Characterization of Diffraction Grating Imaging Quality - diffraction grating images
There are two ways to describe the qualities of depth of field – shallow DOF or deep DOF. Shallow is when the included focus range is very narrow, a few inches to several feet. Deep is when the included range is a couple of yards to infinity. In both cases DOF is measured in front of the focus point and behind the focus point.
It’s important to understand this concept and how it affects exposure because it works in tandem with the shutter speed (we’ll discuss this in another section) to establish a given exposure value.
However, to achieve an identical proper exposure, the shutter speed is probably closer to 1/1000th to compensate for the increased amount of light entering the lens at f/2.8.
FSO has garnered attention for its versatility across various scales of operation. On a global level, it plays a crucial role in establishing high-speed satellite internet projects like Starlink, ensuring global connectivity. At the ground level, particularly in low-altitude scenarios, FSO shines as an attractive option for last-mile connections, disaster recovery efforts, and military communications.
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The aperture range identifies the widest to smallest range of lens openings, i.e., f/1.4 (on a super-fast lens) to f/32, with incremental “stops” in between (f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, and f/22).
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To achieve a deep, rich and expansive DOF, you’ll want to set the f-stop to around f/11 or higher. You may have seen this principle demonstrated when you look at photos taken outside during the brightest time of the day. In such a case, the camera is typically set at f/16 or higher (that Sunny 16 Rule) and the Depth of Field is quite deep – perhaps several yards in front of and nearly to infinity beyond the exact focus point.
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Depth of focusin photography
The FSO system exhibits remarkable tracking capabilities, through the integration of multiple sensors and sophisticated algorithms, which enable automatic, fast, and highly accurate acquisition and fine tracking in just 10 minutes. This precision keeps the tracking error within an impressive 3 microradians (μrad), resulting in a low average link loss of just 13.7 decibels (dB) over the 1-km link. Such precision also eliminates the need for optical amplification. Remarkably, the FSO system can achieve bidirectional data rates averaging 9.27 Gbps over the 1-km link, using only commercial transceiver modules.
In a significant technological leap, researchers from Nanjing University (NJU) have developed a miniaturized FSO system that promises to revolutionize high-speed wireless communication. As reported in the Gold Open Access journal Advanced Photonics Nexus (APNexus), this remarkable system achieved an astonishing communication bandwidth of 9.16 gigabytes per second (Gbps) over a 1-kilometer (km) link. What sets it apart is that it accomplishes such high FSO performance using readily available commercial fiber optical communication transceiver modules (no need for optical amplification).
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Depth of fieldanddepth of focusPDF
The implications of this achievement are profound. This miniaturized FSO breakthrough unlocks the potential for high-speed wireless communication virtually anywhere, making connectivity happen even in the most challenging environments. As we look ahead, these devices are set to play a pivotal role in the future of FSO networks, offering plug-and-play configurations that can establish high-speed FSO channels in minutes. This innovation addresses the growing need for field-deployable, high-speed wireless communication solutions, bridging the connectivity gap in a world where staying connected is more critical than ever.
Shallowdepth of field
In a world that relies on high-speed internet and seamless communication, the absence of a reliable fiber connection can be a significant hurdle. Fortunately, a cutting-edge technology known as free-space optical communication (FSO) offers a flexible solution for field-deployable high-speed wireless communication in areas where fiber connections are unavailable.
image: A free-space optical communication experiment involves a pair of FSO devices with one (“Alice”) fixed on the top floor of a building, while the other (“Bob”) is loaded on a radio-controlled electric vehicle so that it can move around to vary the distance of the FSO link nodes. Image credit: Liu, Zhang, et al., doi 10.1117/1.APN.2.6.065001. view more
Let’s take a look at these two photos as examples. The left side of the photo has an expansive DOF, most likely shot around noon (notice the short, but strong shadows), with an f/22 aperture. The right side of the photo has an extremely shallow DOF; probably an f/2.8 aperture setting.
