Why a full frame camera?

The market of digital cameras is full of different models. In the case of full frame dSLRs just seven choices share the 90% percent of full frame dSLRs market.

So why a full frame camera? What is the difference?

The basic difference is the lenses. The market share of cameras with full frame sensors is dominated by only two companies Canon and Nikon. Usually Canon has slightly bigger share. What makes them so successful is not the bodies of their dSLR cameras but their lenses. Quality photographic lenses unlike the cameras are very tough to be made. They don’t have the rapid electronic progress of the main electronic equipments. They are more mechanical equipments than electronic ones. For example a five year old dSLR is obsolete and can be bought new at a bargain price. A five year old lens for full frame cameras won’t loose its value easily after five years. In the case of prime lenses the technological depreciation is extremely slow.  Lenses force the dSLR users on a specific brand of a camera. The SLR camera manufacturers since the age of film avoided a common mount and common auto focus control of lenses. A Canon user who wants full control of the lens is obliged to use a canon compatible lens. The same with the Nikon users. A lens made 10 years ago is compatible with a new dSLR of the same brand. That is good and a quality lense is a real investment. It doesn’t loose it usefulness even after 20 years.

Most lenses from Canon and Nikon are made for full frame cameras. Why?

Most high quality Lenses are fully compatible with full frame cameras. Nearly all casual photographers without full frame dSLRs are satisfied with their mediocre Kit Lenses. In really the default kit lense is good for the majority of shots. Full frame dSLRs users are willing to pay more for the quality and variety of  lenses designed for full frame cameras. That have placed Canon and Nikon at the top of the photography industry. The other competitors can’t beat them due to their superiority and variety in lenses.

A full frame lens is not fully compatible in a non Full frame dSLR with crop sized APS sensor. That is a bad choice. The lens behaves with lower sharpness, apperture, brightness and different focal length. A lens for full frame cameras is named EF by Canon and AF-S by Nikon.

A Lens for crop sized image sensor APS dSLRs is named EF-S by Canon and AF-S DX in Nikon. An EF-S lens is not compatible with full frame Canon camera body. An AF-S DX lens is compatible to a Nikon full frame body with vignetting. It is an important feature of Nikon dSLR cameras. With Nikon the passage from APS sensor camera to full frame sensor camera is less costly. In general EF-S and AF-S DX lenses are cheaper with inferior quality.

There are three categories of full frame cameras by Canon and Nikon.

  • The cheapest Canon EOS-6D and Nikon D610 for amateurs.
  • The medium sized professional Canon EOS-5Ds and Nikon D810.
  • The big expensive flagships Canon EOS-1D C and Nikon D4S.

Until five year ago a full frame dSLR was only the choice of professionals and rich photographers. Quite resently two affordable models appeared.

 

The Canon 6D is the only full framevcamera with build-in GPS receiver.
The Canon 6D is the only full frame camera with build-in GPS receiver. GPS is a feature that most serious photographers snob. For amateurs travel photographers who want quality photos with embedded GPS tag this camera is s must. That makes Canon 6D a very interesting choice for first time full frame camera users.

The Canon EOS-6D is the best choice for amateurs who want a relatively  affordable full frame camera. The body costs around 1600 euros. It is the cheapest camera which can fully use the EF Canon lenses. Since it is targeted mostly for amateurs it integrates GPS and WiFi. The only negative is the lack of flip screen. Something very popular by amateurs but indifferent by professionals. Please avoid buying it with a kit lens. It doesn’t offer shallow depth of field and the bokeh is hard to appear.

 

The frame Canon 6D is not fully metalic due to GPS receiver.
The frame Canon 6D is not fully metalic due to GPS receiver. The signal of GPS satellites is weak. So the upper body is synthetic. It is a compromise against durability.

The best value for money lens for the Canon EOS-6D is the Canon EF 50mm – f/1.4 USM Lens. It is a normal lens and doesn’t have the unavoidable distortions of wide lenses or telephoto lenses. It has the field of view of a human eye. So photos look natural. It costs around 350 euros. A very good price for an aperture of  f/1.4. One of the things that differentiates an amateur photo from a professional photo is the shallow depth of field that creates bokeh. The f/1.4 aperture and the 50mm focal length is a good combination for bokeh.

