Blair Shaw Jr Loc: Dunnellon,Florida

Incandescent or fluorescent basically.....LED is not a bulb but rather a Diode even though they are used in gangs to create nice lighting effects all the same. Sorry for the over-generalized example about lamp-life.

The basic premise was about calibration of one's gear to satisfy their individual tastes while trying to stay within national recognized standards and the over-stated importance of that folly that so often accompanies these discussions.

At the end of the day all I care about is how I like it and not what others may think. If I am not happy with my results , I will make the corrective adjustments or abandon the effort entirely and try something else.

No disrespect to anyone's opinions and apologies to anyone who took my remarks otherwise.

Thanks Guys

Longshadow Loc: Audubon, PA, United States

LED, incandescent, or flourescent, people will still call it a bulb.

I still am amazed that my 100 watt bulb before it burns out will only be putting put 60 watts worth of lumens.

CHG_CANON Loc: the Windy City

A bulb is a bulb, by any other name
Or is it a Rose?
Or, just noise ...

Longshadow Loc: Audubon, PA, United States

A flash if it's a bad one.

paulf6 Loc: Orono, ME

Excellent explanation. I've always thought of ISO settings to be the equivalent of turning up the volume knob on a radio. -Paul

burkphoto Loc: High Point, NC

Actually, the correct usage in the motion picture community is EI, or Exposure Index. Eastman motion picture film is rated with an EI, which is based on the same exact scale as ASA or ISO.

The reason it is called EI is that motion picture photographers use very accurate hand-held incident exposure meters. A film might have an EI of 200 under 3200K stage and screen lighting conditions, but with a #85 filter over the lens of the camera, the meter must be set to EI 125. It may have a different EI with a different filter over the lens. (Motion picture cameras don't have built-in TTL light meters.)

Exposure and development are very critical in motion picture production, especially when multiple cameras are rolling on the same scene. To match scenes and minimize post-production labor, they use the same film, same emulsion number of that film, same exposure and filtration, and same-brand lenses calibrated in T-stops (Transmission values) rather than f/stops (focal-length-divided-by-aperture calculations).

Motion picture industry labs typically offer push processing for an extra fee. Pushing film is quite a common practice in low light. That's another reason the industry tries to use EI instead of ASA/ISO.

EI is also the correct usage to denote a "pushed" or "pulled" film speed. Back in the 1970s, I used ASA/ISO 400 Tri-X film, developed in D-76. But when I processed it in Acufine, I rated it at EI 1280.

SalvageDiver Loc: Huntington Beach CA

Hi Bill,

Here's an article about the luminous decay of LED's over time

https://www.led-professional.com/lifetime-calculation-of-white-hp-leds-from-16-000-hours-aging-data

Mike

BebuLamar

My question is only whether ISO is fake or real. A lot of discussion here is irrelevant.

philo Loc: philo, ca

All i know is that when i change my iso it changes my exposure output of my image.

nadelewitz Loc: Ithaca NY

Who/Where is this Tony guy whose opinions started this thread? I'd like to see what he (and his wife) are all about.

Longshadow Loc: Audubon, PA, United States

Thanks Mike!

LEDs I can agree, incandescent, no.
(Tests time would give you about 5.5 years at 8 hours a day, 365 days a year, with the light going from 100% to 70 or 80% of the original luminosity. About 3.6% to 5% per year. I doubt the change would be noticeable at all.)

Longshadow Loc: Audubon, PA, United States

Always.
We're human.

cambriaman Loc: Central CA Coast

A little ignorance is dangerous thing!

larryepage Loc: North Texas area

It is a fact that our cameras have a built-in ability to respond to light levels differently. We can see it easily. In the case of film, there were clear physical differences between and within types of filmstock that directly impacted the physical ability of the film to respond to exposure to light. There were also clear chemical differences related to different processing materials and methods (primarily developers, time, and temperature, but not limited to those factors) that further defined how many of which grains of silver in the negative and paper turned darker.

In the case of electronic cameras, there are very strong parallels to chemical photography. Processing and application of the semiconductor materials used to produce the sensor have a similar effect as the physical characteristics of the filmstock. Electronic processing of the signals coming from the sensor roughly parallels the chemical processing of filmstock material. At the core, these reactions and processes are both similar and different. But it's very difficult to see how that render efforts to classify and scale usable sensitivity to light as fake, since turning the dial and changing the set sensitivity does make a difference in the final image that is very similar to the difference in negative density coming out of a processing bath.

So...different? Yes, absolutely.
Fake? Absolutely not.

Longshadow Loc: Audubon, PA, United States

Unless you stayed at a Holiday Inn Express last night.