A full-frame SLR camera with a 50mm standard lens
A smartphone camera is not enough.
I want to take better pictures!
But what kind of camera do you want?
Mirrorless, single-lens reflex, full-frame, APS-C, Four Thirds, it's quite difficult to find the best camera out of many!
For such people, I will write from the author's point of view the information that you should know before choosing a camera, from the sensor size and camera mechanism.
By reading this blog, you can learn the basics of cameras and the relationship between sensors and photography.
I decided to write a blog that can be understood by camera beginners as much as possible as a reflection of my accumulated knowledge of cameras and lenses.
Such articles are summarized here on the camera lens blog.
Please take a peek if you are interested.
The author of this blog is a photographer based in Africa. He has shot TV shows and other photo shoots.
In Japan, there are countless experiences in selling cameras and lenses at mass retailers,
It will be a blog by such a camera lover.
It may be a little biased, but I will try to explain it in an easy-to-understand manner.
【table of contents】
Which camera sensor size is better, full size, APS-C size, or Four Thirds?
Differences between single-lens reflex cameras, mirrorless cameras, and smartphones
The big difference between single-lens reflex cameras and smartphones is the size of the sensor used.
The mechanism for taking pictures is exactly the same for single-lens reflex cameras and smartphones.
sensor size
Sensor aspect ratio, aspect ratio
The number of pixels does not represent the quality of the image
How the camera sensor works
Originally a black and white sensor, a mechanism to make it color
Advantages and disadvantages of high resolution
Reasons why smartphones are disadvantageous compared to single-lens cameras
How many pixels should there be?
Conditions for high pixel count
Should the sensor be bigger?
Full size, APS-C, Four Thirds, Best format?
Full size 36x24mm
Anyway, if you want to arrange compactly, Four Thirds
Balanced APS-C
summary
I would appreciate it if you could keep an eye on it until the end.
Which camera sensor size is better, full size, APS-C size, or Four Thirds?
There are many types of single-lens reflex cameras and Four Thirds cameras with interchangeable lenses, but which format camera should I choose?
First, let's talk about the sensor size of SLR, mirrorless, and digital cameras.
Differences between single-lens reflex cameras, mirrorless cameras, and smartphones
DSLRs and mirrorless cameras are much larger and heavier than smartphones, even without a lens attached.
You can't store it in your pocket like a smartphone and put it in and take it out.
From now on, in this blog, we will unify single-lens reflex cameras and mirrorless cameras to single-lens reflex cameras.
Full-size SLR with a telephoto zoom lens, large and heavy
Smartphones are packed with features other than cameras, so why is it possible to make them so compact?
Why are single-lens reflex cameras so bulky?
What are the benefits of carrying a large and heavy SLR camera?
Let's see why.
The big difference between single-lens reflex cameras and smartphones is the size of the sensor used.
SLRs are large and bulky because of their sensor size.
Roughly speaking, the mechanism of a camera that takes pictures and videos is a combination of a lens and a sensor.
From the subject side, there is the lens, and behind it is the image sensor.
Most of them now use something called the CMOS sensor.
In addition, it is equipped with aperture blades to adjust the amount of light, a shutter, and a focus adjustment mechanism to adjust the focus.
Light from the subject is focused on the surface of the image sensor by a lens, and the light signal is converted into an electrical signal to create a photograph.
The structure of the human eye is similar to that of a camera, the lens being the crystalline lens and the sensor being the retina.
Other details such as aperture mechanism, shutter speed, sensitivity adjustment, etc. are similar.
It may be more correct to say that the camera is the same as the human eye.
A simple lens consisting of a magnifying glass and a close-up lens fixed with a PVC pipe.
Regardless of the image quality, you can still take pictures properly. Telephoto lens made with a close-up lens (500mm, f8.6)
The moon taken with a close-up lens.
The mechanism for taking pictures is exactly the same for single-lens reflex cameras and smartphones.
A surprisingly compact smartphone camera
Broadly speaking, single-lens reflex cameras come in different sizes, such as full size, APS-C size, and Micro Four Thirds size.
Smartphones also use sensors of various sizes.
To make it easier to understand, let's make a diagram that compares the sensor size of a smartphone and a general camera.した。
Sensor Sizes
In the figure above, the squares represent the shape and size of the sensor.
sensor size
The blue numbers inside represent the percentage of the area of each sensor relative to the full size.
* Even with the same manufacturer, the size may be slightly different for each model.
