Leica M (Typ 240): Hyperfocal Distance vs. Infinity Comparison

Introduction | Some Numbers | Test Photos: f/5.6 | f/8 | f/11 | f/16 | f/22 | Diffraction Comparison | Conclusions | References

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On this page, I present comparisons for the Leica M (Typ 240) with M-Rokkor 28mm f/2.8 between shots taken at the hyperfocal distance (HFD) and at infinity with various aperture values (f/5.6, f/8, f/11, f/16, f/22). f/22 is the smallest f-number before diffraction would set in. I use these conditions to compare the traditional depth of field (DOF) approach with the approach proposed by Merklinger.

I did these tests with two other cameras, the Leica X Vario, and the Sony RX100 M1. All three cameras used the same equivalent focal length of 28 mm, which result in the actual focal lengths of 10.4, 18, and 28 mm. Note that, according to the formula for the HFD (and DOF), only the real focal length is of interest. Sensor differences are not reflected in the formula (only via the crop factor for the focal length). Therefore, you may want to take a look at the pages for the Leica X Vario (18 mm) and the Sony RX100 M1 (10.4 mm) to see how the results would look like (with certain restrictions of the aperture range).

 

Introduction

I placed two test objects (mugs) at the hyperfocal and half the hyperfocal distance. I also took care that in the background some far away objects were visible.

I took the photos at five different apertures: f/5.6, f/8, f/11, f/16, and f/22. The f-number f/22 is the smallest aperture for many of the lenses for the Leica M (Typ 240). This is still below the diffraction limit (the recommendation is not to go beyond f/22 with full-format cameras - see details). Depending on the aperture, the HFD is different: the larger the f-number, the smaller it is. This means that the objects get closer and larger (and thus, more detailed), the larger the f-number is. Only the background objects should always be about the same size.

The photos were taken with a focal length of 28 mm (Minolta M-Rokkor28mm f/2.8) (as in my other tests of this subject). The HDF values were read from the lens's DOF marks. Distance could only be set manually on then lens and was checked using the EVF and magnification (easier than with the Leica X Vario) - I did no fine-tuning of the distance.

For each condition and aperture, I present below 100% crops of the mug at HFD/2, the mug at HFD, and a section of the background. The original photos can be downloaded by right-clicking the small versions of the photos or by clicking the "original" link.

 

Some Numbers

The following table lists the circles of confusion (CoC) and disks of confusion (DoC, see Merklinger method) for the conditions listed above and demonstrated in the photos below (objects at HFD/2, HFD, and infinity; f-numbers f/5.6, f/8, f/11, f/16, and f/22):

   
Focused at HFD (H)
   
Focused at Infinity
 
 f-Number
H (m)
CoC (mm)
DoC (mm)
CoC (mm)
DoC (mm)
 Comment
N  
H/2
H
inf
H/2
H
10 m*
inf
 
H/2
H
inf
H/2
H
inf
10 m as "typical" distance
f/5.6
4.7
0.03
0**
0.03
2.47
0**
5.6
inf
 
0.06
0.03
0**
4.95
4.95
4.95
DoC = d = f/N = 4.95 mm
f/8
3.0
0.03
0**
0.03
1.75
0**
8.2
inf
 
0.06
0.03
0**
3.50
3.50
3.50
DoC = d = f/N = 3.50 mm
f/11
2.3
0.03
0**
0.03
1.24
0**
8.3
inf
 
0.06
0.03
0**
2.48
2.48
2.48
DoC = d = f/N = 2.48 mm
f/16
1.6
0.03
0**
0.03
0.88
0**
9.2
inf
 
0.06
0.03
0**
1.75
1.75
1.75
DoC = d = f/N = 1.75 mm
f/22
1.15
0.03
0**
0.03
0.62
0**
9.5
inf
 
0.06
0.03
0**
1.24
1.24
1.24
DoC = d = f/N = 1.24 mm

*) 10 m distance, for details see below ; **) "0" means optimal sharpness, resolution is limited by other factors (diffraction, resolving power of lens and sensor, ...)

Legend: f = focal length = 28 mm; N = f- number (exact values used in calculations); H = hyperfocal distance (HFD); CoC = circle of confusion (image field); DoC = disk of confusion (object field)

H was determined using the table for hyperfocal distances for the Sony RX100 M1. The CoC of 0.011 mm is given by the manufacturer Sony (for an 1" sensor).

According to Merklinger's formula for the DoC and its relationship with the HFD (H), the DoC is d/2 at HFD/2, when the lens is focused at HFD (H). It is zero at HFD (H), d again at twice HFD (2H), and goes beyond every limit far beyond HFD. I therefore also calculated the DoC for a distance of 10 m (see below) to get an impression of how large it is at a closer distance.

I also used the Merklinger method to find out that the CoC is double the "nominal" CoC at H/2 and the same at HFD (H) when the lens is focused at infinity (every DOF scale on a lens will tell you this).

10 m Distance

I calculated the DOC diameter Sy for a distance of Y being a multiple y of H, the HFD, according to Merklinger's formula Sy = (Y - D) / D * d and got:

For Y = 10 m, based on it's being a multiple of H, the results are as follows (using the exact f-numbers, not the "nominal" ones):

Thus, we get the result that, with increasing f-numbers (f/5.6, f/8, f/11, f/16, f/22), the DoC grows from about 0.5 to about 1 cm for objects at 10 m distance.

A Note for Inspecting DoC

The letters on the mugs are about 3 mm high (there are also black letters that are about 2 mm in height). The patterend double lines on the "Darjeeling" mug are about 1 mm high (or thick). I list the DoC for each image so that you can compare it with these objects easily.