Basically, when you change the aperture size one stop, you have to shift the shutter speed one stop in the opposite direction to maintain a consistent exposure… and this change in aperture alters the depth of field (DOF) accordingly.
Focus enables you to isolate a subject and specifically draw the viewer’s eye to exactly where you want it.The first thing to understand about focus is depth of field.1Depth of FieldThe depth of field (DOF) is the front-to-back zone of a photograph in which the image is razor sharp.As soon as an object (person, thing) falls out of this range, it begins to lose focus at an accelerating degree the farther out of the zone it falls; e.g., closer to the lens or deeper into the background. With any DOF zone, there is a Point of Optimum focus in which the object is most sharp.There are two ways to describe the qualities of depth of field – shallow DOF or deep DOF. Shallow is when the included focus range is very narrow, a few inches to several feet. Deep is when the included range is a couple of yards to infinity. In both cases DOF is measured in front of the focus point and behind the focus point.DOF is determined by three factors – aperture size, distance from the lens, and the focal length of the lens.Let’s look at how each one works.2ApertureThe aperture is the opening at the rear of the lens that determines how much light travels through the lens and falls on the image sensor.The size of the aperture’s opening is measured in f-stops – one of two sets of numbers on the lens barrel (the other being the focusing distance).The f-stops work as inverse values, such that a small f/number (say f/2.8) corresponds to a larger or wider aperture size, which results in a shallow depth of field; conversely a large f/number (say f/16) results in a smaller or narrower aperture size and therefore a deeper depth of field.3Small vs Large ApertureManipulating the aperture is the easiest and most often utilized means to adjust Depth of Field.To achieve a deep, rich and expansive DOF, you’ll want to set the f-stop to around f/11 or higher. You may have seen this principle demonstrated when you look at photos taken outside during the brightest time of the day. In such a case, the camera is typically set at f/16 or higher (that Sunny 16 Rule) and the Depth of Field is quite deep – perhaps several yards in front of and nearly to infinity beyond the exact focus point.Let’s take a look at these two photos as examples. The left side of the photo has an expansive DOF, most likely shot around noon (notice the short, but strong shadows), with an f/22 aperture. The right side of the photo has an extremely shallow DOF; probably an f/2.8 aperture setting.However, to achieve an identical proper exposure, the shutter speed is probably closer to 1/1000th to compensate for the increased amount of light entering the lens at f/2.8.4Aperture RangeThe aperture range identifies the widest to smallest range of lens openings, i.e., f/1.4 (on a super-fast lens) to f/32, with incremental “stops” in between (f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, and f/22).Each f-number is represents one “stop” of light, a stop is a mathematical equation (which is the focal length of the lens divided by the diameter of the aperture opening) that determines how much light that enters the lens regardless of the length of the lens. Such that an f/4 on a 50mm has smaller opening than an f/4 on a 200mm, but an equivalent amount of light travels through both lenses to reach the image sensor thus providing the same exposure.Each movement up the range (say f/2 to f.2.8) reduces the amount of light by one-half, and each movement down the range (say f/11 to f/8) doubles the amount of light passing through the lens.It’s important to understand this concept and how it affects exposure because it works in tandem with the shutter speed (we’ll discuss this in another section) to establish a given exposure value.Basically, when you change the aperture size one stop, you have to shift the shutter speed one stop in the opposite direction to maintain a consistent exposure… and this change in aperture alters the depth of field (DOF) accordingly.5Distance from the LensThe last element affecting depth of field is the distance of the subject from the lens – you can adjust the DOF by changing that distance.For example, the closer an object is to the lens (and the focus is set on that object) the shallower the DOF. Conversely, the reverse is true – the farther away an object is and focused on, the deeper the DOF. Changing the distance to subject is the least practical way to manipulate the depth of field, and by changing the distance from a subject to the lens, you immediately change your image’s composition. To maintain the compositional integrity of the shot, but still have the change in DOF from a distance, you can change the focal length (either by changing lenses or zooming in).Why does changing the focal length negate the effects on DOF? This is because the visual properties of a given lens either provide either greater DOF (shorter lenses) or shallower DOF (longer lenses). The physical properties of a lens at a given focal length also affect the depth of field. A shorter focal length lens (say 27mm) focused at 5 meters, set at f/4 has a deeper DOF (perhaps from 3 meters in front and 20 meters behind) than a longer focal length (say 300mm), also set at f/4 focused at 5 meters. The 300mm lens has a remarkably shallow depth of field.Incidentally, to help you with this, every lens has a manual with a DOF chart for each f/stop and the major focusing distances. DOF is just a matter of physics, and it’s important to grasp this concept.CConclusionManipulation of depth of field is a good way to modify the characteristics of your photo, and manipulating the aperture is the ideal way to do this because it has little or no effect on composition.You simply need to change the shutter speed (or change the light sensitivity – ISO) to compensate for the changes in the exposure from the adjustments to the f-number. Changes in distance and focal length also affect DOF, but these changes have trade-offs in terms of composition.Therefore, changes to aperture are the best way to manipulate DOF without affecting a photo’s composition.
