Dynamic Range (I think)

[DougPaul]

Ansel could read most scenes merely with his eyes, and know which exposure to use without a meter. That is something that can be done with some practice. I recall my first film SLR. The batteries would generally go dead in very cold weather, but it fortunately had a mechanical X-sync intended primarily for flash. I successfully learned to read scenes so that I could photograph in cold weather without any battery in the camera. The X-sync dictated the shutter speed, and I set the lens aperture to get the right exposure that I read with my eyes. It is often called the Sunny 16 rule for ISO 100 and sunny conditions. You adjust from there for a different ISO or different scene lighting. The basic exposures were printed on film boxes or on a sheet of paper in the film box. It still helps in general photography today in knowing when to override the digital camera's meter reading.

I similarly successfully used the sunny 16 rule back in my film SLR days when my metering battery failed. I was shooting slides so the exposures were more critical than with negative film and it still was accurate enough to do the job.

BTW, the sunny 16 rule is not limited to ISO 100. Just set the exposure time to 1/ISO and use the rule to get the aperture. Of course, one can then use combination of time and aperture that gives an equivalent exposure. I still keep a few old film boxes/instruction sheets as reminders for the rule...

Doug

 

[DougPaul]

Adams' most famous work was done with a large view camera, often an 8X10. He did not just blast away with a roll film camera and hope for the best. One of his most famous, Moonrise Over Hernandez, New Mexico was a single exposure.

I haven't studied Adams carefully, but I rather doubt that he considered every image publishable either.

Setting up and composing an image in a large view camera is a time consuming process. Since taking any photo is expensive (in effort as well as film), one tends to be more careful.

The blast away approach is more appropriate where the incremental cost of an individual image is small compared to the overall cost of the project.

Doug

 

[skiguy]

Don't forget that back in the darkroom days......

What do you mean "back".....some of us still take our Dinosaurs for a walk now and then

 

[DougPaul]

What do you mean "back".....some of us still take our Dinosaurs for a walk now and then

I still have my film cameras and some film in the freezer.

Somehow they haven't been disturbed in a while...

Doug

 

[smitty77]

BTW - one other thing...the human eye is not capable of distinguishing nearly that many grey levels...maybe only 4 or 5 bits for someone with a lot of training. That's why we prefer color - and when looking at critical scientific or medical images in B&W, it's preferable to pseudo-color them)

A little off topic, but I figure I'd probe the depths of this knowledgeable pool....

Do color-blind people distinguish more grey levels than those with "normal" eyes?

I'm color-blind, yet I find I can "see" colors in black and white images. My brother-in-law has also experienced this, and he is color blind as well.

My eyes prefer B&W images over color, they just seem more visually pleasing to me. For example, my eyes seem to gather more information from B&W infrared images than from those post processed into color.

Just wondering, now back to lurking.
Matt

 

[DougPaul]

A little off topic, but I figure I'd probe the depths of this knowledgeable pool....

Do color-blind people distinguish more grey levels than those with "normal" eyes?

Don't know about more grey levels, but there seem to be advantages in certain situations. See http://en.wikipedia.org/wiki/Color_blindness.

I'm color-blind, yet I find I can "see" colors in black and white images. My brother-in-law has also experienced this, and he is color blind as well.

There are also situations where people with normal vision will perceive color in a b&w scene.

My eyes prefer B&W images over color, they just seem more visually pleasing to me. For example, my eyes seem to gather more information from B&W infrared images than from those post processed into color.

Also relevant comments in the link.

Doug

 

[DougPaul]

Just happened to run across some numbers for DR ranges:

Though the human eye can see tonal detail in objects over a wide brightness range (at least 1:1000 or about 10 stops), photographic recording media (film or digital sensors) have a more limited range. Most 35mm (and APS-C) digital DSLRs have a usable dynamic range of around 8-9 stops. This is more than slide film had (about 5-6 stops), but less than the capability of negative film, which can in some circumstances exceed 15 stops.

From http://bobatkins.com/photography/technical/all_about_exposure_2.html.

BTW, the above reference covers a range of info on determining the exposure, including more info on the sunny-16 rule. Some might also find part 1 worth reading too: http://bobatkins.com/photography/technical/all_about_exposure.html

Doug