Hyperfocal Distance

[flashfromoz]

I am new to this concept. I have a hyperfocal distance chart calculator but am unsure what focal length to enter for my lenses. Do I use the focal length on the lens or do I use the FoV equivalent (mine being 1.5x)?

Thanks in advance.

[Tim Gray]

Here's a calculator link...

http://www.dofmaster.com/doftable.html

You use the "real" focal length, but the difference in sensor size is accomodated by adjusting the size of the circle of confusion.  Unfortunately there is not much concensus as to what size coc you should use which makes the ultimate dof/hyperfocal calculation more of an art than sience.  The basic question is what is "acceptable" sharpness.   Acceptable to who under what viewing circumstances.

[flashfromoz]

Here's a calculator link...

http://www.dofmaster.com/doftable.html

You use the "real" focal length, but the difference in sensor size is accomodated by adjusting the size of the circle of confusion.  Unfortunately there is not much concensus as to what size coc you should use which makes the ultimate dof/hyperfocal calculation more of an art than sience.  The basic question is what is "acceptable" sharpness.   Acceptable to who under what viewing circumstances.
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Hi Tim, thanks for the response. The manufacturer apparently claims a COF of 0.020mm. I guess trial and error is the order of the day. Given the distance guides on lenses these days are just that - a guide, even getting repeatable results to a high degree of sharpness may be challenging.

[dabreeze]

which manufacturer for what product suggests CoC of .020mm? just interested b/c for years the 35mm industry standard has been .030mm. .020mm sounds like what i have heard some good sources suggest is quite applicable to a 1.5 (nikon)/1.6 (canon) crop factor digital sensor.

as the argument goes on regarding acceptable focus, viewing distances, and enlargement factors, I've used a slightly finer CoC of .025 for a FF 1Ds and 1Ds M2 for a few years now and have never been disappointed with the result, even in extremely large, saleable fine art prints (20x50, 32x48, 30x44) shot at f/22 for very close hyperfocal focus (uh oh, i can here the diffraction limited peepers coming to get me as we speak!).

if .020mm is being recommended for a cropped sensor, you're, in 1.6 crop terms, right at the old 35mm industry standard of .030mm.  For my FF 35mm sensor, I reduced my CoC calculation to .025mm on the advice of dudak's online DoF/hyperfocal calculator (Dudak Calculator) which suggests that analysis of human eyesight in the years since the .030mm CoC was adopted has proven we see better and need a more refined hyperfocal calculation.

as they say, your mileage may vary.

but it's always important to remember when considering proper viewing distances, the old adage for photographers: their proper viewing distance is generally only slightly longer than the length of their noses!!! LOL!!

[Ray]

All calculations of hyperfocal distance require a means of measuring that distance.

How do you propose doing that? A laser distance finder, perhaps?

[flashfromoz]

which manufacturer for what product suggests CoC of .020mm? just interested b/c for years the 35mm industry standard has been .030mm. .020mm sounds like what i have heard some good sources suggest is quite applicable to a 1.5 (nikon)/1.6 (canon) crop factor digital sensor.

as the argument goes on regarding acceptable focus, viewing distances, and enlargement factors, I've used a slightly finer CoC of .025 for a FF 1Ds and 1Ds M2 for a few years now and have never been disappointed with the result, even in extremely large, saleable fine art prints (20x50, 32x48, 30x44) shot at f/22 for very close hyperfocal focus (uh oh, i can here the diffraction limited peepers coming to get me as we speak!).

if .020mm is being recommended for a cropped sensor, you're, in 1.6 crop terms, right at the old 35mm industry standard of .030mm.  For my FF 35mm sensor, I reduced my CoC calculation to .025mm on the advice of dudak's online DoF/hyperfocal calculator (Dudak Calculator) which suggests that analysis of human eyesight in the years since the .030mm CoC was adopted has proven we see better and need a more refined hyperfocal calculation.

as they say, your mileage may vary.

but it's always important to remember when considering proper viewing distances, the old adage for photographers: their proper viewing distance is generally only slightly longer than the length of their noses!!! LOL!!
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Thanks for the response. I use a Pentax K10D with a crop factor of 1.5x. I obtained the CoC data from DOF Master [a href=\"http://www.dofmaster.com/digital_coc.html]http://www.dofmaster.com/digital_coc.html[/url] which suggests that Pentax recommends a CoC of 0.020mm for all their DSLR's - all have 1.5x crop factor.

Interstingly I went to my first camera club meet last night and the judge was viewing the images at "length of nose" distance. I guess she may have been checking print quality but it did strike me as strange.

I am yet to try out the distance chart I downloaded from DOF Master, but using the distance guide on the lenses I use as a starting point I hope to have some satisfactory results.

[Ben Rubinstein]

Interstingly I went to my first camera club meet last night and the judge was viewing the images at "length of nose" distance. I guess she may have been checking print quality but it did strike me as strange.