* Canon's APS-C size is not shown in the diagram above, but it is one size smaller than other companies' APS-C (1/1.5 compared to full size). (Full size ratio, 1/1.6)
Many other format sizes exist.
In 2023, smartphone cameras with the largest sensor size will be Sharp and Aquos, 1 inch.
Smartphones using 1/1.7 inch sensors are Sony, Xperia Pro, etc.
The sensor size used in general smartphones is the smallest in the above diagram, around 1/2.55 inch or 1/2.3 inch.
In terms of area, the 1/2.55 inch sensor is a small sensor size that is only 2.1% of the full size.
Sensor aspect ratio, aspect ratio
The aspect ratio of the sensor is 2:3 for full size and APS-C,
Four Thirds and smartphone camera sensors use 3:4.
The aspect ratio of current televisions is 16:9, and when you shoot a video with a photo camera, the top and bottom are blurred.
(In order to make full use of the 4:3 sensor, there is also a special lens called an anamorphic lens that shrinks the left and right to display a 16:9 screen, but it is not common because it is expensive.)
I wouldn't worry too much about the aspect ratio.
The number of pixels does not represent the quality of the image
It is generally thought that the higher the number of pixels, the better the image quality, but in reality, whether or not the number of pixels can be utilized depends greatly on the sensor size.
The number of pixels is one of the important factors for image quality, but the balance with the sensor size is important.
Beautiful colors of the camera using the APS-C 6-megapixel CCD sensor
How the camera sensor works
A camera is designed to create an image by focusing light from a subject through a lens onto the camera sensor.
The light received by the pixel sensor is converted into an electrical signal, and information from millions or tens of millions of pixels gathers together to form a single image.
Originally, it was a black and white pixel sensor, but in order to make it color, filters were attached to the surface of the sensor in order of red, green, blue, and green, and the information from the subject was extracted as color information of the three primary colors.
It is processed in various ways and becomes beautiful color image data.
Originally a black and white sensor, a mechanism to make it color
Most cameras today use CMOS sensors.
In this rectangle, the number of pixels is closely aligned vertically and horizontally.
Each pixel is black and white information, not color.
Explaining the mechanism for converting black and white to color
Filters are attached to each pixel in the order of red, green, blue, and green to extract the three primary color components of the subject's light. (Primary color Bayer sensor)
Each pixel is combined with other color information around each pixel to create a color photo with each pixel and color information.
Primary color Bayer sensor image diagram
What does a typical Bayer sensor look like?
From here on, I've become a maniac, so please skip to the sensor size.
In addition, there are sensors that are devised to achieve higher image quality.
Fuji has changed the arrangement so that moiré is less likely to occur.
Since all red, green, and blue lines are included in vertical, horizontal, and diagonal lines, moiré is prevented and resolution is improved. As for green, once every three rows, only green.
Fuji, X-Trans CMOS
Colors are created with a total of 4 pixels set, 2 pixels each in length and width, and assigned to each pixel.
It's a bit of a joke, isn't it?
It seems that the Sony Alpha 7SIII, which has excellent high sensitivity characteristics, uses such a quad bayer sensor to achieve high sensitivity.
The great thing about the quad sensor is that it processes the same color and 4 pixels as one pixel,
Light information for 4 pixels for red and blue, and 8 pixels for green is captured, and color information is assigned to each pixel.
Compared to other Bayer arrays, it has overwhelmingly high sensitivity.
All are sets of red 1, blue 1, green 2, and get color information
Other Color Mechanisms
Foveon sensor: A method previously used by Sigma cameras. Each pixel is a layered sensor that carries color information for the three primary colors red, blue, and green.
It had excellent color reproduction, but its high-sensitivity characteristics were weak, and before we knew it, sales were discontinued.
3-plate sensor: Using 3CCD, 3CMOS, and a prism, the light is separated into 3, and the separated light is captured by the red sensor, blue sensor, and green sensor, and then synthesized again.
It is used in camcorders with smaller sensor sizes such as 1/3, 1/2, and 2/3 inches. They are complicated, bulky, and costly, so they are only used in small sensors. As with the Foveon sensor, it produces rich color reproduction with 100% color juice.
In the past, many filters used highly transmissive complementary colors such as cyan, magenta, and yellow instead of the primary colors, red, green, and blue, to increase sensitivity.
primary color filter
red
green
blue
補色フィルター
cyan
magenta
yellow
There are CCD, CMOS, etc., but currently almost all models use primary color CMOS sensors from a cost standpoint.