The Nikon D610 is a direct upgrade of the problematic D600.
The Nikon D610 is a direct upgrade of the problematic D600. It is slightly cheaper than Canon 6D because it doesn’t have GPS neither WiFI. The main difference from Canon is that is compatible with DX lens for APS Nikon dSLRs.

The next affordable full frame dSLR is the Nikon D610. It is the upgrade model of the Nikon D600. It costs around 1500 euros. It works fine with AF-S lenses. It accepts AF-S DX lenses with vignetting at some focal lenghts. WiFi and GPS are optional with extra paid accessory. It has two SD cards slots. The Canon EOS-D6 has got only one slot. A double flash card slot is a professional feature. It offers redundancy. The photo is written in both cards simultaneously. If one of the two cards fails, there is a back up. Both Canon EOS-D6 and Nikon D610 don’t have flip screens. Nikon has a built in flash. The built in flash is useless. For serious photography an affordable external flash offers better results.

 

Nikon D750 is the only full frame camera from Canon and Nikon with a flip screen.
Nikon D750 is the only full frame camera from Canon and Nikon with a flip screen. The quality of photos is somewhere between D610 and D810. It has build in WiFi unlike the rest of Nikon full frame cameras. If it had GPS built in receiver it would be the most versatile full frame camera in the market.

The Nikon D750 is a full frame camera somewhere between Nikon D810 and Nikon D610. It is the only full frame camera of both Nikon and Canon with flip screen. This is very useful for special shooting positions.

 

The  metallic frame of the Nikon D750 is more robust than that of Canon 6D.
The metallic frame of the Nikon D750 is more robust than that of the Canon 6D.

 

 

The canon 5D series is the most popular full frame camera by professionals.
The canon 5D series is the most popular full frame camera by professionals. It is not big neither heavy. It is not very expensive neither cheap. It the best value for money if you want top and affordable quality.

The Canon 5Ds and the Nikon D810 are the mainstream cameras for professionals and passionate amateurs. They are not very expensive for the quality of photos they shoot.  They cost around 2.500 euros. Both are weather resistant with frame of magnesium alloy. They had great grip and stability.

 

The fully metallic frame of the Canon 5Ds.
The fully metallic frame of the Canon 5Ds.

The 5Ds has bigger buffer for endless shoots. It is great for filmography and is used by pros as a cheaper alternative to Sony professional video cameras. It has by far the most megapixels by any full frame camera.

 

Until the entry of Canon 5Ds the Nikon D810 was the fullframe camera with the most megapixels.
Until the entry of Canon 5Ds the Nikon D810 was the fullframe camera with most megapixels.

 

 

The body of Nikon D810 is very tough like most of dSLRs of its category.
The body of Nikon D810 is very tough like most of dSLRs of its category.

The Nikon D810 is inferior to Canon 5Ds despite being one year older and with a similar price. For those with nikon lenses is the best solution. It focus great and have good ISO. Nothing very special though.

 

In photography big size counts.
Canon EOS-1D C. In photography big size counts. Manufacturers can add more features or increase performance without the fear of adding weight and bulk.

 

Canon EOS-1D C frame.
Canon EOS-1D C frame. It is built like a rock.

The flagships of Canon and Nikon are the Canon EOS-1D C and Nikon D4S. Both arepricey around 12.000 euros. They cost at least three times more than 5Ds and D810. Its huge size provides a camera grip. They are targeted only for professional who don’t care about size, weight and want reliability and quality. Their body is metallic and the toughest of all. Of course they are water resistant, not just weather sealed. Only 15 Megapixels doesn’t mean inferior photo quality. Their quality is the best in dSLRs. Their shutter is tested to work 400.000 times without problems. A typical dSLR can shoot just 100.000  without shutter problems. 

 

The Nikon D4s is the best camera of Nikon.
The Nikon D4s is the best camera of Nikon. Its image sensor is made by Sony.

 

 

The frame of Nikon D4s.
The frame of Nikon D4s.

Both have incredible ISO above the 256.000. The noise is the lowest it can be. 12.000 euros for a camera is two much. I would prefer a Leica which depreciates fat slower in time. 

