Canon 300D vs 5D Mark III

The Canon EOS 300D (called Canon Rebel in some regions) and the Canon EOS 5D Mark III are two digital cameras that were announced, respectively, in August 2003 and March 2012. Both are DSLR (Digital Single Lens Reflex) cameras that are based on an APS-C (300D) and a full frame (5D Mark III) sensor. The 300D has a resolution of 6.3 megapixels, whereas the 5D Mark III provides 22.1 MP.

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

Headline Specifications

Canon 300D		Canon 5D Mark III
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Canon EF mount lenses
6.3 MP – APS-C sensor		22.1 MP – Full Frame sensor
no Video		1080/30p Video
ISO 100-1,600		ISO 100-25,600 (50 - 102,400)
Optical viewfinder		Optical viewfinder
1.8" LCD – 118k dots		3.2" LCD – 1040k dots
Fixed screen (not touch-sensitive)		Fixed screen (not touch-sensitive)
2.5 shutter flaps per second		6 shutter flaps per second
not weather sealed		Weathersealed body
400 shots per battery charge		950 shots per battery charge
142 x 99 x 72 mm, 649 g		152 x 116 x 76 mm, 950 g

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Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS 300D and the Canon EOS 5D Mark III? 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 physical size and weight of the Canon 300D and the Canon 5D Mark III are illustrated in the side-by-side display below. 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 Canon 5D Mark III is notably larger (25 percent) than the Canon 300D. Moreover, the 5D Mark III is substantially heavier (46 percent) than the 300D. It is noteworthy in this context that the 5D Mark III is splash and dust-proof, while the 300D 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. A larger imaging sensor (as in the 5D Mark III) will tend to go along with bigger and heavier lenses, while more compact options are available for the smaller-sensor camera (300D). You can compare the optics available in the Canon EF Lens Catalog.

Concerning battery life, the 300D gets 400 shots out of its Canon BP-511 battery, while the 5D Mark III can take 950 images on a single charge of its Canon LP-E6 power pack.

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, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons 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.		Canon 300D	142 mm	99 mm	72 mm	649 g	400	n	Aug 2003	899	ebay.com
2.		Canon 5D Mark III	152 mm	116 mm	76 mm	950 g	950	Y	Mar 2012	3,499	ebay.com
3.		Canon 5D Mark II	152 mm	114 mm	75 mm	850 g	850	Y	Sep 2008	3,499	ebay.com
4.		Canon 5D Mark IV	151 mm	116 mm	76 mm	890 g	900	Y	Aug 2016	3,499	amazon.com
5.		Canon 5DS	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
6.		Canon 5DS R	152 mm	116 mm	76 mm	930 g	700	Y	Feb 2015	3,699	ebay.com
7.		Canon 10D	150 mm	107 mm	75 mm	850 g	500	n	Feb 2003	1,999	ebay.com
8.		Canon 20D	144 mm	106 mm	72 mm	770 g	700	n	Aug 2004	1,499	ebay.com
9.		Canon 77D	131 mm	100 mm	76 mm	540 g	600	n	Feb 2017	899	ebay.com
10.		Canon 350D	127 mm	94 mm	64 mm	540 g	400	n	Feb 2005	899	ebay.com
11.		Canon 400D	127 mm	84 mm	65 mm	556 g	370	n	Aug 2006	799	ebay.com
12.		Canon 650D	133 mm	100 mm	79 mm	575 g	440	n	Jun 2012	849	ebay.com
13.		Canon 700D	133 mm	100 mm	79 mm	580 g	440	n	Mar 2013	649	ebay.com
14.		Canon G1 X	117 mm	81 mm	65 mm	534 g	250	n	Jan 2012	799	ebay.com
15.		Canon G1 X Mark II	116 mm	74 mm	66 mm	553 g	240	n	Feb 2014	799	ebay.com
16.		Nikon D70	140 mm	111 mm	78 mm	679 g	400	n	Jan 2004	999	ebay.com
17.		Nikon D610	141 mm	113 mm	82 mm	850 g	900	Y	Oct 2013	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

The price is, of course, an important factor in any camera decision. The listed launch prices provide an indication of the market segment that the manufacturer of the cameras have been targeting. The 300D was launched at a markedly lower price (by 74 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 size of the sensor inside a digital camera is one of the key determinants 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. 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 tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Canon 300D features an APS-C sensor and the Canon 5D Mark III a full frame sensor. The sensor area in the 5D Mark III is 152 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.6 and 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

Technology-wise, the 5D Mark III uses a more advanced image processing engine (DIGIC 5+) than the 300D (DIGIC), with benefits for noise reduction, color accuracy, and processing speed.

