Online flu calculation. Depth of field calculator. Formulas for calculating flu

DOF and hyperfocal distance are some of the basic concepts that a beginner photographer needs to learn. Let's figure it out in order - what it is and what it is used for in photography.

GRIP is an abbreviation for the words Depth of Sharp Space, she's the same Depth of field. In English, the abbreviation GRIP will be called Depth of Field or DOP. This is the region of space, or the distance between the near and far edges, where objects will be perceived as sharp.

Strictly speaking, ideal sharpness, from the point of view of physics, can only be in one plane. Where then does this area come from? The fact is that the human eye, despite all its perfection, is still not an ideal optical system. We don't notice the slight blurring to some extent. It is generally accepted that the human eye does not notice a point blur of up to 0.1 mm from a distance of 0.25 m. All depth of field calculations are based on this. In photography, this slight blurring of a point is called circle of blur. In most calculation methods, the diameter of the circle of confusion is taken to be 0.03 mm.

Based on the assumption that the human eye does not notice some blur, we will no longer have a plane of sharpness in space (called the focal plane), but a certain area that is limited by the acceptable blur of objects. This area will be called depth of field.

What does depth of field depend on?

The depth of field of the imaged space is influenced by only two parameters:

1. Lens focal length
2. Aperture size

How more focal length of the lens, the less depth of field. How wider the aperture is open (smaller f-number), the less depth of field. Simply put, in order to obtain the greatest possible depth of field, you need to use wide angle lens and cover the aperture as much as possible, making its opening smaller. Conversely, to obtain a minimum depth of field, it is advisable to use a long lens and a wide open aperture.

In some sources, which are positioned as very authoritative, you can find the statement that the depth of field is also affected by the size of the matrix or film frame. Actually this is not true. The matrix size or crop factor itself does not have any effect on the depth of field. But why then is the depth of field in compact cameras with a small sensor size significantly greater than in SLR cameras with a large sensor size? Because as the matrix size decreases, the focal length of the lens required to obtain the same angle of view also decreases! And the shorter the focal length, the greater the depth of field.

Depth of field also depends on the distance to the subject - the closer you are to the lens, the shallower the depth of field, and the more pronounced the background blur.

How depth of field is used

Choosing the optimal depth of field depends on the shooting task. The most common mistake made by novice photographers who have recently purchased a fast lens is to shoot everything at the widest aperture. Sometimes it's good, sometimes it's not. For example, if you shoot a portrait with too shallow a depth of field, you may end up with the eyes in sharp focus but the tip of the nose not. Is it beautiful? The question is controversial. If a person's head is turned to the side, the near eye may appear sharp and the far eye blurry. This is completely acceptable, but a client who does not know what depth of field is may have some questions.

Therefore, to obtain optimal depth of field when portrait photography, there is no need to strive to always open the aperture. For most cases, it is better to cover it a couple of steps. Then the background will be pleasantly blurred, and the depth of field will be acceptable. When shooting group portraits, it is especially important to ensure such a depth of field so that all people are sharp. In this case, the aperture closes down further, to f/8 -f/11 when shooting outdoors and in good lighting.

Hyperfocal distance

What if we need, for example, to photograph a landscape where the foreground and background objects should be equally sharp? This is where the ability to use hyperfocal distance. This is the distance to the front edge of the field of view when the lens is focused at infinity. In other words, this is the same depth of field, but when focusing at infinity.

Depending on where it is more important to obtain maximum sharpness - in the foreground or on the most distant objects, they focus either at the hyperfocal distance or at infinity. In the first case, foreground details will be sharper, in the second - distant objects. Hyperfocal distance also depends on the focal length of the lens and aperture. The wider the aperture is closed and the shorter the focal length of the lens, the smaller the hyperfocal distance.

Both the foreground and background are sharp in this photo.

Calculation of depth of field and hyperfocal distance

To calculate the depth of field and hyperfocal distance, special tables are usually used. But I recommend using more in a modern way, namely, a specialized program. It works online directly in the browser. The program is very easy to use and easy to figure out on your own. And the most important thing that will help you choose the right depth of field and hyperfocal distance is constant conscious practice!

