If you look into the formula used by dof calculators you see that magnification is squared but aperture isn't, meaning magnification has more impact on depth of field. Magnification is estimated in calculators to be focal length divided by subject distance, so you see how much more impact  change of focal length has.

Multispectralimaging satellites

The intuitive user interface allows you to easily configure and control the instrument to make the measurements you need.

Our multispectral camera with RGB and NIR bands offers the conventional red, green, and blue spectral bands, as well as a sensitive NIR channel that can ...

Take your favorite every day lens, and photograph a subject by getting as close to the subject as the lens allows.  Then with the same focal length and subject, make an image after moving back two feet, and then another image after moving back 5 feet and then 10 feet.  With each image, try to make the best composition possible of the scene and your original subject.  Your subject can be anything - a flower, a pet, a person, or an object.  Your photo can be inside or outside.  Just make the best image you can

Fixing FoV also fixes the ratio of the focal length to the camera-subject distance - if you step back, you need a longer focal length to keep the framing of your subject constant.

noun something that gives a minutely faithful representation, image, or idea of something else: Gershwin's music was a mirror of its time.

Multispectral remote sensing involves the acquisition of visible, near infrared, and short-wave infrared images in several broad wavelength bands.

It has the performance to analyze a wide range of remote sensing imagery that translates measurements into instant feedback.

Multispectralimaging vs hyperspectral

Although it's true that decreasing distance decreases DOF, and thus the shorter focal length will result in a decrease, it's also true that the longer focal length will have less depth of field to begin with, and and its decrease beats out the distance decrease.  Though they cancel out to a certain degree, the longer focal length decreases DOF more than the shorter distance.  But more importantly for some things, it also changes the actual content of the background, a consequence that cannot be changed by changing aperture.

I think I ran out of edit time, but here, for example, is a very quick and dirty comparison, two shots made at the same aperture (shadow from flash in one), first at 24 mm, and then at 80 on a DX camera.  Neither of these lengths is radical enough to cause odd distortion of the subject, but note not only the difference in background blur, but in the actual content.

For my experiment I just put an object on a table, with a shelf full of assorted stuff a few feet behind the object.  Now take pictures of the object using different focal lengths of the same lens, at the same aperture (make sure it's the same on a variable-aperture zoom), each time with the object the same size in the frame, and if possible at the same level.  You vary only the distance and focal length to make the object the same size in the frame. You will see that not only will the depth of field be different, but the perspective between the object and the background will be different as well. This latter bit becomes really important for composition at times.

Different materials reflect and absorb differently at different wavelengths. As such, it is possible to differentiate among materials by their spectral reflectance signatures as observed in these remotely sensed images, whereas direct identification is usually not possible.

Multispectralimage classification

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I'm trying to get my head around how to balance focal length, subject distance, aperture, magnification and depth of field for an equivalent field of view.

Now the cool part. If this is portraiture or close up or wildlife photography (basically anything but landscape when you shoot close to the hyperfocal distance), under fixed framing, the depth of field (DoF) depends only on the f-stop. You cannot change it in any other way. A head shot at f/4 will have the same DoF whether it was taken using a 50 mm lens from a meter away or using a 200 mm lens from 4 meters away. The perspective will change, the appearance of the background will change but the DoF will stay the same.

Multispectral imagesin Remote sensing

Let's suppose I want to take a picture of a flower and fill the frame. I want the whole flower in focus, but everything else out of focus...w/o stacking.

Although it's true that decreasing distance decreases DOF, and thus the shorter focal length will result in a decrease, it's also true that the longer focal length will have less depth of field to begin with, and and its decrease beats out the distance decrease.  Though they cancel out to a certain degree, the longer focal length decreases DOF more than the shorter distance.  But more importantly for some things, it also changes the actual content of the background, a consequence that cannot be changed by changing aperture.

Fill the frame with every lens you have. Taking macros means f11-f18 and everything in the frame will be in focus regardless what lens you choose.

Hyperspectral sensors pose an advantage over multispectral sensors in their ability to identify and quantify molecular absorption. The high spectral resolution of a hyperspectral imager allows for detection, identification and quantification of surface materials, as well as inferring biological and chemical processes.

Hyperspectral imaging systems acquire images in over one hundred contiguous spectral bands. While multispectral imagery is useful to discriminate land surface features and landscape patterns, hyperspectral imagery allows for the identification and characterization of materials. In addition to mapping the distribution of materials, an assessment of individual pixels is often useful for detecting unique objects in the scene.

Diamond turning, or single point diamond turning as it is sometimes known, was originally a term for turning mirror-quality surfaces on high-precision, air ...

Well-developed scientific application areas include geology and mineral exploration; forestry; marine, coastal zone, inland waters and wetlands; agriculture; ecology; urban; snow and ice; and atmosphere. There are also numerous military applications in camouflage, littoral zone mapping, and landmine detection

Fill the frame with every lens you have. Taking macros means f11-f18 and everything in the frame will be in focus regardless what lens you choose.

Multispectralimage example

FieldSpec is the market leading spectroradiometer which scientists worldwide rely on to address a wide range of applications in the natural environment.

Even at f/16 the depth of field is incredibly narrow at macro distances.  30cm away from the depth of field is like...half a cm according to Photopills.

Perspective on the other hand is only related to camera to subject distance. So if you stay in one place and change focal length you don't change perspective, but if you back up you change perspective meaning something blurry behind the subject can appear bigger relative to the subject than it would if you were closer. Point being its easy to mistake a bigger blur spot for less DOF.

To fill the frame with a subject at a shorter focal length, you have to decrease the subject distance...but if you increase the subject distance, and zoom in to get an equivalent FoV...DoF decreases....

Multispectralimaging in agriculture

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There is no free lunch. If you want to defy the laws of physics, you’ll have to do focus stacking, but running back and forth with a zoom lens will do nothing for DoF.

The differences in your images can be pretty remarkable - especially as you try this with different focal lengths.  You can vary the exercise by using a zoom lens.  Take a series with the widest focal length, and another series with the longest focal length.

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You can't take a picture from farther away and then crop expecting to keep the better depth of field. The reason is when you resize the images for the subject to be the same you also alter the depth of field.

This exercise will allow you to see how close you can get and what a subject looks like when you are really close.  It will also show you what happens to DOF, field of view, composition, and the relative importance of your subject as you move back or change orientation.

Multispectralcamera

What are the OCT components? OCT imaging systems consists of three main components: the software, the system, and the catheter.

Do I get closer with a shorter focal length or stay further away and zoom in, but stop down the aperture? Or shorter and crop? Shut up and stack? Take up stamp collecting instead?

If you want maximum information from the background, showing both subject and environment, go wide.  The depth of field will be greater, and more individual elements will be visible, and identifiable even if blurred.  If you want minimum information, all the attention on the subject, go long.  Not only will the objects be blurrier, but they will be relatively larger and fewer, and likely more abstract and less distracting.

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Multispectral imagesdataset

If you have a zoom lens, here's a quick version of the above that you can do to determine just what changes in the out of focus areas as focal length changes.

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I'm trying to get my head around how to balance focal length, subject distance, aperture, magnification and depth of field for an equivalent field of view.

For these applications, ground truth signatures collected in the field and indexed in spectral libraries are critical for many methods of analysis. While image processing packages often include basic spectral libraries, application distinct libraries containing spectra of the specific materials occurring in the target field area greatly improves the accuracy of generated interpretations. Spectra of vegetation are influenced by such a wide range of environmental conditions that it makes it difficult to adequately represent this variability without the collection of site-specific field spectra.