645Z	Y	stereo / mono	Y	-	mini	3.0	-	-	-

It is notable that the SX420 offers wifi support, while the 645D does not. Wifi can be a very convenient means to transfer image data to an off-camera location.

Studio photographers will appreciate that the Pentax 645D (unlike the SX420) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the SX420 and the 645D have been discontinued, but can regularly be found used on ebay. The 645D was replaced by the Pentax 645Z, while the SX420 was followed by the Canon SX430. Further information on the features and operation of the SX420 and 645D can be found, respectively, in the Canon SX420 Manual (free pdf) or the online Pentax 645D Manual.

Review summary

So how do things add up? Which of the two cameras – the Canon SX420 or the Pentax 645D – has the upper hand? Is one clearly better than the other? The listing below highlights the relative strengths of the two models.

Reasons to prefer the Canon PowerShot SX420 IS:

• Broader imaging potential: Can record not only still images but also 720/25p movies.
• Ready to shoot: Comes with a built-in lens, while the 645D requires a separate lens.
• More compact: Is smaller (104x69mm vs 156x117mm) and thus needs less room in the bag.
• Less heavy: Is lighter even though it comes with a built-in lens (unlike the 645D).
• Sharper images: Has hand-shake reducing image stabilization built-in.
• Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
• Easier file upload: Has wifi built in for automatic backup or image transfer to the web.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More affordable: Was introduced at a lower price, despite coming with a built-in lens.
• More modern: Reflects 5 years and 9 months of technical progress since the 645D launch.

Arguments in favor of the Pentax 645D:

• More detail: Has more megapixels (39.5 vs 19.9MP), which boosts linear resolution by 41%.
• Better image quality: Features bigger pixels on a larger sensor for higher quality imaging.
• Richer colors: The pixel size advantage translates into images with better, more accurate colors.
• More dynamic range: Larger pixels capture a wider spectrum of light and dark details.
• Better low-light sensitivity: Larger pixels means good image quality even under poor lighting.
• Easier framing: Has an optical viewfinder for image composition and settings control.
• Easier setting verification: Features a control panel on top to check shooting parameters.
• More detailed LCD: Has a higher resolution rear screen (921k vs 230k dots).
• Faster burst: Shoots at higher frequency (1.1 vs 0.5 flaps/sec) to capture the decisive moment.
• Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
• More flexible: Makes it possible to change lenses and thus to use specialty optics.
• Longer lasting: Gets more shots (800 versus 195) out of a single battery charge.
• Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
• Better lighting: Features a hotshoe and can thus hold and trigger an external flash gun.
• 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 heavily discounted: Has been around for much longer (launched in March 2010).

If the count of individual advantages (bullet points above) is taken as a guide, the 645D is the clear winner of the contest (17 : 10 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 wildlife photographer will view the differences between cameras in a way that diverges from the perspective of a family photog, and a person interested in architecture has distinct needs from a sports 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 Canon SX420 and the Pentax 645D place the cameras among the top in their class? Find out in the latest Best Superzoom Camera and Best DSLR Camera listings whether the two cameras rank among the cream of the crop.

In any case, while the comparison of technical specifications can provide a useful overview of the capabilities of different cameras, it says little about, for example, the shooting experience and imaging performance of the SX420 and the 645D in practical situations. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased.

Expert reviews

This is where reviews by experts come in. The following table reports the overall ratings of the cameras as published by some of the major 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	Street Price
1.		Canon SX420	..	..	..	..	..	3/5	Jan 2016	US$ 299	ebay.com
2.		Pentax 645D	5/5	..	..	..	..	..	Mar 2010	US$ 9 995	ebay.com
3.		Canon 1D Mark IV	5/5	..	..	89/100	..	..	Oct 2009	US$ 4 999	ebay.com
4.		Canon 1D X	5/5	..	..	..	4.5/5	4.5/5	Oct 2011	US$ 6 799	ebay.com
5.		Canon G5 X	5/5	+ +	..	78/100	4.5/5	4.5/5	Oct 2015	US$ 799	ebay.com
6.		Canon G7 X Mark II	4.5/5	+ +	..	81/100	4.5/5	4.5/5	Feb 2016	US$ 699	ebay.com
7.		Canon SX410	..	o	..	..	..	..	Feb 2015	US$ 279	ebay.com
8.		Canon SX430	..	..	..	..	3.5/5	3.5/5	Jan 2017	US$ 299	ebay.com
9.		Canon SX610	..	..	..	..	4/5	4/5	Jan 2015	US$ 249	ebay.com
10.		Canon SX620	..	..	..	..	..	4/5	May 2016	US$ 279	ebay.com
11.		Canon SX710	..	+	..	..	4/5	3.5/5	Jan 2015	US$ 349	ebay.com
12.		Canon SX720	..	+	..	..	4/5	4.5/5	Feb 2016	US$ 379	ebay.com
13.		Canon SX730	..	+	..	..	4/5	4/5	Apr 2017	US$ 399	ebay.com
14.		Leica S Typ 006	..	..	..	..	..	..	Sep 2012	US$ 21 949	ebay.com
15.		Nikon D3S	5/5	..	..	89/100	4.5/5	5/5	Oct 2009	US$ 5 199	ebay.com
16.		Panasonic ZS70	..	+ +	..	..	4/5	4/5	Apr 2017	US$ 449	ebay.com
17.		Pentax 645Z	5/5	..	3.5/5	..	4.5/5	5/5	Apr 2014	US$ 8 499	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

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. Thus, a score needs to be put into the context of the launch date and the launch price 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.

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Other camera comparisons

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