hyperfocal distance on 17-40

[salinaale]

How can i read the "Hyperfocal distance window" on my 17-40?
I usally used it on different zoom but on 17-40 i can't see any lens aperture label!!!! where i'm wrong?

Ciao
Ale

[tim]

Generally focus 1/3 of the way into the scene, as you get 1/3 of the focal length in front of the focal point and 2/3 behind.

[salinaale]

But the "Hyperfocal distance window" says me only the distance of focal point ? or i' m wrong?
Ale

[Jesper]

I don't know if you can use the scale on the lens reliably. Note that the depth of field (and also the hyperfocal distance) depends on what you choose as the "circle of confusion", which is different for 35mm and 1.6x crop factor DSLRs.

Here is an article about hyperfocal distance: http://www.dofmaster.com/hyperfocal.html
And an online DOF calculator which will also give you the hyperfocal distance for the values you enter: http://www.dofmaster.com/dofjs.html

I made a small table of hyperfocal distances myself with focal lengths on one axis and f-stop numbers on the other axis, made with the correct circle of confusion for the 10D (0.019 mm according to the DOF Master website). I printed the table and carry it in my photo bag.

[griff2]

If anyone's into Excel, I've attached a speadsheet which will instantly give you a table of hyperfocal distances (H), and a graph of H vs. f/n, n=1,..,32 for any lens' focal length. The circle of confusion I've included is for the Drebel, but it also applies to the Drebel 350, 10D and 20D.

[RichardtheSane]

BEcause the 17-40L is a zoom it does not have a hyperfocal distance scale as an accurate hyperfocal reading would not suit all focal lenghs

Best bet is you use that sheet griff2 attached and make a note of the hyperfocal distance at the 5 main focal lenghs on the zoom ring.

[Todd Jacobsen]

BEcause the 17-40L is a zoom it does not have a hyperfocal distance scale as an accurate hyperfocal reading would not suit all focal lenghs

Best bet is you use that sheet griff2 attached and make a note of the hyperfocal distance at the 5 main focal lenghs on the zoom ring.

The 40mm range should give the farthest HFD so he COULD use that as his minimum distance. The COC will be the same regardless.

[joopsnijder]

Thanks for the Excel sheet. Always nice to calculate exactly the distances.

Joop Snijder - http://www.joopsnijder.com
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