The Sony a99 is a case theat worths mentioning. It is decent full frame camera with great features. The truth is that it isn’t a popular camera. Sony don’t have a tradition in full frame cameras. However it is a dominant video camera manufacturer and knows about optics. The Sony bought Minolta resently and is the only with SLT technology. 

 

With SLT there is no movable mirror and that creates fewer vibrations. What differentiates an a99 camera is the image stabilization inside the camera. That stabilization permit the uses of old legacy lenses of other manufacturers. If it is combined with the external lens stabilization of a lens the result is the longest possible exposures without tripod. This is great in handheld photography with super telephoto lenses or with handheld low light photography. Is the camera of choice for paparazzi photo journalist because they use super telephoto lenses and a tripod is not an option. 

 

The frame of Sony a99 is made from magnesium alloy like most of full frame dSLRs.
The frame of Sony a99 is made from magnesium alloy like most of full frame dSLRs.


What is Zoom in lenses;

Most amateurs photographers think that zoom is how many times closer a lens can bring the object they are shooting. That is not right. 

The Zoom in lenses is the ratio of the longest focal lenght to the shortest focal lentgh of a single lens that has variable focal length. 

Professional and experienced amateur don’t view the Zoom characteristic of a lens. They take notice of the 35mm equivalent focal length of a lenses. Lenses with focal lenght above 85mm (equivalent to 35mm sensor) are considered telephoto. Commercial telephoto lenses can reach 600mm.

 

The canon EF 1200mm f/5.6 - f/32 L USM.
The canon EF 1200mm f/5.6 – f/32 L USM. This incredible and unique lens is not a zoom lens. This doesn’t mean that it can’t shoot object at extreme distanses. Its aperture is great relative to the focal length. It weights 16.5 Kgr. Certainly not a handheld lens. It has 13 elements including two synthetical fluorite elements. No more than 100 have been made.
 
But even the focal lenght alone isn’t enough. What really brings the object closer is the field of view which is relative to the focal length and the size of image sensor. 

The image sensor plays a crucial role to the zoom of a lense. A small sensor permits smaller lenses to deliver bigger zoom with a cost of quality. All the super zoom compact digital cameras have small sensors. They have tremendous zooms but they take tremendously bad photos under low light. Small sensors suffers from low lighting. 

 

The Canon EF 600mm f/4 USM lens.
The Canon EF 600mm f/4 USM lens. The 600mm is the limit of commercial and affordable super telephoto lenses. The specific lens is again not a zoon lenses despite been made to capture clear photo from long distances. Lately with the used of synthetic fluorite elements their weight is low.
 
The common size of an image sensor in professional photography is the full frame image sensor which has the size of the classic 35mm film. It is common because old lenses for 35mm film cameras are compatible with full frame digital cameras. During the recent passage from film photography to digital photography the professionals managed to rescue their old expensive 35mm lenses. 

A lens designed  for a full frame sensor behaves as a lens with longer focal length when it is attached to a smaller sensor camera. The difference is called crop factor. APS sized sensors have around 1.5 crop factor. Micro 4/3 have a 2 crop factor. Crop factor is the ratio of the sensors  diagonal lenght.

 

The sony SEL18200 f/3.5 - f6.3 is designed for crop sencor APS-C mirrorless  cameras.
The sony SEL18200 18mm-200mm f/3.5 – f6.3 is designed for crop sencor APS-C mirrorless cameras. The 35mm equivalent lenght of this zoom lens is multiplied by the crop factor. The crop factor is 1.43 so the equivalent full frame 35mm focal lenghts are 25mm-285mm. Zoom lenses have variable focal lenghts and most of them variable apettures.
 
What is the effect of the crop factor? A 100mm lens for a full frame sensor in an APS sensor behaves like a (100mm x 1.5 =150mm) 150mm lens. The same lense on a micro 4/3 sensor behaves like a (100mm x 2 = 200mm) 200mm lens. It seems smart to use a smaller sensor and bring the object you shot closer but there is a quality toll.

Lenses for full frame sensor 35mm are called EF by Canon and  AF-S by Nikon. Cheaper lenses only proper for APS sensor are called EF-S by Canon,  AF-S DX by Nikon and DT by Sony. 

