Accuracy of depth-of-field scale of lenses on M8

[01af]

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Ouch! Too bad Martin Seeliger from Leica's Information Service department has no clue what he's talking about.

 

The magnification (he said, 'reproduction scale' but I'm next to sure he meant reproduction ratio, or magnification) is always the same with the same lens at the same distance, no matter what camera you're using. This much is true. Still this does not mean same depth-of-field because the smaller image format implies a smaller circle of confusion. So Mr. Seeliger is wrong.

[rosuna]

I am gearing myself mentally up for an extended trip where I will be using my M8 gear (body plus 5 lenses) as my my main camera setup. How accurate is the depth-of-field scale of Leica lenses on the M8? Is the scale on the lenses as accurate as on film M bodies? Any feedback is appreciated.

 

Here you have some clues:

 

Luminous landscape

 

R.

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[DWatts]

Dear Mr. Watts

 

thank you very much for your interest in the Leica system.

 

No matter if you use an analogue M camera, a Leica M8 with a slightly smaller sensor or the new Leica M9 with full size sensor, the reproduction scale remains the same, if the same focal length is used. That is why the depth of field engravings do not need to be changed, also with your Leica M8, they are still accurate.

 

 

 

Thank you very much for your understanding and have a nice time with your Leica M8.

 

 

 

 

 

Mit freundlichen Gruessen / kind regards

 

 

 

Martin Seeliger

 

 

 

Leica Camera AG

 

Informationsservice

 

Gewerbepark 8 / D-35606 Solms / Germany

 

Email address removed by Moderator. Please do not post email addresses in the forum.

 

 

 

 

-----Ursprüngliche Nachricht-----

Von: Deiss, Ulli

Gesendet: Donnerstag, 11. März 2010 16:54

An: Seeliger, Martin

Betreff: WG: Depth of field.

Edited June 28, 2010 by andybarton

[mjh]

Even without his email address publicized, Martin Seeliger is still wrong, I’m afraid. 01af is right: While Martin Seeliger acknowledges one factor (the magnification which stays the same, regardless of the image size), he ignores the other factor that does crucially depend on the image size, namely the circle of confusion.

[jaapv]

Well, in a way he is right, provided nothing changes. I.e. the camera-subject distance is unaltered, the focal length is unaltered, the magnification of the print and the viewing distance are unaltered. Which means both field of view and the size of the print are reduced 1.33x. But DOF would be the same.

[mjh]

Yep, the DOF-independent-of-sensor-size party would just have to standardize on a constant viewing distance for all print sizes large and small, and they would eventually be right. With billboards and such it might take some time getting used to, but I guess it beats being wrong.

Edited June 28, 2010 by mjh

[01af]

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Which means both field of view and the size of the print are reduced 1.33x. But DOF would be the same.

Okay. Didn't know that M8 users always print everything 1.33× smaller than M9 users do.

[jaapv]

Not all of them, just Mr. S.

[SJP]

So why don't we yet have a sticky or similar "executive summary" of this, surely we have seen enough DoF threads that only after long and repeated iterations end up at the same conclusion:

1 DoF is different on the M8

2 DoF is slightly outdated if you apply modern standards/expectations

 

1+ 2 gives 2 stops correction on the M8 and 1 stop for the M8

[jaapv]

Typo Stephen; M9 and M8, I guess

[SJP]

Yep, you get a score of 10/10 which is more than I can say for most of my students:D

[jaapv]

You couldn't have said that about me in my student days at TUDelft...

[DWatts]

And this is what Leica told Me :-

 

Dear Mr. Watts,

 

thank you very much for your interest in the Leica system.

 

No matter if you use an analogue M camera, a Leica M8 with a slightly smaller sensor or the new Leica M9 with full size sensor, the reproduction scale remains the same, if the same focal length is used. That is why the depth of field engravings do not need to be changed, also with your Leica M8, they are still accurate.

 

Thank you very much for your understanding and have a nice time with your Leica M8.

 

Mit freundlichen Gruessen / kind regards

 

Martin Seeliger

 

Leica Camera AG

 

Informationsservice

 

Gewerbepark 8 / D-35606 Solms / Germany

 

Leica Camera AG / [Admin Edit: DO NOT PUBLISH EMAIL ADDRESSES]

 

Telephone +49(0)6442-208-111 / Fax +49(0)6442-208-339

 

-----Ursprüngliche Nachricht-----

Von: Deiss, Ulli

Gesendet: Donnerstag, 11. März 2010 16:54

An: Seeliger, Martin

Betreff: WG: Depth of field.

 

-----Ursprüngliche Nachricht-----

 

Von: David Watts

 

Gesendet: Donnerstag, 11. März 2010 16:43

 

An: Deiss, Ulli

 

Betreff: Depth of field.

 

 

As I am now using a Leica M8, will the depth of field engravings on my older lenses, designed for use on film Leica's, still be accurate ?

 

Thanking you in advance for your reply.

 

David Watts,

 

St. Mawes,

 

Cornwall.

 

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[DWatts]

Generally speaking, and benefiting from the fact that the DOF is greater on the M8 compared to film-M's, if you are trying to decide where to set the infinity mark, if you're inside the aperture mark, you can't miss.