Depth of field in photography– this is the distance between the front and rear boundaries of the sharply depicted space ( in optical image space), measured along the optical axis, within which the subjects in the image appear sharp (Fig. 1).

Rice. 1 - Depth of field

There is also the concept of “depth of field” (DOF), which is often confused with the concept of “depth of field”.

DOF- this is also the distance along the optical axis of the lens, but it lies in the space of objects and within which objects will be depicted sharply. (Fig. 2, 3).

It is the result of a depth of field selected by the photographer, which is visible directly in the photograph, i.e. in the plane of optical images behind the lens. The depth of field is located in the plane of the depicted objects. This is the main difference.

DOF is affected by:

• distance to the subject;
• lens focal length;
• lens size.

Rice. 4 - Changing the depth of field at different focal lengths and aperture values

Maximum depth of field

Some photographs, such as landscapes, require a greater depth of field to capture as much of the scene as possible.

To do this you need:

• stand so that the foreground objects are as far as possible from the lens, move away to the maximum possible distance;
• close the aperture to the required value (f11 - f22), checking the depth of field with the aperture repeater;
• If possible, use a wide-angle lens.

Some cameras have an automatic exposure metering mode with depth of field control - DEP. In this case, you need to specify two points that should be displayed sharply and shoot. The shutter speed and aperture values ​​will be determined automatically. The method works when the lens autofocuses.

To achieve an infinite (to the horizon) depth of field, use hyperfocal distance– the distance from which to infinity objects look sharp with a lens focused at infinity (Fig. 5). With depth of field it starts from 1/2 the distance to the focusing point and to infinity (Fig. 6).

The hyperfocal distance values ​​for given parameters (lens focal length, aperture number, distance and lens circle of confusion) are calculated using special programs or tables, for example, Table 1.

Table 1 - Calculation of depth of field and hyperfocal distance values

Minimum depth of field

The task of minimizing depth of field is much more difficult than maximizing it. In many cameras (mostly compact ones) this is practically impossible due to the small size of the sensor, the default short throw lens and focusing by searching for the hyperfocal distance. This is precisely one of the strongest arguments in favor of digital SLR camera– the ability to sharpen that part of the scene that the photographer needs.

Blurring the background or some foreground elements allows you to focus the viewer’s attention on the main subject of photography, highlight it, and is one of the key creative moments and the cause of the phenomenon (Fig. 8, 8).

For achievement minimum depth sharpness you can:

• use the maximum open aperture (f1.2 - f1.8, f2.8) depending on the lens;
• use long telephoto lenses. The longer the focal length, the shallower the depth of field in the image;
• get as close to the subject as possible;
• If possible, increase the distance between the background and the subject.

Degree of lack of sharpness

The amount of image blur varies smoothly along the depth of field. An object is depicted as absolutely sharp only in the plane of focus; all other points begin to gradually blur as they move away from this plane.

To achieve this depth of field, a macro lens was used with the aperture wide open. The shooting was carried out from a tripod as close as possible to the object - the “5 kopeks” coin.

Difficulties associated with depth of field

Often, when using long-focus or macro lenses (long distances or macro photography), a situation arises when it is impossible to ensure such a depth of field that all significant elements are sharp, since the depth of field is several millimeters. This may also be due to the problem of poor lighting, since in this case it is necessary to use open apertures to provide the necessary .

To solve such problems you can:

• choose a viewing angle such that the change in depth of field is minimal (Fig. 11);
• remove from a stop (tripod, monopod);
• when photographing people, focus on the eyes, since we are accustomed to paying attention to them first;
• in macro photography, a series of frames is taken with the camera itself shifted (without changing the focus), which are then combined into one.

Bottom line

Adjusting the depth of field during shooting occurs mainly by changing the aperture value and the distance to the subject.

IN landscape photography use maximum depth sharpness, which is achieved by focusing at the hyperfocal distance, which is calculated using special tables or calculators.

