Canned Photographer Zip File (246 kb)
Canned Photographer Notes (.doc file)

Notes Referenced by the Flowchart:

This tool is designed to illustrate the dependencies which must be considered when making decisions in the field. Once you have learned these dependencies, do not limit yourself to a strict adherence to this method. Just incorporate the logic as ne eded. You can learn to do this �by the seat of your pants.�

If this consistently fails to produce the illusion of sharpness you want, when viewing the final print, it's because the Circle of Confusion diameter chosen by the lens manufacturer for calculating the Depth of Field scale, is too generous for your needs. You can shrink the Circles of Confusion to 67% of the manufacturer's goal, improving apparent sharpness, by refocusing to move the Infinity symbol one full stop down on the depth of field scale -- in the direction of focus index mark. This will mo ve your hyperfocal distance closer to Infinity and now your near sharp will be 1.5 times as far from the camera.

For example, if you are going to expose with f/16, instead of focusing such that the Infinity symbol is opposite f/16, focus instead with Infinity opposite f/11. The new near sharp will be opposite f/11 on the other side of the depth of field scale. Le ave the aperture itself at f/16.

Moving the Infinity symbol two full stops in the direction of the focus index will shrink the Circles of Confusion to 50% of the manufacturer's goal, effectively doubling the perceived sharpness, at the expense of moving the near sharp twice as far awa y. Using the same example, we would expose at f/16, as planned, but focus so that the Infinity symbol is opposite f/8.

Every lens has an aperture at which resolving power and contrast are at their best. This is usually at about the middle of the range of apertures available to a lens, but many fast lenses yield their best resolution and contrast at the wider end of the range. You can obtain published test results, do your own testing or just assume that the middle aperture is best.

Most depth of field calculators do not allow you to specify your own preference for the maximum diameter of Circles of Confusion. Try downloading mdofcal2.xls, a Microsoft Excel spreadsheet that permits you to enter this as a variable. You can find it here:

http://home.sol.no/~gjon/mdofcal2.xls

Print tables for each lens. Try shooting with tables generated for 1/175-inch maximum Circle of Confusion diameters and if after shooting and examining several rolls of film, you decide you want to increase sharpness (at the expense of moving your near sharp further away from the camera), just enlarge the denominator from 1/175-inch to 1/250, for example, and generate new tables.

Critical sharpness can not be achieved without a solid camera support. Heavy, stable tripods, that lock securely yield the best results. Even shots taken with the higher shutter speeds can benefit by use of a tripod. Most importantly, tripods allow you to use much slower shutter speeds, with correspondingly narrow apertures and slower films that yield greater depth of field and better resolution. You can carry plastic grocery bags and fill them with rocks or sand, then hang them on your tripod to i mprove stability. With a good tripod, the length of your exposure will be limited only to the need to stop subject motion. (Exceptions: You might still have to contend with wind-induced camera motion, but there are very few situations where the camera can be buffeted by wind, while the subject itself remains motionless; exterior architecture is an example. Your longest exposure may also be limited by your light meter's sensitivity and its ability to report that slow a shutter speed. Lastly, the lack of co lor correction filters to compensate for the effects of reciprocity failure might force you to use a shorter exposure time.)

Even free standing supports, like tripods, can move. Are you on a bridge or building that might be swaying or transmitting vibrations? Is the wind blowing hard enough to move your camera, even slightly? Does the tripod or camera have a shoulder str ap being tossed by the wind? Are you on a flexible surface that can move if you shift your weight, like a hardwood floor? Will you be firing the shutter release directly? It is far better to use a very flexible cable release, an air release or the camera� s self-timer, but the latter can interfere with your ability to catch the right �moment� if the scene is changing.

Monopods can dampen motion in two of the three axes, pitch and roll, but can actually redirect hand motions or twitches into yaw, inducing unwanted panning oscillations. At best, monopods allow one or two stops longer exposure.

