Hyperfocal distance

linarms wrote in post #2208140
At f/22 you'd probably get diffraction, so no. Don't stop down past f/16 (as a good rule of thumb).

Maybe im not getting the point...but.... what s the purpose of hyperfocal distance if I can stop down to f/16?

linarms wrote in post #2207987
I think it's cos the aperture is digitally controlled. Which makes it harder to put scales on.

I'm not sure in what sense you mean 'digitally controlled', the actual physical opening and closing is mechanical, the DOF preview button works perfectly to close down the aperture whilst you look through the lens. Besides all the scales consist of is a number of lines drawn on the barrel, to show you where the near and far limits of the DOF will occur at any given focusing distance and aperture. How the aperture is determined is irrelevant as those distances are constant.

If you mean that it is digitally controlled by the camera setting the AV, then that is easily solved by using aperture priority or manual settings.

All it would take is a few lines to make things so much simpler

I'm not sure it is so simple ... the lines made sense when you had an aperture ring on the lens ... with the camera controlling aperture (yes, even if you do it manually using Av or M) there is no ring to line a DoF scale up against ... and of course hyperfocal distance is aperture dependent ... so it's not that easy.

But I guess if you're in a fix, you can always use A-DEP. It automagically does hyperfocal focussing and aperture selection for you ...

ChrisBlaze wrote in post #2208325
Maybe im not getting the point...but.... what s the purpose of hyperfocal distance if I can stop down to f/16?

Well, if using a very wide angle lens on a landscape on a nice sunny day, probably no purpose at all. wide angles have large DOF and at f16 would probably extend from a few feet, even when focus is set at infinity. Even then, if you wanted to make a feature of a foreground object only two or three feet in front of the camera (not unusual) it may not be sharp with the focus set to infinity, but would be with the focus set to the hyperfocal distance at maybe 15 feet, which would also extend the DOF to infinity.

Throw in some variables, a longer lens (shorter DOF), a different subject and a twilight shot meaning that you can only use f4 and suddenly hyperfocal distance becomes very important.

If you don't know what the hyperfocal distance is, either by using the formula and some math or looking at DOF scales drawn on the barrel, you can 'back off' the focus from infinity to a distance you feel will be safe (not going soft at infinity) then check using the DOF preview to see what will be sharp and what won't.

linarms wrote in post #2208447
I'm not sure it is so simple ... the lines made sense when you had an aperture ring on the lens ... with the camera controlling aperture (yes, even if you do it manually using Av or M) there is no ring to line a DoF scale up against ...

You don't line them up against the aperture ring, that doesn't come into it except as a way to choose your aperture. The DOF scales line up against the focus distance scale, which does exist on the lens. You just set the focus, then the near and far distances of the DOF (at f8 say) can be read off by choosing the two lines which are marked as f8, one on either side of your focus point, and you simply read off the DOF limits. Yes it is that simple !!

If you want the hyperfocal distance at f8, you simply place the infinity mark on the focus ring over the f8 line, rather than the centre mark (the actual focus). The distance showing at the centre line is where you are actually focused (the hyperfocal distance) and the distance showing over the other f8 mark is the nearest edge of your DOF.

If you are shooting a scene and don't want it sharp at infinity, but there is a subject that you want sharp about 60 feet away and the DOF to extend as far forward as possible, you use the same principle.

If you focus on the subject, the foreground will be OOF and the background may be either in focus or only slightly softened. If you focus on the subject then look at the focus scale and see that it reads 60 ft, you adjust the focus so that 60 ft sits over the upper DOF scale line. The actual focus point may now only be 35 ft away, but the subject is within the DOF and so is still in focus. The foreground is now much more within the DOF and so is sharper, the background is further outside the DOF and so is more pleasingly softened and less distracting.

Technically, this latter technique isn't using the hyperfocal distance as that specifically refers to a distance related to infinity. In practical terms however it is exactly the same technique and dead easy so long as the little scale is drawn on the lens. It is this latter example which is more typical of the times you would use hyperfocal focusing. Simply using f16, as Chris Blaze, suggests is of little value when you want your foreground sharp but an OOF background ( a common desire).

linarms wrote in post #2208447
But I guess if you're in a fix, you can always use A-DEP. It automagically does hyperfocal focussing and aperture selection for you ...

Actually it doesn't. You still have to focus on a subject, the red focus points then light up to tell you what else is in focus and the DOF preview button shows you the scene.

In my example above, you would still have to focus on the subject using A-DEP, so would be focused at 60' with the DOF extending way too far backwards. To use A-DEP in that scenario you would need to have a second subject conveniently placed at the 35' distance to focus on, otherwise you are trying to autofocus on an empty space. You could manually focus at 35' of course, but A-DEP doesn't work with MF so is of no use whatsoever.

