Depth of Field, Magnification, and Closeup Lens Calculator Version 0.8.13Eb dated 10/5/2016, special edition for film and digital photography with table output! Help Download Simpler Calculators Main site  Erik Krause (Javascript must be allowed) 

Closeup lens  
The input of the distance values (and a part of the output) refers to the front main element of the lens or, for closeup lenses, the plane of the closeup lens. It does not refer, as indicated on the lens, to the film plane. This is for the following reasons:
1  For an object distance starting from the film plane (mostly) two different situations exist. One of the two situations is normally reached only with intermediate rings or bellows. Example: 50mm focal length, object 36cm starting from the film plane, results in a magnification with 1cm extension from 1:5, to one of 25cm extension 5:1.
2  The distance to the optical principal planes is unknown for most lenses. To some extent, exact computation with the subject to filmplane distance is therefore impossible. (up)
Original version by Tom Striewisch. Only for small formats:
www.striewischfotodesign.de/lehrgang/anmerk/ts_kb.htm
English calculator with many digital camera formats:
http://www.dofmaster.com/dofjs.html
Detailed comments on depth of field and diffraction: http://www.bobwheeler.com/photo/ViewCam.pdf (Requires Acrobat Reader, English)
How to Select the Sharpest Aperture, Considering Depth of Field and Diffraction http://www.kenrockwell.com/tech/focus.htm (English)
Details of diffraction also found at: http://homepage.swissonline.ch/severin/foto/foerdble.htm
If selected, with this photograph format, the usual maximum becomes the circle of confusion and circle of confusion diameters are automatically assigned. In addition, it is determined roughly according to the relationship of the format diagonals, and can be changed at any time. With selection of Digital for digital cameras, a jump takes place to "Compute circle of confusion", where the conversion factor and the aspect ratio of the digital camera must be entered. (up)
The focal length of the lens in millimetres. With digital cameras, optionally, an equivalent focal length can be used. A small table also gives a few conversion factors (conversion factor).
Calculate circle of confusion
Jumps in to the form "Compute circle of confusion"
Maximum circle of confusion (mandatory)
Based upon those depths of fields, the maximum permitted diameter for the circles of confusion diffraction on the film (in millimetres). In addition, it is given by the selected format and can, for example for particularly high requirements (large enlargements), be selected manually. (up)
With the (No) setting, the effects of the two sources of blurring ( diffraction and scatter) are not added to determine the resulting sharpness depth.
With (Yes), an estimation is made of how large the sharpness depth could be if both sources are considered. (up)
Minimum focus distance (optional)
The shortest distance in centimetres (0 for no indication), adjustable at the lens. It is used for the computation of the range of adjustment with a closeup lens. (up)
The distance of sujects from the front principal plane of the lens. For closeup lenses (distance input), this can optionally be entered using metres or centimetres. (up)
Refractive power of closeup lens (optional)
The preset (0) stands for noncloseup lens. Every other value indicates the refractive power of an attached closeup lens in dioptres. (up)
Default preset is aperture f/8. Up to now this was done without smaller increments. (up)
The distance from the (principal plane of a closeup lens) at which the area of sharpness begins. Everything up to the far point is rendered sharp. (up)
The distance from the (principal plane of a closeup lens) at which the sharpness range ends. Everything between this and the near point is rendered sharp. (up)
Extension of the sharpness range, also the distance between the near point and far point. From the hyperfocal near distance, the sharpness range extends to infinity. (up)
To adjust the hyperfocal distance
The distance that must be set on the lens to obtain depth of field to infinity. (up)
Within the limits of the hyperfocal distances the sharpness range begins with this distance and extends to infinity. (up)
If the aperture is decreased to this value, loss of definition due to diffraction exceeds that due to the certified circle of confusion. Aperture may therefore be limited by diffraction before the sharpness range is exceeded. (up)
At this value the calculated sharpness range is optimally sharp. If one continues to reduce the aperture, the range becomes larger but the total sharpness decreases due to diffraction. Details Ken Rockwell.(up)
The diameter to which a single one point is expanded by diffraction. (up)
The picture angle is calculated from picture width and the given format. Horizontal denotes the longer side, vertical the shorter, and the diagonal is across the picture. (up)
The size of the picture area at the set distance gives the picture angle. (up)
The magnification is the ratio of the size of the subject to its image on the film. (up)
The real aperture given for the extension (up)
At this factor for the lens speed (or longer exposure) through the extension. (up)
This distance must be subtracted on the lens in order to render the given distance sharply. Normally done by means of distance setting on the lens. If this is not sufficient, the necessary intermediate rings from this value can be measured. (up)
Approximate distance to film plane
The subject is found at this distance from the film plane. This distance cannot be indicated precisely because it is very dependent upon the lens design. (Distance input ;Principal plane) (up)
The resulting focal length for closeup lens uage. (up)
The lens must be set at approximately this distance to render the subject sharp.(Distance input) (up)
The minimum distance (to closeup lens) at which the closeup lens can be sharp. It is given by the near adjustment limit provided. (Distance input) (up)
The maximum magnification attainable with closeup lens. (up)
The maximum distance (to closeup lens) at which the closeup lens can be sharp. It comes from the focal length of the closeup lens. (Distance input) (up)
The magnification with closeup lens when set to infinity. (up)
The relationship of the shorter to longer side with digital cameras. It is used for the computation of the image field and the picture angles. After a check within DRF (de.rec.fotografie) and DARD (de.alt.rec.digitalfotografie) the only ratios seem to be 2:3 and 3:4. There should be more, please speak to Erik Krause. (up)
The factor with which equivalent focal length can be calculated from the actual focal length of the smallpicture digital camera. The same picture is therefore then produced by a smallpicture camera. The factor is used to convert the focal length (during input of the KBequivalent) and the format data, among other things, for the computation of the permissible circles of confusion.