The focal lenght effects the field of view. Try to see from inside a tube. From a short tube you see more things than a long one. The field of view is what the sensor receives. The small field of view sends more details of a distant object to the sensor. That is perceived as Zoom. The smaller field of view the less amount of light reaches the sensor. Less amount of light demands longer exposure, tripod and higher ISO.

 

Sigma 200-500 f/2.8 EX DG.
Sigma 200-500 f/2.8 EX DG. This beast super telephoto zoom lens combines everything. Great range of focal lenghts and incredible apperture. It weights 16 Kgr and has 17 elements. It costs 25.000.000 dollars. Not an affordable choice.
 
That’s why quality telephoto lenses parallel to their big length have also big diameter in order to accept more light than cheaper narrower lenses. These quality telephoto lenses are called bright telephoto lenses because they receive more light and have less noise from lower ISO. Thery are also called fast telephoto lenses  because they need shorter exposure in order to bring good results. . 

Aperture control makes the difference between mediocre photos and really good ones.

Aperture in photography is a hidden an obscure feature that most amateur photographers ignore. All the cameras have aperture but can’t be controlled by all them. Mobile phones and tablets can’t control the aperture of their cameras. The same is true with cheap compact cameras.

Aperture affects mainly the depth of field and the shutter speed. Aperture is not the diameter of the lens diaphragm as it is the common misconception. Apperture is the ratio of the focal lenght to the diameter of the diaphragm

https://youtube.com/watch?v=S7ysLp83x54

That sounds scientific and is confusing at the start.

 

The diaphragm of a lens is like the iris of the human eye.
The diaphragm of a lens is like the iris of the human eye. It shrinks in bright areas it expands in shadowy areas.
The human eye is actually a lens. Its sensitivity and accuracy in relation to its weight and size is beyond any image sensor of the present or the near future. Its diaphragm we called iris. It expands and shrinks acording to amount of light. The same happens with the diaphragm of photographic lenses. Like the the human optical nerves, the image sensor in order to bring good results has limits on the duration and the amount of light.

Focal length is not the distance of the image sensor to the furthest element of the lens as it is a common belief. It is the distance from the image sensor to the optical center of the lens. That’s why lenses with the same focal lenght have different physical lengths.

The physical equivalent of the aperture is a tunnel. If the tunnel has short distance (focal length) and has a big diameter (diaphragm) , it is bright inside. If it is very length and has small diameter, it is shadowy inside. That’s the reason why aperture has great importance in low light photography.

Aperture is written with the symbol f/. The f represents the result of the fraction between the focal lenght and the diameter of the diaphragm. The f  is called f-stop. Most cameras uses standarised f-stop scale like f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16. The smaller the f-stop the more light the image sensor receives. The difference between each stop corresponds to the double amount of light is received. For example a lens with f/2.8 aperture receives the double light from the f/4 aperture.

The aperture is controlled in three ways.

  1. Regulating only the diameter of the diaphragm. It is typically used in prime lenses. Prime lenses have a fixed focal length and can’t zoom.
  2. Regulating only the focal length. It is used on cheap compact compact cameras with zoom and fixed diaphragm.
  3. Regulating both the diaphragm and focal lenght of the lens. This is used in lenses with zoom and diaphragm blades .

In practice the aperture usually creates this effects on photographs:

  1. Lower f-stops creates vignetting. Vignietting  is the darkening of the photo’s corners. Sometimes is artistic, sometimes is unpleasant.
    This photo has a very obvious vignetting effect.
    This photo has a very obvious vignetting effect. The vignetting was an unavoidable effect of early black and white photographs. It is used purposesly because it adds romantism.
  2. Higher f-stops produce sharper photos. The group f/64 was a group of photographers like Willard Van Dyke and Ansel Adams. The high f-stop f/64 on large format cameras produced sharpness evenly with great depth of field.
  3. Lower f-stops accept the maximum light and permit the minimum time of exposure. Despite creating less sharp photos, it is the ideal setting in low light handheld photography. Human eye has approximately  f/2.1 in darker places and f/8.3 in brighter places.
  4. Lower f-stops create shallower depth of field. When lower f-stop is combined with larger focal length we have the  bokeh phenomenon. Bokeh is the artistic blur of the out of focus backround and foreground. The object in focus is more evident. It is artistic and very usefull in portraits.
  5. Higher f-stops create more lens flare. lens flare is the artifacts or haze created by a very bright source of light, like sun or a naked lamp. That can be artistic or unpleasant.
    The lens flare can be an artistic feature.
    The lens flare can be an artistic feature. It adds reality to the photos.
  6. Lower f-stops conceal the presence of dust on the sensor or the lens.

