In this tutorial I will explain the fundamental concepts and most important regarding the handling of the camera, this tutorial is applied to programs 3d cameras and cameras in real life (SLR), 3d cameras render engines try to simulate the reflex in handling. Although each application 3d sometimes renames some parameter (F-STOP = f / number) the use and concept are the same.
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I will begin by telling you that just as in real life there is no 2 cameras of different brands with the same settings make identical pictures because each camera has its own calculations to interpret the capture of a single image (color, sharpness, lighting, etc.), in the 3d programs, there not two rendering engine that renders like a scene, because each engine has its own algorithms to render a scene.
Note that the result of an image depends on the control of various parameters and the modification of one influences the other, for example to correct exposure, sharpness, depth of field, etc. depends in turn change the focal length, the aperture, shutter speed and ISO.
Is the distance from the optical center of the lens to the focal point of the lens or mirror of the camera.
These measures make a lens has greater or less breadth of vision, short values such as 10mm or less are called lens “Fish eye” which have a wide field of view and serves very well if you want to panoramic landscapes or in places where there is not much movement space, with this type of lens in a 3d scene Might capture the whole scene of 180 º or 360 º single render; higher values as 150mm or more will telephoto, this lens will have a reduced field vision but you will see distant objects closer.
Comparison of the focal length in millimeters of the objectives
Aperture (F-Stop = f / number)
In SLR cameras, the diaphragm is located as sheets inside the lens and are responsible for controlling the amount of light that passes right through the lens. These blades are opened and closed by forming a hole that passes more or less light into the camera. The diaphragm to control it manually you have the option of going gradually increasing the opening or diminishes it, this gradual control is rendered with values ranging accompanied by the symbol f. So we have commonly the diaphragm has openings with values ranging from f/2.8 to f/22, on some targets may have also f/1 and / or f/32.
The move from one value to another is called Step or EV, between steps there are also intermediate values such as between f/8 and f/11 are the f/9 y f/10, in 3d cameras can put even more numbers f accurate as f/8.08, f/8.1, f/8.156, etc.
Table of values f and intermediate steps
Increase the aperture is the same as saying you have to reduce the values f for more light to enter and close the diaphragm is the same as saying you have to increase the values of f so less light, such a value f/22 indicates that the diaphragm is closed enough so it will get a little light and f/2.8 aperture value is quite open so it will get more light.
Remember to close the diaphragm equals higher values f therefore less light enters and opening the aperture is equal to low values f therefore more light entering.
It is the time that elapses from entering the light until it reaches the sensor, the sensor is the chip where the light coming through the lens falls and is responsible for capturing the image. In the 3d programs as there is no real light either shutter, this speed and image capture is done by algorithmic calculations.
Moment when the light enters the chamber and passes through the diaphragm into the sensor, the shutter controls the time the sensor is exposed to light
Shutter speeds commonly cameras is 1/2000 to 30″ through 1/1000, 1/500, 1/250 … 1/60 … 4″, 8″, 15″, most modern SLRs speed increases to 1/4000 and/or 1/8000.
We can say that the change from one value to another is known as Step or EV, ie for example the change of 1/8 to 1/15 is 1 Step (1 EV) or 2″ to 15″ are 3 Steps (3 EV ). There are also intermediate values between Paso and Paso for example between 1/2 and 1″ is the 1/1.6 and 1/1.3, this rendering engine is more accurate because it allows you to manually set values more accurately for example 2, 1.75, 1.6 , 1.52, 1.3, etc., where 2 is 1/2.
Table of shutter speeds and intermediate steps
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The shutter speed is reflected in the exposure time of the image, as both come to the same thing, if you take a picture at a shutter speed of 1/2s image have an exposure time of 0.5 s, ie when we refer to the camera we are talking about shutter speed and when we refer to the image we’re talking about exposure time.
Imagine doing a photo correctly exposed where speed is 1/60 with respect to that first picture high speeds such as 1/2000 or 1/8000 will make the resulting image out more underexposed (dark) and low speed as 8 or 30 will make the picture come out overexposed (lighter), regardless of this example is considered high speed above 1/60 and low speed at speeds below this speed.
Left photo taken at a speed of 1/2000, central picture at 1/500 and right picture at 1/125.
Therefore a faster shutter speed shorter exposure time and at lower shutter speed longer exposure.
