Infinity Setting

[ECohen]

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They’re never going to get that.

 

 

You guys crack me up. You all are very exact very opinionated and very ..... black and white ....except when your not.

 

Yes I know what "approximate" means.

However the question is ......Is a lens's DOF the same in film as it is in digital? ...a  simple yes or no answer.

 

......I'm good with how I work ..... but you all are far more technical than me ....or maybe not ?

 

Is the current DOF scale on my current M lenses accurate for digital or not?

 

I may be wrong but judging by the answers I'm getting and please know I respect you all....jaapv.....Ict....and jmahto

 

The answer is no. It is a historic film scale and not accurate to digital ...off by ..... a stop or maybe 2? (which,as a working Pro is a lot!)

 

I've worked in film 30 years  and the scale for most ...... if not on all pro cameras was accurate  to within an inch...... so much so, that you could bank professional jobs by a tape measure.

 

Correct me if I'm wrong, the current DOF scale marked on my lenses is historic and designed to be accurate for only film......period ???

As for digital, the current marked scale is off ....... by (according to you all )  a stop or two.....making it approximate.

 

I'm  not sure why this was such a difficult question to answer? Its really science and math and not a question of opinion.

 

Do I understand the  DOF scale on my camera has a variance ?

........Its accurate for film but if I'm shooting digital its approximate .... off by a stop or maybe 2 ?

 

 

Sorry to be snarky but I'm a trained film guy trying to figure out digital....some things relate some don't

......I rely on this forum ......you really are a great source of photography information.

Thank You for your patience guidance and  help

Edited July 15, 2018 by ECohen

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[jaapv]

There is no "lens DOF" as such.  DOF is determined by the magnification throughout the system, from subject distance to viewing the print.

The basic point is whether the detail in the subject is resolved by the eye and brain of the viewer. The lens is but one factor amongst many.

Yes, the DOF scale is based on a COC of 0.03 mm (Leica uses 0.024) since time immemorial, and should be adapted to present-day use, i.e. more precise sensors , higher reolutions and larger prints.

 

And yes, DOF can be approached mathematically and often is, but the results can only be an approximation.

It is the gradual (not absolute) zone of acceptable (to the viewer) unsharpness, and thus subjective. On top of that, the visual impression of sharpness is strongly influenced by the subject. A low-contrast, low frequency subject like a misty landscape or a romantic portrait will exhibit a far deeper DOF than a high-contrast brick road or a stark image of a craggy face.

The way the lens renders the OOF areas makes a difference too.

[ECohen]

 

There is no "lens DOF" as such.  DOF is determined by the magnification throughout the system, from subject distance to viewing the print.

The basic point is whether the detail in the subject is resolved by the eye and brain of the viewer. The lens is but one factor amongst many.

Yes, the DOF scale is based on a COC of 0.03 (Leica uses 0.024) mm since time immemorial, and should be adapted to present-day use, i.e. more precise sensors , higher reolutions and larger prints.

 

And yes, DOF can be approached mathematically and often is, but the results can only be an approximation.

It is the gradual (not absolute) zone of acceptable (to the viewer) unsharpness, and thus subjective. On top of that, the visual impression of sharpness is strongly influenced by the subject. A low-contrast, low frequency subject like a misty landscape or a romantic portrait will exhibit a far deeper DOF than a high-contrast brick road or a stark image of a craggy face.

The way the lens renders the OOF areas makes a difference too.

 

Wow

Glad I didn't know this when I was a working Pro ;-)

Thousands upon thousands of 4x5" catalog photos, 8.5x11" full page magazine ads .....11x16 double page spreads .....32 , 48 and 64 sheet billboards.

All shot day in and day out with a tape measure and a DOF scale....no kidding!

 

Man-o-man ..... Do I feel lucky to have not understood how depth of field really works.

30 years of doing it wrong ........ I want to take this opportunity to thank David Simpson a teacher or mine for teaching me to cover my ass.

 

How many years did I do it wrong and get it right.

 

Thank you to this forum....... I continue to learn each day....... This makes me laugh.

 

This is not a sarcastic post ! I had no idea  that I missed the lesson in my college years back in 1974.

