 Alex T. Mizuno |
Depth of Field: Measuring Hyperfocal Distance I'm very much interested in landscape photos, and have just started learning about hyperfocal distance. I have a basic idea and a chart. But how do landscape photographers measure hyperfocal distance each time in reality? I don't suppose they use a tape measure. Do they use their eye to measure one-third distance in the frame? Thanks!
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Bob Cammarata |
In practice, you will find it easier to set your lens aperture to f-16 or f-22 and critically focus just beyond the closest object within the frame. (Typically, the infinity symbol will be directly over your chosen f-stop number at this focal range ... but not always.) It's also wise to bracket critical focus points just beyond and in front of your original focus setting on key shots, especially if you plan to enlarge them.
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Alan N. Marcus |
Hi Alex, While knowledge of the hyperfocal distance can be valuable, it is unlikely that anyone attempts to calculate this value. Allow me to explain. When you focus your camera the lens actually moves closer or further away from the focal plane. We measure from the lens to film/chip surface (focal plane). When focusing on close by objects the lens distance to focal plane is extended. When we focus on far distant objects the lens distance to the focal plane is the shortest (minimum). The measurement taken when the camera is focused at distance (infinity) is the published focal length. Measurement is taken from a specific point on the lens called the rear nodal. This point generally is at about at the middle of the lens barrel. On true telephoto designs the rear nodal is far forward of the lens. This allows the lens barrel length to be condensed for convenience. On super wide angles lenses the rear nodal falls behind the barrel allowing short lenses to be place further forward avoiding interference with the mirror movement and the like of the SLR. The job of the lens is to project an image of the outside world and bring it to focus at the focal plane. Now when we focus at an object, say 10 feet away, there will be a zone of acceptable focus that extends both forward and rearward from the 10 foot mark. This zone is known as depth-of-field. Now the length of the span of the depth-of-field zone is a variable. It is dependent on aperture. Tiny lens openings like f/32 – f/22 – f/16 have wide zones (f/32 is wider than f/16). Large lens openings like f/1.4 – f/2 – f/2.8 have shallow zones. If you are building a simple camera like a Kodak Brownie, you don’t want the user to focus (complicates the picture taking experience). So you permanently fix the aperture to a tiny opening. This will be about f/16. The idea is cause the optical system to have great depth-of-field. The lens is then pre-focused and fixed in place to the hyperfocal distance. When so set, depth-of-field carries from close through to infinity. Thus the photographers need not worry about focus during his/her picture taking session. The price paid is severe limitations on when the camera can be utilized. Most box cameras are limited to between 9 AM and 4 PM on sunny days. To expand the picture taking experience you must provide focus and aperture control. Now the camera can be utilized most anytime but the price is; attention must be paid to setting focus and aperture. Most modern fixed lenses have a depth-of-field scale on the lens barrel. Some zooms do too. You can use these scales to set the far end of the depth-of-field zone at infinity. This is the best technique to set the hyperfocal distance. I won’t bore you guys with the equation. However the definition: Maximum depth-of-field in any situation is given by setting the camera’s focus distance manually via the focusing scale the hyperfocal distance. Depth-of-field then carries from close to infinity. Alan Marcus (marginal technical gobbledygook)
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Pete H |
Hello Alex, They also use their Depth of Field preview. But at small apertures, though, DOF preview is difficult to visualize ... very dark. As Alan correctly points out, few if any pros calculate this figure anymore. NO real need with instant previews. Now with macro photography, you may indeed want to figure this out ... but again, I doubt you will need to. All the best, Pete
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Bruce A. Dart |
Hi Alex, Alas, with the advent of digital, most camera manufacturers are not printing a distance scale and depth of field scale on the lenses anymore. There are a few but not many lenses with this valuable aid on them.In my estimation, a great loss. Manually at a small aperture is the first step. Since one cannot focus past infinity focus beyond that point is impossible. However, using the distance scale to "focus" with infinity set on the maximum depth of field for that f-stop, one will notice that the depth of field (acceptably sharp focus in an image) will increase on the nearer end of the scale, actually giving more depth of field to the overall image. Instead of the depth of field, for example, being 17 feet to infinity, it might be 8 feet to infinity using hyperfocal. That data used to be on every lens but the manufacturers do not include it on the newer lenses.Landscapes would be the primary place one would use that and since most people did not understand that function I think the camera makers just dropped it.
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Bill Boswell |
Just got back from a Tony Sweet seminar and his suggestion was to focus one-third into the scene. This means to look for a point that is about one-third the way from the camera to the most distant object you want sharp and to focus at that point. Now, the smaller the aperture (larger f number) the greater the range of objects that will be in focus. This is a fast technique and based on the outstanding quality of Tony's images, it works.
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Brad Mangas |
Hi Alex, I too have spent much time figuring out the best hyperfocal distance since I love shooting landscape as well. I have found that I can get very sharp images when focused as little as 3-5 feet into a scene that may have hills, trees or whatever miles away! One thing that has not been mentioned so far in answers given to this question is that it is extremely important to preform a lens defraction test on all your lenses. I would suggest visiting radiantvista.com and looking for the podcast on depth of field it explains lens defraction very well. Basically it is the f-stop of that lens that will give you the best Overall sharpness. I use a cannon ef-s 18-55mm and have found I get the best overall sharpness at f/8 and when I use f/16 and above the overall quality of my images decreases tremendously.