Scheme shutter speed and exposure time
One advantage of a short exposure is when the surroundings have much lighting is the same as saying fast shutter speeds for when you want to freeze a moving picture.
Photo with fast shutter speed of 1/1000
and the advantages of long exposure is applied when the environment has little lighting or is the same as saying slow shutter speeds for when you want to do ghosting.
Photo with slow shutter speed of 25 seconds
Another advantage of the different exposure times is to capture a sequence of images by varying the shutter speed to obtain a HDR (High Dynamic Range image), in tutorial “What is HDRi? differences and profits” explained concerning this technique and the EV.
Takes 6 photos to create an HDR
The ISO in digital cameras is responsible to tell the sensor how to behave with the light it receives. This light receiving sensor transforms electrical impulses to digital image (pixels).
A low ISO values will cause the sensor to capture the optimum image quality, but a high ISO will make the sensor amplifies their “sensitivity” to capture an image when using high ISO appear points (small circles) in the image. With a low ISO there are also points but are less noticeable.
Left picture with ISO 100, ISO 400 photo center and right picture with ISO 1600
100% detail photo (left ISO 100, ISO 400 center and right ISO 1600)
ISO is low when in 50 or 100 and a high ISO is usually above 400. A high ISO will allow you to tighten the diaphragm and therefore a low ISO lets you open the aperture more, therefore a higher ISO allows you to capture an image at shutter speeds faster than with low ISO
In some 3d programs the ISO is something that does not matter because there is no actual sensor.
Combining Aperture and Focal Length get the “Depth of Field”
The depth of field is the portion of the image that is in focus, ie which sees sharp, this depth is regulated by the diaphragm, the object distance and focal length.
Consider these three points:
Closed aperture = more depth of field and aperture open = less depth of field
When the diaphragm is more closed, greater f numbers, there will be more depth of field (more sharp objects) and when the diaphragm is more open, lower f numbers, there will be less depth of field (less sharp objects).
More focal length = a shallower depth of field and less focal length = more depth of field
When the focal length is longer (eg 300mm) depth of field is smaller and when the focal distance is smaller (16mm) depth of field is greater.
Focused objects that are far away = more depth of field and focus objects that are a short distance = more depth of field
Regardless of the aperture diaphragm have but considering the diaphragm influences the DOF if you focus an object that is very close to the camera, depth of field is less and if you focus an object that is far from the camera depth field is increased, both having the same aperture diaphragm.
Target distance is the distance at which objects are properly aimed and therefore will be sharp.
One of the advantages of 3D cameras is that accounts with placing the focusing distance in the scene, this is the point at which to take a picture or rendering objects close to it will be more sharp and while farther to it will be more blurred.
In some engines render this Target Distance is no use when the depth of field is disabled.
Without fear of Post-Production
99.9% of the images and render are passed through post-production and it did not go through post-production should be passed because there is always something that should be adjusted. We always want our picture or render them perfect from the original, otherwise we would not know how to use well the camera or the rendering engine and start our internet search on super tutorial to show us the final adjustment, and tried to one and another and another and nothing, disappointment! not as I wanted it to look. Remember that large tv and film productions that are supposed to have a great management tools to create believable images (surrealist) also spend their post images even spend more time engaged in post than to the creation of the initial image.
What is the best?
As in many other things which the debate to defend camera or render engine is the best is endless. I think it is important to have the knowledge of handling different tools in order to have a wide range of possibilities they could be used as agreed according to emerging needs. It has happened with the engine regularly render I use did not get the results I wanted, and testing another engine I got it very quickly and others jump to a third rendering engine, like I know photographers who have more than one camera different brands. What do you think?
What makes a photo or render is good your own creativity and how much knowledge you have of the settings or parameters for what you want to express in a photo or render is what you thought.
3d sharpness depends not only on the correct camera settings
Unlike in real life by having properly set the parameters of the camera does not need any more so you have a very distinct picture in 3d plus you have to properly configure the sharpness rendering engine that certainly no one that serves to all but depends on the scene, materials, lighting, etc., the materials found by the network are only a help and you come a little goal you want for your scene, but the real setting you find yourself investing your time in testing, testing and more testing.
Helpful references and links
Here I leave a list of external links related to functionality for cameras, if you know of other useful pages that you can add to the list write it in the comments.
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