2.7 The Simple Magnifier - University Physics Volume 3 - how to find magnification
The “rainbow colored” rectangle on the graphic shows the sensor grid. Pixels are so small that it’s hard to see each individual unit.
I am a landscape & outdoor photographer. I don’t shoot weddings, for clients or do product work. Therefore I can’t recommend cameras that I haven’t personally tested.
Larger sensor widths yield larger sensor surface areas providing more area for the capture of light information over a standard interval, known as exposure time.
CMOS Sensors are defined by their physical size ( surface area for capturing light information ) and the number of light information collecting pixels which make up this surface area.
Digital photography is the process of recording real world color information represented by the image grid, and relaying it into the digital world represented by the pixel grid.
Pretend the following graphics are the real world scenes that you’re seeing through the camera viewfinder or on the back of your camera live view screen.
We have surpassed the 2-year-old child that can barely speak, we have surpassed the adult with a vivid and detailed vocabulary, we have arrived at a degree of precision that only machines can record and communicate.
In the graphic below, the pixel wells on the left have lower signal to noise ratios where the pixel wells moving towards the right have higher signal to noise ratios.
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The example below shows the tonal values of black to white communicated with varying degrees of precision, by different bit depth systems.
The crop factor is a dimensionless reference number, associated with image sensors. It compares the diagonal distance across each specific camera sensor to the diagonal distance across the full frame camera sensor.
Humans perceive green as the brightest, red as the second brightest, and blue as the darkest, out of the three primary colors. This perception of color brightness, known as lightness or luminosity, is only a function of the eye’s physiology. Remember the Bayer Filter!
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Selecting the best overall camera settings (ISO, shutter speed, f-stop) and image quality attributes (dynamic range, noise, bit-depth, sensor size) is impossible without a basic understanding of how a camera sensor works.
To the human eye, the perceived brightness of green is greater than that of red or blue, thus green filtered pixels are represented twice as often in the Bayer Filter.
I think Sony makes great low-end models with great sensors. Their high end models have fantastic sensors but are plastic and cheaply made. I prefer Nikon at the high end, with metal bodies, and the same Sony sensors. This is my personal preference.
12 megapixelCamera price
The photographer’s goal is to select the correct camera settings relaying this information with precision & accuracy, producing a digital image that matches what they see through the viewfinder.
In terms of color & tone, machines have bypassed the precision that the human eye, engineered by trial and error, through millions of years of evolution, can discern.
This charge is used to transfer the light information, collected by each pixel, into digital information which cameras & computers can understand.
In turn, a digital image is produced, from millions of pixels, which matches the real world composition seen through the viewfinder.
Becoming a histogram expert is critical to understanding why camera sensor size matters, in turn producing the best image quality.
The ISO determines the amplification of the signal & inherent noise. The ISO also determines how much light is required for optimal exposure.
Canon continues to produce their own sensors which significantly lack in dynamic range, comparatively, rated at approximately 11.8 stops for their top model cameras. They also produce a much larger amount of noise at high ISO values.
The example below shows the 4-bit color scale for RGB Primary colors red, green and blue. Bin 15 in each of the color channels is pure fully saturated color, also known as hue.
For example, Red ( 12 ), Blue ( 6 ), Green ( 15 ) would create unique color and Red ( 1 ), Blue ( 2 ), Green ( 4 ) would create another unique color.
Digital cameras can be broken up into 3 different categories for sensor sizes, largest to smallest respectively, Medium Format, Full Frame, and Crop.
The 3 & 4 bit systems provide a larger selection of choices used to communicate varying tonal values within the tonal range.
The camera sensor, also known as an image sensor, is an electronic device that collects light information, consisting of color & intensity after it passes through the lens opening, known as the aperture.
Take a look at different objects around you. If you look closely, under a large amount of magnification, everything becomes a single color on a very small scale.
Along with the number of pixels, sensors are also rated in terms of physical sensor size or surface area. The sensor surface area also determines the size of each pixel.
CMOS camera sensors and pixels inherently produce a small amount of noise. This is similar to radio static heard at low volumes in headphones. Even the best cameras with the optimal settings create small amounts of noise.
