Hyperfocal technique

[vandergus]

Originally Posted by chandrashekharbapat

Dear Sir,
I have gone through the article you have referred "Excerpt from Luminous landscape".
Still I am of the opinion that circle of confusion has nothing to do with the size of format upon which the picture is being recorded. It only concerns with the Focal length of the lens used. The writer is under some confusion. Arther Cox in his book Lens Optics has given a formula to calculate the size of circle of confusion as Focal length / 1000 in inches. Encyclopedia of photography also says the same thing.
The writer is mixing perspective with the size of circle of confusion.
chandrashekhar

Here's three more references for you giving different circles of confusion for different formats.

DOFmaster FAQ
Digital Depth of Field
DOF limits, diffraction, and format

Would you like more.

[kencaleno]

Originally Posted by chandrashekharbapat

Dear Sir,
I have gone through the article you have referred "Excerpt from Luminous landscape".
Still I am of the opinion that circle of confusion has nothing to do with the size of format upon which the picture is being recorded. It only concerns with the Focal length of the lens used. The writer is under some confusion. Arther Cox in his book Lens Optics has given a formula to calculate the size of circle of confusion as Focal length / 1000 in inches. Encyclopedia of photography also says the same thing.
The writer is mixing perspective with the size of circle of confusion.
chandrashekhar

This is where your statement is wrong-we know for a fact that the circle of confusion for a 35mm format is 0.033333333mm...recurring,but if we use your division we get 1000/50=0.050mm-which is why diagonal of format/1500 is the more accurate.This whole system was originally developed in the 1930's, with the advent of 35mm precision cameras, as Leica and Contax,etc., The dof calculators and charts are only "near enough" indicators of dof and hyperfocal distance nowadays- they were designed for enlarging prints no more than 8 times magnification-maximum 11"x 14" held at arm's length-but when we look at our digital images at 100%(actual pixels) size is approx 40"x 50" so these calculators and charts are no longer 100% accurate.Ken.

[ldrider51]

OKAY - Now I find that the circle of confusion is squarely fitted to my head, right between my ears where the square root of the hypotenuse of the distance between my ears and the tip of my nose is asymmetrically related to the color of my eyes (blue) and the color of my hair (none). If I use the cube root of the log of my eye separation in milliliters, I find that I can adjust for the variances that seem to occur on odd Tuesdays and even Thursdays.

My brain hurts now, so I'm gonna' go polish my boots in the closet where I can keep the fumes of the Kiwi polish all to myself.

[ogram23]

Seem to remember setting hyperfocal distance on my film cameras. All I did was set infinity to the f number so that all images from the distance at the other same f stop to infinity were in focus. Or was this too simple?

[kencaleno]

Only thing about that is you lose any foreground-where if you set focus at 5 feet and aperture at f11-all from two feet six to infinity will appear acceptably sharp. And if you use any older 35mm lenses with DOFscale, with DX (crop)cameras, you need to set one stop larger to allow for the crop-ie: instead of F11; use F8 regards,Ken

[vandergus]

Originally Posted by ldrider51

OKAY - Now I find that the circle of confusion is squarely fitted to my head, right between my ears where the square root of the hypotenuse of the distance between my ears and the tip of my nose is asymmetrically related to the color of my eyes (blue) and the color of my hair (none). If I use the cube root of the log of my eye separation in milliliters, I find that I can adjust for the variances that seem to occur on odd Tuesdays and even Thursdays.

My brain hurts now, so I'm gonna' go polish my boots in the closet where I can keep the fumes of the Kiwi polish all to myself.

Sounds like you got it.

Originally Posted by ogram23

Seem to remember setting hyperfocal distance on my film cameras. All I did was set infinity to the f number so that all images from the distance at the other same f stop to infinity were in focus. Or was this too simple?

Nope, it's that simple.

[chandrashekharbapat]

Dear sir,
I am forwarding a site address for the reference of forum members DOF in which it is made clear that the DoC does not depend upon the size or media. I am reproducing a paragraph from the article for the ready reference "Digital Vs. Film, and What About Medium & Large Format

There was a query in October, 2001 on my Discussion Forum as to whether Depth of Field was calculated any differently for digital Vs. film. The answer is, no. There is no difference whosesoever. DOF doesn't care about the recording media type or size, though a lower COF is used for medium and large format, since the amount of magnification to make a decent sized print is much less than for 35mm".

I think the science behind is clear to members of the forum
Chandrashekhar

[chandrashekharbapat]

Dear sir,
I am forwarding a site address for the reference of forum members DOF in which it is made clear that the DoC does not depend upon the size or media. I am reproducing a paragraph from the article for the ready reference "Digital Vs. Film, and What About Medium & Large Format

There was a query in October, 2001 on my Discussion Forum as to whether Depth of Field was calculated any differently for digital Vs. film. The answer is, no. There is no difference whosesoever. DOF doesn't care about the recording media type or size, though a lower COF is used for medium and large format, since the amount of magnification to make a decent sized print is much less than for 35mm".

I think the science behind is clear to members of the forum
Chandrashekhar

[diminutive]

Dear Irider51,

Is your closet big enuf for 2? My brain isn't big enuf to wrap itself around this, at times, pretentious discourse. I'd like to breath some of those fumes with you.

Diminutive

[vandergus]

Originally Posted by chandrashekharbapat

Dear sir,
I am forwarding a site address for the reference of forum members DOF in which it is made clear that the DoC does not depend upon the size or media. I am reproducing a paragraph from the article for the ready reference "Digital Vs. Film, and What About Medium & Large Format

There was a query in October, 2001 on my Discussion Forum as to whether Depth of Field was calculated any differently for digital Vs. film. The answer is, no. There is no difference whosesoever. DOF doesn't care about the recording media type or size, though a lower COF is used for medium and large format, since the amount of magnification to make a decent sized print is much less than for 35mm".

I think the science behind is clear to members of the forum
Chandrashekhar

The reference you gave has been disputed by many and I think if you poll the general knowledge out there, you will find that the majority disagree with mister Reichmann. He even seems to contradict himself in places.

There is no difference whosesoever. DOF doesn't care about the recording media type or size, though a lower COF is used for medium and large format, since the amount of magnification to make a decent sized print is much less than for 35mm.

The mistake that he makes is assuming that DoF is concerned with how much detail is being resolved on the sensor/film. In that case, no, the size of the film/sensor doesn't matter. But that isn't consistent with the definition of DoF. DoF is concerned with the apparent sharpness in the final print, so magnification must be taken into account. It's not about resolution, it's about what appears to be sharp. Small films/sensors are magnified more than large sensors/film so the DoF is different.

I'm sorry, I don't know how to explain it any more than that. I think you'll just have to do a lot more reading on the subject, from multiple sources, and perhaps you'll come to a different conclusion.