I got a little too deep into it.
Advantages and disadvantages of high resolution
If you increase the number of pixels, you will be able to capture fine details in the image, but if you increase the number of pixels without changing the sensor size, each pixel will become smaller.
The smaller the pixel, the less light it can receive.
The reason why single-lens reflex cameras use a large sensor size is to increase the number of pixels while increasing the area of each pixel.
The lion photo above was taken with a Nikon D70, a single-lens reflex camera two years ago.
APS-C 6 megapixel camera with CCD sensor.
At 6 megapixels, it's much smaller than today's cameras, but it produces very rich and impressive colors.
No matter what you do with the full-size, high-resolution 45-megapixel D850, this color will not come out.
Compared to the D70, the D850 has increased from 6 million pixels to 45 million pixels even though it is full size, so the area per pixel is about 1/3.3 smaller.
The change in sensor type from CCD to CMOS has an effect, but I think the smaller pixel pitch also has a big impact.
Reasons why smartphones are disadvantageous compared to single-lens cameras
As an even more extreme example, let's compare a full-frame SLR and a smartphone.
Consider the full-frame and 1/2.55-inch sensor smartphone cameras pictured above.
Assuming the same number of pixels, the 1/2.55-inch sensor can receive only 2.1 light under the condition that it can receive 100 light at full size.
That's all, there will be a difference in the gradation expression of the pixel.
Gradation is the subtle light and dark tones of light.
A full-size camera can express 100 gradations, but a 1/2.55-inch sensor can express only 2 gradations.
If you don't get enough tonal information, the vividness and depth of the colors will be lost and will be lost in the noise.
This is why smartphones are weak in dark shooting conditions.
Modern smartphones that claim to be photographic quality use larger sensors and have a modest number of pixels.
The reason is to make the pixels as large as possible.
A past blog I wrote about colors,
How many pixels should there be?
The number of pixels you need depends on how you view your photos.
For example, 2.1 megapixels is enough for viewing on a full high-definition monitor with 1920x1080 pixels.
If this becomes a 4K monitor with 3840x2016 pixels, it will have 8.3 million pixels.
The number of pixels displayed on the monitor may have been much smaller than expected.
Considering viewing on a monitor, you can see that a single-lens reflex camera with more than 20 million pixels is overspec.
Most of the photos used in this blog are reduced and compressed to 900x600. It is only 540,000 pixels.
I think you can see that the number of pixels is not so necessary if you appreciate it on a smartphone or PC screen without enlarging it.
A large number of pixels can only be used when enlarged on a monitor display.
You can think of it as expansion resistance.
Consider the case of printing a photograph and viewing it.
Generally, the necessary print resolution is said to be 300dpi to 350dpi.
dpi is an index that expresses how many dots there are in 1 inch (2.54 cm).
You may not print a lot of photos these days, but if you want to print a general service print, L size (127x87mm) at 350dpi, you need 2.1 million pixels.
Number of pixels required for print resolution 350dpi
11.5 million pixels on A4 size
24 million pixels in A3 size
However, if the print size increases, the viewing distance will also increase, so the resolution to that extent is not necessary.
Comparing a photo printed at 350dpi with an inkjet printer and a photo printed at 200dpi, the difference is almost unnoticeable.
Because of the high-spec settings, even with a lower number of pixels, the photos will be worthy of viewing.
It is generally said that 150dpi is sufficient for large size prints.
This is because the viewing distance for a large photograph is that far.
However, most of the current cameras use a set of Bayer sensors with 4 pixels, so there is a characteristic that a slightly larger number of pixels than the final output will result in a beautiful finish.
Conditions for high pixel count
High pixels are useful when printing on a huge size,
Even small prints can benefit from the resolution when cropping a portion of the photo.
For example, when projecting a 24-megapixel photo onto a 4K monitor, even if the image is enlarged to 200%, the image will be sharp and clear.
A slightly larger number of pixels is necessary due to the aspect ratio, but I will omit it.
The same is true for printing.
The larger the number of pixels, the better the cropping resistance.
However, as mentioned earlier, the smaller the number of pixels and the larger the sensor size, the clearer the image can be obtained even in dark conditions.
Therefore, the balance between the number of pixels and the sensor size becomes important.
For a full size, around 24 megapixels is strong in high sensitivity and high in definition, so I think it's the most well-balanced resolution.