In portrait photography, the depth of field is limited to such that it allows you to highlight the necessary elements. It's best to focus on your eyes. An exception may be documentary filming, when you need to show a person in his environment, which should be clearly recognizable (sharp).

When shooting macro, sports, or wildlife with long lenses, photographers may experience insufficient depth of field. To do this, close the aperture to possible values ​​(f4-8) within the required exposure.

The program can open four windows.

The program can be used as a simple calculator. In this case, use the arrows above and below the values ​​of focal length, aperture number and acceptable circle of confusion to select the necessary parameters, use the arrows at the bottom of the window to select the distance at which the focusing object is located, and read the value of the foreground and background. The bottom line shows in red the position to the beginning of infinity and the position of the foreground when focusing at the hyperfocal distance. The program allows you to graphically present the results obtained. So, the focus point is marked by a green man on the road. Depth of field can be assessed by which trees are sharply depicted on the side of the road. If the background is at infinity, mountains on the horizon become visible. The distance can be changed by dragging the man along the road. If the distance becomes less than 1 m, then a window opens that shows the value of the depth of field, the position of the sharp plans relative to the flower, which can also be dragged across the screen. A red flag on the road marks the hyperfocal distance, a red stripe on the road marks the boundary of the sharply registered foreground when pointing at it. This part of the program has not changed since the very first version. The calculation is carried out in accordance with the formulas below, which give an unambiguous result if the focal length, aperture and circle of confusion are specified. All changes in the program are associated with additional reference information that facilitates the selection of an acceptable circle of confusion. This part is not intended to provide an exact number, but rather to provide a rough estimate and better understanding of the criteria that determine the selection of an acceptable circle of confusion. The latest version of the program has added a window that allows you to estimate the angle of the field of view and the size of objects falling into the frame. The horizontal viewing angle is displayed, indicated as hfov, and vertical, denoted as vfov. The angles are calculated for the frame, the size of which is displayed in the upper right corner of the screen in red. The display of corners and the expected picture on the screen can be disabled by clicking on the camera screen in the lower left corner of the screen. Angle of view is useful when shooting panoramas to estimate the number of frames required for a given focal length and sensor size. In addition, this parameter seems to me to be significantly more reasonable than the reduced focal length that is often used instead. Today, when the percentage of people with experience working with film SLR cameras with a set of lenses with different focal lengths is negligible compared to the shooting public, this does not make life easier for experienced photographers and misleads beginners, since the concept of focal length accepted in optics has no relation, and determines not the distance from the lens to the point at which the parallel beam converges, but the angle at which the object occupying the entire frame is visible. The calculation of angles in the program is carried out for normal (rectilinear) lenses and cannot be applied to fisheye lenses. The focal length in the program can be changed to unrealistic values ​​for some combinations of a normal lens + matrix, and, therefore, the picture displaying the expected image on the camera screen will also be unrealistic :-) So, a normal lens with a focal length of 15 when working with a 36x24 frame mm gives a horizontal angle of view of 100 degrees, and a fisheye lens with a similar focal length is already 140 degrees. Read more about the difference in angle of view between lenses different designs see the article "Ultra-wide-angle lens Mir-47".

The acceptable circle of blur is assessed by clicking on the question mark in the upper right corner. To get the correct value, you must make a selection in the top and one of the two lower drop-down menus. The top menu is used to set the frame size, the next menu allows you to set the number of pixels in the matrix, or the AgBr item, which implies the use of medium film with relatively good lens. If you select a frame size of 36x24 mm in the top menu and AgBr in the next menu, the program will give values ​​close to those printed on the lens frame. The bottom drop-down menu allows you to set the size of the desired print. It is advisable to use it if your camera has a spare number of pixels, but you are not going to print large prints. In this case, the assessment is made from the printing condition, for example, on a sublimation printer with a resolution of 300 dpi. This is close to what the eye can see from a distance of best vision of 25 cm. In this case, the second window will display the number of megapixels of the matrix, the size of two pixels of which is equal to the calculated circle of blur.

I recommend taking a series of test photographs of the world to determine the experimentally acceptable circle of dispersion for your device. It is very likely that it will be determined by the capabilities of the lens, not the matrix.