If using your camera�s meter, proceed as you normally would to mimic an aperture priority mode. We have already selected an aperture in the steps above. Use your camera�s meter to determine what shutter speed it recommends to go with that aperture. Most would agree that a 1-degree spot meter, properly used, will give you the best exposures, consistently. A limited primer on using spot meters:

For negative films, sweep the entire scene looking at the shadow areas in the subject. When you have found them, ask yourself which must be rendered with some texture or detail retained and which may be allowed to go to pure black in the final print. C hoose the darkest shadow area where you must retain some texture or detail and meter it. Then read the meter�s recommendation for a shutter speed that coincides with our pre-selected aperture. When you have deciphered the meter�s recommended shutter speed , set your camera�s shutter to a speed that is 2.5 to 3 times faster than the meter�s recommendation. This will place the selected shadow area 2.5 to 3 stops below average density. The density of all other values will be placed relative to this one.

For slide films, sweep the entire scene looking at the highlight areas in the subject. Choose the brightest highlight area where some texture and detail must be retained and meter it. Then read the meter�s recommendation for a shutter speed that coinci des with our pre-selected aperture. When you have deciphered the meter�s recommended shutter speed, set your camera�s shutter to a speed that is 1.5 to 2 times slower than the meter�s recommendation. This will place the selected highlight area 1.5 to 2 st ops above average density. The density of all other values will be placed relative to this one.

Car-window clamps, mini-pods, railing clamps, and even bean bag rests can offer some improvement over handholding the camera. Pressing one side of the camera (or even the back of one hand that is clasping a camera) against a tree or the corner of a building or light pole can also permit longer exposures. A taut string can be used as a light-weight equivalent to a monopod. At one end of the string is tied a short section of �" wooden dowel you can stand on. At the other end, the camera is fastened t o a �" x 20 thread tripod screw. Critical evaluation must be done over time before reaching conclusions as to how long an exposure can be with any of these techniques. Most of these options force you to acquire a point of view that forfeits good compositi on for convenience.

For 35mm cameras, marginal results can be had when handholding the camera at a shutter speed equal to 1 / f where ' f ' is the focal length, down to a limit of about 1/30th of a second. As the size of the format increases, this improves somewhat, a llowing longer exposures. Medium format cameras are usually heavier than 35mm cameras and the increase in mass is accompanied by an increase in inertia, the resistance to change in direction or velocity.

Knowing how fast is fast enough can be best learned by taking notes. You will learn very quickly what works in different situations. Without exposure notes, you will go through a lot more film, but will eventually develop the skill, just the same, especially if you examine the results closely, soon after shooting. Near subjects will show motion more readily than similar subjects (similar in size and motion) that are further away. Subjects approaching or moving away from the camera can be captured w ith longer exposures than similar subjects moving across the field of view.

You might choose to permit some subject motion for aesthetic effect � blurred waterfalls for example.

The sensitivity of film is linear only within a range of exposure times that usually runs from about 1/10,000^th of a second to one or two full seconds or longer. When exposure times fall outside a given film�s range, reciprocity failure occurs. The point at which this happens varies from one film to another. Use the film manufacturer�s data sheet to determine what increase in exposure must be given, if any. Sometimes, reciprocity failure causes a color shift which must also be compensate d, using CC (color correction) filters, as specified in the film data sheet.

Here is reciprocity correction information for Fujichrome Velvia:

Postings:

From: "Michael K. Davis" [email protected]
Newsgroups: rec.photo.equipment.35mm,rec.photo.equipment.medium-format
Subject: Canned Photographer v1.0
Date: 16 Jan 1999

Hi!

I have just finished creating a 5-page flowchart titled *Canned Photographer - A Learning Aid for Full Manual Landscape Photography*

Designed for use with any rollfilm camera capable of full manual operations, it is a logical schematic covering several factors that influence decisions made in the field, decisions often overlooked. Much more than a checklist, this comprehensive flowchart grahically illustrates when to consider many variables, including factors like camera motion, subject motion, desired depth of field, diffraction, filter factors, shutter speed selection, film selection, point of view, choice of focal length, reciprocity failure, selection of camera supports, metering technique and bracketing.

Best of all, the logical interdependencies of all these variables are mapped such that the actions you must take in response to your creative choices are clearly defined and easy to implement. As you step through the flowchart, all the major variables impacting image quality are presented with over 40 decision boxes soliciting your input.

This is a thorough condensation of many years of landscape photography, a brain dump of my decision-making strategies for technically excellent images. I'm offering it just for the asking to interested parties.

Send me an e-mail request and I'll reply with canphoto.zip, a 763K zip file containing canphoto.jpg and canphoto.doc, the latter is a MS-Word 7.0 file, containing 3 pages of notes meant to accompany the grahic.

Mike Davis

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