This is a handout that I came up with for one of my photography classes I teach (Page 5): LOL "a fact that is incorrect" sat at the corner of a round table one fine day on a dark and...

Abo

rmalarz wrote:

Unfortunately, it isn't hair-splitting. It's a matter of stating a fact that is incorrect.
--Bob

LOL

"a fact that is incorrect" sat at the corner of a round table
one fine day on a dark and stormy night when two dead men
got up to fight; they drew their swords and shot each other.

rmalarz Loc: Tempe, Arizona

Ok, if you wish to descend into absurdity, there's no reason to continue discussing this with you.
--Bob

Abo wrote:

LOL

"a fact that is incorrect" sat at the corner of a round table
one fine day on a dark and stormy night when two dead men
got up to fight; they drew their swords and shot each other.

JD750 Loc: SoCal

1grumpybear wrote:

SORRY BUT IS DOES, IT IS PART OF THE SYSTEM. ISO CONTROLS THE SENSITIVITY OF THE SENSOR TO LIGHT. IT IS THE FINIAL STAGE OF THE LIGHT ENTERING THE CAMERA.

1grunpy your caps lock is stuck.

So let’s think about Film. When I change film to a higher speed, say ISO 64 to ISO 200, changing nothing else, does that effect the light entering the camera?

Obviously it does not.

Why are you having a hard time with this concept?

1grumpybear

rmalarz wrote:

Again, the last statement on the chart, "One step to the right on any of these three settings will cut the light in half into your camera", is completely incorrect. Either of the first two will change the amount of light entering the camera, and only the first two. (the emphasis on any is mine)

ISO will only control how the photo-sensitive material will react to that light.
--Bob

bob, how is changing a diameter or changing a speed is different from changing the sensitivity? the first two are mechanical and iso is electronically controled. all three control the amount of light in the finial product.

Abo

rmalarz wrote:

Ok, if you wish to descend into absurdity, there's no reason to continue discussing this with you.
--Bob

"a fact that is incorrect" is an oxymoron... You descended into absurdity
rmalarz, and unlike yours truly, you did it without knowing it.

Now you've got your knickers in a knot because I have bought that to your attention.

Dance with the devil and he is likely to hand you your arse on a plate on a sunny Monday morning.

srt101fan

1grumpybear wrote:

SORRY BUT IS DOES, IT IS PART OF THE SYSTEM. ISO CONTROLS THE SENSITIVITY OF THE SENSOR TO LIGHT. IT IS THE FINIAL STAGE OF THE LIGHT ENTERING THE CAMERA.

You are wrong. Yelling doesn't change that..

linda lagace

thanks. this is great.

rmalarz Loc: Tempe, Arizona

To answer your question:
Exposure is simply the amount of light and the duration, aperture and shutter speed.
Photographic Exposure is the, above referenced, amount of light falling on a photosensitive material. That's where ISO comes into play.
--Bob

1grumpybear wrote:

bob, how is changing a diameter or changing a speed is different from changing the sensitivity? the first two are mechanical and iso is electronically controled. all three control the amount of light in the finial product.

rmalarz Loc: Tempe, Arizona

OK, I'll grant you, I mis-typed.

Unfortunately, it isn't hair-splitting. It's a matter of stating something that is incorrect as if it were factual
--Bob

Abo wrote:

"a fact that is incorrect" is an oxymoron... You descended into absurdity
rmalarz, and unlike yours truly, you did it without knowing it.

Now you've got your knickers in a knot because I have bought that to your attention.

Dance with the devil and he is likely to hand you your arse on a plate on a sunny Monday morning.

srt101fan

rmalarz wrote:

Again, the last statement on the chart, "One step to the right on any of these three settings will cut the light in half into your camera", is completely incorrect. Either of the first two will change the amount of light entering the camera, and only the first two. (the emphasis on any is mine)

ISO will only control how the photo-sensitive material will react to that light.
--Bob

I agree with you, Bob!

User ID

Lukabulla wrote:

But it does effect the amount of light hitting the sensor / film

It’s ok to be ignorant but being proud of it is not so ok.

R.G. Loc: Scotland

grandpaw wrote:

Before commenting on my statement at the bottom of my handout, please take the time to read my two replies and it might save you time in trying to explain why it is a wrong statement. I addressed this in my replies.

You have presented yourself as an instructor and I hope you appreciate the responsibility that comes with fulfilling that role. Being an instructor means you have the potential to create confusion, which in itself can have unfortunate consequences for your students' learning process. Another thing you need to be wary of is presenting misinformation, especially the kind that hinders the acquisition of a proper understanding of the subject.

The facts of the matter are, as stated, that aperture and shutter speed are the only factors which determine the amount of light captured. ISO will affect the amount of captured light only in so far as it affects either aperture or shutter speed (for example when using a semi-automatic mode). On its own, ISO won't affect the amount of captured light. What it does do is affect the amplification of the sensor's signal, and in doing so it affects the brightness of the resulting capture. Departing from these facts won't be doing your students any favours.

User ID

1grumpybear wrote:

For those of you complaining a Jeff and his statement about the light he is correct. Whether the amount of light is changed mechanically or electronically it still effects the final picture.

Typical “UHH Experts”. Evidently neither you nor Jeff know anything about light.

Light is not electronic. You cannot control, govern, or alter it electronically.

The only thing electronics can do with light is measure its quantity. Thaz what a camera sensor does. It’s just a bunch of light meters reporting quantities to a computer which records that data.

######################

The computer is also programmed to display that data in human readable form via devices such as a screen or a printer. There are programs that can alter the recorded data but editing data cannot bring more photons to an event that is already in the past.

If you wire some bigger batteries into your Gossen or Sekonic so that it reads higher, have you increased any light ? It may tell you to use sunny midday shutter and lens settings when you’re taking a reading in a dimly lit room but the bigger batteries cannot actually brighten up that dimly lit room.

srt101fan

1grumpybear wrote:

bob, how is changing a diameter or changing a speed is different from changing the sensitivity? the first two are mechanical and iso is electronically controled. all three control the amount of light in the finial product.

My understanding and one I'll stick with until convinced otherwise:

ISO does not change the sensitivity of the sensor. An amount of light - controlled by the size of the lens "hole" (aperture) and the length of time that hole is open (shutter speed) - enters the camera and hits the sensor. Up to that point ISO has no effect. The sensor does its electronic tap dance and creates an electronic signal. ISO settings above base modify that signal. You can call it boosting, amplifying, goosing, manipulating, pumping up, whatever - as long as you don't call it "changing the amount of light entering the camera"....😊

juan_uy Loc: Uruguay

R.G.'s comment and the latest one from srt101fan make a nice, sort and direct explanation that all should be able to understand.
Wish there was some sort of "voting" system on the site :)