In addition to the permissible focus circle, the program also displays the value of the linear resolution limit (dp). If the linear resolution limit exceeds the specified size of the allowable focus circle d, then the background under the aperture values ​​of the allowable focus circle and the linear limit of resolution will turn pink. In this case, to get real values, you need to change either the aperture or the acceptable focus circle.

1. Focal length
2. Diaphragm
3. Acceptable circle of blur
4. Linear resolution limit
5. Frame size
6. Number of pixels in the matrix
7. Print size
8. Distance
9. Foreground and background position
10. Hyperfocal distance
11. Foreground position when focusing at hyperfocal distance

The program can be used without leaving this article; it can be recorded separately and launched using Macromedia Flash Player or through a browser by running the rezkost.html file. Latest version When running the program on the local machine, it allows you to edit the starting values. To do this, you need to edit the datarzk.txt file. You can set values ​​for the matrix that are not available from the program menu; they will remain in effect until you enter new ones in the menu. Recording formats:

dn6=0.016&fn=35&dnr1=24&wc=3&hc=2&mp=9&
or
fn=35&dnr1=24&wc=3&hc=2&mp=9&

Where fn=35&- means that the initial focal length is 35 mm, and dn6=0.016&, that the permissible circle of confusion is 16 microns. This circle of confusion value is valid until the button with a question mark is pressed. After entering the menu for evaluating the permissible circle of blur, priority will be given to the parameters specified in this menu. If the acceptable circle of confusion is not specified, then it is calculated from the number of sensitive elements in the matrix, specified in MP. dnr1=24&- the size of the long side of the frame is 24 mm, wc=3&hc=2&- the aspect ratio of the frame in this case is 3:2, mp=9&- the number of sensitive elements in the matrix is ​​9 MP.

Using a PDA imposes certain limitations due to the fact that you do not have a right mouse button, and the fact that the computer knows about the position of the cursor only when the pen touches the screen. It is not able to distinguish between the pen being over the button and actually pressing the button, so you may have to make an extra press when moving from one button to another.

The program uses a Latin font, since this allows, firstly, to use PDA fonts without problems and not waste space on introducing letter styles into the program file, and secondly, I was unable to find a small Cyrillic font that would be clearly readable on PDA.

Theory and practice

Depth of field is calculated based on fairly simple formulas, however, doing calculations during the shooting process is not always convenient; during the calculations, the bee may fly away. ; ; where p is the distance between the image plane and the guidance plane, A is the relative aperture, f is the focal length, d is the permissible circle of dispersion, p 1 is the foreground position, p 2 is the background position.

The photographic resolution of a photographic lens is characterized by the number of parallel strokes (lines) that a given lens can reproduce on a piece of photographic material 1 mm long. The resolution of photographic material is determined similarly. The linear resolution of a photographic lens is the reciprocal of the line resolution. To estimate the resolution of a photographic lens taking into account the resolution of the photolayer, the linear resolutions of the lens and the photolayer should be summed. To determine the depth of sharply imaged space of objects, the permissible defocus circle must correspond to the sum of the linear resolutions of the lens and the photographic layer. However, no matter how well we focus on the object, and no matter how high the resolution of the lens, the maximum resolution of the optical system to separately image two closely spaced points is limited by diffraction at the boundary of the pupil. According to the diffraction theory, a luminous point, due to diffraction by the diaphragm, is depicted in the form of a scattering circle. This circle consists of a bright central core, called the Airy circle, and surrounding dark and light rings. Rayleigh concluded that two equally bright points are visible separately if the center of the Airy circle of one point coincides with the first minimum of the second point. From the Rayleigh criterion it follows that the resolution of an ideal photographic lens when using absolute contrast and illuminated with monochrome light depends only on the ratio of the focal length to the diameter of the pupil, that is, on the aperture number. And the linear resolution limit of the optical system is: where K is the aperture number, f is the focal length, lambda is the wavelength. At a wavelength of 546 nm, we obtain a value equal to K/1500 for the linear resolution limit.

