Hyperfocal distance

[songtsen]

I've read that depth of field extends from infinity to 1/2 the hyperfocal distance when a lens is focused at the hyperfocal distance.

Using the DOF calculator on lensplay.com, I discovered that the hyperfocal distance for a 35mm lens is 7.3 m at f5.6 and 5.1m at f8. However, the distance markings on some of my lenses jump quite abruptly from 2 or 3m to infinity.

 

To focus at the hyperfocal distance of 5m or more, should I set the distance closer to the 3m mark or the infinity mark on the distence scale? Or use a smaller aperture like f11 with a 35mm FL?

[dave_s]

(i) If you want sharpness in the distance, focus a bit closer to infinity. Many photo.netters will argue that if you're calculating a hyperfocal distance based on f/5.6 (for example), you should use an actual aperture of f/8. This is a different way of saying the same thing.

 

(ii) If you really want to focus on 5m, or 7m, or whatever, forget about the distance markings on your lens. Choose an object that estimated distance away, and focus on it manually.

 

(iii) If you want great depth of field, sure, go to f/11 or f/16. You will pay for it with a tiny amount of image degradation due to diffraction. There is no free lunch.

[frank uhlig]

If you intend to see stuff infinitely far away clearly and sharp in your picture and not have mush of the far away treeline instead: focus at infinity and close the lens down to about an 2.5 mm opening. For a 35 mm lens that would be about f/11. You did right. Hyperfocal distance focusing is quite bad for the sharpness of your pics. Focus on infinity if that is what you want to include and close down to at least 2.5 mm opening. 35 mm / 11 = 3. 2 mm is fine!

[James G. Dainis]

<center><img src=http://www.geocities.com/dainisjg/hassey2.jpg></center><P>

 

The lens on the left has been set to f/22 and focused at infinity. In the photo on the right the infinity mark has been moved above 22 on the right side and 9 feet falls above 22 on the left side. The focus pointer is at 18 feet, the hyperfocal distance. Everything should be in acceptable focus from 9 feet to infinity while previously it was 18 feet to infinity.<P>

 

At f/5.6 the hyperfocal distance is so close to the actual focus that it takes only about a 1/16 turn of the focus ring to get from infinity to the hyperfocal distance.<P>

[alec_myers]

Something to remember about "Hyperfocal" distances - it's not a figure set in stone because it depends on your

definition of acceptable focus, so there's no point in worrying about getting it right to the nearest cm.

 

It's just where the plane of sharpest focus falls, when an object at infinity is "just on the borderline of acceptable

focus". Depending on who's definition of 'acceptable' you're using that can still be pretty blurry. So the others are

right, if you like sharp horizons, focus beyond what the guide tells you.

[James G. Dainis]

<center><img src=http://www.geocities.com/dainisjg/hyper_min.jpg></center><P>

I think what Frank is saying above is if you want greater depth of field, use f/11. True, but you can still use

the hyperfocal distance with that to get even greater depth of field.<P>

 

The lens on the left has been set to f/11 and focused at infinity. Everything is in acceptable focus from 19 feet

to infinity. In the photo on the right the infinity mark has been moved above 11 (between 8 and 16) on the right

side and 9.5 feet falls above 11 on the left side. The focus pointer is at 19 feet, the hyperfocal distance.

Everything is now in acceptable focus from 9.5 feet to infinity. <P>

 

What it all amounts to is moving the infinity mark over the aperture opening mark to automatically set the

hyperfocal distance. Before auto focus lenses, people would use this zone focusing rather than trying to set the

split prism in dimly lit areas or if they were in a hurry to get the shot.

[songtsen]

I wouldn't have guessed that moving the infinity mark to the aperture mark on the DOF scale would set the hyperfocal distance! As suggested, I will use a smaller aperture too. Thanks to everyone for all the helpful replies.

[William Michael]

> As suggested, I will use a smaller aperture too.<

 

I would like to reinforce a comment from Dave Sims, which might be overlooked.

 

It is most likely you will get best performance (sharpest images) using apertures from about F5.6 to F11.

 

Once you get up to F16 (maybe even F11), and beyond you have to deal with diffraction, so I suggest you take that into consideration.

 

***

 

Also, as a side comment, that lens above looks very much like a Rokkor 45mm/F2, one of the least expensive, but yet most useful pancake lenses I have ever used, I just love mine.

 

WW

[James G. Dainis]

William,

 

It is indeed a Rokkor 45mm, f/2 lens and I agree with you.