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Bruce A. Dart |
Hi, Brad brings up an excellent and often overlooked point -- most lenses do not perform their best at the extreme apertures (widest and smallest) and testing needs to be done to see what works best for your lens.
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Stanley C. Sims |
This may help. Long.long ago I read this somewhere. First focus on the nearest point, and then the farthest point that you want sharp. Say the nearest point is 3 ft.and the far point is 45 feet. Here is the formula: Deduct the 3ft. from the 45 ft., which leaves you with 42ft. Divide that by 3, which gives you 14ft. Add the 14ft. to the original close point 3ft., and set your lens focus scale to 17ft. Stop down (DOP) until everything comes into focus. I've also read about the one-third focus also.
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Bob Cammarata |
Brad's point is indeed relevant...in that most lenses have their optimum working "range" at which they are most sharp. Usually this parameter for sharpness falls somewhere within the wide to middle aperture settings...and tends to fall off toward each extreme. For this reason, even with landscapes when maximum DOF is required, I will rarely select the smallest aperture setting on any of my lenses. Bob
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Bruce A. Dart |
Alex, One of the unique and often challenging aspects of photography is that every "rule" has an exception. Many of the seminar instructors often joke that "always" and "never" are 80% of the time. Depth of field changes with distance to the subject from the lens. The same lens at f/8 for example, might have trouble keeping a railing in focus for a 12 foot length if the lens is say 6 feet from the nearest object. Move back to more than 12 feet away and you can probably, with the same lens, get in all sharp with an aperture of f/2.8!! Therefore, in landscape photography because your nearest object in focus is most often farther away, you can keep it sharp without having to resort to the smallest aperture. While I am admittedly guilty of not always using a tripod personally, I still teach that the greatest single thing a photographer can do to improve their images is to use a tripod. Not only will it hold the camera steadier but it forces the photographer to stop and look closer in the viewfinder as to what all is really there and is it what you want. Of course some of this changes when you have an interesting foreground which makes a critical part of the composition.
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Bob Cammarata |
Bruce, It's true that backing up will increase DOF but the most powerful landscape images have strong foreground elements positioned very close to the lens. In this scenario, the smallest aperture within the optimum range of your lens would be the best option to choose. A tripod IS a benefit as well but with decent light, experienced hand-held techniques can be used with great results when a wide-angle lens is chosen.
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Bruce A. Dart |
Hi Bob, You are absolutely correct. The balance of an interesting foreground does make an often somewhat routine image into one that is quite powerful. I use the tripod every day in making portraits for a living and only sometimes use it for landscapes, partially because I get tired of lugging it around. As with most things, it depends on how you use the final result. A web image or personal album is vastly different than wall decor. Can it be done? Of course. Many of us do it all the time. Will I eventually mess up something really great because I tried to hand hold it instead of using the tripod? Probably. But in the words of hockey's Wayne Gretsky, "You miss 100% of the shots you don't take!!" Learning to optimize each situation is part of being a better photographer. While most of my landscape images have utilized a greater depth of field and wide angle lenses, there are times when folks like George Lepp advocate even a telephoto to give a different perspective of a landscape. Great landscape images in your gallery!! Keep smiling and keep shooting. I don't have a Better Photo gallery but do have a web site at www.photosbydart.com Best wishes.
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Ken Henry |
I tried hyperfocal one time. The skyline of the mountains weren't quite sharp. So I focus on the background at f16 or f22. People view the backgroud and they expect it to be sharp in focus. If your landscape subject is in the forground which is where you need more detail sharpness. This is where you can be a little more creative and dramatic by putting your background out of focus by using f8 and below. Take a few different focusing photos and pick out the one you like best.
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Alex T. Mizuno |
Guys, I'd like to thank each one of you for such informative and helpful feedbacks! Bob: Thank you for the practical advise. Bracketing of focus is a good idea. Alan: Thank you for the detailed explanation of optics. This brings back memory of the physics class from years ago. I didn't expect that it would be useful to understand mechanism of hyperfocal distance. Also, now I stand why simple point and shooters can take sharp perspective photos. But like you say, they are limited to certain time zone of the day. That's why my wife is bored when I shoot at dawn and at night :) Unfortunately, like Bruce pointed out, my Nikkor 18-135mm zoom lens does not have a DOF scale. Bruce: Thank you for the great tip. I will try the nearer end of the DOF scale. I just wish manufacturer did not stop printing a DOF scale on the lenses. I also appreciate your realistic info about the use of various apertures depending on each scenario. Bill: Thank you for another good tip. Focusing at one third in the frame is a well known theory but I have not tried that enough yet. Thank you for the confirmation. Brad: Thank you for the very useful tip. It reminds me of what Scott Kelby writes in his book. He talks about the best aperture for each lens also. I bookmarked radiantvista.com. Thank you for the info!! Stanley: Your formula is unique. I'd never heard that before. Thank you for sharing. I'll definitely try that. But I wonder how I calculate if the furthest focus I want is infinity. Ken: Thank you for your feedback. I agree, different focusing is a good way to experiment. Again, thank you everybody!! I value your inputs. I think the bottom line for me is, as Bruce stated, "learning to optimize each situation is part of being a better photographer." I'm gonna grab my camera, go out and start experimenting. I really appreciate you all for taking time to have such a precious discussions. I wish you all a very Happy Holiday!!!\ Alex
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Alex T. Mizuno |
Pete, thank you very much for your input also! (I'm sorry, I was just being careless and overlooked your name.) I forgot my camera has DOF preview. Thank you for reminding!!
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