Manipulation of depth of field is a good way to modify the characteristics of your photo, and manipulating the aperture is the ideal way to do this because it has little or no effect on composition.
A free-space optical communication experiment involves a pair of FSO devices with one (“Alice”) fixed on the top floor of a building, while the other (“Bob”) is loaded on a radio-controlled electric vehicle so that it can move around to vary the distance of the FSO link nodes. Image credit: Liu, Zhang, et al., doi 10.1117/1.APN.2.6.065001.
From space-wide internet to last-mile connectivity, portable free-space optical communication promises to bridge connectivity gaps on-demand
Each movement up the range (say f/2 to f.2.8) reduces the amount of light by one-half, and each movement down the range (say f/11 to f/8) doubles the amount of light passing through the lens.
In this section we’re going to discuss several crucial elements for exercising greater creative control over your final photographic image.Other than lighting, composition and focus (which includes depth of field) are the main elements that you can exercise complete command over.Focus enables you to isolate a subject and specifically draw the viewer’s eye to exactly where you want it.The first thing to understand about focus is depth of field.1Depth of FieldThe depth of field (DOF) is the front-to-back zone of a photograph in which the image is razor sharp.As soon as an object (person, thing) falls out of this range, it begins to lose focus at an accelerating degree the farther out of the zone it falls; e.g., closer to the lens or deeper into the background. With any DOF zone, there is a Point of Optimum focus in which the object is most sharp.There are two ways to describe the qualities of depth of field – shallow DOF or deep DOF. Shallow is when the included focus range is very narrow, a few inches to several feet. Deep is when the included range is a couple of yards to infinity. In both cases DOF is measured in front of the focus point and behind the focus point.DOF is determined by three factors – aperture size, distance from the lens, and the focal length of the lens.Let’s look at how each one works.2ApertureThe aperture is the opening at the rear of the lens that determines how much light travels through the lens and falls on the image sensor.The size of the aperture’s opening is measured in f-stops – one of two sets of numbers on the lens barrel (the other being the focusing distance).The f-stops work as inverse values, such that a small f/number (say f/2.8) corresponds to a larger or wider aperture size, which results in a shallow depth of field; conversely a large f/number (say f/16) results in a smaller or narrower aperture size and therefore a deeper depth of field.3Small vs Large ApertureManipulating the aperture is the easiest and most often utilized means to adjust Depth of Field.To achieve a deep, rich and expansive DOF, you’ll want to set the f-stop to around f/11 or higher. You may have seen this principle demonstrated when you look at photos taken outside during the brightest time of the day. In such a case, the camera is typically set at f/16 or higher (that Sunny 16 Rule) and the Depth of Field is quite deep – perhaps several yards in front of and nearly to infinity beyond the exact focus point.Let’s take a look at these two photos as examples. The left side of the photo has an expansive DOF, most likely shot around noon (notice the short, but strong shadows), with an f/22 aperture. The right side of the photo has an extremely shallow DOF; probably an f/2.8 aperture setting.However, to achieve an identical proper exposure, the shutter speed is probably closer to 1/1000th to compensate for the increased amount of light entering the lens at f/2.8.4Aperture RangeThe aperture range identifies the widest to smallest range of lens openings, i.e., f/1.4 (on a super-fast lens) to f/32, with incremental “stops” in between (f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, and f/22).Each f-number is represents one “stop” of light, a stop is a mathematical equation (which is the focal length of the lens divided by the diameter of the aperture