how to use the depth of field scale with the apeture? : LUSENET : Canon FD : One Thread

hi i have black and white photography this quarter, my teacher said to research about how my depth of field scale will go with the apeture settings. im clueless. i have a picture of what my lens looks like, this is not MY lens, but it's the same one. if you know the answer could you please let me know thank you!

-- Tiffany rothgeb (, April 01, 2002


Tiffany, I also have the same lens as you, recently bought on ebay and I got the "owners manual" with it. And like you I also searched for a depth of field scale with little clue. However, here's my best reading (with some interpolation). Between the focusing and zooming collars there are red marks to the right of the orange "in focus" line. According to the manual they serve two purposes. One purpose is to indicate focus shift for Infrared film (no clue?). The other is to show depth of field at the selected zoom setting for aperture f16 ONLY. In other words, if you set the aperture at f16, zoom to 70mm, and focus is at 30 ft, by shifting the focus so that 30 ft is above the 70mm red mark (third mark to the right of the orange "in focus" line) then you have set the lens for maximum depth of field AT THAT DISTANCE FOR THAT ZOOM SETTING. I have seen this referred to as the hyperfocal distance for that lens at those settings. Apologize for the complex explanation but after pouring through the manual (short, in four languages, and not very complete) and playing with my "new" toy, this is the best I can come up with. Wish you luck Don

-- Don Boyd (, April 02, 2002.

hi tiffany:

first, do you have to use a zoom lens for this exercise? it's much easier to explain with a regular lens. on the lens, on either side of the focus index mark, are a series of marks which are identified with aperture numbers... the smallest number being nearest the index mark and 11, 16 and 22 being out at the far edges. what these mean is that (for instance) when your lens is set at f/11, everything between the two "11" marks is in focus. as you can see from the location of the marks, you have a lot more in focus at f/11 than you do at f/4.

another way to use the marks is to decide which near and far objects you want to be in focus in your picture; then focus on one and then the other to see how far away they are, and then adjust your lens so that the near and far distances line up with DOF marks of the same number on each side of the center. Set your lens at this number (whatever it turns out to be), leave the focus setting where it is, and shoot.

this all becomes more complicated with a zoom, because the depth of field changes as you zoom, and many zoom lenses don't have very useful DOF scales.

good luck....

rick :)=

-- rick oleson (, April 02, 2002.

The first thing I would ask you is, is your lens say for example 50mm or are they 35-70mm? zoom. Then what kind of camera are you using a manual or automatic?


-- Lyle Mann (, April 02, 2002.

Ok well the Camera is a AE-1 Canon, the lens is a canon zoom lens FD 35-105mm 1:3.5. where there normally is a DOF scale at on most reg. lens there is a orange line and only to the right of is has 105 then two lines and then 35. so i got lost. thanks for your help im going to show your suggestions to my teacher tomorrow to see if she now has an idea how to use the DOF on my lens. But i'll probably end up getting a standard lens for this class anyway. Thanks a bunch!

-- Tiffany Rothgeb (, April 02, 2002.

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