On this page, I present depth of field tables that I calculated using Excel for the Leica X Vario. The table calculations are based on formulae that I found on the DOFMaster Website and described on page Calculating Hyperfocal Distance and Depth of Field.
To make life easier "in the field," I also offer simplified tables for one distance (1 m, 1.5 m, 2 m, 4 m > these values are found on the Leica X Vario's distance scale).
See the "disclaimer" regarding the validity of depth of field and hyperfocal distance calculations as well as of the circle of confusion, on which these calculations are based.
Note: I hit on a discusion in the l-camera-forum that DOF is different for digital cameras than for analog (film) cameras. According to an article, entitled Profondeur de champ et capteurs numériques (English version: Depth of field and digital sensors) that was cited there, the coc is to be calculated as the photosite size multiplied by a factor of 1.5 However, before I create new tables, I will first wait how this issue is further discussed in the above-mentioned thread...
For details, see my general page Calculating Hyperfocal Distance and Depth of Field.
In the following, I present the results of my calculations of the depth of field for the Leica X Vario in various tabular formats. The tables show the depth of field near and far limits based on a circle of confusion of 0.02 mm (and 0.019 mm for a focal length of 18 mm) and on one-third f-numbers (because you can set these on the Leica X Vario's aperture dial). The tables appear in a window of their own, because I exported them from Excel in order to simplify my life.
Since there are three parameters that can be varied, namely focal length, distance, and aperture, a DOF table calculation would actually create a "data cube". In order to arrive at two-dimensional tables, one of the parameters has to be fixed during a calculation, and a separate table calculated for each of its values. I calculated tables for fixed focal length and for distance values.
Since the Leica X Vario is said to incorporate four prime lenses, 28 mm, 35 mm, 50 mm, and 70 mm, I calculated a DOF table for each of these focal lengths (actually for the "correct" values of 18 mm, 23 mm, 33 mm, and 46 mm).
Transposing the tables made it easier for me to manually compose tables for distances (see below) and to experiment with graphical representations.
With depth of field scales on zoom lenses, you can keep the distance constant and vary the focal length. As a first step in this direction, I composed tables that show the DOF for certain distances. With the exception of the 10 m table, all of them have labels on the Leica X Vario's focus ring.
Depth of field scales on zoom lenses also allow you to turn the focus ring to change the distance while leaving the focal length constant. However, I do not know, how I can achieve this effect graphically. I suppose that distance values have to be transformed mathematically so that the lines for the near and the far limits are the same for all distances (obvioiusly not using a logarithmic transformation...).
When I calculated the tables, I did not care whether aperture values were valid for a certain focal length on the Leica X Vario. I therefore marked invalid f-numbers red in the tables.
Infinity values appeared in the calculations as negative numbers. I replaced these with the text "inf" and marked the respective cells with a dark gray background. Since I dod not know, which distance can practically regarded as "infinity" for the Leica X Vario (and for a coc of 0.02 mm), I arbitrarily decided that infinity starts at about 35 m. I marked cells with distances beyond 35 m also with a dark gray background, but it is a little bit lighter than that of the "inf" cells.
I hope to improve the readability of the tables in the future...
In addition to my own calculations, I used DOFMaster to calculated tables of depth of field values for the four "prime" zoom values of the Leica X Vario.
To make using the DOF tables for one distance easier, I created three simplified variants of them. These simplified tables provide only the distances 1 m, 1.5 m, 2 m, and 4 m, because these are marked on the X Vario's distance scale. For example, you may want to preset of of these and then ask yourself, which DOF you will get for one of the standard focal lengths (18 mm, 23 mm, 33 mm, and 46 mm) and a given aperture.
To simplify the tables even more, I also reduced the numbers of aperture values (f/3.5, f/4, f/5.6, f/8, f/11, f/16).
Finally, I offer the tables in three degrees of precision (mm, cm, and 1/10th of a m). Since I did this manually, I cannot exclude that there may be errors in the less precise tables.
Here they are:
Later, I may also offer diagrams created from these tables.
Probably, it is a much better idea to buy a calculator for the DOF than using my tables. But perhaps they can make one or the other suggestion as to how to set distance manually on the Leica X Vario. The simplified tables may be a step in the right direction for using DOF tables "in the field."
All in all, I find the usefulness of these calculations rather limited, particularly considering the design of the lens' distance scale. Nevertheless, here are some of my "key findings":
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Probably, these statements need some cleanup to be useful "in the field." For example, Carduelis wrote in the l-camera-forum that, on the basis of my DOF tables, he uses the following settings:
Here is an attempt at capturing the "key findings" above in a table:
|70 (46) mm||4 m||3 m to nearly 6 m||less than 3 m to 7 m||2.5 m to 10 m|
|50 (33) mm||2 m||1.5 m to nearly 3 m||1.25 m to nearly 5 m|
|4 m||2.5 m to 10 m||a bit more than 2 m to more than 20 m||less than 2 m to infinity|
|35 (23) mm||1.5 m||1 m to 4 m||less than 1 m to more than 10 m|
|2 m||1.25 m to 5 m||a little more than 1 m to more than 10 m||less than 1 m to infinity|
|4 m||less than 2 m to infinity||1.5 m to infinity||a bit more than 1 m to infinity|
|28 (18) mm||1 m||0.5 m to more than 10 m|
|1.5 m||less than 1 m to 5 m||0.75 m to nearly infinity||0.6 m to infinity|
|2 m||1 m to nearly 30 m||less than 1 m to infinity||0.7 m to infinity|
|4 m||1.5 m to infinity||a little more than 1 m to infinity||a little less than 1 m to infinity|
|a little more than 2 m to more than 20 m||about 2 m to nearly infinity||less than 2 m to infinity|