The best resolution will change depending on what you prioritize.
Sony's full-frame mirrorless Alpha series is a good example.
α7sⅢ 12 million pixels, should sensitivity be given priority?
α9 24 million pixels, balance
α7rIV 61 million pixels, (Resolution) should be prioritized
We have released a lineup with the same full size but with a different number of pixels.
There are advantages and disadvantages to each.
The meaning of R and S used in the model name conveys the development philosophy.
Should the sensor be bigger?
To make the sensor bigger, it is necessary to make the lens bigger to cover the sensor size.
The reason why a smartphone camera can be so small is because of its small sensor size.
As you can see from the diagram above, the lens required for full frame will need a lens that focuses on 50 times the area of the 1/2.55 inch sensor.
The larger the pixels, the less resolution is required for the lens, but it requires a lens that can focus over a wider range. (Lens with a large image circle)
This difference is the size difference between a smartphone and an SLR camera.
To take advantage of the large sensor, you need a large, high-performance lens.
Full size, APS-C, Four Thirds, Best format?
I found that the larger the sensor size, the less noise and the larger the lens.
So, which size is the best to choose when choosing a camera?
We will look at full size, Four Thirds, and APS-C.
Full size 36x24mm
Anyway, if performance is important, full size
Full size is recommended if you want higher image quality without worrying about the size of the equipment.
Although the price is high as it is, I think that you can feel the advantage of the sensor size.
However, as the size and weight of the equipment increases, the telephoto lens in particular becomes considerably larger, so there is a drawback that the footwork deteriorates.
As the focal length increases, the foreground and foreground of the focal point are more defocused than other formats, making the front and back of the subject highly defocused.
Conversely, it becomes disadvantageous when you want to focus on the whole.
More severe focusing is required.
The range of focus is shallower than other formats, so the whole image is sharp.
It's going to be a little harder to shoot, because it's going to be harder to take pictures.
This effect is particularly noticeable when shooting close-ups.
High-sensitivity characteristics are advantageous, making it the most advantageous format for shooting in dark places and starry skies.
Anyway, if you want to arrange compactly, Four Thirds
1/2 of full size in terms of focal length ratio,
By simple calculation, the volume and weight will be 1/8 of the full size.
It will be a format that has a great advantage in telephoto shooting.
In terms of angle of view, a full frame 600mm angle of view is covered by a 300mm lens with Micro Four Thirds.
Conversely, if you use a 600mm lens, you get a full-frame super-telephoto angle of view equivalent to 1200mm.
Of course, from the wide-angle side to the lens in general, it will be more compact, so if you want to reduce the amount of equipment, it will be a more effective format.
Also, because the sensor is small, power-saving and high-performance in-body image stabilization is possible.
On the downside, it is disadvantageous in terms of noise when shooting at night or starry skies, which require high sensitivity characteristics.
Since the front and back of the subject can be focused in a wider range, this camera is suitable for shooting where you do not want to blur the front and back of the subject too much.
Compared to full size, it's easier to take pictures with the whole frame clearly in focus.
This characteristic becomes more pronounced in close-up photography.
Balanced APS-C
It can be said that it is an almighty format size that combines the full size and the deliciousness of Micro Four Thirds.
Except for extreme conditions such as starry skies and celestial bodies, you will hardly feel inferior in terms of image quality compared to full size.
The fact that the converted focal length is 1.5 times that of a full-frame lens is a big advantage when shooting telephoto shots.
It can be said that it is an almighty format that combines the best of both full-size and Four Thirds.
summary
In this blog, I have touched on the relationship between sensor size, number of pixels, and image quality.
More pixels doesn't mean better quality
In order to increase the number of pixels in order to improve image quality, the image sensor must also be enlarged at the same time.
Single-lens reflex cameras and mirrorless cameras are large and bulky to increase the sensor size and improve image quality.
Full size, APS-C, and Four Thirds each have advantages and disadvantages.
Full-size has excellent image quality, but the lens and camera are large, heavy, and bulky, and the range of focus is narrow.
Four Thirds allows you to make the equipment smaller than the full size, and you can focus more deeply.
APS-C combines full size with the good points of Four Thirds
Until the end Thank you for reading.
In the next article, I will talk about the attractiveness of the coloring of slightly older single-lens reflex cameras, and how you can purchase such attractive cameras at a low price if you consider second-hand cameras.
We will also touch on the appeal of film cameras and talk about information you should know before purchasing a camera.
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