Re: Precision and Accuracy in LF Photography: How much is enough?
Quote:
Originally Posted by
Drew Bedo
There have been a couple of interesting threads lately on gear and technique that devolve into discussions of accuracy and precision.
I like my darkroom thermometer to be accurate each and every time.
Precision is less important.
I don’t think I have that backwards, right? :D
Re: Precision and Accuracy in LF Photography: How much is enough?
LF is problematic and frustrating in many ways. Rather than necessarily giving up all of photography my two cents worth of a suggestion would be to shoot medium format or 35mm. In my experience, most people do better work with smaller formats anyway, and the smaller formats remove certain aggravating things about LF, in particular certain aspects of camera operation, dust, and film development issues. You can also go digital, which affords even greater flexibility in image editing.
Quote:
Originally Posted by
Havoc
I think another thing that is missing is repeatability. This is different from accuracy and precision.
Has anyone thought about how much a camera changes when you use it at any other temperature than (25 +/- 0.01) °C? A wooden camera of even a metal one (and certainly one using plastics) will often change/distort more than the accuracy some want to attribute to their spirit levels and parallelism of their standards.
I gave up on photography. My latest tests with 4x5 were so dreadfull that I can't continue. I mean if you focus on a bloody wall at infinity (200 meters) then you at lease expect to see if it is brick or concrete. But exposure is all over the place (all measures with a sekonic L-578) developed at the same temperature and chemicals as usual, the same lens/shutter as other photos. And still, one is sharp with plenty of detail and nice greys. the other a blur with a clear sky and complete black.
Only thing I ever get consistent results are slides (provia and velvia) shot in a Mamiya 6x4.5 and developed in a lab. Even a Praktica with slides and the internal meter is better than 4x5.
Re: Precision and Accuracy in LF Photography: How much is enough?
I can't remember the last time I made a LF exposure shorter than a second, and most are much longer so shutter accuracy is basically a non issue for me. I don't buy used equipment so I kind of just assume my shutters are decent shape. When they stop working I'll just go digital I guess.
Quote:
Originally Posted by
Drew Bedo
A lot of responses about how we approch work . . .all good stuff.
So what actually is acceptable performances for a shutter?
What should we expect from "modern" gear? What can we expect from a well CLA'd vintage lens/shutter.
What is acceptable performance in a light meter? Do we need to know 1/10th stop?
Just how square, level and plumb must a camera be?
Re: Precision and Accuracy in LF Photography: How much is enough?
Quote:
Originally Posted by
Drew Bedo
...Just how square, level and plumb must a camera be?
Sometimes being square just looks wrong.:cool:
But I'll admit, as far as accuracy, precision and repeatability are concerned...thank you Ilford, Kodak and Fuji films.
Re: Precision and Accuracy in LF Photography: How much is enough?
Up in the redwoods, they square up everything after they've cut the tree down. I happen prefer the natural look over the stacked lumberyard look. But the owner of the lumberyard made a helluva lot more money that way than I ever did selling pictures of the woods.
Re: Precision and Accuracy in LF Photography: How much is enough?
Quote:
Originally Posted by
Heroique
I like my darkroom thermometer to be accurate each and every time.
Precision is less important.
I don’t think I have that backwards, right? :D
Getting the correct temperature reading is accuracy.
Getting it right every time is precision.
The cartoon with the targrts is spot on for illustrating these points.
Re: Precision and Accuracy in LF Photography: How much is enough?
Quote:
Originally Posted by
Drew Bedo
Getting the correct temperature reading is accuracy.
Getting it right every time is precision.
The cartoon with the targrts is spot on for illustrating these points.
Accuracy can be thought of as "correctness"
Precision is basically "fineness" of measurement
Repeatability is consistency
Re: Precision and Accuracy in LF Photography: How much is enough?
Quote:
So how close is close enough?
The nice thing about photography is the 'product' shows all and answers all questions; just look at the print.
Re: Precision and Accuracy in LF Photography: How much is enough?
Consistent practice is important in any respect.
Re: Precision and Accuracy in LF Photography: How much is enough?
Nothing betters uber quality studio electronic strobe (Bronocolor, Elinchrome, Comet and etc) for consistent, reliable, dependable source of high power, high quality light source for color work. Achieving 1/10 f-stop with near absolute stable color temperature per exposure is not that difficult. Arri makes GOOD true 5000K constant light sources, as does Mole-Richardson for tungsten and others. Light sources can be "gel" filtered to adjust color temperature and color rendition as needed. Coupled with an in camera metering system like Sinar Expolux works good to control exposure, compensate for bellows factor and all those potential small sources of exposure error. These days, it would be surprising if this is done much at all these days for color transparency film images.
1/10 f-stop needed, depends. For uber quality color transparency images that is a nice luxury. More often than not 1/3" f-stop is ok enough. Negative films can tolerate 1/2 f-stop mostly easy.
For outdoor color images, the color temperature and intensity varies LOTs over the course of a given day. Give up trying to achieve what can be done using highly controlled studio environment. Knowing this, shutter accuracy, shutter repeatability can be a variable as much as actual light transmission from the front element of the lens to film. What has worked good for ~me~ single Sinar shutter (yes, Drew despises this approach) with barrel lenses where possible. Single quality, reliable-consistent-accurate shutter can greatly reduce exposure variations due to shutter variations. It works good, been doing it this way for decades without fail. Exceptions to this would be modern wide angle lenses. This is why I've essentially given up on using lenses in shutter with some exceptions (modern wide angle lenses) decades ago. And no, this solution-method can never work for all view camera image makers.
Bernice
Quote:
Originally Posted by
Drew Bedo
So what actually is acceptable performances for a shutter?
What should we expect from "modern" gear? What can we expect from a well CLA'd vintage lens/shutter.
What is acceptable performance in a light meter? Do we need to know 1/10th stop?
Just how square, level and plumb must a camera be?