The Best Lenses for Minimal Depth of Field

[rs-eos]

When wanting to achieve the narrowest possible depth of field, there are several factors.  Three of which are focal length, aperture, and minimum focusing distance.

What follows is a current listing of mostly RF L-series lenses (with two EF L-series lenses sprinkled in which I own):

Key: MFD (Minimum Focus Distance), DOF (Depth of Field).

1. RF 70-200mm f/4 L @ 200mm, 60 cm MFD, 0.14 cm DOF
2. RF 100-500mm f/4.5-7.1 L @ 500mm, 120 cm MFD, 0.14 cm DOF
3. RF 70-200 f/2.8 L @ 200mm, 70 cm MFD, 0.15 cm DOF
4. RF 135mm f/1.8 L, 70 cm MFD, 0.23 cm DOF
5. RF 24-105mm f/2.8 L @ 105 mm, 45 MFD, 0.24 cm DOF
6. RF 800mm f/5.6 L, 260 cm MFD, 0.25 cm DOF
7. RF 28-70mm f/2L @ 70mm, 39 cm MFD, 0.31 cm DOF
8. RF 24-105mm f/4 L @ 105 mm, 45 cm MFD, 0.34 cm DOF
9. RF 50mm f/1.2 L, 40 cm MFD, 0.4 cm DOF
10. RF 24-70mm f/2.8 L @ 70mm, 38 cm MFD, 0.41 cm DOF
11. RF 1200mm f/8 L, 430 cm MFD, 0.44 cm DOF
12. EF 135mm f/2 L, 90 cm MFD, 0.45 cm DOF
13. EF 50mm f/1.2 L, 45 cm MFD, 0.51 cm DOF
14. RF 100-300mm f/2.8 L, 180 cm MFD, 0.51 cm DOF
15. RF 400mm f/2.8 L, 250 cm MFD, 0.56 cm DOF
16. RF 85mm f/1.2 L (both DS and non-DS), 20 cm MFD, 0.64 cm DOF
17. RF 14-35mm f/4 L @ 35mm, 20 cm MFD, 0.65 cm DOF
18. RF 200-800 f/6.3-9 @ 800mm, 330 cm MFD, 0.69 cm DOF
19. RF 15-35mm f/2.8 L @ 35mm, 28 cm MFD, 0.95 cm DOF
20. RF 600mm f/4 L, 420 cm MFD, 1.01 cm DOF
21. RF 10-20mm f/4 L, 25 cm MFD, 3.47 cm DOF

Takeaways:

• Sometimes, it's not lenses with the widest apertures that will produce the narrowest results.
• The top prime (hurray!) is the RF 135mm f/1.8 L
• The top zoom is a tie between the RF 70-200 mm f/4 L and RF 100-500mm f/4-7.1 L.  Though the 70-200 f/2.8 version is just 1/10 of a millimeter behind them, so practically a three-way tie.

[Tronhard]

Ricky, this is a very comprehensive list!
Just one point ... for me the actual DoF depends on:

Focal length - the longer the shallower the DoF
Aperture - the smaller the f/stop the shallower the DoF
Distance to subject: (as opposed to minimum focusing distance) the closer the subject the shallower the DoF.  I totally get your point that the closer one can focus, the less DoF one can get and I think that is more the theme of your post.
On a more general basis. To me that is a function of the distal relationship with the subject, rather than the potential minimum distance, so the variation in DoF relative to subject distance extends out past that, as per this:

What do you think?

[rs-eos]

Wouldn't minimum focusing distance be equal to distance to subject?

[Tronhard]

Not really.  Minimum focus distance indicates the closest potential distance that a lens can find focus on a subject. As I understand it, subject distance is a variable from that (minimum focus distance), out to infinity.  So, distance to subject could be 1m, 10m, 100m or a km and as that value increases, so does the DoF.

So in this diagram, Minimum focusing distance is #3, while subject distance #9

[rs-eos]

Gotcha.  I still think they are equivalent though for this exercise since the distance between the actual focal plane and the "start" and "end" of the DOF region is mere millimeters for most part.

[Tronhard]

I totally agree that for the absolutely smallest DoF, the minimal focusing distance will be applicable.  I am simply making the observation that this is a relationship of subject distance that continues as the it varies from that - so more of a generalized observation that actually underpins your point - I hope!

[johnrmoyer]

Good stuff from all. Thanks @RS-EOS and @Tronhard . In case some who are less knowledgeable might read this, here is more.

One more thing to consider for depth of field is circle of confusion. This will depend upon spacing of pixels on sensor, viewing surface for the photo after it has been made (print or screen), viewing distance, and eyesight ability of the person viewing the photo. This helps define what is in focus and what is out of focus.

Depth of field will be different for a photo printed and hung in a gallery with a rope to keep people at a distance compared to viewing on a screen where a person may zoom in to look at detail.

There is a simplified explanation of depth of field and circle of confusion at: https://www.cambridgeincolour.com/tutorials/depth-of-field.htm (Some who post on forums do not like the way this site simplifies things, but I find it helpful.)

Canon support has: https://support.usa.canon.com/kb/index?page=content&id=ART157204

"

Permissible circle of confusion

DEFINITION:

A limiting circle of confusion within which a spot image can be identified as a spot in the photo lens, etc.

DESCRIPTION:

The range of sharpness of an image (picture) is determined by taking the resolving power of the human eye into consideration. A circle of confusion within the limit where the image is actually perceived as sharp is called the permissible circle of confusion (equal to or similar to the minimum circle of confusion). In commonly used photo lenses, the basis used to calculate the depth of field, hyperfocal distance, etc. is generally 1/30mm for a 24x36mm format or 1/20mm for a 6 x 6 cm format.

"

There is a draft copy of the CIPA standard on image stabilization at https://www.cipa.jp/image-stabilization/documents_e/DC-X011-2014_E.pdf and PDF page 42 of 56 has a discussion of circle of confusion.

[kvbarkley]

If you set it at the minimum focus distance, aren't you cutting the DOF in half since, by definition, nothing in front of the MFD will be in focus?

[rs-eos]

Good question!

[johnrmoyer]

I expect that the minimum focus distance specification for a lens will be based upon someone's idea of a correct or standard circle of confusion. Depending upon how the photo will be viewed, one might be able to focus on an object closer than the minimum focus distance in the specification or may need to focus at a further distance than the specification.

Also, for a zoom lens, a single distance is usually given for minimum focus distance, but that will sometimes change when one zooms.