Dear Mr. Watts,

 

 

 

thank you very much for your interest in the Leica system.

 

 

 

No matter if you use an analogue M camera, a Leica M8 with a slightly smaller sensor or the new Leica M9 with full size sensor, the reproduction scale remains the same, if the same focal length is used. That is why the depth of field engravings do not need to be changed, also with your Leica M8, they are still accurate.

 

 

 

Thank you very much for your understanding and have a nice time with your Leica M8.

 

 

 

 

 

Mit freundlichen Gruessen / kind regards

 

 

Leica Camera AG

 

Informationsservice

 

Gewerbepark 8 / D-35606 Solms / Germany

 

Leica Camera AG / [Admin Edit: DO NOT PUBLISH EMAIL ADDRESSES]

 

Telephone +49(0)6442-208-111 / Fax +49(0)6442-208-339

 

 

 

-----Ursprüngliche Nachricht-----

Von: Deiss, Ulli

Gesendet: Donnerstag, 11. März 2010 16:54

An: Seeliger, Martin

Betreff: WG: Depth of field.

 

 

 

 

 

 

 

-----Ursprüngliche Nachricht-----

 

Von: David Watts

 

Gesendet: Donnerstag, 11. März 2010 16:43

 

An: Deiss, Ulli

 

Betreff: Depth of field.

 

 

 

As I am now using a Leica M8, will the depth of field engravings on my older lenses, designed for use on film Leica's, still be accurate ?

 

 

 

Thanking you in advance for your reply.

 

 

 

 

 

 

 

David Watts,

 

 

 

St. Mawes,

 

 

 

Cornwall.

 

 

 

 

 

Aus Leidenschaft zum perfekten Bild / Passion for perfect picture.

html.de Forum - HTML für Anfänger & Fortgeschrittene

----------------------------------------------------------------------------------

Leica Camera AG / Oskar-Barnack-Strasse 11 / D-35606 Solms

AG mit dem Sitz in Solms / AG Wetzlar HRB 966

Vorsitzender des Aufsichtsrats: Franz Jung

Vorstand: Rudolf Spiller (Vorstandsvorsitzender)

Dr. Martin Picherer (stellvertretender Vorsitzender),

Andreas Lobejäger

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Privileged/Confidential Information may be contained in this

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please

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from

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Opinions,

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Edited June 30, 2010 by admin
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[stunsworth]

I'm not sure what you are trying to prove by posting the same email again and again over a period of several days without any comment, but could you please at least respect the mods request that you don't post people's email addresses in the open forum.

[Peter Branch]

It seems that forum members could be correct and that Leica could be correct. It all depends on the set of assumptions adopted. In this thread I get the impression that the assumptions relate solely to Circle of Confusion size with some reference to viewing distance.

 

However in some of the early literature on this subject, including that published by Leica, one of the key assumptions made is that prints, (It is always prints!), would be viewed from the vantage point that gave the “correct” perspective. This is defined in terms of the focal length of the taking lens and the degree of magnification of the viewed print relative to the negative. Thus objects in the print will, if viewed “correctly”, subtend the same angle to the eye of the observer as the object photographed did to the entry pupil of the lens. This implies that prints made with the same magnification and the same focal length camera lens, regardless of the negative size, will be viewed from the same distance. An M9 print will be larger than an M8 print but for a given lens and the same print magnification using this set of assumptions the viewing distance “should” be the same. Therefore Leica are correct?

 

However another possible assumption is that prints will always be viewed from a “standard” distance; sometimes take to be as little as 20cm – in those days prints were small! If this is the assumption being made then Leica is certainly not correct.

 

There are many other potentially confusing assumptions. It is true that if a normal photograph, i.e. not a macro, is taken on an M8 with say a 35mm lens at say f4 and the same photograph is taken from the same position with a 50mm lens at f4 on an M9, i.e. near enough the same angle of view, then, whatever assumption is made about viewing distance, the picture taken with the M8 will exhibit greater Depth of Field. Precisely how much is virtually impossible to say or calculate because of the many factors involved including Pupil Magnification, MTF characteristics etc. The markings on the lens are at best only an approximate guide and should be treated as such.

[01af]

... one of the key assumptions made is that prints [...] would be viewed from the vantage point that gave the “correct” perspective. [...] Therefore Leica are correct?

Yes.

 

But that's an entirely preposterous assumption to begin with. No-one looks at prints that way, and it wouldn't make any sense anyway.

[Jeff S]

 

The markings on the lens are at best only an approximate guide and should be treated as such.

 

This much is true, film or digital, M8 or M9. I find that actually trying something, using your own capturing and viewing methods and preferences, is all that matters.

 

Jeff

[pgk]

The markings on the lens are at best only an approximate guide and should be treated as such.

Bingo! Its better to have something as a guide than nothing, how you then use it and adjust your interpretation of it depends on your own specific requirements. 'Accuracy' is not a word that I would use with dof scales - I prefer 'Viability'.

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[Jeff S]

Bingo! Its better to have something as a guide than nothing, how you then use it and adjust your interpretation of it depends on your own specific requirements. 'Accuracy' is not a word that I would use with dof scales - I prefer 'Viability'.

 

So, I guess you agree with post above yours.

 

Jeff