Hyperfocal distance

Im reading a book and it says when you trying to get the hyperfocal distance you need to focus 1/3 into the picture. Can this be clarified? How do you focus 1/3 into the picture.

Hmm odd

Yeah that doesn't quite make sense.

There is an old wive's tale about depth-of-field being 1/3 in front of the subject and 2/3 behind. But it's a thumbrule that's wrong more often than right, so I don't put much stock in it.

Hyperfocal distance is the nearest distance you can focus to achieve "acceptable sharpness" from half that distance to infinity. It's also related to depth-of-field, but different from the 1/3 - 2/3 wive's tale.

Here's a website with lots of info about depth-of-field.
http://dofmaster.com/a​rticles.html

ChrisBlaze wrote in post #2207296
Im reading a book and it says when you trying to get the hyperfocal distance you need to focus 1/3 into the picture. Can this be clarified? How do you focus 1/3 into the picture.

Poorly worded. The comment relates to the fact that DOF at normal (non-macro) shooting distances are deeper behind the main point of focus than in front of the main point of focus. For example 50mm lens on a 20D, set to be focused at 100', has DOF range from 72' to 161'. 28' of the 89' total DOF (or approximately 31%) is in front of the point of focus. So you see where the rule of thumb comes from. For macro work, it is closer to 50:50.

With the same 20D and 50mm lens, if the lens is focused at 66', the DOF is from 33' to infinity when the lens is f/8. One would have a hard time imagining that 66' is located about 1/3 of the way between you and infinity.

Who is the author...I want to remember who NOT to read!

instead of hyperfocal distance couldnt you just sent your lens to infinity to get a great depth of sharpness?

ChrisBlaze wrote in post #2207573
instead of hyperfocal distance couldnt you just sent your lens to infinity to get a great depth of sharpness?

That could work somewhat...

For f/8...it would have DOF of 20' to infinity if the focus was at 10000'! By focusing at 60' you could have DOF of 15' to infinity at f/8, so the difference is small.

For f/2.8, focusing at 10000' would have DOF of 56' to infinity. By focusing at 60' you could have DOF of 29' to infinity at f/2.8...noticeably deeper.

Yes, poorly worded but hyperfocal distance is useful if you have a specific distance in front of, and behind, the subject that you want to be in focus. DOF does generally extend further behind than in front of the focus point, typically in the vicinity of 1/3 : 2/3 front /rear.

There are times when you might not want to actually focus on the subject, if you have a specific area of DOF you want to be sharp, you focus on the point that allows the DOF to cover the area you want. This is in combination with selecting the aperture that allows the necessary amount of DOF.

This technique is especially useful when shooting landscapes and wanting to know where to focus to give maximum DOF, getting the nearest point possible sharp whilst still being in focus to infinity. The DOF preview button is handy for seeing this, but is not as simple, or easy to see, as the old hyperfocal scales that were marked on lenses in the pre-EOS era. Back then you only had to glance at the lens to see the nearest and furthest point in focus at each aperture. Focus on the nearest & furthest points you want sharp, to measure the range, turn the focus barrel until both distances are equally within a particular aperture band and set that aperture to give appropriate DOF, the lens will be focused at a point (roughly) 1/3 of the way into the zone in most cases (unless using macro or working to infinity). The point at which the lens is focused is the hyperfocal distance for that DOF at that range.

Saying 1/3 of the way into the picture is a very vague way of describing the use of hyperfocal distance, for a start it should read 'into the zone you require to be sharp' rather than 'into the picture' which is misleading. The 1/3 : 2/3 rule is also vague (as mentioned by others above) but gives a guideline to be used as a starting point with the DOF preview facility. Sadly crop sensor bodies, with their smaller viewfinders, make it hard to see this properly. As modern lenses aren't marked up with DOF scales like their predecessors, you need to carry charts around giving the DOF for each lens at all ranges and apertures.

Because of this DSLRs are not as suitable for using hyperfocal distance properly, compared to the older Canon FD SLR system. In effect, the modern way seems to be to simply remember that DOF extends roughly twice as far behind as in front of your focal point, and work accordingly.

ChrisBlaze wrote in post #2207573
instead of hyperfocal distance couldnt you just sent your lens to infinity to get a great depth of sharpness?

NOOO, that is the opposite. You are wasting a large part of your DOF. With hyperfocal / DOF scales you would set infinity on the focus ring to sit on the scale line for the aperture that you are using , with the focus actually being set for maybe 20 ft, but the edge of the DOF reaching infinity. Naturally the near edge of the DOF will be closer with the focus set at 20 ft, than with focus set to infinity.

Focussing 1/3 of the way into a scene is what Bryan Peterson suggests in his book "Understanding Exposure". It assumes that it's easy to work out what point is 1/3 of the way into a scene (which is harder than it sounds). It also assumes that you're using a small enough aperture to compensate for the fact that you're not going to be focussing at the real hyperfocal distance.

But then, focussing at the hyperfocal distance assumes that your circle of confusion constant is adequate for the image resolution you want to achieve!! Which, in many cases, it is not... meaning that you end up with an OOF background even though the maths says it should be adequately focussed!!

In the end, it's usually best to just pick a large f-stop (f/11 or so - depending on how wide your lens is) and focus at infinity. Unless you have a very close foreground, in which case it might be worth experimenting with different focus points.

linarms wrote in post #2207760
But then, focussing at the hyperfocal distance assumes that your circle of confusion constant is adequate for the image resolution you want to achieve!! Which, in many cases, it is not... meaning that you end up with an OOF background even though the maths says it should be adequately focussed!!

In the end, it's usually best to just pick a large f-stop (f/11 or so - depending on how wide your lens is) and focus at infinity. Unless you have a very close foreground, in which case it might be worth experimenting with different focus points.

This is where the old film cameras were so much better to use, I used to regularly use the DOF scales, when doing landscapes etc., and always managed to achieve maximum DOF without losing sharpness in the distance. Without the scales, I have to back the focus off from infinity a bit, use the DOF preview to sort of check it (but this is not as clear to see as on film cameras) and then leave a decent margin for error. I would never actually focus on infinity (unless intending to reduce foreground sharpness), but I do focus nearer to it than I probably need.

Does anybody know why they no longer put DOF scales on lenses? Surely it wouldn't be expensive just to add some extra markings to the barrel, especially considering the cost to purchase the things. I really miss having them.

I think it's cos the aperture is digitally controlled. Which makes it harder to put scales on.

sandpiper wrote in post #2207704
NOOO, that is the opposite. You are wasting a large part of your DOF. With hyperfocal / DOF scales you would set infinity on the focus ring to sit on the scale line for the aperture that you are using , with the focus actually being set for maybe 20 ft, but the edge of the DOF reaching infinity. Naturally the near edge of the DOF will be closer with the focus set at 20 ft, than with focus set to infinity.

I guess I just dont understand hyperfocal distance. I am trying to use it for landscapes but I dont get it. If I stop down to.... lets say f/22, shouls my whole scene be sharp?

At f/22 you'd probably get diffraction, so no. Don't stop down past f/16 (as a good rule of thumb).

What they're trying to get across is that you'll best match DoF to the subject if you focus on a point about 1/3 between the nearest and furthest points you want in focus. At "normal" distances DoF extends about 1/3 before and 2/3 behind point of focus. As point of focus moves closer to the camera, the separation between front point and point of focus approaches that of rear point and poingt of focus, so close up DoF is about 1/2 in front and 1/2 in back.

http://en.wikipedia.or​g/wiki/Hyperfocal_dist​ance