I'm afraid that this just about sums up all that is worthless with camera clubs!  

[howiesmith]

All calculations of hyperfocal distance require a means of measuring that distance.

How do you propose doing that? A laser distance finder, perhaps?
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Wrong.  Hyperfocal distance is:

F*F/(f * c)

where F is the lens focal length (usually engraved on the lens)
F is the f/stop (usually seen on the lens too) and c is the circle of confusion (a small number not requiring a laser distance finder, even if you use the pixel pitch).

I use as my reference Ansel Adams, The Camera

[Ray]

Wrong.  Hyperfocal distance is:

F*F/(f * c)

where F is the lens focal length (usually engraved on the lens)
F is the f/stop (usually seen on the lens too) and c is the circle of confusion (a small number not requiring a laser distance finder, even if you use the pixel pitch).

I use as my reference Ansel Adams, The Camera
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As impractical as ever, Howard.

Whatever the hyperfocal distance is, it's a distance and most modern people with modern cameras and zoom lenses cannot measure that distance even approximately by looking at the markings on the lens.

[howiesmith]

As impractical as ever, Howard.

Whatever the hyperfocal distance is, it's a distance and most modern people with modern cameras and zoom lenses cannot measure that distance even approximately by looking at the markings on the lens.
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But to "calculate" that distance, you don't have to measure a thing.  Hyperfocal length can be used to calculate DoF (and not used for anything else).  DoF can be small and close at hand - like measured with a yard stick.

[Ray]

But to "calculate" that distance, you don't have to measure a thing.  Hyperfocal length can be used to calculate DoF (and not used for anything else).  DoF can be small and close at hand - like measured with a yard stick.
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That's true, but generally with landscape work there's a problem and most hyperfocal distances become great approximations. With a DSLR it's often faster to just do f/stop bracketing.

The lens I used for the first photo I ever sold, a Tamron 70-300 zoom has no distance markings at all.

[howiesmith]

That's true, but generally with landscape work there's a problem and most hyperfocal distances become great approximations. With a DSLR it's often faster to just do f/stop bracketing.

The lens I used for the first photo I ever sold, a Tamron 70-300 zoom has no distance markings at all.
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Well, that settles that.  No one ever has any need to calculate hyperfocal length or DoF or deterimine any distances.  Just bracket.

Ray has spoken (or should I say jumped to yet another conclusion).  Thanks for straightening out the rest of the photo world on this too.

Actually, if you read the original question, it did not mention landscapes or any particular or practicle application.

[Ray]

Actually, if you read the original question, it did not mention landscapes or any particular or practicle application.
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The original question has been answered. We're now into ramifications. I notice that my first post in this thread stated 'all calculations of hyperfocal distance require a means of measuring that distance'. Of course that was badly expressed.

I meant, of course, the use of hyperfocal calculations requires a means of measuring distances. If you weren't so antagonistic Howard, you would have understood this immediately.

The point I make is a valid one. It makes little sense to quibble over minute variations of CoC if you can't measure distances precisely. If you have the means to measure distances precisely, then of course my comment doesn't apply.

Why anyone should have difficulty understanding this beats me.

[howiesmith]

I meant, of course, the use of hyperfocal calculations requires a means of measuring distances. If you weren't so antagonistic Howard, you would have understood this immediately.

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Wrong again.  The use of hyperfocal length calculations does not require a means of measuring distances.  It can, but does not have to, nor does such a measurement have to be especially accurate or difficult to make.  Sometimes an estimate will do.  Or an unquantified comparison with thte distance to another object.

As a practicle matter, I don't try to understand what you or others claim they meant to write but didn't, especially when what they wrote is clear on its face.  As another practicle matter, try to avoid statemets that include "all," every," "never," and such as they are frequently wrong.  It only takes a single exception to prove that "all calculations" require something.

[dabreeze]

as to distances, often i'll actually pace off the distance. if i can't pace it, i've gotten very good at estimating it. and when i estimate if i have doubt, i bracket toward a slightly smaller aperture (as per ray's methodology).

the real value for me, in using hyperfocal charts, has been understanding how important it is to focus in the correct spot in an image in order to retain sharpness throughout. how much closer focus needs to be often than the old one-third rule.

although i rarely have to get it out of my bag anymore, the chart over time gave me a focusing process that never fails: find the close object (CO), estimate or pace the distance to the CO, double it, focus there, then take that distance (CO x 2) and check or remember appropriate f/stop from hyperfocal chart (at CO x 2) and set camera. if in doubt underestimate distance and this will move you toward a smaller aperture and you'll be bracketed safely.

never fails although it's often a tough concept/calculation to impart to students (too much math & a tough/ambiguous concept [CoCs, 'acceptable' focus, viewing distances, enlargement factors, crop sensors, the human eye, larger f/stop/smaller aperture . . .] !!!). but for me, understanding hyperfocality was a huge step forward in controlling and achieving the exact results i wanted vis-a-vis focus in the field.

then again (and slightly OT) now there's helicon focus . . . i've been amazed at the ability of this new software to work in a landscape setting, with probably a 30% increase in overall sharpness as the result of having multiple sharp focal planes in a series of images that can be flawlessly merged (most of the time) to create significantly better than 'acceptable' focus throughout an image.

hey, it actually works . . .