 

A classical example of Bokeh.
A classical example of Bokeh. The baground is blur. The foreground is sharp and the cat catch the eye of the viewer. This phot was shot with low f-stop.
Since the lower f-stops results in the beneficial bokeh but also to softer photos, the construction of sharp lenses with very low f-stop is very demanding.

 

A canon lens with  85mm focal length and big maximum aperture  f/1.8.
A canon lens with 85mm focal length and big maximum apperture f/1.8. That lens is ideal for bokeh without being very expensive. It combines big focal lentgh with big aperture. Portait lens between f/1.8 – f/1.4 are reasonably priced because there is a huge demand for them. Les popular focal lengths or bigger apertures have extraordinary prices.
That kind of lenses are called portrait lenses because bokeh helps the eye to focus on persons. They are also called fast lenses because they send more light to the sensor and require minimum shutter speed. Normal and wide angle sharp lenses below f/1.4 and telephoto sharp ones below f/4 cost thousands of dollars each. They make the difference between amateurs and professionals.

Sources:

http://web.archive.org/web/20150519181818/http://www.digitalcameraworld.com/2012/09/07/what-is-focal-length-definition-comparison-every-question-answered/

Image sources:

Wikipedia commons

Digital image sensor size in cameras. Does it matter?

Even if it is a crucial thing for the quality of photos, most ordinary photographers are ignorant of the image sensor size they use.    

Image sensor size is the most important factor of the camera’s cost. Manufacturers tend to conceal it and focus their marketing on other specifications. In the case of small cameras doesn’t even exist on their manuals and brochures. Consumer compare megapixel, body size, weight, optical zoom, connectivity and forget the most important which is the image sensor’s size.   

 

Image sensor wafer
Image sensor wafer are pieces of high technology. The purity of the silicon and the precission of transistors is awesome. If you notice the wafer edges a lot of space is lost due to larger image sensors.
 Image sensors are cut from a big silicon disk called wafer. Silicon wafers are expensive. VERY EXPENSIVE. Usually only one in three wafers is pure enough to make sensors. A wafer can be cut in more smaller sensors than big ones. Since the wafer is circular bigger rectangular sensors create more waste space at the disk edges than smaller ones. So a small image sensor is by far more cheap than a bigger one and more profitable.   Big sensors shouldn’t be related with more megapixels. Actually what counts more is the size of every individual pixel than the total amount of them. A bigger pixel receives more light than a smaller one. More light reduce the need of higher sensitivity ISO. Low ISO produce lower image noise and sharper images. Image noise is the equivalent of the grain in high ISO films. Big sensors are ideal in low light photography. That’s the reason why  mobile phones no matter how expensive they are shot low quality photographs under poor lighting. It is impossible to insert a large sensor in such a slim device.  

 

Lenses for full frame cameras are typically larger.
Lenses for full frame cameras are typically larger. That piece of art is a canon EF lense with aperture 1.2. It is perfect for shallow depth of field. It is heavy, big and expensive around 2.000 dollars.
 Big image sensors require bigger lenses in diameter. The bigger the elements of a lens the more expensive they are. That doesn’t have to do with the cost of the material like in the silicon wafers case. When an element of a lense is big requires more time and effort to be perfectly polished and multi layered than a smaller one. Imperfections are more visible, like barrel distortion, chromatic aberration, sharpness, flaring, clarity etc. Larger lenses are exponentially more expensive from small ones of the same materials and technology. For example full frame cameras have bigge lenses in diameter than crop sized compact cameras.  

