Using the Hyperfocal Distance in Practice

[tmyuen]

I've followed the link on "setting the camera/lens to the hyperfocal distance" in the thread on using automatic depth of field (A-DEP), and read the article there. I still can't figure out how I can set, in practice, the focus to the hyperfocal distance. Say I'm going to shoot an object some 20 ft in front of me, and I want everything in the background to be sharp. Where should I put the focus point at? at the object? or at somewhere in front of the object?

[McQ]

Welcome to the forums tmyuen! Is this object 20 ft away the central subject in your photograph? If yes, then it sounds to me like the hyperfocal distance may not be the best option. This is because you likely do not want your 20 ft object to lay at the edge of the depth of field (where the sharpness criterion is close to no longer being met).

When using the hyperfocal distance, one typically specifies (i) the focal length of their lens and (ii) the nearest subject matter that they want in focus (even if this subject matter is not central to the image, such as grass in the foreground of a landscape). The hyperfocal distance (HFD) is the focusing distance whose depth of field extends from HFD/2 all the way to infinity.

Regardless, here's how to focus using this website's (1) hyperfocal chart calculator or (2) the standard depth of field calculator:

(1) Using this website's Hyperfocal Distance Chart Calculator

Set your camera's sensor size and leave everything else at their default settings for now. Click "Calculate Hyperfocal Distances" and find the column which corresponds to your chosen focal length.

If this focal length were 35 mm and you were using a 1.6X cropped sensor, then one option would be to focus at 34.8 ft and use an aperture of f/5.6. This would produce a DoF that would extend from 17.4 ft (HFD/2) all the way to infinity--if going by the standard hyperfocal definition. However, in practice I usually prefer to go as far beyond the sharpness criterion of the hyperfocal distance as possible (more on this at the end).

(2) Using this website's Depth of Field Calculator

Enter the appropriate settings for your camera's sensor size, focal length and subject distance (in your case, 20 ft or 6.096 meters). Leave the aperture at a small number such as f/1.4 for now. Click "calculate". You will then see the closest and furthest distances of acceptable sharpness. Next, progressively increase the f/# (clicking calculate each time it is changed) until the furthest distance of acceptable sharpness says "infinity". For a 20 ft focusing distance, a 35 mm lens and a 1.6X crop factor camera this first occurs for an aperture of f/11.

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As mentioned earlier, I usually prefer to go as far beyond the sharpness criterion as possible (loosely defined to be objects which are not noticeably soft when enlarged to an 8x10 in print and viewed at 1 foot). A smaller aperture then this is usually advisable if it will not visibly soften the photo from diffraction, or will not cause you to use a prohibitively slow a shutter speed. In the examples above, focusing at or ever so slightly beyond 20 ft and using f/11 would likely yield the best results. This yields a DoF that extends beyond infinity, and also has the benefit of placing the plane of sharpest focus close to the main subject. Anything beyond f/11 and you will start to see some diffraction with a high megapixel 1.6X crop factor camera sensor.

A bit of caution is that for some situations, there may not be an adequate hyperfocal distance or depth of field which achieves your sharpness goals (at least without substantial diffraction). This is particularly true with longer focal lengths.

[tmyuen]

Thank you so much McQ for the detailed explanation. I'm extremely pleased that I found this site and joined this forum.

Being a newbie in DSLR photographing, I'm sure I'm going to have more questions than you might imagine ;-)

[xeliex]

A bit of caution is that for some situations, there may not be an adequate hyperfocal distance or depth of field which achieves your sharpness goals (at least without substantial diffraction). This is particularly true with longer focal lengths.

I realize that this might be a scenario specific question; but what would you typically do in such situations?

Edit:
Compromise between sharpenss and diffraction or err on one side versus the other?

[McQ]

I realize that this might be a scenario specific question; but what would you typically do in such situations? Compromise between sharpness and diffraction or err on one side versus the other?

Well, there's nothing one can really do except to prioritize their subject matter. In which areas is sharpness most critical from an artistic perspective? Unfortunately photography is often about compromise--at least technically. I would have no problem erring on the side of diffraction in order to achieve a greater depth of field, if my subject matter warranted it. Just be absolutely sure that this is a compromise you have to make; in other words, that you are already focusing at the best distance for positioning DoF, etc.

The only other option, which really does not apply here because it requires more than one photo, is to combine a series of photographs using different focusing distances. This is another topic unto itself though...

