Pentax K-S1 vs Sigma fp
The Pentax K-S1 and the Sigma fp are two digital cameras that were revealed to the public, respectively, in August 2014 and July 2019. The K-S1 is a DSLR, while the fp is a mirrorless interchangeable lens camera. The cameras are based on an APS-C (K-S1) and a full frame (fp) sensor. The Pentax has a resolution of 20 megapixels, whereas the Sigma provides 24 MP.
Below is an overview of the main specs of the two cameras as a starting point for the comparison.
Going beyond this snapshot of core features and characteristics, what are the differences between the Pentax K-S1 and the Sigma fp? 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.
The physical size and weight of the Pentax K-S1 and the Sigma fp are illustrated in the side-by-side display below. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All width, height and depth measures are rounded to the nearest millimeter.
The K-S1 can be obtained in four different colors (black, grey, orange, white), while the fp 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 Sigma fp is notably smaller (30 percent) than the Pentax K-S1. Moreover, the fp is markedly lighter (24 percent) than the K-S1. It is noteworthy in this context that the fp is splash and dust-proof, while the K-S1 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.
The power pack in the fp can be charged via the USB port, which can be very convenient when travelling.
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.
|1.||Pentax K-S1||121 mm||93 mm||70 mm||558 g||410||n||Aug 2014||749|
|2.||Sigma fp||113 mm||70 mm||45 mm||422 g||280||Y||Jul 2019||1,899|
|3.||Canon T6i||132 mm||101 mm||78 mm||555 g||440||n||Feb 2015||749|
|4.||Fujifilm X-Pro3||141 mm||83 mm||46 mm||497 g||440||Y||Oct 2019||1,799|
|5.||Nikon D780||144 mm||116 mm||76 mm||840 g||2260||Y||Jan 2020||2,299|
|6.||Nikon D5300||125 mm||98 mm||76 mm||480 g||600||n||Oct 2013||799|
|7.||Panasonic S5||133 mm||98 mm||82 mm||714 g||440||Y||Sep 2020||1,999|
|8.||Panasonic S1||149 mm||110 mm||97 mm||1017 g||400||Y||Feb 2019||2,499|
|9.||Panasonic S1H||151 mm||114 mm||110 mm||1052 g||400||Y||May 2019||3,999|
|10.||Pentax K-S2||123 mm||91 mm||73 mm||678 g||410||Y||Feb 2015||749|
|11.||Pentax K-3 II||131 mm||100 mm||77 mm||800 g||720||Y||Apr 2015||1,099|
|12.||Pentax K-50||130 mm||97 mm||71 mm||650 g||410||Y||Jun 2013||599|
|13.||Pentax K-500||130 mm||97 mm||71 mm||646 g||710||n||Jun 2013||549|
|14.||Pentax K-3||131 mm||100 mm||77 mm||800 g||560||Y||Oct 2013||1,299|
|15.||Pentax K-30||130 mm||97 mm||71 mm||650 g||410||Y||May 2012||849|
|16.||Sony A68||143 mm||104 mm||81 mm||610 g||540||n||Nov 2015||699|
|17.||Sony A58||129 mm||95 mm||78 mm||492 g||690||n||Feb 2013||599|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
The price is, of course, an important factor in any camera decision. The retail prices at the time of the camera’s release place the model in the market relative to other models in the producer’s line-up and the competition. The K-S1 was launched at a markedly lower price (by 61 percent) than the fp, 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.
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 Pentax K-S1 features an APS-C sensor and the Sigma fp a full frame sensor. The sensor area in the fp is 134 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.5 and 1.0. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.
With 24MP, the fp offers a higher resolution than the K-S1 (20MP), but the fp nevertheless has larger individual pixels (pixel pitch of 5.98μm versus 4.28μm for the K-S1) due to its larger sensor. Moreover, the fp is a much more recent model (by 4 years and 10 months) than the K-S1, and its sensor will have benefitted from technological advances during this time that further 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 Sigma fp implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the fp for good quality output (200 dots per inch) amounts to 30 x 20 inches or 76.2 x 50.8 cm, for very good quality (250 dpi) 24 x 16 inches or 61 x 40.6 cm, and for excellent quality (300 dpi) 20 x 13.3 inches or 50.8 x 33.9 cm. The corresponding values for the Pentax K-S1 are 27.4 x 18.2 inches or 69.5 x 46.3 cm for good quality, 21.9 x 14.6 inches or 55.6 x 37.1 cm for very good quality, and 18.2 x 12.2 inches or 46.3 x 30.9 cm for excellent quality prints.
The Pentax K-S1 has a native sensitivity range from ISO 100 to ISO 51200. The corresponding ISO settings for the Sigma fp are ISO 100 to ISO 25600, with the possibility to increase the ISO range to 6-102400.
Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. 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 adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.
| DXO |
|2.||Sigma fp||Full Frame||24.0||6000||4000||4K/30p||..||..||..||..|
|5.||Nikon D780||Full Frame||24.3||6048||4024||4K/30p||..||..||..||..|
|7.||Panasonic S5||Full Frame||24.0||6000||4000||4K/60p||..||..||..||..|
|8.||Panasonic S1||Full Frame||24.0||6000||4000||4K/60p||25.2||14.5||3333||95|
|9.||Panasonic S1H||Full Frame||24.0||6000||4000||6K/30p||..||..||..||..|
|11.||Pentax K-3 II||APS-C||24.1||6016||4000||1080/60i||23.6||13.6||1106||80|
Many modern cameras are not only capable of taking still images, but also of capturing video footage. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the fp provides a better video resolution than the K-S1. It can shoot movie footage at 4K/30p, while the Pentax is limited to 1080/30p.
Beyond body and sensor, cameras can and do differ across a range of features. For example, the K-S1 has an optical viewfinder, which can be very useful when shooting in bright sunlight. In contrast, the fp relies on live view and the rear LCD for framing. The table below summarizes some of the other core capabilities of the Pentax K-S1 and Sigma fp in connection with corresponding information for a sample of similar cameras.
|11.||Pentax K-3 II||optical||Y||3.2||1037||fixed||n||1/8000s||8.3||n||Y|
One difference between the cameras concerns the presence of an on-board flash. The K-S1 has one, while the fp does not. While the built-in flash of the K-S1 is not very powerful, it can at times be useful as a fill-in light.
The reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, the fp is one of those camera that have an additional electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).
The Sigma fp 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 K-S1 and the fp write their files to SDXC cards. The fp supports UHS-II cards (Ultra High Speed data transfer of up to 312 MB/s), while the K-S1 can use UHS-I cards (up to 104 MB/s).
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 K-S1 and Sigma fp and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|11.||Pentax K-3 II||Y||mono||mono||Y||Y||mini||3.0||-||-||-|
It is notable that the fp has a microphone port, which can help to improve the quality of audio recordings by attaching an external microphone. The K-S1 does not feature such a mic input.
The fp is a recent model that features in the current product line-up of Sigma. In contrast, the K-S1 has been discontinued (but can be found pre-owned on eBay). As a replacement in the same line of cameras, the K-S1 was succeeded by the Pentax K-S2. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Pentax and Sigma websites.
So what conclusions can be drawn? Is the Pentax K-S1 better than the Sigma fp or vice versa? The listing below highlights the relative strengths of the two models.
Reasons to prefer the Pentax K-S1:
- Easier framing: Has an optical viewfinder for image composition and settings control.
- Longer lasting: Can take more shots (410 versus 280) on a single battery charge.
- 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.
- More affordable: Was introduced into a lower priced category (61 percent cheaper at launch).
- More heavily discounted: Has been available for much longer (launched in August 2014).
Advantages of the Sigma fp:
- More detail: Has more megapixels (24 vs 20MP), which boosts linear resolution by 10%.
- 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.
- Better video: Provides higher definition movie capture (4K/30p vs 1080/30p).
- Better sound: Can connect to an external microphone for higher quality sound recording.
- 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 (2100k vs 921k dots).
- Fewer buttons to press: Has a touchscreen to facilitate handling and shooting adjustments.
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/6000s) to freeze action.
- Faster burst: Shoots at higher frequency (12 vs 5.4 flaps/sec) to capture the decisive moment.
- Less disturbing: Has an electronic shutter option for completely silent shooting.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- More compact: Is smaller (113x70mm vs 121x93mm) and will fit more readily into a bag.
- Less heavy: Has a lower weight (by 136g or 24 percent) and is thus easier to take along.
- Easier travel charging: Can be conveniently charged via its USB port.
- Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
- More legacy lens friendly: Can use many non-native lenses via adapters.
- Faster data transfer: Supports a more advanced USB protocol (3.1 vs 2.0).
- Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
- More modern: Reflects 4 years and 10 months of technical progress since the K-S1 launch.
If the count of individual advantages (bullet points above) is taken as a guide, the fp is the clear winner of the contest (22 : 6 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 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 Pentax K-S1 and the Sigma fp place the cameras among the top in their class? Find out in the latest Best DSLR Camera and Best Mirrorless Interchangeable Lens Camera listings 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 partial and cannot reveal, for example, the shooting experience and imaging performance when actually working with the K-S1 or the fp. 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 provides a synthesis of the camera assessments of some of the best known photo-gear review sites (amateurphotographer [AP], cameralabs [CL], 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.
