Hyperfocal technique

[PRH]

some time ago, someone on the DPS forums posted this link to DOF Master.

Online Depth of Field Calculator

Its an online calculator but if you own a windows based PC or Palm Pilot, you can download the software. Best of all its free.
You can create discs to print so that you can estimate the DOF for a given lens, aperture combo, or charts that allow you to determine HFD.
I've had great fun with it. I wish I can remember who originally posted it so that I can thank them again.
PS don't use the default settings for circle of confusion because its way off.

there are probably other online calculators too if you do a search.

Edit: Sorry Inkista, I just went through this thread again and you were the one that originally posted the link to DoF Master on page 1 of this thread...how embarrassing
Didn't mean to repeat what was already posted.

[potterm]

I use this one: Digital SLR DoF Calculator MIDlet for Mobile Phones. It's a free Java application that you can install on your mobile phone. You can set the camera crop (1.5 for Nikon DX, 1.6 for Canon etc.) along with focal length, focus distance and aperture and it will tell me the near and far point of the DoF, plus the hyperfocal distance (point at which you'll achieve DoF to infinity if you focus there).

It's a great little app which I find far more useful than charts because I always have my phone with me.

Martin.

[chandrashekharbapat]

Dear Sir,
The hyperfocal distance depends upon the focal length of lens and the lens aperture used. It will not at all depend upon the format upon which the picture is being recorded. when a small format is used, and the focal length is 50 mm. which is is a normal lens to 35 mm full frame camera, the Hyperfocal distance will be same for both formats, 35 mm or a smaller one.
chandrashekhar bapat

[kencaleno]

Originally Posted by chandrashekharbapat

Dear Sir,
The hyperfocal distance depends upon the focal length of lens and the lens aperture used. It will not at all depend upon the format upon which the picture is being recorded. when a small format is used, and the focal length is 50 mm. which is is a normal lens to 35 mm full frame camera, the Hyperfocal distance will be same for both formats, 35 mm or a smaller one.
chandrashekhar bapat

You omitted the third element of hyperfocus-distance from subject; and the fourth element-the most important of all-the circle of confusion, which determines sharp focus,and this varies with sensor - or format size,so you are wrong in your assumption.Ken

[chandrashekharbapat]

Sir,
The size of circle of confusion depends upon the focal length of the lens. The formula is Focal length divided by 1000, all in inches. So when focal length is lesser the size of circle of confusion is smaller. When focal length is larger the size of circle of confusion is greater. Any small circle of the size smaller than 0.01 inches is a sharp point to the human eye when viewed from Ten inches. Hence though the circle of confusion plays a vital role in calculating hyperfocal distance, the size of sensor or format does not. Please, let me have your opinion.
Chandrashekhar.

[kencaleno]

Size of circle of circumference for 35mm was dependent on a 36mmx 24mm format, the diagonal of which was 50mm ,so the circle of confusion was 0.033mm (50/1500 = 0.333333......recurring.The circle of confusion is determined by sensor's/film format's diagonal length divided by 1500-lens has nothing to do with it.

Excerpt from Luminous landscape: http://www.luminous-landscape.com/es...t-Lenses.shtml

What this means is that the CoC for a given sensor is taken to be sensor diagonal length divided by 1500. For the FF sensor (or 35 mm film) this gives a CoC of about 30 micrometers while for the PS sensor the CoC is only 5 micrometers. There is nothing sacred about this choice of CoC. If very large prints are to be made, perhaps the CoC should be reduced; and vice versa if only 4" by 6" prints are needed one can get away with a larger CoC. Note that for an 11" by 14" print the CoC is about 0.3mm. .




Ken

[jgredline]

Great stuff folks..I for one use hyperfocal (zone focusing) 90% of the time while street shooting. Infact it is closer to 99% and when shooting film, I use it 100% of the time now.

[vandergus]

I'll have to agree with Ken on this one. Smaller formats, must be enlarged more to achieve the same final print size, so the circle of confusion must be smaller to achieve the same level of detail after enlargement. Therefore, sensor/film size must also be considered when calculating depth of field and hyperfocal distance.

[jgredline]

Originally Posted by vandergus

I'll have to agree with Ken on this one. Smaller formats, must be enlarged more to achieve the same final print size, so the circle of confusion must be smaller to achieve the same level of detail after enlargement. Therefore, sensor/film size must also be considered when calculating depth of field and hyperfocal distance.

Same here. Ken is spot on. I go back and forth with prime lenses between full frame and a 1.5 crop factor and it is different.

[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