Mamiya 7 and the foggy art of hyperfocal focusing

[AlexBC]

I don't have the answers yet, but I am searching for them.

I recently acquired a Mamiya 7 and 80mm lens and am working to replace my RZ67 as my main medium format system, but I'm having a bear of a time deciphering accurate hyperfocal focusing. As I understand it, the lens distance scale can be conservative and I should not follow it precisely for calculating my near and far limit of acceptable sharpness. With my RZ67, focusing is very easy for me as the subject pops into view as a rack the lens slowly so I have not had to worry much about hyperfocal distance as I choose my subject, compensate with the aperture and am generally pleased when I stop down the lens to preview the dof. For online use and prints smaller than 19", I have no complaints. The Mamiya 7 is extremely slow and difficult for me to focus as it is entirely different. With time I'll get quicker, but I'm always hunting for tricks and tips to speed up the process. I do mainly urban landscapes (buildings, streets, those sorts of things), so I usually have vertical and, if I'm lucky, horizontal lines to focus on. That said, I've been trying to do more hyperfocal focusing so that instead of straining my eye to focus on a fine line through the patch, compose through the viewfinder, and then focus by the lens numbers to save time. Most of the website hyperfocal calculators seem to imply that regardless of subject distance, as long as the composition is greater than 11 feet from the camera, I should set the lens' focus to 21 feet (roughly) to achieve maximum dof at f/16. However, when I look at the calculator on cambridgeincolor.com, the values are quite different depending on print size and viewing distance. What am I missing? Some of these values seem to be quite useless to me as I would never be able to zero in on a hyperfocal distance greater than the available etchings on my lens. Just setting it to infinity would be my only option.

TL;DR I am reading some articles that say setting the hyperfocal distance is extremely important, however, some of the calculated hyperfocals at larger f-stop holes (say, f/8, f/5.6, etc.) appear to need the lens to be set to infinity to achieve hyperfocal. What's the real truth on this? Is my 22 feet hyperfocal setting at f/16 bogus or good to go? I know not to live by hard and fast rules in photography because there are always choices to make, I'm just stumbling on the best way to approach a landscape with this camera.

Thanks!

 

[cramej]

Here, let me get that for you...

Just kidding

Anyway, the easiest way I have found to understand hyperfocal distance focusing is:

• Set your desired aperture
• On the focusing scale (showing your 80mm lens below), set infinity to the selected aperture to the right side of the DOF scale
• 
  
  
• Check the left side of the DOF scale for the near distance. If this is not satisfactory, change the aperture and adjust the focus to match up infinity with the selected aperture.
• This method is an approximation - the technical method end result deals with a specific circle of confusion (pick your poison there...) and final image size for what is acceptably in or out of focus.
• If what I am shooting does not need to be critically sharp, this gets me good results.

I'm sure someone else can offer a more detailed explanation than I.

 

[cramej]

Most of the website hyperfocal calculators seem to imply that regardless of subject distance, as long as the composition is greater than 11 feet from the camera, I should set the lens' focus to 21 feet (roughly) to achieve maximum dof at f/16.

Looking at the lens scale and comparing to my method described above, I'd say that your method is correct. Setting infinity to f/16 looks like it would be focused roughly at 20ft and 10ft would be at the near end.

 

[tedr1]

Perhaps this website might help? http://www.dofmaster.com/

 

[DREW WILEY]

One more reason to hate rangefinders. At least the Fuji 6x9 RF is recently bought has a hard infinity stop.

 

[AlexBC]

Thanks for the help guys, the 7's 80mm definitely has a hard infinity stop, but that's not always the best way to focus, as I'm figuring out. Thanks to the private messages as well, I've been told that the Circle of Confusion that Mamiya uses is not .059 as most of those online calculators have listed for "Medium 6x7," but .090. While it probably doesn't make a huge difference for my uses, that would explain why some hyperfocal calcs online spit out slightly different numbers when supplied with identical apertures and focal lengths.

I think I know enough to get myself into trouble, now.

 

[Alan W]

Have you looked at Ken Rockwell's site?He goes into detail with this,I found it useful.

 

[Jim Jones]

Circle of confusion: a bunch of photographers discussing DOF. As a quick rule of thumb, to approximate the hyperfocal distance in inches, I use 2000 times the diameter of the aperture as it appears through the front of the lens. This works for all formats, large and small. For small prints and posting online only, the constant of 2000 can be reduced. For critical work, increase it. Based on rough measurements and quick calculations, my Leica lenses appear to use a constant of about 2000. Ultimately, each individual's preference should be a major factor in hyperfocal and DOF calculations. Formulae make assumptions that can't apply to everyone.