[David W]

Hi, just joined.
There is a good depth of field/angle of view/hyperfocal focus etc calculator for downloading to windows or a palm device on 'www.tangentsoft.net'
Regards David W

[xeliex]

Hey David,

Welcome to the forums and thanks for the link.

I keep on my Nokia phone a site link from DOF Master since they don't have a Symbian compatible application.

Anyone knows of a DOF calculator that works with Symbian OS?

Thanks.

[Antonio Correia]

...A bit of caution is that for some situations, there may not be an adequate hyperfocal distance or depth of field which achieves your sharpness goals (at least without substantial diffraction). This is particularly true with longer focal lengths.

I would like to drop a line here because there is something I am missing for sure.

Let's assume to make things easier for me to explain, that I have an object at - and I will be using your feet - 10 feet, with a 55mm lens at f/2.8 and I am shooting with a Canon 20D, 30 D or the new 40D.

The table will return:
Near limit = Near limit of acceptable sharness = 9.5 feet
Far limit = Far limit of acceptable sharness = 10.6 feet
Total = 1.07 feet

This means that I will have everything in focus from 9.5 to 10,6 feet.
Then, if I keep the settings of the camera and move it forward or backward inside this distance I will have my target in focus.
Or, vice-versa: move the object within that range of distance and it will always be in focus.
So, this way I can "move" my DoF forward or backward the object, according to my interest.

Let me explain - or try to - another way.
I will be using for this new example a 35mm at f/5.6 with the same camera crop factor and CoC.
I have an object at 13 feet.
I want everything in focus from 8 feet to the object.
To get this purpose I have to set the focus at 10 feet for example.

I mean, I displace the DoF the way I want. forward or backword.
I just have to use a distance meter to set my 10 feet focusing distance on the lens, switch off the auto focus, compose and shoot.

Remember those lenses we used before digital and some - very few still have it (Zeiss does have it so I read ?!) - with the distances in the barrel ?

I made some time ago this "instrument" for this purpose. And I use sometimes my laser 7 years old distance meter with it.
This is an important concept if we want to shoot landscape for example or we want to make a guess of how deep is the DoF when shooting a portrait with teh 70-200 with a Canon 5D just to get an example.



At last: just move the Focal Plane and you get what you are looking for.

Did you read all this ? Congratulations ! UUfff

[xeliex]

Antonio, that is an intersting post / perspective.
I see how it might be useful to prefocus (autofocus at desired pt), lock focus (change to manual), and recompose.

I will double check my 12-24 Tokina. I don't think it has hyperfocal scales, but I think it has focus distance readings which is great!

[McQ]

Thanks for the follow-up post!

I have an object at 13 feet.
I want everything in focus from 8 feet to the object.
To get this purpose I have to set the focus at 10 feet for example.

If this object is of importance to the composition, I would definitely not place it at the edge of your depth of field. Always try and give some padding room if you can, because the criterion for sharpness as defined by the DoF is not noticeably less sharp than your camera/lens can resolve. Depending on the subject matter, this might look odd in the photo.

I just have to use a distance meter to set my 10 feet focusing distance on the lens, switch off the auto focus, compose and shoot.

Remember those lenses we used before digital and some - very few still have it (Zeiss does have it so I read ?!) - with the distances in the barrel ?

Be careful because the distance meters on the lens can sometimes be quite off-- at least relative to the precision of focusing you are trying to achieve. It might be a good idea to first focus at an object of known distance (and see what that corresponds with on your lens distance markings) to verify your lens markings are sufficiently accurate.

[sebasj]

Be careful because the distance meters on the lens can sometimes be quite off-- at least relative to the precision of focusing you are trying to achieve. It might be a good idea to first focus at an object of known distance (and see what that corresponds with on your lens distance markings) to verify your lens markings are sufficiently accurate.

Indeed, the barrel not only doesn't have enough space to allow drawing of the scale with enough precision, but also sets on that scale 50% of in focus space in front of subject and 50% behind, while most lenses render approximately 30% in front and 70% behind subject (in example, if the lens barrel scale shows a depth of field of 2m, it's not going to be 1m in focus in front of the subject and 1m in focus behind, but 140cm behind and 60cm in front, approximately).

I tend to try to have my subject in the middle of the depth of field scale when using hyperfocal... or well, zone focusing in this case.

Best regards,
Sebas.