|1.||Pentax K-S1||4/5||..||..||4.5/5||4/5||Aug 2014||749|
|2.||Sigma fp||4/5||..||..||4/5||4.5/5||Jul 2019||1,899|
|3.||Canon T6i||5/5||..||75/100||4.5/5||4.5/5||Feb 2015||749|
|4.||Fujifilm X-Pro3||4/5||+||85/100||4/5||..||Oct 2019||1,799|
|5.||Nikon D780||5/5||..||87/100||4.5/5||4.5/5||Jan 2020||2,299|
|6.||Nikon D5300||4/5||+ +||79/100||4.5/5||4.5/5||Oct 2013||799|
|7.||Panasonic S5||4.5/5||+ +||..||4.5/5||4.5/5||Sep 2020||1,999|
|8.||Panasonic S1||4.5/5||+ +||88/100||4.5/5||4/5||Feb 2019||2,499|
|9.||Panasonic S1H||..||..||90/100||..||..||May 2019||3,999|
|10.||Pentax K-S2||4.5/5||..||..||5/5||4.5/5||Feb 2015||749|
|11.||Pentax K-3 II||4.5/5||..||..||5/5||5/5||Apr 2015||1,099|
|12.||Pentax K-50||5/5||..||..||5/5||4.5/5||Jun 2013||599|
|13.||Pentax K-500||..||..||..||4.5/5||4.5/5||Jun 2013||549|
|14.||Pentax K-3||4/5||..||83/100||5/5||5/5||Oct 2013||1,299|
|15.||Pentax K-30||4/5||..||78/100||4.5/5||4.5/5||May 2012||849|
|16.||Sony A68||3/5||..||..||4/5||4/5||Nov 2015||699|
|17.||Sony A58||3/5||..||..||4.5/5||4.5/5||Feb 2013||599|
|Notes: (+ +) 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. Hence, a score should always be seen in the context of the camera's market launch date and its price, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. It should also be noted that some of the review sites have over time altered the way they render their verdicts.
Other camera comparisons
Did this review help to inform your camera decision process? If you would like to see a different side-by-side camera review, just make a corresponding selection in the search boxes 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.
Specifications: Pentax K-S1 vs Sigma fp
Below is a side-by-side comparison of the specs of the two cameras to facilitate a quick review of their differences and common features.
|Camera Model||Pentax K-S1||Sigma fp|
|Camera Type||Digital single lens reflex||Mirrorless system camera|
|Camera Lens||Pentax K mount lenses||Leica L mount lenses|
|Launch Date||August 2014||July 2019|
|Launch Price||USD 749||USD 1,899|
|Sensor Specs||Pentax K-S1||Sigma fp|
|Sensor Format||APS-C Sensor||Full Frame Sensor|
|Sensor Size||23.5 x 15.6 mm||35.9 x 23.9 mm|
|Sensor Area||366.6 mm2||858.01 mm2|
|Sensor Diagonal||28.2 mm||43.1 mm|
|Sensor Resolution||20 Megapixels||24 Megapixels|
|Image Resolution||5472 x 3648 pixels||6000 x 4000 pixels|
|Pixel Pitch||4.28 μm||5.98 μm|
|Pixel Density||5.45 MP/cm2||2.80 MP/cm2|
|Moiré control||no AA filter||no AA filter|
|Movie Capability||1080/30p Video||4K/30p Video|
|ISO Setting||100 - 51,200 ISO||100 - 25,600 ISO|
|ISO Boost||no Enhancement||6 - 102,400 ISO|
|DXO Sensor Quality (score)||78||..|
|DXO Color Depth (bits)||23.5||..|
|DXO Dynamic Range (EV)||13.0||..|
|DXO Low Light (ISO)||1061||..|
|Screen Specs||Pentax K-S1||Sigma fp|
|Viewfinder Type||Optical viewfinder||no viewfinder|
|Viewfinder Field of View||100%|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.2inch|
|LCD Resolution||921k dots||2100k dots|
|LCD Attachment||Fixed screen||Fixed screen|
|Touch Input||no Touchscreen||Touchscreen|
|Shooting Specs||Pentax K-S1||Sigma fp|
|Focus System||Phase-detect AF||Contrast-detect AF|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/6000s||1/8000s|
|Continuous Shooting||5.4 shutter flaps/s||12 shutter flaps/s|
|Electronic Shutter||no E-Shutter||up to 1/8000s|
|Time-Lapse Photography||no Intervalometer||Intervalometer built-in|
|Image Stabilization||In-body stabilization||Lens stabilization only|
|Fill Flash||Build-in Flash||no On-Board Flash|
|Storage Medium||SDXC cards||SDXC cards|
|Second Storage Option||Single card slot||Single card slot|
|UHS card support||UHS-I||UHS-II|
|Connectivity Specs||Pentax K-S1||Sigma fp|
|USB Connector||USB 2.0||USB 3.1|
|HDMI Port||micro HDMI||micro HDMI|
|Microphone Port||no MIC socket||External MIC port|
|Wifi Support||no Wifi||no Wifi|
|Body Specs||Pentax K-S1||Sigma fp|
|Environmental Sealing||not weather sealed||Weathersealed body|
|Battery Life (CIPA)||410 shots per charge||280 shots per charge|
|In-Camera Charging||no USB charging||USB charging|
121 x 93 x 70 mm
(4.8 x 3.7 x 2.8 in)
113 x 70 x 45 mm
(4.4 x 2.8 x 1.8 in)
|Camera Weight||558 g (19.7 oz)||422 g (14.9 oz)|
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