Physical sensor sizes are provided in terms of width and height, usually in millimeters. A standard sensor size such as 36mm × 24 mm is known as a full frame 35mm format camera.
Total Color Choices Per Pixel = 16*16*16 or 16^3 which equals 4096 total choices. 16 represents the number of color choices per channel. There are 3 primary color channels.
When a pixel well contains no electrons it produces no signal. The corresponding tonal value is a black, producing a black pixel in the photo.
Over a 3-day weekend, I can teach you everything I know, plus provide 1 on 1 feedback that will quickly improve your skills.
When photons collide or interact with certain materials, such as silicon CMOS image sensors, free electrons are released from the sensor material, producing a small electric charge. This is known as the Photoelectric effect.
Each pixel can only collect the primary color information of it’s assigned red, green or blue filter, along with the number of electrons collected in the pixel well, which determine tonal value.
When making the following comparisons of image sensors, assume that each sensor compared is from the same fabrication year.
The number of electrons collected by each pixel well produces a corresponding tonal value for that pixel. This tonal value is displayed in the final photo, along with the color.
The combination of the following, provide a reasonable estimate of a camera’s image quality. They are discussed in further detail below.
For diagonal distance think of a straight line from the top right corner to bottom left corner. This is also known as the hypotenuse.
Understanding camera sensor size and why it actually matters is one of the most important aspects of learning photography.
NOTE: This image was captured before twilight, in the pouring rain, on the Li River in China. This shooting scenario is the ultimate test for a camera sensor.
In photography, the number of bits determines the possibilities of color or tone a single pixel can display, known as bit depth.
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Each pixel is covered with a color filter, either red, green or blue. The color of each pixel is determined by the color of light (frequency of light wave) which passes through this filter.
None of the information the pixel collected prior to filling can be recovered or used in the final image. It’s gone forever!
12 megapixelvs 50megapixel
Think of a sensor like the sail on a boat. The larger the sail, the greater the surface area, the more wind it will catch.
In some shooting scenarios such as star, Milky Way & night sky photography, the light levels are so low that the image noise will be very high. Even the best camera sensor for low light, such as models made by Sony, still produce some noise.
The best way to improve quickly is by learning firsthand from someone that’s optimized their skills, over a decade or more through trial and error.
The precision of the communication is rated on the scale of bit depth. Larger bit depth systems allow more precision in describing the information collected by each pixel.
The digital language takes the form of zeros and ones ( bits ) & communicates the values of color ( Red, Green, Blue ) & tone collected by each pixel.
Red light passes through the red filtered pixels, while green and blue light do not. Blue light passes through the blue filtered pixels, while red and green light do not. You get the gist…
Images that contain larger proportions of lighter tonal values will have higher Signal to Noise Ratios revealing less visible noise.
Bit depth specifies the number of unique color & tonal choices that are available to create an image. These color choices are denoted using a combination of zeros and ones, known as bits, which form binary code.
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The free electrons are collected and counted by individual pixels on the sensor grid. Each pixel well has a maximum capacity of electrons it can collect. This maximum is known as full well capacity.
As a sensor collects more light, producing a larger signal, less overall noise is seen in the final image. The Signal to Noise Ratio (SNR or S/N) is used to describe the phenomena.
Consider this like a child that only speaks two words, yes & no, black & white. You wouldn’t depend on this child to communicate a landscape scene with a large degree of accuracy or precision.
Each electron produced during the Photon sensor collision carries a small electric charge. The more electrons a pixel collects, the more charge the pixel well contains. Electric charge is a physical measured value.
Smaller camera sensors such as a standard 22.3mm width, APS-C Sensor ( see graphic above ), would have a crop factor of approximately 1.6.
As the bit depth of the system increases the degree of precision which information is communicated from the real world into the digital world also increases.
Light is made of photons or small packets for carrying light information. Photons are elementary particles which have no weight but carry information about light.
Imagine an image composition, seen through a camera viewfinder, with an imaginary overlaid grid, containing millions of tiny uniformly sized squares, as seen in the graphic below.