Under normal conditions the difference between small or bigger sensors is negligible. Outdoor daylight photography without shadows, or well lighted indoor photography doesn’t demand big sensors. 

The iPhone during daylight produces resespectable photos.
The iPhone during daylight produces resespectable photos.
An iPhone can shot decent but boring photographs under ideal lighting. Impressive photographs are under special lighting.  Sunset or sunrise, blue hour, artificial lighting in sports et are very demanding. A bigger sensor offers creativity to the photographer.   

The bigger sensors have better dynamic range. Dynamic range is the difference of the amount of light the sensor receives from the brightest and darkest areas. 

The iPhone during daylight produces resespectable photos.
The upper photo has low dynamic range and the shadows vanishes everything. The lower photo has high dynamic range. Shadows and hilights are properly exposed. Difficult dynamic range of a photo can be post processed with the cost of extra noise sometimes.
A classic example is photos during sunny middays. The shadowy and the bright areas can’t be captured equally well. In this case there is a large dynamic range of light. During a cloudy day there aren’t any shadows and the dynamic range is small. The large pixels of a large sensor copes with this problem better. 

 

Canon 5D is one of the most popular full frame cameras.
Canon 5D is one of the most popular full frame cameras. It is not cheap around 2.500 dollars but it can be purchased by both professionals and enthousiastic amateurs. Its low noise at very high ISO is legendary.
The size of a digital image sensor varies a lot. However for compability reasons with legacy lenses of the film era the main sensor is the full frame one. The full frame sensor has the same size of a 35mm film, 36mm length X 24mm width. Its aspect radio is 3:2. The aspect radio of 3:2 is considered the standar in photography. The 35mm film is named from the width of the perforated film gauge. 24mm width + 11mm holes = 35mm.  The full frame sensor is considered big today. However the 35mm film was also known as small format film for amateur in comparison to professional medium format and large format films of the film era.  The compatible lenses for full frame digital cameras are named EF by Canon and AF-S by Nikon.  

 

Canon 7D is the most succesfull dSLR camera.
Canon 7D is the most succesfull APS format dSLR camera.
The APS-C sensor size derives from the APS film. Advanced Photo System type Classic was introduced in 1996 a few years before the expansion of digital cameras. Its classic type size was 25.1mm × 16.7mm. It had a magnetic coating that could store informations like shutter speed, aperture size, aspect ratio etc. It was created to be more practical but not better than 35mm film. It was short lived. By 2002 the compact digital cameras were cheap enough to replace APS film cameras but not 35mm cameras yet. First mass produced digital SLR cameras appeared the early 2000. They were not affordable by anyone at the begging. Despite being compatible with 35mm lenses, they didn’t have full frame sensors. That came later. The size of the first dSLR sensors was  similar to the APS-C. Even nowadays most dDSLRs have APS-C sensors because they are easier to be mass produced and offer good quality. Also most lenses are constructed for APS-C sized  sensors. Canon name them EF-S and Nikon AF-S DX.   

 

The swidish Hasselbald is one of the few medium format digital cameras.
The swidish Hasselbald is one of the few medium format digital cameras.It was as mych as a car with its default lens. For an extra lens the cost is increadibly hight.
Every digital sensor bigger than full format (35mm) is named medium format. Medium format films were the choice of professionals. The 35mm film was inferior but cheap and good enough for amateurs. Medium format digital cameras are still very expensive. They have the same price of a car. Their quality is second to none. They offer by far more megapixels without reducing the size of pixels. Their Dynamic Range is perfect as their sharpness and light sensitivity. Additionally these lenses are not mass produced. That makes  them very expensive. It’s a niche market. The dominant Canon and Nikon brands haven’t ever created a medium format digital camera. The both very prestigious and historical German Leica and Danish Hasselbald offer medium format digital cameras. These are cameras for the very successful professional photographers or the uber rich amateurs.   