[tmyuen]

I have another question related to the subject of this thread (Hyperfocal Distance, HFD). Say for a specific shot I have come up with a HFD of 20 ft, and I'd like to set my focus at this distance. However, there is no obvious or suitable object for me to focus at (20 ft away from my camera). Under this situation what am I supposed to do?

[sebasj]

Well, if you are using the hyperfocal technique, you don't need to focus on your subject at 20ft away. The hyperfocal technique allows you to get a depth of field enough so subject between p and q distance will be in acceptable focus (I note "acceptable" because in closer examinations you may find that it is not in perfect focus, however from what is called "normal viewing distance" it'll be in focus).

Let's suppose that you come up with a setting on the lens that allows everything to be in focus from approximately 17ft to infinity (for example, a 50mm lens at f/8 focused at 30ft). As long as your subject is not nearest than 17ft from you, will be in focus. Now, let's close the aperture to f/16, and you can focus your lens at approximately 17ft, and everything will be in focus from 9ft to infinity (I'm reading the scale on my CZ 50/1.4 lens). As long as your subject is not closer than 9ft from you, will be in focus when printed and the print is viewed at a normal viewing distance.

As you can see, the idea of the HF technique is to avoid focusing. As long as you can keep your subject inside the HF range (and because one end of the HF technique is always infinity, you have to worry that your subject is not too close to you), will be acceptably sharp.

There's a different technique that sometimes is confused with hyperfocal, that is called "Zone Focusing". With experience, you more or less learn to know an approximate distance to a given subject by just viewing it. One can then play with the depth of field, keeping in mind that now there are determined limits, which are set by the aperture and focus point. For example, when I go to do some street shooting, sometimes I play with zone focusing when I know I don't have the time to focus. I focus my 50mm lens at 4m (12ft) and set aperture at f/8, which gives me a depth of field approximately from 3m to 7m. As long as I keep my subject inside that range, it'll be acceptably sharp. But, this is zone focus technique, not HF technique.

I hope this helps a little!

Best,
Sebas.

[tmyuen]

Thanks for the detailed explanation. I am using a Canon XSi/450D with the 18-55 kit lens. There is no distance scale on the lens barrel and I can't figure out a good way to set my focus at a specifc distance (20 ft in my example) besides trying to find something that is close to that distance so that I can focus at, and then recompose. Any advice?

[xeliex]

Nothing wrong with your technique of trying to find a focus point near your desired subject

[sebasj]

As Xeliex said, there's nothing wrong. In fact, once focused at a point that is inside the hyperfocal zone, you don't have to refocus again. Just keep your subjects inside that zone (which means, not nearest than the minimal distance for acceptable focus). You could perhaps try to mark the lens with a soft tip pen (that's what I would do of course, after all my camera is a tool hehe).

Now, is it me or manufacturers are making photographers more and more dependant on technology? By means of taking away "old school tools" and relying on technological resources... well, you are left on the dust in case something goes wrong. Feels to me it kills photography in its essence...

I don't feel it so much because on my K100D I only mount manual lenses, and I replaced the stock focusing screen with one that has split image with microprism. So, more or less my camera feels like an SLR with Aperture priority mode, kinda my old Yashica Electro 35. But I've seen my friends depending all the time on technology. This wouldn't be so bad, as long as resources are not lost (what happens with some of my friends for example, is that "if the camera can't focus because there's not enough light, the photo can't be taken" to quote a phrase I hear too much lately).

Just a thought... but well.

Best,
Sebas.

[batcher]

A new guy here with maybe a dumb question for Antonio,

I'd like to make one of those calculators and see where I can print them out but I'm wondering how did you get the outer ring lines extended to the center and how did you get red numbers and lines?

Did you use an older version that was that way or put into another program and redo? What program?

Thanks

[Antonio Correia]

Thanks for the follow-up post!



If this object is of importance to the composition, I would definitely not place it at the edge of your depth of field. Always try and give some padding room if you can, because the criterion for sharpness as defined by the DoF is not noticeably less sharp than your camera/lens can resolve. Depending on the subject matter, this might look odd in the photo.



Be careful because the distance meters on the lens can sometimes be quite off-- at least relative to the precision of focusing you are trying to achieve. It might be a good idea to first focus at an object of known distance (and see what that corresponds with on your lens distance markings) to verify your lens markings are sufficiently accurate.

Thank you for commenting.
You are absolutely right about the precision of the focusing distance.