This factor should be taken from the users manual, or be calculated by dividing the KB equivalent focal length by the genuine focal length.
Here is a short list of the models, data from dard and drf:
Model  Factor 

Canon D30  1.60 
Canon G1  4.86 
Canon Powershot Pro 90  5.29 
Fuji FinePix 1400 Zoom  6.33 
Fuji FinePix 6900  4.49 
Kodak DC 4800  4.67 
Kodak DC 265  4.77 
Minolta Dimage 7  3.94 
Nikon Coolpix E950  5.43 
Nikon Coolpix E995  4.75 
Olympus C 2100 UZ  5.43 
Olympus C2000  5.38 
Olympus C3040  4.93 
Ricoh RDC5000  4.78 
The size of the picture and/or the projection in cm. The longer side must be used thus, for example, with an enlargement of 20 x 30 cm 30 is used. (up)
The smallest distance from which the picture or projection is to be viewed. The two buttons "optimum" and "usual" supply reference values. (up)
Normal
The usual viewing distance that corresponds to the diagonals of the enlargement (calculated by using the longer side and the format of the photograph). This value is the basis of the usual computation of the maximum circles of confusion. (up)
Optimum
The optimum viewing distance is that from which the picture appears to the viewer to have the same picture angle as the scene itself. With this viewing distance the relative importance within the picture appears as in reality, and does not change as with wideangle photographs which are viewed from a large distance. This value depends on the enlargement factor, the photograph format and the focal length of the lens. (up)
The print fom the negative or the projection of the slide increased in size by this factor. (up)
A healthy human eye sees yet another circular area which appears, when subtending an angular dimension of 2 minutes of arc or less, as a point. Depending upon viewing distance this corresponds to a circle in the observed picture which arises from the size of the maximum permissible blur circle on the film/sensor.
This field also accepts inputs. When leaving the field the 'necessary megapixels' are updated (eg to recalculate using the value with the given diffraction). Picture detail is still reagrded as sharp if individual pixels are perceived as smaller than or equal to this indistinct circle. It is insignificant whether blurring results from diffraction, or whether the picture detail lies outside of the sharpfocus region (ie  circle of confusion). (up)
Update
Recalculates according to the formula: "Calculate circle of confusion ". (up)
Transfer new value
Transfers the calculated blur circle to the field "Maximum circle of confusion" of the form data; and performs a new computation of the depth of field (etc). (up)
A healthy human eye can differentiate two points as such where they are separated by approximately 1 minute of arc. Depending upon viewing distance, this corresponds to a certain resolution in the viewed picture.
In order to avoid the perception of individual pixels in digital images, at the given viewing distance and given size, the resolution of the picture should exceed a certain level. (up)
The aperturedependent results (depth of field, hyperfocal distance, diffraction circle, effective aperture) are calculated for these aperture values and also those lying between them. (up)
The distancedependent results are calculated for these steps between distance from and distance to. The incrementation is computed using the reciprocal value of the distance, and should therefore correspond with the steps printed on lens. (up)
Shortest and longest distances for which the values are calculated. The shortest distance must be larger than the effective focal length. (up)
The relative print size for which the HTMLtable is provided. (up)
With 'Units  Yes', all measurements and sizes are formatted in m, cm or mm. With 'Units  No', all measurements are imported to a table calculation in mm and given without units. (up)
One writes text here (eg lens type etc.) which appears in the second section of the table with the static data. (up)
The two hyperfocal distances each have their own line at the end of the table. If a closeup lens is used, these values are not used. (up)
Sharpness calculation, effective aperture and diffraction circle diameter depend both on the screen value and on the distance and therefore generate an additional line per distance value. (up)
All results which depend only on the distance are found in a new column at the end of the table (in the same order). (up)
Results and data, which depend neither on picture nor distance, are given in the second section. (up)
For all columns and additional lines a short reference is provided below the table. Print size, viewing distance and enlargement factor are indicated only if specified under "calculate circle of confusion" and the calculated circle of confusion is identical with the one specified in the top form.. (up)
Table writing
The program opens a new browser window to write the table. (up)
Diffraction Light which passes close to an edge is diverted from it. The smaller the aperture opening, the larger the portion of the light deflected at the diaphragm blade. A single point thus becomes a small wafer with indistinct edges. (Calculate) (back)
Principal planes The planes in the lens starting from which the focal length is measured. Lenses usually have two principal planes, the positions of which are dependent upon the lens design. For accurate computations however it should be admitted that some values are therefore uncertain. (back)
Internal focusing is defined (here) as a technology which achieves focus by moving only one or more internal groups of lens elements rather than the whole lens. Such lenses often change their focal length when focusing. (back)
Closeup lens Supplementary lens which acts almost as a magnifying glass when placed in front of the actual lens. (back)
Rectilinear  A characteristic of a lens to render straight lines and angles as such. A fisheye lens is an example of a nonrectilinear lens. (back)
Depth of field The range of distances over which an image appears sharp. (back)
Symmetrical Lens A lens having a symmetrical arrangement and sequence of elements. With smallpicture lenses only a focal length of approximately 50mm is realizable. (back)
Circle of confusion A point of light which passes through the lens effectively approaches the film in a cone, at the apex of which the film should lie if the point of light is to be resolved as a point. If the film lies film uniformly before or behind this apex, a point is recorded as a circular area. The maximum circle of confusion is the diameter in metres of these circles which are still regarded subjectively as points. (back)
March 2008
Erik Krause
German version translated to English by The Open Photographic Society  May 2009
0.8.13Eb  Minor updates  10 May 2016