Narrowest depth of field?

[105012]

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As someone who usually likes as much depth of field as possible this is a strange question: which of the Leica M lenses has the narrowest depth of field at maximum aperture?

 

For example, I know that the depth of field of the f/3.4, 135mm APO-Telyt is considerably narrower than the f/0.95, 50mm Noctilux, so I am guessing the winner (loser?) is the APO-Telyt?

[105012]

Of course, forgot about the f2.8, 135mm... !

[Jared]

It depends a bit on how you measure it. If you mean which has the narrowest FOV at a given distance, then I think it would be the 135 f/2.8. If you mean narrowest for a given framing, I.e., if you moved in closer for a shorter focal length, then it would be the f/0.95 50mm.

 

- Jared

[105012]

Thanks Jared, agreed. For reference, according to Leica using their CoC spec, at 1.5m the f/0.95 has a depth of field of 4.9cm, whereas the APO-Telyt has a depth of field of 2.4cm.

[Jared]

Yup. At a fixed distance the 135 would have a narrower DOF.

[otto.f]

It depends a bit on how you measure it. If you mean which has the narrowest FOV at a given distance, then I think it would be the 135 f/2.8. If you mean narrowest for a given framing, I.e., if you moved in closer for a shorter focal length, then it would be the f/0.95 50mm.

- Jared

Is that so? The Noctilux can't come closer than 1m, hasn't the 75Summilux at 70cm not the narrower depth then?

[Jared]

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Yes, but it doesn't contradict what I said. At a given distance the 135mm has the narrowest. At a given framing, the Noctilux. If you want to compare all lenses at their closest focus rather than at a given distance or framing, the 75 would be narrower than either, but the 90mm Macro-Elmer-M with adapter would be narrower still--it's a macro lens, after all.

 

- Jared

[NB23]

90mm f1.0, I guess

[tobey bilek]

If the field of view is the same,  the depth is the same. 

 

If you keep your feet planted,  the longer lens will have less.

[otto.f]

https://cvp.com/pdf/Noctilux-M50-TechnicalData.pdf

 

http://www.overgaard.dk/pdf/Summilux-M_75_mm_Technical_Data_en.pdf

http://www.overgaard.dk/pdf/Apo-Telyt-M_135_mm_Technical_Data_en.pdf

 

The Summilux 75 is at 1.4 slightly narrower at 1m meter than the Noctilux at 0.95. At 1,5m the 75 and the 135 are about equal, the Noctilux has more depth there

[otto.f]

If the field of view is the same,  the depth is the same. 

 

If you keep your feet planted,  the longer lens will have less.

You can't just rule out the aperture, that's where Leica is doing all the effort

[adli]

You can't just rule out the aperture, that's where Leica is doing all the effort

 

[luigi bertolotti]

Consider also the venerable Summarex 85 1,5...

 

(and, not an M lens, but adaptable to, there is also a Summicron 180 f2...)

[lct]

As far as M lenses are concerned:

 

1. 90/1

2. 135/2.8

3. 135/3.4

4. 135/4

5. 90/2

6. 75/1.4

7. 90/2.4

8. 90/2.8

9. 75/2

10. 50/0.95

 

... If i'm not wrong 

 

[michaelwj]

^

Assuming we're at a distance that they can all focus at (i.e., 1.5m not 0.7m)

The 90/1.0 close focuses at 10m or so with a fixed focus we can ignore it for practical photography.

So at each focal distance the minimum depth of field is;

1.5m and up: 135/2.8

1.0m to 1.5m: 90/2.0

0.7m to 1.0m: 75/1.4

 

(Don't let the Noctilux shallow depth of field crowd see the list, the could have saved a lot and got an old 90/2.8 or even better, an old 135mm! The horror!)

[adan]

Simple equation.

 

If the aperture value and the magnification/framing are the same, the DoF will be the same across all focal lengths.

 

If you use a 50 Noctilux at f/3.4 and a 135 APO-Telyt at f/3.4, and move in closer with the Nocti for the same framing - the shorter focal length of the Nocti 50mm is negated by the shorter subject distance. One increases DoF, the other reduces it, they cancel out.

 

Or - to get the same picture, you need to shoot with the Nocti from 1 meter (20x focal length), and with the 135 from 2.7 meters (20x focal length). And compare DoF tables for those TWO different distances.

 

The same would be true if there existed a 135 Noctilux - shoot the same framing with either lens at f/1, and you'll get the same DoF.

 

Conversely, shoot a whole room with a 21 f/1.4, and then back far away to include the same area with a Noctilux at f/1.4, and you'll get the same DoF.

 

If you shoot the same framing (not-not-not the same distance) with different apertures - then the larger aperture will, of course, produce less DoF. So the 90 f/1 and the 50 f/1 tie, and the 50 f/0.95 may beat them both by some tiny amount.

 

If you do not shoot the same framing/composition/magnification, then you are talking about completely different pictures anyway, and which does or doesn't have more DoF becomes a nonsense question.

 

I mean, who cares that a whole-room f/2.8 50mm picture, with a person in the middle distance, 10 feet away, has different DoF than a tight portrait made with a 135 f/2.8, from 10 feet away?

 

If you have not even figured out whether you want a tight portrait, or a loose room picture - you're still too confused about your artistic intentions to be wasting mental effort on DoF.

[otto.f]

You could also ask what's the sense of the original question

[lct]

Or simply compare hyperfocal distances which are based on focal length, aperture and circle of confusion.

[105012]

...

 

If you have not even figured out whether you want a tight portrait, or a loose room picture - you're still too confused about your artistic intentions to be wasting mental effort on DoF.

 

 

Thank you for your well reasoned response, apart from this last comment. The truth is, what do you know about my artistic intentions or the source of the question (...cropping...)? Might a polite query be more appropriate and dignified? That said, like many here, I enjoy reading your thoughtful and helpful contributions, so no hard feelings on my part.

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Hallo,

Look here: Leica M

[jaapv]

Maybe Andy came across a bit harsh, but he has a point. Framing and composition (including perspective through distance and focal length) first, DOF and subject separation second