Focus and Depth of Field

Outlined in this informative video are 4 different techniques for accurate focus as well as a discussion on DOF (depth of field) as it relates to each method. Additional information is provided on off-center focus using a rangefinder camera such as a Leica M. Video length: 12 minutes 11 seconds.

LINKS Discussed in the video:

CORRECTION!…. on the section related to Hyperfocal Distance the quick example is not accurate for the 90mm lens I was using as an example. In fact, the actual hyperfocal distance for that lens is 40′ and not 20′ as mentioned and as such in the example I gave it would have a depth of field from around 20′ to infinity and not 10′ to infinity.

One final note: You will notice that I have not posted any sample images featuring the above described techniques- this is on purpose… go out and shoot a roll of test film! Determine what is your best working solution based on your sharpness needs and shooting style.

9 thoughts on “Focus and Depth of Field

  1. I do not understand the infinity focus technique, although I read it several times.

    There is no real life example in that text, only scientific approach IMHO.

    Could you give an example of using this method( steps I need to take before shot) when making a portrait or a landscape.

    Please!!!

    1. Jack… try this…. shoot one landscape frame using the hyperfocal distance method outlined, make it a landscape with some middle range to infinity content, then shoot the same image but now focus at infinity…. say use F16 for both… I think it will become clear that at infinity the distant objects are very sharp and that the near and middle objects are also acceptably sharp. All of the other info in the article is nice tech stuff to know but seeing a side by side that you just shot is the best proof. For a portrait at a standard working distance of say 5-10 feet I would use the point or spot focus method.

      Cheers-
      Stephen

  2. Stephen-

    Great video.

    However, don’t forget about the “circle of confusion”. Different formats have different “COC”. This can help one be more accurate in terms of “acceptablly sharp” within the “DOF”.

    Best,

    DM Brown

  3. I was hoping to see a demonstration of how to deal with shallow DOF when focusing with a RF but the video was a non-stop talkie with hardly any useful visual information apart from the time you pointed at the DOF markings on the lens. The “studio” setting didn’t help me to get in the mood of listening either. Just thought of giving some honest feedback regarding the effort because I appreciate your motives.

    Best,
    GTW

    1. The studio setting is my dining room, nothing hi tech here… also I provided several very useful links that when used with the info in the video provides very powerful information on focus and depth of field but you need to look at all the info provided and put it into a working solution for your shooting needs.

      Stephen

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