chomiczewski Posted June 16, 2004 Share Posted June 16, 2004 I've read much about the difference between depth of focus and depth of field, circles of confusion and its importance to focus. What I am still confused about is how do you use a depth of focus calculator. If the information tells you the COC for a given situation, how do you relate that to how you set up the shot, focus etc? Do most people only use this if the output is film or is it also used for video output? Thanks Link to comment Share on other sites More sharing options...
Premium Member Wendell_Greene Posted June 16, 2004 Premium Member Share Posted June 16, 2004 What I am still confused about is how do you use a depth of focus calculator. I believe you meant to write "Depth of FIELD" calculator. You have to know three things in order to determine your Depth of Field or DOF. The focal length of the lens, the size of the aperture or f-stop, and the distance of the subject from the plane of the camera. Then you can use depth-of-field tables in the American Cinematographers Manual or in many other books These charts or tables list a variety of focal lengths, the COC, and the f-stop and there are separate lists for both 35mm and 16mm. The chart will also show the DOF field as being from the "near" or closest point to the "far" or farthest point. Many assistants also use some type of depth-of-field calculator that allows them to dial in the focal length, f-stop, COC, and subject distance and then read the depth of field. Some types of depth-of-field calculators are the Guild Kelly Calculator for both 16mm and 35mm and the Samcine Mark II Calculator. And for those of you with a Palm Pilot or similar device, there is software that calculates your depth of field for you. How you relate all this, including other things like the 1/3 rule or hyperfocal distance and other things that you don't learn in a book but on set all depends on a number of things: Do you want to see a great deal of depth in the shot, with many point in sharp focus or do you the shot very limited in depth so there is perhaps only one point in focus? A great deal depends on what the director and/or dp want to show in the shot to support the story and characters. Link to comment Share on other sites More sharing options...
Premium Member Max Jacoby Posted June 16, 2004 Premium Member Share Posted June 16, 2004 Many assistants also use some type of depth-of-field calculator that allows them to dial in the focal length, f-stop, COC, and subject distance and then read the depth of field. Some types of depth-of-field calculators are the Guild Kelly Calculator for both 16mm and 35mm and the Samcine Mark II Calculator. And for those of you with a Palm Pilot or similar device, there is software that calculates your depth of field for you. Also if you are shooting with LDS lenses on Arricams or the 435, you will have the depth of field displayed on your on-camera monitor. A little hint though: if you tend to rock and roll if you are not sure that you got your subject in focus, then I'd suggest you disable the option that the camera info be displayed on the video assist monitor as well. Otherwise your Director or Dop might start questioning you why the focus keeps on moving although the actor isn't... Link to comment Share on other sites More sharing options...
harryprayiv Posted June 16, 2004 Share Posted June 16, 2004 Hi there. I know all about the other stuff that you refer to, but what is "the 1/3 rule". I'd appreciate an answer from anyone...not just Wendell_Greene. Thanks. Link to comment Share on other sites More sharing options...
Alvin Pingol Posted June 16, 2004 Share Posted June 16, 2004 Hi there. I know all about the other stuff that you refer to, but what is "the 1/3 rule". I'd appreciate an answer from anyone...not just Wendell_Greene. Thanks. There are different ways to look at the 1/3 rule, but they all deal with composition. One is to mentally divide the frame into thirds both horizontally and vertically (9 "boxes") and place the desired subject on one of the intersections of the thirds. Another I've seen is mainly for landscape photography, but states that one should get a third of sky, a third of background, and a third of foreground in the frame. Link to comment Share on other sites More sharing options...
Premium Member Max Jacoby Posted June 16, 2004 Premium Member Share Posted June 16, 2004 Hi there. I know all about the other stuff that you refer to, but what is "the 1/3 rule". I'd appreciate an answer from anyone...not just Wendell_Greene. Thanks. There are different ways to look at the 1/3 rule, but they all deal with composition. One is to mentally divide the frame into thirds both horizontally and vertically (9 "boxes") and place the desired subject on one of the intersections of the thirds. I think he means the rule that 1/3 of your depth of field will be in front of your point of focus and 2/3 behind it. That is however only a rule of thumb and does not always apply. Link to comment Share on other sites More sharing options...
Premium Member Wendell_Greene Posted June 17, 2004 Premium Member Share Posted June 17, 2004 I think he means the rule that 1/3 of your depth of field will be in front of your point of focus and 2/3 behind it. That is however only a rule of thumb and does not always apply. So true. It only applies if you focus at a distance that is exactly 1/3 the hyperfocal distance for that particular lens and f-stop. Link to comment Share on other sites More sharing options...
stijnbarbe Posted June 17, 2004 Share Posted June 17, 2004 does anybody know of a DOF-calculator to use on Windows? I've heard about these apps for palmtops, but do they exist for Windows/Linux/Mac??? the ones I found googling are either online(usually don't have 'movie' settings) or hardware (and sold out everywhere) thanx Link to comment Share on other sites More sharing options...
Premium Member John Pytlak RIP Posted June 17, 2004 Premium Member Share Posted June 17, 2004 Some links to DOF calculators: http://dfleming.ameranet.com/custom.html http://www.pilotzone.com/palm/preview/220147.html http://www.xs4all.nl/~wiskerke/html/toollink.html http://www.101science.com/101_calculations_page.htm#Depth of field http://www.martindalecenter.com/Calculators.html Link to comment Share on other sites More sharing options...
Alvin Pingol Posted June 18, 2004 Share Posted June 18, 2004 I think he means the rule that 1/3 of your depth of field will be in front of your point of focus and 2/3 behind it. Ahh... so many variations! :rolleyes: Link to comment Share on other sites More sharing options...
stijnbarbe Posted June 21, 2004 Share Posted June 21, 2004 thanks for the links John, DOFmaster is really great! Still have a few questions: What circle of confusion(CoC)- values does Kodak use for their cine products? I found three(!) different values for 16mm. Apparently the ASC recommends 0.0152mm/0.0007inch. Also doesn't the CoC 'grow' with S16? thanks, Stijn Link to comment Share on other sites More sharing options...
Mister X Posted June 21, 2004 Share Posted June 21, 2004 Sorry. Post was for another thread. Link to comment Share on other sites More sharing options...
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