opening) that determines how much light that enters the lens regardless of the length of the lens. Such that an f/4 on a 50mm has smaller opening than an f/4 on a 200mm, but an equivalent amount of light travels through both lenses to reach the image sensor thus providing the same exposure.Each movement up the range (say f/2 to f.2.8) reduces the amount of light by one-half, and each movement down the range (say f/11 to f/8) doubles the amount of light passing through the lens.It’s important to understand this concept and how it affects exposure because it works in tandem with the shutter speed (we’ll discuss this in another section) to establish a given exposure value.Basically, when you change the aperture size one stop, you have to shift the shutter speed one stop in the opposite direction to maintain a consistent exposure… and this change in aperture alters the depth of field (DOF) accordingly.5Distance from the LensThe last element affecting depth of field is the distance of the subject from the lens – you can adjust the DOF by changing that distance.For example, the closer an object is to the lens (and the focus is set on that object) the shallower the DOF. Conversely, the reverse is true – the farther away an object is and focused on, the deeper the DOF. Changing the distance to subject is the least practical way to manipulate the depth of field, and by changing the distance from a subject to the lens, you immediately change your image’s composition. To maintain the compositional integrity of the shot, but still have the change in DOF from a distance, you can change the focal length (either by changing lenses or zooming in).Why does changing the focal length negate the effects on DOF? This is because the visual properties of a given lens either provide either greater DOF (shorter lenses) or shallower DOF (longer lenses). The physical properties of a lens at a given focal length also affect the depth of field. A shorter focal length lens (say 27mm) focused at 5 meters, set at f/4 has a deeper DOF (perhaps from 3 meters in front and 20 meters behind) than a longer focal length (say 300mm), also set at f/4 focused at 5 meters. The 300mm lens has a remarkably shallow depth of field.Incidentally, to help you with this, every lens has a manual with a DOF chart for each f/stop and the major focusing distances. DOF is just a matter of physics, and it’s important to grasp this concept.CConclusionManipulation of depth of field is a good way to modify the characteristics of your photo, and manipulating the aperture is the ideal way to do this because it has little or no effect on composition.You simply need to change the shutter speed (or change the light sensitivity – ISO) to compensate for the changes in the exposure from the adjustments to the f-number. Changes in distance and focal length also affect DOF, but these changes have trade-offs in terms of composition.Therefore, changes to aperture are the best way to manipulate DOF without affecting a photo’s composition.
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Depth of field vs depth of focusreddit
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Incidentally, to help you with this, every lens has a manual with a DOF chart for each f/stop and the major focusing distances. DOF is just a matter of physics, and it’s important to grasp this concept.
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Depth of field vs depth of focusnikon
The last element affecting depth of field is the distance of the subject from the lens – you can adjust the DOF by changing that distance.
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The core of this miniaturized FSO system comprises a pair of FSO devices. Each FSO device is compact, measuring just 45 cm × 40 cm × 35 cm, with a weight of 9.5 kilograms and a power consumption of approximately 10 watts. Each houses an optical transceiver module, an acquisition, pointing, and tracking (APT) device, and its control electronics, all safely sealed within a box for rugged outdoor operation. The APT device stands out with its low-diffraction optical design and a highly efficient 4-stage closed-loop feedback control system.