 

[John Koehrer]

I seldom focus with a RF anymore and just use the scale & f stop. With a larger f stop
I'm more critical and actually (gasp) focus.

 

[wiltw]

The fundamental problem of most DOF calculators -- and the DOF scales on most lenses -- is that they assume human vision is poorer than what your optometrist tries to acheve when calculating your prescription diopter strength for each eye.

For the 6x7 format, with 80mm lens at f/16, assuming 20/20 vision in the viewer (and looking at an 8x10" print from 25cm) the Hyperfocal Distance is 17.62m or 57.8', and DOF zone is from 29' to 21531'.

Now for the challenging part of the Hyperfocal Distance concept:

• Can YOU identify a point which is 57.8' away, with some degree of accuracy, so you can focus on it?
• Or, can YOU identify a point on the distance scale of the lens which is at 58', so you can preset focus?
• Can YOU identify whether or not some near point of interest in the scene falls inside the DOF zone and is 30' away, with some degree of accuracy?

In using the DOF scale on the lens, you CAN use a larger aperture mark than your shooting aperture, to compensate for 'manufacturer standard' estimation of (poorer) visual perception rather than for 20/20 vision...e.g. use DOF scale marks for f/11 rather than for f/16, when shooting at f/16.

 

[RalphLambrecht]

I don't have the answers yet, but I am searching for them.

I recently acquired a Mamiya 7 and 80mm lens and am working to replace my RZ67 as my main medium format system, but I'm having a bear of a time deciphering accurate hyperfocal focusing. As I understand it, the lens distance scale can be conservative and I should not follow it precisely for calculating my near and far limit of acceptable sharpness. With my RZ67, focusing is very easy for me as the subject pops into view as a rack the lens slowly so I have not had to worry much about hyperfocal distance as I choose my subject, compensate with the aperture and am generally pleased when I stop down the lens to preview the dof. For online use and prints smaller than 19", I have no complaints. The Mamiya 7 is extremely slow and difficult for me to focus as it is entirely different. With time I'll get quicker, but I'm always hunting for tricks and tips to speed up the process. I do mainly urban landscapes (buildings, streets, those sorts of things), so I usually have vertical and, if I'm lucky, horizontal lines to focus on. That said, I've been trying to do more hyperfocal focusing so that instead of straining my eye to focus on a fine line through the patch, compose through the viewfinder, and then focus by the lens numbers to save time. Most of the website hyperfocal calculators seem to imply that regardless of subject distance, as long as the composition is greater than 11 feet from the camera, I should set the lens' focus to 21 feet (roughly) to achieve maximum dof at f/16. However, when I look at the calculator on cambridgeincolor.com, the values are quite different depending on print size and viewing distance. What am I missing? Some of these values seem to be quite useless to me as I would never be able to zero in on a hyperfocal distance greater than the available etchings on my lens. Just setting it to infinity would be my only option.

TL;DR I am reading some articles that say setting the hyperfocal distance is extremely important, however, some of the calculated hyperfocals at larger f-stop holes (say, f/8, f/5.6, etc.) appear to need the lens to be set to infinity to achieve hyperfocal. What's the real truth on this? Is my 22 feet hyperfocal setting at f/16 bogus or good to go? I know not to live by hard and fast rules in photography because there are always choices to make, I'm just stumbling on the best way to approach a landscape with this camera.

Thanks!

foggy issue is correct.With the hyperlocal distance, You're always working at the threshold of sharpness near and far and yes, DOFscales on less are usually a bit too liberal with sharpness.true sharpness is only at one distance where the focal plane is.everywhere else you're making a compromise you may or may not want to live with.One remedy is to stop down a stop or two more than what you are reading off the scale.For example,read off the DOF for f/8 but really use f/11.That will give you some room for error.In any case if you work with hyperlocal distances for landscapes focus at infinity or infinity focus will always be at the threshold of sharpness and look fuzzy.

 

[DREW WILEY]

I love your definition of circle of confusion, Jim, and fully agree with it!

 

[Allen Friday]

I do as Ralph recommends above with my Mamiya 7 II. If shooting at f16, I use the scale for f11.

The other thing to keep in mind is the drop off in quality on lenses as you stop down. You may be temped by the scale to stop down to increase the area of acceptable sharp focus, but the more you stop down, the lower the overall quality of the shot. It's a balance and only you can answer what is acceptable to your photography.