In relation to the matrix of a digital camera, we can assume that 2 lines will be distinguishable if the diameter of the focusing circle is less than the linear size of the two sensitive elements. In this case, if the image of 2 white lines is drawn exactly to the centers of two non-adjacent sensitive elements, then the signal on them will be maximum, while in the element located between them - minimal. Of course, the slightest shift of the image relative to the matrix will lead to the fact that we will not be able to distinguish the lines. If the strokes of the test object go at a certain angle to the columns of the sensitive elements, then, examining the image line by line, you can see alternating solid and dotted lines. The result is a structure reminiscent of moiré fabric.

My measurements of the lens + matrix system show that the real resolution is one and a half times worse than the maximum theoretical resolution for one matrix, and to obtain linear resolution the size of two sensitive cells must be multiplied by 1.6.

When shooting landscapes, knowing the hyperfocal distance, or the beginning of infinity, is very important. These terms denote the distance to an object, when focusing on which the sharp background is at infinity. If we set the hyperfocal distance on the camera scale, then the background will lie at infinity, and the foreground will be twice as close to the focus point. If we point the camera at infinity, the foreground will coincide with the hyperfocal distance. That. By pointing the camera not at infinity, but at the hyperfocal distance, we double the edge of the sharp foreground.

For orientation in the permissible scattering circles, the table below gives the characteristic values ​​of the linear resolution limits of typical lenses, photographic films and matrices.

On good film you can distinguish up to 100 lines per mm. Good lenses for 35 mm film cameras have a center resolution of 40-60 lines per mm. To estimate the resolution of a lens + film system, the linear resolution limits for film and lens are added, i.e. in a typical case, about 50 lines per mm can be recorded. Those. The permissible focusing circle for this system is 20 microns.

Lenses designed for manual focusing usually have a depth of field scale. Using the program, it is easy to solve the inverse problem and determine the acceptable circle of confusion, which was taken to calculate the scale.

Sharpness scale on the Volna -3 lens for the Kyiv 88 camera with F=80 mm. The scale is drawn on the basis that the permissible circle of confusion is approximately 65 microns.



Table of depth of field on a Welta camera with a Xenon F=50 mm lens. The table is based on the assumption that the permissible circle of blur is approximately 40 microns

I analyzed the scales on the rest of my lenses, and this is what I came up with:

As we see in most cases, the scale is constructed on the assumption that the result will be a print of 10x15 cm. The greatest variation in the size of the circle of confusion is observed in lenses of medium format cameras. That. If we want to get the most out of the film and lens, then we must take into account that the depth of field imaged will be less than the range indicated on the lens. Download latest version

License agreement

It is now customary to preface any program with a license agreement. Following the spirit of the times, I did this in 2001. Having summarized the experience of others in writing a similar document, I came to the conclusion that it all comes down to the following statement:

Dear user, eat for your health.
If you choke, then you are a fool.
If you feed others, forgetting about the cook, then get ready for a confrontation with Kuzka’s mother.

This license agreement applies to all executable modules of the program. The latest version 2.1 can also be downloaded with source codes, and in this case I found it necessary to change my wishes for its use and, therefore, the license agreement. The Free Software Foundation has done a great job of refining the language, and I decided to take advantage of their efforts. This program is distributed under a license identical to .

I'll try to explain why I didn't just use the GNU GPL license.

1) My understanding of the conditions put forward must be maximum. Obviously, this must be done in the native language, regardless of the level of foreign language proficiency and trust in the translator. Most people know their native language better than a foreign one, and they trust themselves more than anyone else :-).

2) The preface to the translation says:
"This translation of the GNU General Public License into Russian is not an official translation. It is not published by the Free Software Foundation and does not establish legally binding terms for distribution software, which is distributed under the terms of the GNU General Public License. The only legally binding terms are set forth in the authentic text of the GNU English General Public License."

However, in my understanding, the hierarchy of conditions that determine the operation of the Internet is based first on and then on all documents that do not contradict it.