 

Who says Art and Business isn't a bit of luck!

 

 

 

[jaapv]

Come on, you know as well as I do that experience beats theory any day.

Precise DOF was not something we thought about back then. There was no way to pixel-peep. Now you just hit  cmd-1 and you get the image on your screen without any DOF at all.

[lct]

There is no such thing as digital or film DoF. DoF is a distance depending on aperture, focal length, subject distance and circle of confusion (CoC). The latter depends on different factors like visual acuity, viewing distance and enlargement or magnification. DoF scales are based on average CoC values (0.030mm for FF by example) calculated for a viewing distance of 25 cm or something and 7x enlargement (don't recall exactly). As long as those factors don't change, DoF scales of lenses stay acceptable on both film and digital cameras. But suffice it to change one of those factors, typically enlargement when pixel peeping, to change CoC values and then DoF scales are not relevant any more. 

Edited July 15, 2018 by lct

[jaapv]

Precisely. The COC value is based on 1930-ies film  photography. Basically it should be halved  for present-day use.

 

For a rather in-depth abstract on the subject:

 

http://dougkerr.net/Pumpkin/articles/Depth_of_Field.pdf

 

Pay attention to his "note of caution"

[papimuzo]

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With all the respect due to the questionner, my only comment is: take pictures, note the conditions, analyse the results, and extract your own conclusion.

Believe me, and old engineer physicist, nothing can replace the experiments, nothing can replace the experiments, nothing can rep.....

 

Happy and precise pictures.

[lct]

Precisely. The COC value is based on 1930-ies film  photography. Basically it should be halved  for present-day use. [...]

 

Rangefinders would have to be twice as long then since their critical base length is based on the same CoC values.

[jaapv]

Remember the focus calibration problems when switching from film to digital  M in 2006 ?

[willeica]

Zone focus can be used with both film and digital cameras, but the situation is more critical with the latter. I regularly use zone focus with early cameras which have no rangefinder built in. I prefer this to using a separate rangefinders, even though I have a lot of them. Even when a built in rangefinder (or even autofocus for that matter) is available, where you place the point of actual focus is critical, taking the aperture into account as well.  The only way of doing this successfully is by experience. Jaap is correct in saying that experience will always trump theory. To be successful at this game a general grasp of theory is all that is required. Only an idiot stands 'in the field' taking photographs with a headful of theory buzzing around. It has to become instinctive for a photographer to succeed.

 

Digital with its flat planes and precisely defined parameters does place greater emphasis on accuracy. One example of this is the older 35mm Summilux Asph which shows 'focus shift' with digital Ms but none at all with film Ms.

 

William

Edited July 15, 2018 by willeica

[jmahto]

You guys crack me up. You all are very exact very opinionated and very ..... black and white ....except when your not.

 

Yes I know what "approximate" means.

However the question is ......Is a lens's DOF the same in film as it is in digital? ...a simple yes or no answer.

 

......I'm good with how I work ..... but you all are far more technical than me ....or maybe not ?

 

Is the current DOF scale on my current M lenses accurate for digital or not?

 

I may be wrong but judging by the answers I'm getting and please know I respect you all....jaapv.....Ict....and jmahto

 

The answer is no. It is a historic film scale and not accurate to digital ...off by ..... a stop or maybe 2? (which,as a working Pro is a lot!)

 

I've worked in film 30 years and the scale for most ...... if not on all pro cameras was accurate to within an inch...... so much so, that you could bank professional jobs by a tape measure.

 

Correct me if I'm wrong, the current DOF scale marked on my lenses is historic and designed to be accurate for only film......period ???

As for digital, the current marked scale is off ....... by (according to you all ) a stop or two.....making it approximate.

 

I'm not sure why this was such a difficult question to answer? Its really science and math and not a question of opinion.

 

Do I understand the DOF scale on my camera has a variance ?

........Its accurate for film but if I'm shooting digital its approximate .... off by a stop or maybe 2 ?

 

 

Sorry to be snarky but I'm a trained film guy trying to figure out digital....some things relate some don't

......I rely on this forum ......you really are a great source of photography information.