 

[Oldwino]

I think you just need to practice with the rangefinder more. It can be incredibly quick. Once you have some rolls under your belt, you will learn to trust it. Unless the rangefinder is off, which I understand happens with these Mamiyas often

I find using hyper focal to be a way to get a very quick grab shot, but I never have been happy with the sharpness. Kind of defeats the purpose of using a camera with very sharp lenses.

 

[DREW WILEY]

I just don't find rangefinders a very satisfying experience at the moment of shooting. You're kinda interpolating what your expect in your mind rather
than concurrently seeing it like with an SLR. That being said, I just stuffed my 6x9 Fuji RF into my weekend pack last night, cause it amounts to just one more little pouch in my 8x10 camera kit. Fits in nice, light, and compact in a way my P67 just doesn't, which I generally have to tote by itself,
format-wise. So I can have my cake and eat it too - my beloved 8x10 for those meditative slow setups, and the 6x9 RF for spontaneous shots.

 

[zilch0md]

I've been using Mamiya 7ii bodies for over 15 years. My approach would be too obsessive for some applications, where the need for speed is critical, but here's how I manage aperture and focus distance, ameliorating degradation caused by both defocus and diffraction, to secure a specific final image resolution, at an anticipated combination of enlargement factor and viewing distance...

Dead Link Removed

Mike

 

[wiltw]

A DOF program which assumes the viewer has 20/20 vision (rather than having the inferior visual acuity assumed by 'manufacturer standard' in engraved DOF scales on lenses) would indicate these focus distances and DOF zones extending to Infinity...

6x7 format, 80mm lens

• would need to be focused at 85' when set to f/11, to have DOF zone of 42' to Infinity
• would need to be focused at 59' when set to f/16, to have DOF zone of 29' to Infinity
• would need to be focused at 43' when set to f/22, to have DOF zone of 21' to Infinity

 

[Cholentpot]

Here, let me get that for you...
View attachment 161536

Just kidding

Anyway, the easiest way I have found to understand hyperfocal distance focusing is:

• Set your desired aperture
• On the focusing scale (showing your 80mm lens below), set infinity to the selected aperture to the right side of the DOF scale
• View attachment 161537
  
• Check the left side of the DOF scale for the near distance. If this is not satisfactory, change the aperture and adjust the focus to match up infinity with the selected aperture.
• This method is an approximation - the technical method end result deals with a specific circle of confusion (pick your poison there...) and final image size for what is acceptably in or out of focus.
• If what I am shooting does not need to be critically sharp, this gets me good results.

I'm sure someone else can offer a more detailed explanation than I.

I use the scale for my 35mm Nofocus cameras. I used to hate hate hate them. Once I learned the trick and stopped fearing narrow aperture I tend to nail just about every shot. On sunny days with my Signet 50 I have no problems. Once in a while I measure with my feet.

 

[Jim Jones]

Depth of field pertains not only to a specific lens, but to many other factors such as ultimate image size, viewing distance, subject matter, and personal preferences. Long ago, before personal calculators were available, I went through many calculations with pen, paper, and Rudolf Kingslake's Lenses in Photography, and finally understood hyperfocal distance and depth of field a little better. There's a much richer variety of information and calculators online now. One is Harold Merkingler's book for those who really want to research the topic; http://trenholm.org/hmmerk/TIAOOFe.pdf. Even it may not answer all questions.

 

[zilch0md]

Harold Merklinger's book, The INs-and-Outs-of-Focus, makes a case for the convenience of focusing at Infinity, rather than using hyperfocal methods, but even though he admits that the resolution of Near subjects will be compromised when focusing at Infinity, that's often overlooked by fans who have (willfully?) misinterpreted his writings - in their quest for convenience.

For more on what Merklinger actually wrote, regarding Infinity focus, see:
Dead Link Removed

 

[one90guy]

I read all the posts yesterday and reread them again today. This all seems to me like taking something, focus, and making it so much more difficult. Now have never taken a magnifying glass to any of my photos and the ones that are enlarged almost always look fine. I have sold a few, given lots away, and shot a car show for pay with zero complains and also sold some prints. My F4 tells me when its focused and the Canon P lens gives good focus.

This is just my take on the subject, no trying to disagree with anyone. Am sure there are folks that have way more experience in this subject.