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For example, the closer an object is to the lens (and the focus is set on that object) the shallower the DOF. Conversely, the reverse is true – the farther away an object is and focused on, the deeper the DOF. Changing the distance to subject is the least practical way to manipulate the depth of field, and by changing the distance from a subject to the lens, you immediately change your image’s composition. To maintain the compositional integrity of the shot, but still have the change in DOF from a distance, you can change the focal length (either by changing lenses or zooming in).
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The aperture is the opening at the rear of the lens that determines how much light travels through the lens and falls on the image sensor.
Each f-number is represents one “stop” of light, a stop is a mathematical equation (which is the focal length of the lens divided by the diameter of the aperture opening) that determines how much light that enters the lens regardless of the length of the lens. Such that an f/4 on a 50mm has smaller opening than an f/4 on a 200mm, but an equivalent amount of light travels through both lenses to reach the image sensor thus providing the same exposure.
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Depth of field vs depth of focusphotography
According to Zhenda Xie, professor at the NJU School of Electronic Science and Engineering and corresponding author for the APNexus article, “This work highlights the potential for achieving FSO using commercially available fiber optical transceiver modules.” Xie notes that the effective distance of 1 km may be extended; his team also tested the optical links at up to 4 km, where the average loss increased to 18 dB – likely due to a foggy test environment. “With better weather conditions and optical amplification, longer FSO can be expected,” Xie concludes.
The size of the aperture’s opening is measured in f-stops – one of two sets of numbers on the lens barrel (the other being the focusing distance).
Depth of field vs depth of focuscamera
The f-stops work as inverse values, such that a small f/number (say f/2.8) corresponds to a larger or wider aperture size, which results in a shallow depth of field; conversely a large f/number (say f/16) results in a smaller or narrower aperture size and therefore a deeper depth of field.
As soon as an object (person, thing) falls out of this range, it begins to lose focus at an accelerating degree the farther out of the zone it falls; e.g., closer to the lens or deeper into the background. With any DOF zone, there is a Point of Optimum focus in which the object is most sharp.
Depth of field vs depth of focusmicroscope
For details, read the Gold Open Access article by Liu, Zhang, et al., “High-speed free-space optical communication using standard fiber communication components without optical amplification,” Adv. Photon. Nexus 2(6) 065001 (2023), doi 10.1117/1.APN.2.6.065001.
You simply need to change the shutter speed (or change the light sensitivity – ISO) to compensate for the changes in the exposure from the adjustments to the f-number. Changes in distance and focal length also affect DOF, but these changes have trade-offs in terms of composition.
Why does changing the focal length negate the effects on DOF? This is because the visual properties of a given lens either provide either greater DOF (shorter lenses) or shallower DOF (longer lenses). The physical properties of a lens at a given focal length also affect the depth of field. A shorter focal length lens (say 27mm) focused at 5 meters, set at f/4 has a deeper DOF (perhaps from 3 meters in front and 20 meters behind) than a longer focal length (say 300mm), also set at f/4 focused at 5 meters. The 300mm lens has a remarkably shallow depth of field.