The declaration reads:
"Governments derive their powers from the consent of the governed. You didn't ask for it, and you didn't get it from us. We didn't invite you. You don't know us, you don't know our world. Cyberspace is not within your borders. Don't think you can build it as if it were a public building project. You cannot do that. It is a natural phenomenon and it grows on its own through our collective actions.

You have not participated in our vast and growing dialogue, you have not created the wealth of our market. You do not know our culture, our ethics, our unwritten laws, which already provide more order in our society than could be obtained from any of your prescriptions.

You claim that we have problems that you must solve. You are using this claim as an excuse to invade our domain. Many of these problems simply don't exist. Where there are real conflicts, where there are violations, we will identify them, applying our own funds. We form our own Social Contract. This leadership will arise according to the conditions of our world, but not yours. Our world is different."

So the question is about legal force disappears. By violating my wishes as expressed in this license, you are making an enemy. You cannot know what is significant and what is not, and what reaction will follow. You just need to follow the letter of the license or be prepared for a reaction that may not be adequate in your understanding. People are different - some live with the slogan Freedom or death, others are ready to agree to a search at the airport for the sake of illusory security. As Benjamin Franklin, one of the creators of American statehood, wrote: He who sacrifices liberty for safety deserves neither liberty nor safety. It seems that his descendants did not heed his behests, and there is no need to idealize modern American legislation and follow it by distributing a license in English with the program.

• Version 2.1 for desktop -(rezk21f1.html, rezk21f1.swf, datarzk.txt)
• Version 2.1 with source codes - Zip archive, including five files(rezk21f1.html, rezk21f1.swf, rezk21f1.fla, datarzk.txt, GPL russian translation.htm)
• Version 1.19 for older PDAs - Zip archive including three files(rezk19f4.html, rezk19f4.swf, datarzk.txt)

Version 2.1 dated September 9, 2009

Added a help feature to display the angle of the field of view and the size of the object falling into the frame in the focusing plane. The number of starting parameters specified in the datarzk.txt file has been increased. Slightly optimized code.

For the first time, the program is distributed along with source codes. The reason for this step, first of all, is that I am gradually completely abandoning the use of Windows operating systems in my work. And support for flash technology under Linux does not allow its development to continue, so if someone decides to improve or supplement the program, then the flag is in their hands. The Flash4linux program currently does not allow you to open and edit the text of this program. To work and modernize it, you probably need to purchase an Adobe software package and work under Windows, which is not part of my immediate plans.

Version 1.9 dated September 15, 2007

Fixed some display issues when long work without reboot. The list of matrices for selecting an acceptable scattering circle has been expanded. This version of the program, when run on a local machine, allows you to edit the starting values ​​of the focal length and the permissible circle of dispersion. To do this, you need to edit the datarzk.txt file.

Version 1.5 dated January 11, 2005

Version 1.4 dated November 27, 2004

The starting values ​​of the permissible circle of dispersion, focal length and aperture have been changed.

Added the ability to estimate the acceptable circle of dispersion based on the matrix size and number of pixels, or the desired print size, assuming that printing occurs on a sublimation printer or photo paper with a resolution of 12 dots per mm. The acceptable circle of blur is assessed by clicking on the question mark in the upper right corner. To get the correct value, you must make a selection in the top and one of the two lower drop-down menus. The top menu is used to set the frame size, the next menu allows you to set the number of pixels in the matrix, or the AgBr item, which implies the use of average film with a relatively good lens. If you select a frame size of 36x24 mm in the top menu and AgBr in the next menu, the program will give values ​​close to those printed on the frame of Industar type lenses. The bottom drop-down menu allows you to set the size of the desired print. It is advisable to use it if your camera has a spare number of pixels, but you are not going to print large prints.

The version assumes the use of Flash Player 6.

Version 1.01 dated November 13, 2001

In order to install the program on a PDA, it is enough to unpack the archive and place its contents (two files, html and swf) in an arbitrary directory of the PDA. The "Fit to Screen" option must be selected in Microsoft Internet Explorer settings. This choice takes effect after the page is reloaded. When tested on the Cassiopeia E-125, it turned out that although the 150 MHz processor seems to be quite powerful, graphics processing causes significant delays. The PDA video system does not like translucent areas and the need to constantly recalculate the image. Of course, not only the computer is to blame here, but also the Flash interpreter.