 

[zilch0md]

I read all the posts yesterday and reread them again today. This all seems to me like taking something, focus, and making it so much more difficult. Now have never taken a magnifying glass to any of my photos and the ones that are enlarged almost always look fine. I have sold a few, given lots away, and shot a car show for pay with zero complains and also sold some prints. My F4 tells me when its focused and the Canon P lens gives good focus.

This is just my take on the subject, no trying to disagree with anyone. Am sure there are folks that have way more experience in this subject.

Hey one90guy,

It's always nice to hear someone who is content with their focus and aperture selection method. It means you have a good grasp on the fundamentals and you are achieving some measure of consistency at meeting your own requirements for print resolution. Congratulations! You're a lot better off than folks who sometimes find themselves disappointed.

Taking tight control of all the variables that affect print resolution is only necessary when trying to use enlargement factors that are at the limit of what the system can deliver, without dropping below a desired resolution. Notice there are two variables mentioned in that sentence: enlargement factor and desired resolution.

Most people's disappointment with hyperfocal focusing, stems from their failure to consider either of these, and it's manifested as a failure to select an appropriate CoC diameter for use with their DoF calculator of choice. No single CoC diameter can satisfy every possible combination of enlargement factor and desired print resolution, for a given film format (or sensor size).

The maximum permissible diameter for circles of confusion, to be used when calculating DoF, can be calculated as follows:

CoC (mm) = viewing distance (cm) / desired final-image resolution (lp/mm) for a 25 cm viewing distance / enlargement / 25

This equation, when used to greatest effect, requires that you select both a print size (to get the enlargement factor) and a desired final print resolution, in lp/mm (to govern how demanding your DoF will be) in advance of making each exposure (something between 2 lp/mm, which would be somewhat "soft" for a print viewed at a distance of 25cm (about 10 inches) and 8 lp/mm, which is generally considered to be at the limit of acuity for human vision.) Enlargement factor is just the print diagonal divided by the post-crop diagonal of the film (or sensor).

Once you've calculated the Max. Permissible CoC, the f-Number at which diffraction will just begin to inhibit your desired print resolution can be calculated as follows:

f-Number = CoC / 0.00135383

This is the f-Number beyond which you should not stop down, for this particular combination of Enlargement factor and desired print resolution.

If your DoF calculation suggests using a larger f-Number for the range of distances in your framed subject space, you'll have to use a shorter lens, move away from the nearest subject, choose to reduce the enlargement factor (by accepting, in advance of exposure, to make a smaller print), or some combination of these actions. The last thing you should do is compromise your desired print resolution, but that's what most photographers end up doing, in part because they don't know how to quantify their personal choice for a "desired" print resolution, not to mention an unwillingness to use calculators and laser rangefinders when shooting. But they can end up being disappointed when they make a print and, by their own unquantified, subjective requirements, discover excessive defocus at the Near or Far limits of DoF, or diffraction softening the entire print at that enlargement factor and viewing distance.

This approach is beyond most people's willingness to control all of the variables, but it can be done, though best applied with more or less static subjects - landscapes, architecture, tabletop, etc.

 

[DREW WILEY]

Nothing could be more appropriately named than "circle of confusion". One more tidbit of nonsense to ignore, just like "normal viewing distance"; and the two are interrelated. "Circle of mush" at a certain degree of enlargement. So it all depends on what you want the mush to look like, and what you really need to keep in acute focus if push comes to shove. So I'm always looking for the key details I want the eye to home in on in a big print. A bit of practice with particular lenses will give you a pretty good idea of depth of field in relation to that. View cameras are particularly nice not only for plane of focus control, but for allowing you to use a loupe on a relatively big groundglass to begin with. But still, I'm always concerned about what is specifically in focus, and not just so-so.

 

[DREW WILEY]

Sorry to have seemingly shifted the topic momentarily away from RF's. But just a couple of hrs ago I took a freshly dried roll of film taken with my 6x9 RF and looked at it thru a magnifier. Everything frame tack sharp, even handheld shots. No "confusion". I knew what I wanted to begin with. The next roll, however, will be from a 300mm lens on a 6x7 SLR. What I want in acute focus will be. What I want soft instead will be soft. Hyperfocal theory would have just been a compromise overall, and the negatives to the trash can.

 

[zilch0md]

Here comes the can of worms. That was a pretty harsh, yet unqualified condemnation of hyperfocal focusing. I can only assume you've not learned how to control it, perhaps by choice, but that's perfectly OK. Whatever your methods, they are apparently working very well for you. Your disappointment with hyperfocal focusing is not unusual.