Each photographer has different sensor size requirements to produce the images they desire. I’m not going to tell you what camera to buy, but will provide some of my personal favorites.
The human eye, the second most (known) complex object on the planet, after the brain, has no problem discerning approximately 12 million different colors.
These color photographs are produced using the three primary colors, red, green, and blue determined by the Bayer filter.
The aperture diameter & shutter speed control how much light is captured by each pixel, thus increasing or decreasing the signal strength.
The number of electrons each pixel well collects determines it’s brightness, also known as value, on a scale of black to white. The scale of black to white is known as the tonal range or tonal scale.
12 MegapixelSecurity Camera
Dynamic Range is defined as the difference or range between the strongest undistorted signal (brightest tonal value) & the weakest undistorted signal (darkest tonal value) captured by an image sensor, in a single photo.
Noise is dependent of camera make and model as well as settings. Different types of noise makeup the overall noise profile for a given image.
The 2-year-old child, seeing the same thing, has a hard time describing the scene accurately, having a limited vocabulary.
Due to the higher performance, especially in low light, and lower cost the CMOS Sensor is found in nearly all modern digital cameras.
An adult and a 2-year-old child looking at the same landscape see close to the same thing, consisting of color and tonal values (light intensity).
Camera sensor size is the most important factor in determining overall camera performance & image quality, given the optimal focus, f-stop, ISO, and shutter speed settings have already been obtained.
Therefore the number of possible choices, for each pixel, in a small 8-bit file is 256^3 power, or 256*256*256 which equals 16,777,216.
Most, but not all, CMOS sensors use a Bayer Filter which looks like a quilt of Red, Green, and Blue screens, with a single color screen covering each pixel as shown in the graphic.
The red channel can display 255 different variations of red, the green can display 255 variations of green and the blue, 255 variations of blue.
That being said, I’m happy to recommend a few different camera models for landscape & nature photographers. These may not be specific to you, but they can help in cutting down decision fatigue. They may also work for other niches of photography, but I can’t guarantee it:)
JPEG files are usually 8-bit whereas RAW files are usually 12 to 16 bit. Some cameras have the ability to change their current bit rating through user defined settings.
Mega is the mathematical term denoting 10^6 also stated as “10 to the 6th power” which can be written as 1,000,000 or 1 million.
There is a much smaller difference between the APS-H vs APS-C. These cameras will produce close to the same image quality, with slight variations.
The 14-bit file contains 2^14th power of possible variations for each of the 3 color channels. That’s 16,384 possible choices per color channel.
They both see and collect the same real world information, but one can describe it in vivid detail, while the other cannot.
The pixel specific tonal value is determined from the number of electrons ( charge ) collected and the color is determined using the Bayer Filter.
Larger physical sensor sizes combined with larger megapixel counts provide increased camera performance, with less noise, especially in low-light shooting situations.
Sony currently produces some of the highest dynamic range sensors on the market for full frame cameras. These camera sensors are rated at approximately 14.8 stops. Many Nikon cameras use Sony sensors due to this fact.
ISO determines the amplification the light information receives as it’s conveyed into the digital world, where it’s stored on a memory card as a picture file.
For example, the number of possible choices for a 3-bit system is found by using the binary base 2 and raising it to the power of 3, 2^3 = 8.
The tonal values produced by each signal are combined with collected color information to produce each pixel’s final color within the photo.
Smaller pixel pitch (width), combined with larger sensor size, and the latest software & hardware, will produce the best image quality.
By gaining an understanding of how camera sensors actually work, and experimenting on your own, is the best way to figure out which camera and sensor size best fits your needs.
Notice the massive difference in light collecting surface area between the APS-C vs full frame camera sensors. These cameras will produce much different overall image quality, with the larger far exceeding the smaller.
Unlike megapixel counts, having a larger dynamic range is always a positive camera attribute. Dynamic range is provided in stops, which is a measure of light. For each stop increase the amount of light information collected doubles.
The precision and accuracy which this information is communicated and displayed in the final image is determined by the bit depth.
The goal is to fill each pixel well to it’s corresponding tonal value maximum without clipping or losing data off the top end, thus increasing the Signal to Noise Ratio and image quality.
