Are you familiar with crop factor times aperture?
Jun 7, 2017 23:03:23 #
As I understand these matters, the sensor captures only the light that reaches it as controlled by the aperture and shutter speed. This amount of captured light varies only by a change in aperture or shutter speed, or both.
This captured light may receive amplification during processing. Increasing the ISO value boosts the signal that the processor derives from the fixed amount of light. The starting quantity of light remains the same.
This captured light may receive amplification during processing. Increasing the ISO value boosts the signal that the processor derives from the fixed amount of light. The starting quantity of light remains the same.
SS319 wrote:
Bruce, GoofyNewfie, et.al. I apologize for my outb... (show quote)
Jun 8, 2017 06:41:02 #
Brucej67 wrote:
if we keep shutter speed the same and ISO the same and just vary the aperture, you are decreasing or increasing the amount of light hitting the sensor, so all things being equal and just varying aperture does affect the incoming light (which is F-Stop). .
IF we keep the Shutter Speed the same and ISO the same and just vary Aperture... Aperture does affect incoming light TRUE
IF we keep the Aperture the same and ISO the same and just vary Shutter Speed... Shutter Speed does affect incoming light TRUE
IF we keep the Shutter Speed the same and Aperture the same and just vary ISO... ISO does affect incoming light TRUE
So why do we (only) call Aperture (Image Brightness)?
Jun 8, 2017 07:28:24 #
Both you and UHH member "anotherview" are right. He "anotherview" is right in saying that ISO just effects the sensitivity of the sensor and has no effect on the amount of light being passed through the lens which is only affected by aperture while shutter speed (like ISO) is only affected at the camera itself and is the duration that same amount of light can hit the sensor. So the only thing that the lens does to allow light to enter the camera is the control over aperture (and this is true whether we set the aperture manually on older lenses or tell our modern camera to tell the lens what aperture to set).
You are right on total light control, but shutter speed and ISO are a function of the camera, while aperture is a function of the lens. Back in the 1960's I owned Leica M series cameras and everything was manually set, film speed (ASA or ISO film) came as a set amount depending what film you purchased (100ASA, 200ASA and so on), shutter speed was controlled at the camera by setting a dial on top of the camera and aperture was set by a dial on the lens. My point is that this has existed in photography since the first cameras only today with modern DSLR cameras we can control all three (ISO sensitivity, Shutter duration, aperture blades in the lens) from the one source on the camera. So from the lens perspective the aperture is the only control on the lens that determines the amount of light entering the camera. All three items you mentioned are important for a balance amount of light to accomplish taking a photograph so you are not wrong. I hope this long winded explanation helps clarify why aperture is refereed to image brightness.
You are right on total light control, but shutter speed and ISO are a function of the camera, while aperture is a function of the lens. Back in the 1960's I owned Leica M series cameras and everything was manually set, film speed (ASA or ISO film) came as a set amount depending what film you purchased (100ASA, 200ASA and so on), shutter speed was controlled at the camera by setting a dial on top of the camera and aperture was set by a dial on the lens. My point is that this has existed in photography since the first cameras only today with modern DSLR cameras we can control all three (ISO sensitivity, Shutter duration, aperture blades in the lens) from the one source on the camera. So from the lens perspective the aperture is the only control on the lens that determines the amount of light entering the camera. All three items you mentioned are important for a balance amount of light to accomplish taking a photograph so you are not wrong. I hope this long winded explanation helps clarify why aperture is refereed to image brightness.
SS319 wrote:
IF we keep the Shutter Speed the same and ISO th... (show quote)
Jun 8, 2017 10:50:24 #
SS319 wrote:
IF we keep the Shutter Speed the same and ISO th... (show quote)
Actually, ISO doesn't affect the incoming light arriving at the sensor. It affects the electrical signal from the sensor in one or more of several ways depending on the particular camera including: amplification of the signal prior to digitizing, changing the reference voltage of the digitizer, or increasing the digitized value of the signal in SW. Not to be nit-picking, but in the interest of accuracy...
Jun 8, 2017 10:54:47 #
You are right with the possibility of effecting noise.
TriX wrote:
Actually, ISO doesn't affect the incoming light arriving at the sensor. It affects the electrical signal from the sensor in one or more of several ways depending on the particular camera including: amplification of the signal prior to digitizing, changing the reference voltage of the digitizer, or increasing the digitized value of the signal in SW. Not to be nit-picking, but in the interest of accuracy...
Jun 11, 2017 00:16:06 #
Thank you for the explanation.
TriX wrote:
Actually, ISO doesn't affect the incoming light arriving at the sensor. It affects the electrical signal from the sensor in one or more of several ways depending on the particular camera including: amplification of the signal prior to digitizing, changing the reference voltage of the digitizer, or increasing the digitized value of the signal in SW. Not to be nit-picking, but in the interest of accuracy...
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