Question about focusing and hyperfocal distance

[davidedric]

Hello,

This may be a horribly silly post, but what the heck.

I want to get better control over DoF, especially for landscapes.

I think I understand hyperfocal distance, and I have downloaded the app which allows me to calculate it.
Of course, shooting with a zoom, there is no focus distance on the lens barrel.

I have a gx7, so if I put it into manual focus it also has focus peaking. In fact, it also has a little scale, which shows in analogue whereabouts I am focused (supplementary: surely, with the information the camera has it could add actual metres to the scale?).

So my question is, if the hyperfocal distance is 40m, say, how do I set the lens to focus there. Do I have to estimate? There may be no actual object at 40m.

Any illumination appreciated

Dave

[Shadowman]

Does the app give you a work around when you don't have scale on your lens? Without the scale you have to estimate the distance.

[Manfred M]

Dave - I've been shooting using hyerfocal distance for years. I just ball-park the distance and if I'm worried about being right on, I give myself an extra f-stop leeway (use the hyperfocal chart for f/8 but shoot at f/11).

For focus, I use the backbutton technique (yes I do that on the GX7 too) and make sure that the shutter release does not change focus when I press it. Works well enough for me.

[DanK]

Estimating is usually all you can do. Even if the lens has a distance scale, the scales are so compressed on most modern lenses (to make the rotation needed for AF small) that they are not all that useful. I rarely use mine except at macro distances, where the rotation per unit distance is larger.

[Mike Buckley]

I suppose you could use an infrared device that automatically measures the distance of whatever the infrared ray falls upon.

[William W]

I want to get better control over DoF, especially for landscapes. I think I understand hyperfocal distance, and I have downloaded the app which allows me to calculate it. Of course, shooting with a zoom, there is no focus distance on the lens barrel. I have a gx7, so if I put it into manual focus it also has focus peaking. . . .

So my question is, if the hyperfocal distance is 40m, say, how do I set the lens to focus there. Do I have to estimate?

There may be no actual object at 40m.

Any illumination appreciated

If I correctly understand the functionality of your camera, then the answer is your specific question is that you have to estimate the distance.

*

In response to the question "any illumination"-

In practical terms, if you want to use the HD, the we'd assume your goal is to 'maximize the DoF'. In which case I think that you are worrying about many 'problems' that are rarely going to happen with your gear, because for mostly all landscape shots, "estimating" the HD is really easy, because the HD will be quite close (rarely 40m away) and also with your 4/3rds camera, for most landscape shots, you will have a large DoF anyway.

Let’s look at what is likely to be the more common situation that you will find yourself shooting, I think these are reasonable assumptions which outline those situations:

1. You would want to use the HD to maximize your DoF
2. Typically you would want to maximize the DoF for a wider shot, compared to a narrower shot
3. Inherently a 4/3 Camera (smaller sensor) will exhibit a wide DoF rather than a shallow DoF
4. A Zoom Lens will have a relative small, Maximum Aperture
5. For mostly all landscape work we would expect the lens would working at F/5.6, or smaller
6. For most Landscape work there is usually a bit of TIME to set up the shot

*

So, if you can accept those as reasonable assumptions applicable for most of the Landscape Images that you will make, then, let’s extract a typical example shooting scenarios. Let's say for the first shot you’d have the lens set at about FL = 20mm and you’d use F/5.6 (or smaller). The HD for that scenario - HD ≈ 5.5m. (Using CoC = 0.013mm and rounding the HD)



So, one easy technique to estimate is:

1. where you are standing to frame the shot, drop your camera bag, boots, red flag or any other article
2. take 5½ “big steps” in any direction and then focus and lock focus on the marker that you dropped
3. return to the marker and make the shot

*

Further indicatives for your gear:

At FL = 30mm, and F/5.6 the HD ≈ 12m, that’s only 12 "big steps"
At FL = 40mm, and F/5.6 the HD ≈ 22m, that’s only 22 "big steps"
(Using CoC = 0.013mm and rounding the HD)

So, even (in what I think is an unlikely circumstance) if you are using FL = 40mm, (note: which is a short telephoto lens on your camera) AND you are using F/5.6 (and not F/8 or F/11) you still only have to pace out 22 big steps to make a very accurate focus point for your camera . . .

BTW - even if you were using a 40mm Lens: if you could use F/11, then the HD ≈ 11m.

*

When using the method described above, or even if one is 'guesstimating by sight', with a small sensor camera, I'd usually always take one extra "big step" or alternatively estimate a bit more distance, because to focus a bit farther than the actual HD, you only miss a bit of the foreground of the shot; but if you underestimate the HD, then you miss all at the background and there's usually so much DoF in the shot to begin with.

*

All that stated: there are a few rational arguments that for most Landscape work, focusing just a tad short of infinity is a very good, if not a better method to use than using the HD method.

WW

[pnodrog]

For landscapes generally I find softly focused foreground detail more annoying than softly focused distant hills etc. So if I err I opt for focusing slightly closer than needed. However unless the lighting is very low I use DOF preview. The few times I have used a camera without DOF preview I stick it on a tripod and shoot with a very small aperture (the longer the focal length then the smaller the aperture and the more necessary the tripod.)