DOF (depth of field) calculators are one of the most popular types of software designed to provide the photographer with specific information about shooting parameters and make it easier to obtain high-quality images. There are a lot of different implementations of depth of field calculators on the Internet, but the one created by Polish photographer and programmer Michael Bemowski is without a doubt one of the best.

The Bemowski calculator has many settings, adjustable parameters, fixed presets and saved configurations. It not only calculates parameters numerically, but also visualizes the results in a visual form.

First of all, you can set specific shooting parameters - lens focal length and matrix size, aperture, distance to the subject and to the background. By the way, these very objects and backgrounds are also customizable - selected from several proposed options.

As you play with the shooting parameters, the visualization (the image in the window on the right) works out in real time all the changes you make.

Even background blur (bokeh) is simulated, the degree of this blur corresponds to the parameters entered (and calculated) at the moment.

At the bottom of the page there is the actual depth of field calculator, which calculates the location and depth of the field of focus and presents the results in a visual way.

If you accessed the site from mobile phone, clicking the button in the upper left corner will change the interface to the “mobile” option. The application does not require a connection to the server to work, so the author also offers an offline version that you can download to your computer. The entire project is completely free and relies on advertising and donations.

In our opinion, the calculator has not only (and not even so much) serious practical significance, but, first of all, educational value. We recommend that beginning photographers thoughtfully play with the settings, and perhaps return to this activity more than once in order to better understand and feel what lens to take, what aperture to set, whether to approach the subject closer or further - in order to get the desired result, as with from the point of view of depth of field and bokeh, as well as the ratio of the scales of the object and the background.

Beginning photographers often wonder why in a photo of a group of people only one person is in focus, while the rest are blurry. Or how to take a photo of a school class so that everyone is sharp in the photo. Actually, this requires experience and a lot of practice. But if there is not enough practice yet, but you want to figure it out, then the depth of field calculator will come to the rescue.

It’s convenient to have a calculator on hand, so if you have a modern smartphone, here are other options:

Correct free calculators for Android http://android.lospopadosos.com/dof

Correct paid calculator for iPhone http://www.neuwert-media.com/dof.html

The iPhone disappointed me the most because I could find the only calculator that worked correctly, and that was for money. Although, Apple fans, as you know, do not count money and are charged for every sneeze. The peak of idiocy was calculators, where the depth of field depends on the crop factor, and you also have to pay for it! Hello, we've arrived...

In fact, I understand where these misconceptions come from. It is assumed that if you change the crop factor, then the viewing angle changes, and therefore the composition of the frame. People who try to preserve the composition of the frame naively believe that the depth of field, which changes during this procedure, depends on the crop factor. In fact, the distance to the object s or the focal length f changes. It is incorrect to say that the depth of field depends on the crop factor, because this would mean that, all other things being equal, changing the crop factor should also change the depth of field, but we have no other things equal. Scammers and swindlers who claim this change, along with the crop factor, either the distance to the object, or the focal length, or both. You can correctly carry out the experiment only from a tripod, using one FX camera, switching FX and DX modes, but this is equivalent to cropping the photo at the edges. Obviously, the depth of field will not change.

Attentive readers have already noticed the keyword “slightly blurred” just above and became wary. Indeed, when viewing photographs, sharpness is subjective. Everyone perceives it differently. It makes no sense to measure depth to the nearest millimeter, unless we are talking about macro, of course. Do not try to go deeper in pursuit of depth of field. specifications, since you will simply be sucked into the fractal of details and you will become even more confused.

The decision about whether the depth of field is sufficient or not must be made quickly and emotionally, otherwise it will turn out like in the well-known case with a patient who underwent surgery in the frontal lobe area: http://olegart.ru/wordpress/2011/07/05/3413 / This, by the way, also applies to the choice of photographic equipment in general, the choice of which turned out to be the most difficult for the human brain:

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