Electrons counts can’t determine specific color information, therefore, a color filter is placed over each pixel helping to determine it’s color. This is discussed in detail below.
The graphic below shows an 8-bit system with 256 or ( 2^8 ) different bins. Due to the vast number of possible tonal choices the transition from one to the next isn’t discernible to the human eye. A JPEG image is 8-bit.
Images that contain larger proportions of dark tonal values will inherently have lower Signal to Noise Ratios revealing more visible noise. This is one reason low light and night sky images contain so much noise.
Due to this fact, slightly overexposing images, known as Expose to the Right or ETTR , provides higher Signal to Noise Ratios and overall better image quality, provided that the brightest pixels are not “clipped” or “blown out”.
Using this information, and a series of algorithms & interpolations, the camera can determine the color of each pixel contained on the sensor grid.
Each individual square pixel represents a small sample of the image composition as a whole, consisting of a single color. No more.
The bit depth determines how many steps or possible choices within the tonal range can be communicated. Each step or possible choice is known as a bin. The more bins the more choices.
When the correct camera settings, shutter speed, ISO and f-stop, are selected, each pixel on the sensor grid will collect & record the exact color of the corresponding square on the image grid.
As the ISO becomes larger less overall light (signal) is required to produce the same tonal value. As the ISO increases the noise levels are amplified creating more overall noise in the image.
Since color information can’t be determined directly by the number of electrons in each pixel well, a color filter is placed over each pixel.
After the exposure time, defined by shutter speed, has elapsed, the signal information produced by each pixel is processed & converted into a digital language known as binary code.
TECHNICAL NOTE: Although each of the color channels have the same amount of steps, the variation of green can still be seen all the way down to 1, where it’s hard to tell any difference in red at 1, and blue drops off at 2.
For example, the diagonal distance or hypotenuse of the 36mm by 24mm full frame can be found as follows: =SQRT((24^2)+(36^2)). The outcome is approximately 43.3mm.
This is a scientific fact, there is no dispute. Sony makes better sensors than Canon for landscape and outdoor photography.
For example, a camera with high dynamic range capability could shoot directly into the bright sunlight & still collect information from dark shadow regions, without producing much noise. This is shown in the video above.
No matter the camera, higher ISO values will always produce more overall noise and less overall dynamic range in the final RAW file.
There are two popular types of image sensors, CMOS sensors (complementary metal-oxide semiconductor) & CCD sensors (charge-coupled device).
Each tonal value, on the scale of black to white, has a corresponding signal required to produce it. Specific signal levels produce specific tonal values. The more electrons a pixel collects the stronger the signal it creates.
For example, although a crop sensor usually provides less quality & detail than a full frame sensor, a crop sensor from 2017 would most likely provide more quality and detail than a full frame sensor from the year 2000.
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When a pixel well fills to the top with electrons, creating the maximum signal, it’s corresponding tonal value is white, producing a white pixel in the photo.
Digital photography is the process of recording real world color and tones, from a scene or composition, using individual pixels.
NOTE: Not all cameras process color the same way. The following example allows you to conceptualize this concept. It’s not meant to be technically accurate for a specific camera.
PRO TIP: If you really enjoy photography buy the best camera you can afford. Then you don’t have to upgrade multiple times over the coming years. It saves money in the end. I know from experience…
It only means that each generation of camera will get slightly better in the areas noted above, as software, hardware, and engineering improves.
A pixel can only display a single color, including black, white, greyscale, and RGB Color values. The color of each pixel is determined by the amount & kind of light information it collects.
When the incorrect camera settings are selected, the squares on the pixel grid don’t match the squares image grid, producing a digital image that doesn’t match the scene being photographed.
For the following example, assume the latest pro model full frame camera from Nikon or Sony. The exact model does not matter.
That’s almost 17 million different possible choices for every single pixel. There are millions of pixels on each sensor! This is a small JPEG file that the worst modern digital cameras can capture.
As shown in the graphic below, a 1-bit system can only communicate black and white. A 2-bit system can communicate black, white and two tones of gray.