 

Olympus and Panasonic opened the road to mirroless cameras.
Olympus and Panasonic opened the road to mirroless cameras. However Sony proved to be more versatile in the mirrorless sector with the APS-C sensors, the full format sensor of the cheapest full format A7 camera and numerous lenses for the E Mount format.
Micro Four-thirds sensor size doesn’t derive from a film size but from the 4/3 inch diameter of the common video camera tube. The standard aspect ratio of glass TV sets was 4:3. A Micro four third sensor has 17.3mm length and 13mm width. It is inferior than the previous sensor sizes. However the recent advances in low noise ISO and dynamic range have created four-thirds sensors with equal quality of a five year old APS-C sensor. The first mirrorless digital cameras in 2008 had a micro four-thirds sensor. Most mirrorless cameras still have micro four-thirds sensor. It is the only decent solution in high quality small cameras with reasonable price. It saved brands like Olympus, Fujifilm, Panasonic, Samsung that couldn’t compete with Nikon and Canon at the dSLR sector.   

 

The sony DSC-RX100 is the most popular premium conpact digital canera.
The sony DSC-RX100 is the most popular premium conpact digital canera. It is truly small with acdecent one inch sencor. Despite being compact with fixed lens it offers good photos under low lighting.
1″ sensor is a the more recent popular sensor size. The size of one inch sensor is 13.2mm length X 8.8mm. Nikon names it CX format and puts it in his mirroless cameras. Sony uses it in his premium compact and super zoom cameras like the series of compact Sony Cyber-shot DSC-RX100 and super zoom Sony Cyber-shot DSC-RX10. The one inch sensor is the smallest size for serious photography. Mobile phone after 2007 with first iPhone had gradually elbowed the digital compact cameras with tiny sensors. The 1″ inch sensor is big enough for quality photos and small enough to be inserted into small compact or mirrorless camera. It has reopen the gap between mobile phones and very small digital cameras.   

 

The Nokia Lumia 1020 is the king of the mobile phone photographic cameras.
The Nokia Lumia 1020 is the king of the mobile phone photographic cameras. Its sensor size is so big 2/3″ 8.8mm X 6.6mm that exceeds the main body of the camera. The sensor’s size is proper more for a compact camera. Also the 41 megapixel it delivered in 2013 is something we won’t see again for many years by another mobile phone. Unfortunatetly the poor operating system of Windows mobile diched such a wonderfull effort from Nokia. The phone wasn’t able to save Nokia from defaulting. The initial price of Nokia Lumia 1020 was 800 dollars, a year later it was sold for 350 dollars. The phone was a flop. However the trend for cameras exceeding the main body is followed by others. Something not so obvious with the canera had been mimicked by iPhone 6.
Smaller sensors are measured in fractions of the inch. For example the legendary Nokia Lumia 1020 mobile phone has a 2/3″  8.8mm X 6.6mm image sensor with the amazing 41.3 megapixel. The iPhone 5 with its decent camera has a 1/3.2″ 4.54mm X 3.42mm sensor. The iPhone 6 plus with its electronically stabilized lens has a 1/3″ 4.8mm X 3.6mm image sensor.   

Crop factor is relative to size of an image sensor. Crop factor or Focal Length Multiplier FLM is the ratio of the diagonal length of  a full frame image sensor  to the diagonal length of the actual image sensor. The typical diagonal length of image sensors are: Full Frame 43.2mm, APS-C 30.1mm and Micro 4/3 21.6mm. For example if the camera has a full frame lens its crop factor is (43.2/43.2=1) 1. If the camera has an APS-C sensor  then the ratio is (43.2/30.1=1.43) 1.4 crop factor. If the camera has a micro 4/3 sensors then the ratio is (43.2/21.6=2) 2 crop factor. That ratio in practice affects the field of view of the lens. In simple words a 100mm lens of a full frame (crop factor 1) camera when is put on a APS-C (crop factor 1.43) camera acts like a (100 X 1.43 = 143) 143mm lens. On a micro four thirds camera (crop factor 2) it acts like a (100 X 2 = 200) 200 mm lens. The smaller the sensor the more powerful a telephoto lens is. Super zoom compact cameras have small image sensors in order to avoid lengthy lenses.                                              

 Sources:  

https://web.archive.org/web/20150518060022/http://www.digitalcameraworld.com/2012/11/21/full-frame-sensor-size-explained-how-to-exploit-its-advantages-and-cool-effects/  

http://web.archive.org/web/20150518094229/http://www.gizmag.com/camera-sensor-size-guide/26684/