With 22.1MP, the 5D Mark III offers a higher resolution than the 300D (6.3MP), but the 5D Mark III has smaller individual pixels (pixel pitch of 6.25μm versus 7.38μm for the 300D). Yet, the 5D Mark III is a much more recent model (by 8 years and 6 months) than the 300D, and its sensor will have benefitted from technological advances during this time that enhance the light gathering capacity of its pixel-units.

The resolution advantage of the Canon 5D Mark III implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the 5D Mark III for good quality output (200 dots per inch) amounts to 28.8 x 19.2 inches or 73.2 x 48.8 cm, for very good quality (250 dpi) 23 x 15.4 inches or 58.5 x 39 cm, and for excellent quality (300 dpi) 19.2 x 12.8 inches or 48.8 x 32.5 cm. The corresponding values for the Canon 300D are 15.4 x 10.2 inches or 39 x 26 cm for good quality, 12.3 x 8.2 inches or 31.2 x 20.8 cm for very good quality, and 10.2 x 6.8 inches or 26 x 17.3 cm for excellent quality prints.

The Canon EOS 300D has a native sensitivity range from ISO 100 to ISO 1600. The corresponding ISO settings for the Canon EOS 5D Mark III are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 50-102400.

Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) 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 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. Of the two cameras under consideration, the 5D Mark III offers substantially better image quality than the 300D (overall score 26 points higher). The advantage is based on 3 bits higher color depth, 0.9 EV in additional dynamic range, and 2.1 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 Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Canon 300D	APS-C	6.3	3072	2048	none	21.0	10.8	544	55
2.		Canon 5D Mark III	Full Frame	22.1	5760	3840	1080/30p	24.0	11.7	2293	81
3.		Canon 5D Mark II	Full Frame	21.0	5616	3744	1080/30p	23.7	11.9	1815	79
4.		Canon 5D Mark IV	Full Frame	30.1	6720	4480	4K/30p	24.8	13.6	2995	91
5.		Canon 5DS	Full Frame	50.3	8688	5792	1080/30p	24.7	12.4	2381	87
6.		Canon 5DS R	Full Frame	50.3	8688	5792	1080/30p	24.6	12.4	2308	86
7.		Canon 10D	APS-C	6.3	3072	2048	none	21.1	10.9	571	57
8.		Canon 20D	APS-C	8.2	3504	2336	none	21.9	11.0	721	62
9.		Canon 77D	APS-C	24.0	6000	4000	1080/60p	23.6	13.3	971	78
10.		Canon 350D	APS-C	8.0	3456	2304	none	21.8	10.8	637	60
11.		Canon 400D	APS-C	10.1	3888	2592	none	22.1	11.0	664	62
12.		Canon 650D	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	722	62
13.		Canon 700D	APS-C	17.9	5184	3456	1080/30p	21.7	11.2	681	61
14.		Canon G1 X	1.5-inch	14.2	4352	3264	1080/24p	21.7	10.8	644	60
15.		Canon G1 X Mark II	1.5-inch	13.0	4160	3120	1080/30p	21.5	10.8	581	58
16.		Nikon D70	APS-C	6.0	3008	2000	none	20.4	10.3	529	50
17.		Nikon D610	Full Frame	24.2	6016	4016	1080/30p	25.1	14.4	2925	94