Other than lighting, composition and focus (which includes depth of field) are the main elements that you can exercise complete command over.Focus enables you to isolate a subject and specifically draw the viewer’s eye to exactly where you want it.The first thing to understand about focus is depth of field.1Depth of FieldThe depth of field (DOF) is the front-to-back zone of a photograph in which the image is razor sharp.As soon as an object (person, thing) falls out of this range, it begins to lose focus at an accelerating degree the farther out of the zone it falls; e.g., closer to the lens or deeper into the background. With any DOF zone, there is a Point of Optimum focus in which the object is most sharp.There are two ways to describe the qualities of depth of field – shallow DOF or deep DOF. Shallow is when the included focus range is very narrow, a few inches to several feet. Deep is when the included range is a couple of yards to infinity. In both cases DOF is measured in front of the focus point and behind the focus point.DOF is determined by three factors – aperture size, distance from the lens, and the focal length of the lens.Let’s look at how each one works.2ApertureThe aperture is the opening at the rear of the lens that determines how much light travels through the lens and falls on the image sensor.The size of the aperture’s opening is measured in f-stops – one of two sets of numbers on the lens barrel (the other being the focusing distance).The f-stops work as inverse values, such that a small f/number (say f/2.8) corresponds to a larger or wider aperture size, which results in a shallow depth of field; conversely a large f/number (say f/16) results in a smaller or narrower aperture size and therefore a deeper depth of field.3Small vs Large ApertureManipulating the aperture is the easiest and most often utilized means to adjust Depth of Field.To achieve a deep, rich and expansive DOF, you’ll want to set the f-stop to around f/11 or higher. You may have seen this principle demonstrated when you look at photos taken outside during the brightest time of the day. In such a case, the camera is typically set at f/16 or higher (that Sunny 16 Rule) and the Depth of Field is quite deep – perhaps several yards in front of and nearly to infinity beyond the exact focus point.Let’s take a look at these two photos as examples. The left side of the photo has an expansive DOF, most likely shot around noon (notice the short, but strong shadows), with an f/22 aperture. The right side of the photo has an extremely shallow DOF; probably an f/2.8 aperture setting.However, to achieve an identical proper exposure, the shutter speed is probably closer to 1/1000th to compensate for the increased amount of light entering the lens at f/2.8.4Aperture RangeThe aperture range identifies the widest to smallest range of lens openings, i.e., f/1.4 (on a super-fast lens) to f/32, with incremental “stops” in between (f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, and f/22).Each f-number is represents one “stop” of light, a stop is a mathematical equation (which is the focal length of the lens divided by the diameter of the aperture opening) that determines how much light that enters the lens regardless of the length of the lens. Such that an f/4 on a 50mm has smaller opening than an f/4 on a 200mm, but an equivalent amount of light travels through both lenses to reach the image sensor thus providing the same exposure.Each movement up the range (say f/2 to f.2.8) reduces the amount of light by one-half, and each movement down the range (say f/11 to f/8) doubles the amount of light passing through the lens.It’s important to understand this concept and how it affects exposure because it works in tandem with the shutter speed (we’ll discuss this in another section) to establish a given exposure value.Basically, when you change the aperture size one stop, you have to shift the shutter speed one stop in the opposite direction to maintain a consistent exposure… and this change in aperture alters the depth of field (DOF) accordingly.5Distance from the LensThe last element affecting depth of field is the distance of the subject from the lens – you can adjust the DOF by changing that distance.For example, the closer an object is to the lens (and the focus is set on that object) the shallower the DOF. Conversely, the reverse is true – the farther away an object is and focused on, the deeper the DOF. Changing the distance to subject is the least practical way to manipulate the depth of field, and by changing the distance from a subject to the lens, you immediately change your image’s composition. To maintain the compositional integrity of the shot, but still have the change in DOF from a distance, you can change the focal length (either by changing lenses or zooming in).Why does changing the focal length negate the effects on DOF? This is because the visual properties of a given lens either provide either greater DOF (shorter lenses) or shallower DOF (longer lenses). The physical properties of a lens at a given focal length also affect the depth of field. A shorter focal length lens (say 27mm) focused at 5 meters, set at f/4 has a deeper DOF (perhaps from 3 meters in front and 20 meters behind) than a longer focal length (say 300mm), also set at f/4 focused at 5 meters. The 300mm lens has a remarkably shallow depth of field.Incidentally, to help you with this, every lens has a manual with a DOF chart for each f/stop and the major focusing distances. DOF is just a matter of physics, and it’s important to grasp this concept.CConclusionManipulation of depth of field is a good way to modify the characteristics of your photo, and manipulating the aperture is the ideal way to do this because it has little or no effect on composition.You simply need to change the shutter speed (or change the light sensitivity – ISO) to compensate for the changes in the exposure from the adjustments to the f-number. Changes in distance and focal length also affect DOF, but these changes have trade-offs in terms of composition.Therefore, changes to aperture are the best way to manipulate DOF without affecting a photo’s composition.