For these comaprisons, it is useful to remember, what Merklinger (p. 34 writes about the readability of letters:

 

Test Photos

Note: You can download the original photos to view them on your monitor(s), or print them in the sizes you are interested in.

Aperture f/5.6

   

Hyperfocal Distance (ca. 4.7 m)

   

Infinity

Leica M (Typ 240) at ISO 400 - overview (original)

 

Leica M (Typ 240) at ISO 400 - overview (original)

Leica M (Typ 240) - detail at HFD/2 (100% crop), DoC = 2.47 mm, f/5.6

 

Leica M (Typ 240) - detail at HFD/2 (100% crop), DoC = 4.95 mm, f/5.6

Leica M (Typ 240) - detail at HFD (100% crop), DoC = 2.47 mm, f/5.6

 

Leica M (Typ 240) - detail at HFD (100% crop), DoC = 4.95 mm, f/5.6

Leica M (Typ 240) - detail at infinity (100% crop), DoC = 2.47 mm, f/5.6

 

Leica M (Typ 240) - detail at infinity (100% crop), DoC = 4.95 mm, f/5.6

     

Aperture f/8

   

Hyperfocal Distance (ca. 3 m)

   

Infinity

Leica M (Typ 240) at ISO 400 - overview (original)

 

Leica M (Typ 240) at ISO 400 - overview (original)

Leica M (Typ 240) - detail at HFD/2 (100% crop), DoC = 1.75 mm, f/8

 

Leica M (Typ 240) - detail at HFD/2 (100% crop), DoC = 3.50 mm, f/8

Leica M (Typ 240) - detail at HFD (100% crop), DoC = 1.75 mm, f/8

 

Leica M (Typ 240) - detail at HFD (100% crop), DoC = 3.50 mm, f/8

Leica M (Typ 240) - detail at infinity (100% crop), DoC = 1.75 mm, f/8

 

Leica M (Typ 240) - detail at infinity (100% crop), DoC = 3.50 mm, f/8

     

Aperture f/11

   

Hyperfocal Distance (ca. 2.3 m)

   

Infinity

Leica M (Typ 240) at ISO 400 - overview (original)

 

Leica M (Typ 240) at ISO 400 - overview (original)

Leica M (Typ 240) - detail at HFD/2 (100% crop), DoC = 1.24 mm, f/11

 

Leica M (Typ 240) - detail at HFD/2 (100% crop), DoC = 2.48 mm, f/11

Leica M (Typ 240) - detail at HFD (100% crop), DoC = 1.24 mm, f/11

 

Leica M (Typ 240) - detail at HFD (100% crop), DoC = 2.48 mm, f/11

Leica M (Typ 240) - detail at infinity (100% crop), DoC = 1.24 mm, f/11

 

Leica M (Typ 240) - detail at infinity (100% crop), DoC = 2.48 mm, f/11

     

Aperture f/16

   

Hyperfocal Distance (ca. 1.6 m)

   

Infinity

Leica M (Typ 240) at ISO 400 - overview (original)

 

Leica M (Typ 240) at ISO 400 - overview (original)

Leica M (Typ 240) - detail at HFD/2 (100% crop), DoC = 0.88 mm, f/16

 

Leica M (Typ 240) - detail at HFD/2 (100% crop), DoC = 1.75 mm, f/16

Leica M (Typ 240) - detail at HFD (100% crop), DoC = 0.88 mm, f/16

 

Leica M (Typ 240) - detail at HFD (100% crop), DoC = 1.75 mm, f/16

Leica M (Typ 240) - detail at infinity (100% crop), DoC = 0.88 mm, f/16

 

Leica M (Typ 240) - detail at infinity (100% crop), DoC = 1.75 mm, f/16

     

Aperture f/22

   

Hyperfocal Distance (ca. 1.15 m)

   

Infinity

Leica M (Typ 240) at ISO 400 - overview (original)

 

Leica M (Typ 240) at ISO 400 - overview (original)

Leica M (Typ 240) - detail at HFD/2 (100% crop), DoC = 0.62 mm, f/22

 

Leica M (Typ 240) - detail at HFD/2 (100% crop), DoC = 1.24 mm, f/22

Leica M (Typ 240) - detail at HFD (100% crop), DoC = 0.62 mm, f/22

 

Leica M (Typ 240) - detail at HFD (100% crop), DoC = 1.24 mm, f/22

Leica M (Typ 240) - detail at infinity (100% crop), DoC = 0.62 mm, f/22

 

Leica M (Typ 240) - detail at infinity (100% crop), DoC = 1.24 mm, f/22

 

Diffraction Comparison

The distant crops at f/5.6, f/8, f/11, f/16 and f/22 can be compared to look for diffraction effects:

Leica M (Typ 240) at ISO 400 - detail at infinity (100% crop) - f/5.6

   

Leica M (Typ 240) at ISO 400 - detail at infinity (100% crop) - f/8

Leica M (Typ 240) at ISO 400 - detail at infinity (100% crop) - f/11

 

Leica M (Typ 240) at ISO 400 - detail at infinity (100% crop) - f/16

Leica M (Typ 240) at ISO 400 - detail at infinity (100% crop) - f/22

 

Leica M (Typ 240) at ISO 400 - detail at infinity (100% crop) - f/22

 

Conclusions

Just a few observations from viewing the photos on a computer screen at 100% (or 200% for a Retina display):

Just a few observations from viewing the photos on a computer screen in full-screen mode (Retina display, 5 MP):

And here a few observations from prints in postcard size (6" x 4" or 15 cm x 10 cm):

Finally, one general conclusion:

One more note:

 

References

Merklinger

Hyperfocal Distance, DOF

 

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04.07.2024