 

Thank You for your patience guidance and help

We are being black and white when we say it depends.

 

Let me give simplest and very black and white reply. The DOF scale is such that the zone will appear sharp in A4 print from reasonable distance (not nose to print), with good eye sight, of course.

 

Larger print and DOF scale should be conservatively used.

 

Now getting back to using the tool and experience. I won’t be surprised if many great photographers don’t have full grasp of technical details. One’s own experience trumps theoretical knowledge every time.

Edited July 15, 2018 by jmahto

[pico]

Wow

Glad I didn't know this when I was a working Pro ;-)

Thousands upon thousands of 4x5" catalog photos, 8.5x11" full page magazine ads .....11x16 double page spreads .....32 , 48 and 64 sheet billboards.

All shot day in and day out with a tape measure and a DOF scale....no kidding!

 

Were you by chance a reproduction camera operator?

[ECohen]

Were you by chance a reproduction camera operator?

 

 

Day in and day out I shot  National Advertising .... self employed 1981 to 2015

Tripod, tape measure and a DOF scale for 80% of the shots, right or wrong or just theory, it works like a charm.

 

Anybody remember those great red markings on the old Hasselbald lenses?

How else would you have focused a Super wide C if not with a tape measure?

View cameras took a bit more thinking and calculating to achieve "perfect" focus.

Whats perfect focus ...? Perfect is what the client expects every time.

 

I'm getting kinda old so I think I'll keep doing it wrong;-)

 

OK enough about me LOL ....

Edited July 15, 2018 by ECohen

[jmahto]

...since I can’t edit my above comment...

My reference of A4 size print was from 35mm. 7 times enlarged from original film/sensor size.

[lct]

Remember the focus calibration problems when switching from film to digital  M in 2006 ?

 

Sure and nothing has changed since the M8 or the R-D1 in 2004. This is just a matter of film or sensor format and image enlargement or magnification. What is new with digital is the way photogs are viewing pictures by way of pixel peeping, 100% crops and so on. Not a reason to change average CoC values in any way IMHO as long as most people don't watch larger photos than those taken with film in the past. "A4 print from reasonable distance" Jayant said above with a probably good approximation. Now we may perfectly use different CoC values if we wish so provided we keep in mind that RF accuracy depends on CoC as well so that halving CoC values as you suggested above would end up to require rangefinders twice as long as they are currently, at least when using difficult to focus lenses like 135/4, 90/2, 75/1.4, etc.

[jaapv]

Which only goes to prove - much as the absolute values are a mathematical exercise - that the whole concept of DOF is subjective and depends solely on the viewer of the image. 

[lct]

Which only goes to prove - much as the absolute values are a mathematical exercise - that the whole concept of DOF is subjective and depends solely on the viewer of the image. 

 

Relativism is not my cup of tea but whichever ways DoF is calculated, it will always depend on objective factors allowing to explain, for example, why DoF is different on APS, FF and MF cameras. 

[jaapv]

And different in your eye and mine

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Hallo,

Look here: Leica M

[jaapv]

Rangefinders would have to be twice as long then since their critical base length is based on the same CoC values.

Not necessarily - the magnification is another factor.

[wizard]

 

...

 

Is the current DOF scale on my current M lenses accurate for digital or not?

 

...

 

It all depends on your personal expectations, really. As there will be only a single image plane precisely in focus at any given distance settting, DOF is and always has been an acceptable sharpness concept. However, you may only decide for yourself what is acceptable to you and what is not.

 

So to answer your question, why don't you simply do some comparison shots to find our for yourself. Put the camera on a tripod, choose a suitable subject at mid-distance, set the distance on your lens such that your subject is just included within the DOF at your chosen f-stop, and shoot. Repeat the shot by closing the aperture one f-stop (and compensate the exposure time appropriately) while changing nothing else. Then evaluate whether the first shot provides 'acceptable' sharpness of your subject or whether you are more inclined to find the second shot acceptably sharp. If so, do not rely on the engraved DOF scales, but use those for one f-stop lower. That is, if shooting at f8, use the DOF scale for f5.6, and so on.

 

Cheers, Andy

Edited July 16, 2018 by wizard