You still need to know where to focus to place your DOF where you want it and the easiest way is with a DOF scale on the lens barrel. Camera makers are very good at giving us gizmos and features to do jobs that are much simpler done (and better) with good photographic technique and (in this case) a few lines drawn on a lens.

sandpiper wrote in post #2207869
Does anybody know why they no longer put DOF scales on lenses?

It's hard to do this on zoom lenses, since DOF varies with focal length. Though I have seen push-pull type zooms with DOF marks on the barrel which spread out as you extend the lens.

Perhaps the main reason is that lenses are now used on a variety of camera formats. And camera format (sensor size) will affect DOF, since there is more magnification required to make the same size print from a smaller sensor. So the DOF at a given aperture & focal length depends on what camera the lens is attached to.

just marking this thread for reading later

Curtis N wrote in post #2208653
It's hard to do this on zoom lenses, since DOF varies with focal length. ...Perhaps the main reason is that lenses are now used on a variety of camera formats. And camera format (sensor size) will affect DOF...

Add the fact that the number of degrees of rotational range in the focus has been significantly reduced in order to make it easy for motors to quickly focus the lens, so even if DOF scales were on the lens they would be compressed together and somewhat difficult to use.

Curtis N wrote in post #2208653
Perhaps the main reason is that lenses are now used on a variety of camera formats. And camera format (sensor size) will affect DOF, since there is more magnification required to make the same size print from a smaller sensor. So the DOF at a given aperture & focal length depends on what camera the lens is attached to.

Again, no.

The image projected by a lens onto the sensor is identical whatever the size of the sensor, the only difference being that a crop sensor will only record a smaller central area of that image, thus giving the appearance that it was shot with a longer lens. An image shot with a full-frame camera and then cropped to the same image as a 1.6 sensor will be essentially identical. The only difference being that one is cropped in camera by not recording the edges, the other is done in software afterwards. DOF does not change simply because you don't record the whole image, no camera does anyway, even FF crops it - just less so (otherwise you would have a circular image).

Wilt wrote in post #2209285
Add the fact that the number of degrees of rotational range in the focus has been significantly reduced in order to make it easy for motors to quickly focus the lens, so even if DOF scales were on the lens they would be compressed together and somewhat difficult to use.

Well spotted, that man.

Yes, you are right, go to the top of the class and collect a gold star. That is probably the reason. I've just compared a couple of FD lenses to their EF equivalents and you are quite right, the DOF scales would be too close together.

I'll call off the hit squad on Canons design team.

Oh well, it looks as if DOF scales are consigned to the history books, only to be seen on those funny old cameras that use film and manual focus only lenses.

This probably also explains why I used to use the old FD gear and never see the point in AF, as I could focus quicker myself, but hate focusing manually on the DSLRs. The shorter travel makes it harder to locate the exact spot, as a slight movement will take you off it - not to mention the VF not being as clear as the old FD cameras beautiful split screen focusing system.

Another reason why the old 'uns are more pleasurable to use (as discussed on another recent thread). If only they didn't cost so much to feed

Oh well, this doesn't affect the theory of hyperfocal focusing, only how simple it is to do it.

What's the big deal? If you want everything from 5-50 meters to be in focus them you focus around 20m in. Futher than 100 m or so can be considered to be infinity so focussing around 30m in should work.

I use this method all the time with my landscape shots and it seems to work well enough.

sandpiper wrote in post #2209584
Again, no.

The image projected by a lens onto the sensor is identical whatever the size of the sensor, the only difference being that a crop sensor will only record a smaller central area of that image, thus giving the appearance that it was shot with a longer lens. An image shot with a full-frame camera and then cropped to the same image as a 1.6 sensor will be essentially identical. The only difference being that one is cropped in camera by not recording the edges, the other is done in software afterwards. DOF does not change simply because you don't record the whole image, no camera does anyway, even FF crops it - just less so (otherwise you would have a circular image).

DoF is different on crop factor cameras, because the circle of confusion is different on crop factor cameras. See here: http://www.outsight.co​m/hyperfocal.html Just one example of the crop factor being used to vary the circle of confusion constant in DoF calculations.

sandpiper wrote in post #2207704
NOOO, that is the opposite. You are wasting a large part of your DOF.

Not quite: A different opinion here.

sandpiper wrote in post #2209584
Again, no.

Again, almost, not quite: Read this.

Sandpiper, as has been pointed out, DOF is indeed format sensitive. Lots available on this topic, but to simply provide it to yourself, find a DOF calculation program and try it out.