Many modern cameras are not only capable of taking still images, but also of capturing video footage. The 5D Mark III indeed provides for movie recording, while the 300D does not. The highest resolution format that the 5D Mark III can use is 1080/30p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a variety of features. The 300D and the 5D Mark III 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 5D Mark III offers a wider field of view (100%) than the one in the 300D (95%), so that a larger proportion of the captured image is visible in the finder. In addition, the viewfinder of the 5D Mark III has a higher magnification (0.71x vs 0.55x), 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 Canon 300D and Canon 5D Mark III 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.		Canon 300D	optical	n	1.8 / 118	fixed	n	1/4000s	2.5/s	Y	n
2.		Canon 5D Mark III	optical	Y	3.2 / 1040	fixed	n	1/8000s	6.0/s	n	n
3.		Canon 5D Mark II	optical	Y	3.0 / 920	fixed	n	1/8000s	3.9/s	n	n
4.		Canon 5D Mark IV	optical	Y	3.2 / 1620	fixed	Y	1/8000s	7.0/s	n	n
5.		Canon 5DS	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
6.		Canon 5DS R	optical	Y	3.2 / 1040	fixed	n	1/8000s	5.0/s	n	n
7.		Canon 10D	optical	Y	1.8 / 118	fixed	n	1/4000s	3.0/s	Y	n
8.		Canon 20D	optical	Y	1.8 / 118	fixed	n	1/8000s	5.0/s	Y	n
9.		Canon 77D	optical	Y	3.0 / 1040	swivel	Y	1/4000s	6.0/s	Y	n
10.		Canon 350D	optical	n	1.8 / 115	fixed	n	1/4000s	3.0/s	Y	n
11.		Canon 400D	optical	n	2.5 / 230	fixed	n	1/4000s	3.0/s	Y	n
12.		Canon 650D	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
13.		Canon 700D	optical	n	3.0 / 1040	swivel	Y	1/4000s	5.0/s	Y	n
14.		Canon G1 X	optical	n	3.0 / 922	swivel	n	1/4000s	1.9/s	Y	Y
15.		Canon G1 X Mark II	optional	n	3.0 / 1040	tilting	Y	1/4000s	5.2/s	Y	Y
16.		Nikon D70	optical	n	1.8 / 130	fixed	n	1/8000s	3.0/s	Y	n
17.		Nikon D610	optical	Y	3.2 / 921	fixed	n	1/4000s	6.0/s	Y	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 300D has one, while the 5D Mark III does not. While the built-in flash of the 300D is not very powerful, it can at times be useful as a fill-in light.

The 300D writes its imaging data to Compact Flash cards, while the 5D Mark III uses Compact Flash or SDXC cards. The 5D Mark III features dual card slots, which can be very useful in case a memory card fails. In contrast, the 300D 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 EOS 300D and Canon EOS 5D Mark III 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 300D	Y	- / -	-	-	-	1.1	-	-	-
2.		Canon 5D Mark III	Y	mono / mono	Y	Y	mini	2.0	-	-	-
3.		Canon 5D Mark II	Y	mono / mono	Y	-	mini	2.0	-	-	-
4.		Canon 5D Mark IV	Y	mono / mono	Y	Y	mini	3.0	Y	Y	-
5.		Canon 5DS	Y	mono / mono	Y	-	mini	3.0	-	-	-
6.		Canon 5DS R	Y	mono / mono	Y	-	mini	3.0	-	-	-
7.		Canon 10D	Y	- / -	-	-	-	1.1	-	-	-
8.		Canon 20D	Y	- / -	-	-	-	1.1	-	-	-
9.		Canon 77D	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
10.		Canon 350D	Y	- / -	-	-	-	2.0	-	-	-
11.		Canon 400D	Y	- / -	-	-	-	2.0	-	-	-
12.		Canon 650D	Y	stereo / mono	Y	-	mini	2.0	-	-	-
13.		Canon 700D	Y	stereo / mono	Y	-	mini	2.0	-	-	-
14.		Canon G1 X	Y	stereo / mono	-	-	mini	2.0	-	-	-
15.		Canon G1 X Mark II	Y	stereo / mono	-	-	mini	2.0	Y	Y	-
16.		Nikon D70	Y	- / -	-	-	-	1.0	-	-	-
17.		Nikon D610	Y	mono / mono	Y	Y	mini	2.0	-	-	-

Studio photographers will appreciate that the Canon 5D Mark III (unlike the 300D) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Both the 300D and the 5D Mark III have been discontinued, but can regularly be found used on ebay. The 300D was replaced by the Canon 350D, while the 5D Mark III was followed by the Canon 5D Mark IV. Further information on the features and operation of the 300D and 5D Mark III can be found, respectively, in the Canon 300D Manual (free pdf) or the online Canon 5D Mark III Manual.

Review summary

So what is the bottom line? Which of the two cameras – the Canon 300D or the Canon 5D Mark III – has the upper hand? Is one clearly better than the other? Below is a summary of the relative strengths of each of the two contestants.

