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Author Topic: Bumping the punch bowl  (Read 3596 times)

KirbyKrieger

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Bumping the punch bowl
« on: November 30, 2009, 12:50:31 pm »

What is the mental space of camera work?

I am new to making pictures with a machine.  The machine itself presents a seemingly steeply-stacked set of variables, most of which are inter-related, and all of which effect the picture being made.  I have looked and not found a sensible explanation of these variables and how they inter-relate.  Is there such a thing?

In the just published review of the Leica S2 (right here on L-L: http://www.luminous-landscape.com/reviews/cameras/s2.shtml), the author refers to ISO as "the third exposure variable" for digital cameras.  The other two, I assume, are aperture and shutter speed.  Each of these varies in one dimension (though not linearly).  The intersection of the three is what makes up -- so goes my thinking -- the mental space of camera work.  For every point in that space there is an image-specific reason to use it, and for every picture making desire there is either a point in that space or the picture is not makable with this particular kind of picture-making machine.  Can anyone suggest a good guide to that space?

At it's simplest, this shakes out to four general questions:
• Aperture can be raised or lowered to the limit of the lens.  Why would one raise it?  Lower it?  Get a lens with a higher maximum or a lower minimum?
• ISO can be raised or lowered within a range determined by the camera body.  Why would one raise it?  Lower it?  Get a camera body with a higher maximum or lower minimum?
• Shutter speed can be raised or lowered within the range determined by the camera body.  Why would one raise it?  Lower it?  Get a camera body with a higher maximum or lower minimum?
• What changes to any of the above effects the others?  How?

Other variables I'd throw right into the mix are breadth of viewing angle and focal length.  Depth of field will have to be discussed, but it is a result (afaik), not a variable.

Yes, questions from a novice.  Your responses are most appreciated.
« Last Edit: November 30, 2009, 12:51:52 pm by KirbyKrieger »
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michael

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Bumping the punch bowl
« Reply #1 on: November 30, 2009, 01:26:57 pm »

Kerby,

These are the most fundamental questions concerning the mechanics of photography. They are answered in any number of beginner's books.

My suggestion is that you spend some time studying these on your own first.

Michael
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KirbyKrieger

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Bumping the punch bowl
« Reply #2 on: November 30, 2009, 03:37:44 pm »

Quote from: michael
They are answered in any number of beginner's books.  
My suggestion is that you spend some time studying these on your own first.
Michael -- thank you (I hope my rankness isn't despoiling).  I would like to -- that was my question:   Can anyone suggest a good guide?

I have tagged the book you recommend (Stephen Johnson's) for purchase and reading after I know more.  I have purchased and read David Pogues' "Guide to Digital Photography" (or some such title) -- in essence it's empty hand-holding -- as well as Scott Kelby's first book on digital photography, which is non-empty hand-holding, but still doesn't explain anything.

I want to learn to fish -- and I have a need to map the contours of the bottom of the lake.
« Last Edit: November 30, 2009, 03:44:51 pm by KirbyKrieger »
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wolfnowl

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Bumping the punch bowl
« Reply #3 on: November 30, 2009, 03:53:09 pm »

I wouldn't limit yourself to books on 'digital' photography.  The concepts of f/stop, shutter speed, ISO (used to be ASA in North America), depth of field, etc. and their relationships to each other haven't changed much, although the way they're implement has been.  Go to your local library and find out what's there.  I have a Time-Life series of photo books from several decades ago that would answer the questions you've asked here.

Mike.
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NikoJorj

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Bumping the punch bowl
« Reply #4 on: November 30, 2009, 04:53:53 pm »

Yes, those questions are already answered many times in many books (I liked the National Geographic ones but there are cohorts of others, let's only cite Ansel Adams The Camera), but still, I find it quite interesting for me to try to answer them at least a bit clearly. The parts in italic are second-order effects and may not be as evidently visible as the others.
I won't post illustrations - for that, I'd hope you won't mind me linking to this page - it may first look like a dumb satire, but not quite, and indeed well-carved odd-degree humour, meaning there is some part of truth on either sides of the rules (as others have pointed, some left-side images are gems).

Quote from: KirbyKrieger
• Aperture can be raised or lowered to the limit of the lens.  Why would one raise it?  Lower it?  Get a lens with a higher maximum or a lower minimum?
First, get that the lower the number, the bigger the aperture (you can verify that with your depth-of-field-preview button or an old manual lens).
A bigger aperture (smaller number) :
- lets more light in (useful when light is scarce), and
- makes a narrower depth of field (double-edged sword : can isolate a subject from a distracting background, but can ruin a picture if the background tells some part of the story and asks for a more precise focus).
An aperture at the widest (smallest number) generally makes for poorer sharpness, and at the narrower settings (number above say f/16 or f/22) also makes some small blur and loss of contrast due to diffraction, so the best for sharpness is to stay around f/8. That said, sharpness is not always a major factor in an image's strength (think of the iconics photos of Robert Capa : they're f- unsharp).

Quote
• ISO can be raised or lowered within a range determined by the camera body.  Why would one raise it?  Lower it?  Get a camera body with a higher maximum or lower minimum?
For the ISO, aim at the lower that the other parameters allow, to avoid noise. Make tests with your camera to see for yourself at which ISO noise begins to be annoying.

Quote
• Shutter speed can be raised or lowered within the range determined by the camera body.  Why would one raise it?  Lower it?  Get a camera body with a higher maximum or lower minimum?
If anything moves in your image, you'll have to use a faster speed to freeze that motion, otherwise it will appear as a blur on the image (and that blur needs some fair amount of control to look good).
The same applies for the motion of the camera in your hands - for that, it is generally advised to set the speed at the inverse of the focal length. Id est, with a 50mm lens, don't go slower than 1/50s (and 1/100s is generally still sharper with a DSLR, particularly with smaller sensor like Nikon D90 or Canon Rebel).

Quote
• What changes to any of the above effects the others?  How?
The mix between these 3 variables determine the amount of light reaching the sensor, and the exposure of your image. Too much and it's white, too little and it's black, in between it may look right - the best is to aim for "nothing plain white, but almost", as explained here.
« Last Edit: December 01, 2009, 06:54:50 am by NikoJorj »
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Nicolas from Grenoble
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Slobodan Blagojevic

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Bumping the punch bowl
« Reply #5 on: November 30, 2009, 05:43:01 pm »

Quote from: KirbyKrieger
... Can anyone suggest a good guide?...
http://www.cambridgeincolour.com/tutorials.htm

KirbyKrieger

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Bumping the punch bowl
« Reply #6 on: November 30, 2009, 06:05:45 pm »

Quote from: NikoJorj
... you won't mind me linking to this page ... for the motion of the camera in your hands ... The mix between these 3 variables determine the amount of light reaching the sensor, and the exposure of your image. Too much and it's white, too little and it's black, in between it may look right - the best is to aim for "nothing plain white, but almost", as explained here.

Nicolas -- Wow!
Thanks for the thoughtful response.  I understood your explanations, I laughed at the 78 rules, but I loved the panoramas -- they have made my day.  Still looking.  Thank you.
« Last Edit: November 30, 2009, 06:13:31 pm by KirbyKrieger »
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