The 17-40L and focusing by using the Hyperfocal Distance Technique

Hi guys, for those of you who are familiar with the Hyperfocal Distance Technique for focusing when shooting landscape or Architecture, how do you do it with the 17-40L? I learned how to do it on a 35L first and have been able to set up my focus without looking into the viewfinder. I'd look at the little scale on top of the lens and knowing what my aperture setting is, I can set up the lens so it focuses from a certain distance to infinity just manually. I would use the viewfinder only to compose the shot. But the 17-40 is a zoom and is set up differently. Is there away to set up my focus the same way I mentioned above? Thanks much in advance!

What is the red index number next to the white line, on the distance scale? That index number should be the preferred aperture to use when the infinity mark (a side way L) is place on it. I believe that index number should indicate the zoom range too? If you have to use a different aperture setting, is not possible to use the scale. You probably need to use an online calculator and to plug in the numbers to get the min focus distance, at a specific aperture value, under a specific zoom range.

hey pixel, wanna share how you do it with the 35?

I don't own either of those lenses, but I'm guessing that the 35L, being a prime, has distance and DOF scales on it. The zoom probably doesn't, so you won't be able to set it the same way.

You'll need to calculate the hyperfocal distance and guesstimate your focusing distance manually.

I do it manually using an app. on my cell phone... something like this which you can find on-line (just find one for your cell phone so it will be with you all the time).. and when taking the picture, dial in the hyperfocal distance..

http://www.dofmaster.c​om/dofjs.html

TooManyShots wrote in post #10362202
What is the red index number next to the white line, on the distance scale?=.

Red index mark is used only for Infrared film focus...if 10' physical distance, you set 10' mark opposite the red index mark.

With distance marks only at 3' and infinity, it is supremely difficult to focus the 17-40mm at the hyperfocal distance (no matter what it happens to be for any given f/stop or FL)!

The lack of DOF scale on zoom lenses is only a small fraction of the problem of using hyperfocal settings these days.

ah, the joys of modern AF lenses

Hm, okay. I just learned a semi-reliable technique to focus and I can no longer use it, that bites .... So then what would be another reliable way to focus for landscape and architectural photography? How do you guys do it? Focusing on an object which is a third into your scene doesn't seem to be the most reliable method.

pixel_junkie wrote in post #10369245
Hm, okay. I just learned a semi-reliable technique to focus and I can no longer use it, that bites .... So then what would be another reliable way to focus for landscape and architectural photography? How do you guys do it? Focusing on an object which is a third into your scene doesn't seem to be the most reliable method.

Right, simply because 1/3:2/3 distribution of DOF limits only applies at one very specific focus distance per FL + aperture combination. DOF near and far limits can be 50:50 at macro distances yet can also be 1:99, and every other ratio in between those examples. For example, 100mm lens at f/5.6 focused at 110m has rear DOF at 3895m...2.5% in front, 98.5% in rear!!!

Usually there is a primary subject in a scene, so I simply focus there and hyperfocal DOF is simply dismissed as a useful technique! If there is no primary subject, as might be the case in a landscape, guessing a point out at 1000x FL and then focusing at that point will result in very deep DOF.

Grab a pen. these numbers are calculated for a 5dII. On a crop body, you may need to focus a touch further away. Your depth of acceptable focus will be from 1/2 the hyperfocal distance (HFD) to infinity.

At 17mm:
f/4 - Set to 8ft.
f/5.6 - Set to 5 1/2ft
f/11 - Set to approx 3ft (2.8ft)

At 24mm (notice how these approx DOUBLE the distances for 17mm?):
f/4 - Set to 16ft.
f/5.6 - Set to 11ft
f/11 - Set to approx 5 1/2ft

At 35mm (notice how these approx DOUBLE the distances for 24mm?):
f/4 - Set to 33ft.
f/5.6 - Set to 24ft
f/11 - Set to approx 12ft

Just to be more clear - the 17-40mm lens really doesn't have much focus travel between 3ft and infinity (maybe 1/8 a turn of the focus knob). I typically use HFD via autofocus.

1) Determine what focal length and f/stop you'll use
2) Eyeball an object at approx the HFD away from you
3) Use AF to lock onto that object
4) Switch to MF

Now you're all set at approx the HFD and knowing the HFD will let you know the nearest object that will appear "acceptably sharp"