[tao2]

Hi Dave,

Leaving aside the second part of yer question re. how tae set the lens at a particular distance.

Ye say

I want to get better control over DoF, especially for landscapes.

and ah get that.

Then ye say......

if the hyperfocal distance is 40m,

If ye already know the hyperfocal distance, why would ye then want tae focus there?

[Polar01]

Bill not sure where you got your numbers ie: "At FL = 30mm, and F/5.6 the HD = 12m, that’s only 12 "big steps"", 2 apps that I have on my phone, both state for a FF Nikon it states that it is 18 ft not meters and you would get a DOF from 8.87ft to infinity, and at 40mm focus distance is 31ft so DOF is 15.5ft to infinity.

Cheers: Allan

[William W]

Bill not sure where you got your numbers

Thanks.
Maybe I made a mistake, can't double check my numbers ATM, but will do though and reply later.

WW

[dem]

...2 apps that I have on my phone, both state for a FF Nikon ...

Just did a quick check with two different apps on my phone for an MFT sensor (not full frame, but crop factor 2!), 20mm, f/5.6 and got the hyperfocal distance of 4.73m with one app and 5.91m with the other. So Bill's 5.5m is spot on.

[Mike Buckley]

The few times I have used a camera without DOF preview I stick it on a tripod and shoot with a very small aperture (the longer the focal length then the smaller the aperture and the more necessary the tripod.)

If you're using a tripod, you could use Live View (one of your cameras has it). You could examine the closest and farthest parts of the scene when magnified in the LCD at 100% to determine whether everything is in focus. If not, you could make adjustments and examine again. If you're using the camera that doesn't have Live View, you could do the same after capturing the image. Once I began using a digital camera, I stopped using DOF preview.

[Polar01]

Bill my error I used my info based on a FF camera, I missed or it went completely over my head, that it was a Micro 4/3 camera, once I plugged in the correct camera your big steps were very close. Sorry for the confusion.

Cheers: Allan

[rpcrowe]

I don't really worry about hyperfocal distance. I have had no problems with focusing using autofocus. If I want to maximize DOF, I will pick an subject about 1/3 of the way into the area I want to cover and focus on that.

In my old Navy terminology. "If it ain't broke, don't fix it"

In the days of manual focus lenses, which had comprehensive focusing scales, perhaps using the hyperfocal distance might have been the way to go. However, most of the lenses in those days had a larger focus turn, with a more detailed distance scale. In fact many, if not most, of the older manual focus lenses had this type of a very helpful focus scale included.



You simply placed the f/stop scale (image right) on the infinity symbol (figure 8 laying on its side) and you would be in focus from infinity to the corresponding f/number image left. Basically, that would put you focused on the hyperfocal distance - resulting in the image being in focus from half the hyperfocal distance to infinity...

Anytime you focused the lens - either with a rangefinder or zone focusing, the two f/stop scale would show you the area in focus from where the image right f/stop corresponded to the distance scale to where the f/number image left corresponded.

BTW: as an aside. The red dot on the lens is the infrared focus point. If shooting with infrared film, you focused normally and then, before shooting, would switch from the standard distance scale (yellow indicator) and turn the focus ring so that the red dot would be in the spot where the standard focus mark had been. This should take care of the difference in focus between visible and IR wavelengths...

Obviously, this type of focus scale would not be practical with a zoom lens since the zoom has an almost infinite focal length range between the shortest and longest focal lengths.

However, if a person is dead set on wanting to know exactly the distances of various subjects/objects within the image, the photographer could step into the world of the hunter or competitive shooter for a range finder.

http://www.cabelas.com/catalog/searc...h-All+Products

These are pretty expensive and, IMO, not all that applicable to shooting with autofocus equipment.

[lukaswerth]

Dave,

I know this is not the answer you want to hear, but for what it's worth, I think hyperfocal distance is a pretty ineffective concept with modern cameras.

Reasons:
1) As a relative concept, it depends on a predefined acceptable circle of confusion, and with that on a maximum print size.
2) As you observed yourself, you don't necessarily focus on important parts of the motiv, but at the calculated distance (or, at least you try).
3) And this is the most important issue: in the distance, details are smaller, so our eye expects more resolution in the image background (we are much more tolerant for the foreground). With hyperfocal distance, however, the distance only shows what is thought an acceptable minimum resolution, and therefore often appears, well, wanting in sharpness - this is particularly true if you want to go a bit larger in size than previsaged, but it is a general drawback of the whole concept.

I therefore think it is much better to focus on important image parts or infinity. Hyperfocal distance was somewhat okay in the days you had a 35mm or medium format negative which you wanted to print as 8x10", but these days are, for most of us at least, gone.

My two cents,

Lukas

[russellsnr]

I bought the two on the right
http://www.georgedouvos.com/douvos/O...s_Stacker.html
Russ

[William W]

Allan, Dem, Thanks. Also I amended my post to include the CoC that I used.

[davidedric]

Thanks for all the feedback. Some useful hints and ideas there.

Dave