Advantages of the Canon EOS 300D:

• More compact: Is smaller (142x99mm vs 152x116mm) and thus needs less room in the bag.
• Less heavy: Is lighter (by 301g or 32 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 (74 percent cheaper at launch).
• More heavily discounted: Has been available for much longer (launched in August 2003).

Reasons to prefer the Canon EOS 5D Mark III:

• More detail: Has more megapixels (22.1 vs 6.3MP), which boosts linear resolution by 88%.
• Better image quality: Scores substantially higher (26 points) in the DXO overall evaluation.
• Richer colors: Generates noticeably more natural colors (3 bits more color depth).
• More dynamic range: Captures a broader range of light and dark details (0.9 EV of extra DR).
• Better low-light sensitivity: Can shoot in dim conditions (2.1 stops ISO advantage).
• Better jpgs: Has a more modern image processing engine (DIGIC 5+ vs DIGIC).
• Broader imaging potential: Can capture not only stills but also 1080/30p video.
• More complete view: Has a viewfinder with a larger field of view (100% vs 95%).
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.71x vs 0.55x).
• Easier setting verification: Features a control panel on top to check shooting parameters.
• 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 (1040k vs 118k dots).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (6 vs 2.5 flaps/sec) to capture the decisive moment.
• Longer lasting: Gets more shots (950 versus 400) 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 (2.0 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 8 years and 6 months of technical progress since the 300D launch.

If the count of individual advantages (bullet points above) is taken as a guide, the 5D Mark III is the clear winner of the contest (20 : 5 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 before making a decision on a new camera. A professional sports photographer will view the differences between cameras in a way that diverges from the perspective of a street photog, and a person interested in family portraits has distinct needs from a landscape 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 300D and the Canon 5D Mark III 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 technical specifications can provide a useful overview of the capabilities of different cameras, it remains partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the 300D or the 5D Mark III. 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 why expert reviews are important. 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 (USD)	Street Price
1.		Canon 300D	..	..	..	+ +	..	..	Aug 2003	899	ebay.com
2.		Canon 5D Mark III	..	+ +	..	82/100	4.5/5	4.5/5	Mar 2012	3,499	ebay.com
3.		Canon 5D Mark II	4/5	91/100	..	79/100	4/5	..	Sep 2008	3,499	ebay.com
4.		Canon 5D Mark IV	4.5/5	+ +	4/5	87/100	4.5/5	4.5/5	Aug 2016	3,499	amazon.com
5.		Canon 5DS	..	+	..	83/100	4.5/5	4.5/5	Feb 2015	3,699	ebay.com
6.		Canon 5DS R	5/5	+	..	83/100	5/5	4.5/5	Feb 2015	3,699	ebay.com
7.		Canon 10D	..	..	..	+ +	..	..	Feb 2003	1,999	ebay.com
8.		Canon 20D	..	..	..	+ +	..	..	Aug 2004	1,499	ebay.com
9.		Canon 77D	4.5/5	..	4/5	82/100	4.5/5	4/5	Feb 2017	899	ebay.com
10.		Canon 350D	..	80/100	..	+ +	o	..	Feb 2005	899	ebay.com
11.		Canon 400D	..	+ +	..	+ +	o	4/5	Aug 2006	799	ebay.com
12.		Canon 650D	4/5	+ +	..	77/100	4.5/5	4.5/5	Jun 2012	849	ebay.com
13.		Canon 700D	..	..	..	76/100	4.5/5	4.5/5	Mar 2013	649	ebay.com
14.		Canon G1 X	5/5	+	..	76/100	4/5	4.5/5	Jan 2012	799	ebay.com
15.		Canon G1 X Mark II	3/5	+	..	77/100	4/5	4.5/5	Feb 2014	799	ebay.com
16.		Nikon D70	..	..	..	+ +	..	..	Jan 2004	999	ebay.com
17.		Nikon D610	4/5	+ +	..	87/100	4.5/5	4.5/5	Oct 2013	1,999	ebay.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The above review scores should be interpreted 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. Hence, a score should always be seen in the context of the camera's market launch date and its price, and comparisons of ratings among very different cameras or across long time periods have little meaning. Also, please note that some of the review sites have changed their methodology and reporting over time.

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Other camera comparisons

Did this review help to inform your camera decision process? In case you are interested in seeing how other cameras pair up, just make a corresponding selection in the search boxes below. There is also a set of direct links to comparison reviews that other users of the CAM-parator app explored.

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