[howiesmith]

as to distances, often i'll actually pace off the distance. if i can't pace it, i've gotten very good at estimating it. and when i estimate if i have doubt, i bracket toward a slightly smaller aperture (as per ray's methodology).

the real value for me, in using hyperfocal charts, has been understanding how important it is to focus in the correct spot in an image in order to retain sharpness throughout. how much closer focus needs to be often than the old one-third rule.

although i rarely have to get it out of my bag anymore, the chart over time gave me a focusing process that never fails: find the close object (CO), estimate or pace the distance to the CO, double it, focus there, then take that distance (CO x 2) and check or remember appropriate f/stop from hyperfocal chart (at CO x 2) and set camera. if in doubt underestimate distance and this will move you toward a smaller aperture and you'll be bracketed safely.

never fails although it's often a tough concept/calculation to impart to students (too much math & a tough/ambiguous concept [CoCs, 'acceptable' focus, viewing distances, enlargement factors, crop sensors, the human eye, larger f/stop/smaller aperture . . .] !!!). but for me, understanding hyperfocality was a huge step forward in controlling and achieving the exact results i wanted vis-a-vis focus in the field.

http://i.pbase.com/o6/10/364410/1/75458711...b_wcopyv2CC.jpg[/img]
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Very good ways of determining distances.  Of some interest may be the situation where there is nothing in the photograph anywhere near the distance you wish to focus.  The scale on the lens is helpful then, or estimating to some other object, focus and then shift to the frame you want.  Practice abd experience usually helps.

Understanding the concepts and how to use them is a huge step in getting better.  The student's attitude that "it's too hard" makes me a bit crazy.  They seem to want to let the camera do it all and just jump to the expert level right away.  (Depth of field is too hard,makes my brain hurt and I have to use numbers.  I'll let the camera figure it for me and bracket.)  Then you get the questions about why is this out of focus or why is this underexpeosed?  What's wrong with my camera?  Or better yet, "I need a better camera."

[Jack Varney]

Wrong.  Hyperfocal distance is:

F*F/(f * c)

where F is the lens focal length (usually engraved on the lens)
F is the f/stop (usually seen on the lens too) and c is the circle of confusion (a small number not requiring a laser distance finder, even if you use the pixel pitch).

I use as my reference Ansel Adams, The Camera
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If in the formula your "F" is for the lens focal length and your "F" is for the f/stop, what is your "f"? (Of course it is the f number.)

BTW, it might have been helpful to mention that all of the units in your equation are in millimeters. Only some of us have The Negative.

[howiesmith]

If in the formula your "F" is for the lens focal length and your "F" is for the f/stop, what is your "f"? (Of course it is the f number.)

BTW, it might have been helpful to mention that all of the units in your equation are in millimeters. Only some of us have The Negative.
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Sorry.  F is focal length.  f (small f) is f/stop.  F*F/(f*c)

Focal length F and CoC c must be in same units and hyperfocal length will be in those units. Millimeters is fine, then hyperfocal length will be in mm too.

[flashfromoz]

as to distances, often i'll actually pace off the distance. if i can't pace it, i've gotten very good at estimating it. and when i estimate if i have doubt, i bracket toward a slightly smaller aperture (as per ray's methodology).

the real value for me, in using hyperfocal charts, has been understanding how important it is to focus in the correct spot in an image in order to retain sharpness throughout. how much closer focus needs to be often than the old one-third rule.

although i rarely have to get it out of my bag anymore, the chart over time gave me a focusing process that never fails: find the close object (CO), estimate or pace the distance to the CO, double it, focus there, then take that distance (CO x 2) and check or remember appropriate f/stop from hyperfocal chart (at CO x 2) and set camera. if in doubt underestimate distance and this will move you toward a smaller aperture and you'll be bracketed safely.

never fails although it's often a tough concept/calculation to impart to students (too much math & a tough/ambiguous concept [CoCs, 'acceptable' focus, viewing distances, enlargement factors, crop sensors, the human eye, larger f/stop/smaller aperture . . .] !!!). but for me, understanding hyperfocality was a huge step forward in controlling and achieving the exact results i wanted vis-a-vis focus in the field.

then again (and slightly OT) now there's helicon focus . . . i've been amazed at the ability of this new software to work in a landscape setting, with probably a 30% increase in overall sharpness as the result of having multiple sharp focal planes in a series of images that can be flawlessly merged (most of the time) to create significantly better than 'acceptable' focus throughout an image.

hey, it actually works . . .
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Thanks dabreeze for the very well explained and practical "in the field' advice. I will note your comments and practice them on my shoots. Your contribution is appreciated.