Actual Light on ccd
Nov 28, 2020 08:41:29 #
Does using a full-frame f/1.4 lens on an apc camera provide any more light than using an f/1.8 lens specifically designed for an apc camera?
Nov 28, 2020 08:46:09 #
Nov 28, 2020 09:05:56 #
Ysarex
Loc: St. Louis
The whole point of f/stop values is to normalize exposure. f/x is the same then for all lenses and camera systems.
Nov 28, 2020 09:40:44 #
IDguy
Loc: Idaho
Ysarex wrote:
The whole point of f/stop values is to normalize exposure. f/x is the same then for all lenses and camera systems.
Maybe not for DOF. Search Northrup on this.
https://youtu.be/f5zN6NVx-hY
You’ll find dissenting views too.
Nov 28, 2020 09:43:03 #
larryepage
Loc: North Texas area
grahamfourth wrote:
Does using a full-frame f/1.4 lens on an apc camera provide any more light than using an f/1.8 lens specifically designed for an apc camera?
There are several recent nonsense-filled discussions on this forum that will seek to confuse you on this subject. I use a mix of DX and full frame lenses on my cameras all the time. There is no difference in exposure.
What is often a real difference is that many crop lenses are not as "fast" as many full frame lenses...they simply do not offer the wider apertures.
Nov 28, 2020 09:43:09 #
IDguy wrote:
Maybe not for DOF. Search Northrup on this.
Did we switch to discussion of DOF?
Are we done with light?
Nov 28, 2020 09:44:37 #
grahamfourth wrote:
Does using a full-frame f/1.4 lens on an apc camera provide any more light than using an f/1.8 lens specifically designed for an apc camera?
if you set both lenses at the same f/stop and you use the lenses on the APS-C camera then the light falling on the CCD or CMOS sensor are the same. With the FF lens there is more light entering the camera but the extra light doesn't fall on the sensor.
Nov 28, 2020 09:46:26 #
IDguy
Loc: Idaho
Longshadow wrote:
Did we switch to discussion of DOF?
Are we done with light?
Are we done with light?
I generalized question. If you are too pedantic you are welcome to ignore.
Also the total light hitting sensor is reduced by crop factor. Mathematical fact.
The intensity is the same.
Nov 28, 2020 09:53:13 #
IDguy wrote:
I generalized question. If you are too pedantic you are welcome to ignore.
Also the total light hitting sensor is reduced by crop factor. Mathematical fact.
The intensity is the same.
Also the total light hitting sensor is reduced by crop factor. Mathematical fact.
The intensity is the same.
But not the intensity of the light, just the surface area it covers (photons per square cm).
The sensor sees the same light intensity for whatever the area of the sensor.
Each sensor (size) will see the same photons per square cm.
Sensor size DOES affect the total amount of photons captured (volume, mathematical fact), but it does not affect the [i]exposure[i/] for a given amount of photons per square centimeter.
Physical fact.
Not pedantic, DOF is a different subject.
DOF is not dependent on the amount of light, but the optics.
Another physical fact.
Northrup is a physicist, correct?
Nov 28, 2020 09:57:03 #
Ysarex
Loc: St. Louis
IDguy wrote:
Maybe not for DOF. Search Northrup on this.
https://youtu.be/f5zN6NVx-hY
You’ll find dissenting views too.
https://youtu.be/f5zN6NVx-hY
You’ll find dissenting views too.
Responding to the OP's question I said nothing about DOF. I said; "The whole point of f/stop values is to normalize exposure.
There are no dissenting views relative to exposure.
Nov 28, 2020 11:08:25 #
[quote=Longshadow]But not the intensity of the light, just the surface area it covers (photons per square cm).
The sensor sees the same light intensity for whatever the area of the sensor.
Each sensor (size) will see the same photons per square cm.
Sensor size DOES affect the total amount of photons captured (volume, mathematical fact), but it does not affect the [i]exposure[i/] for a given amount of photons per square centimeter.
Physical fact.
Not pedantic, DOF is a different subject.
DOF is not dependent on the amount of light, but the optics.
Another physical fact.
Northrup is a physicist, correct?[/quote]
When using full frame lens on an APS-C body more light entering the camera body but more than half of it doesn't fall on the sensor thus you gain nothing. And no I don't think Northrup is a physicist.
The sensor sees the same light intensity for whatever the area of the sensor.
Each sensor (size) will see the same photons per square cm.
Sensor size DOES affect the total amount of photons captured (volume, mathematical fact), but it does not affect the [i]exposure[i/] for a given amount of photons per square centimeter.
Physical fact.
Not pedantic, DOF is a different subject.
DOF is not dependent on the amount of light, but the optics.
Another physical fact.
Northrup is a physicist, correct?[/quote]
When using full frame lens on an APS-C body more light entering the camera body but more than half of it doesn't fall on the sensor thus you gain nothing. And no I don't think Northrup is a physicist.
Nov 28, 2020 11:21:41 #
BebuLamar wrote:
When using full frame lens on an APS-C body more light entering the camera body but more than half of it doesn't fall on the sensor thus you gain nothing. And no I don't think Northrup is a physicist.
The amount of light entering via a full frame lens does not change when put on a APS-C body. No more, no less. The same amount of light goes through a given lens at a given aperture regardless to what the lens is attached. The amount of light does not change, only how much light is caught by the sensor, depending on the sensor size.
Nov 28, 2020 11:28:01 #
Longshadow wrote:
The amount of light entering via a full frame lens does not change when put on a APS-C body.
The same amount of light goes through a given lens at a given aperture regardless to what the lens is attached. The amount of light does not change, only how much light is caught by the sensor.
The same amount of light goes through a given lens at a given aperture regardless to what the lens is attached. The amount of light does not change, only how much light is caught by the sensor.
More light goes thru the FF lens than APS-C lens but if using on the APS-C body more than half of the light hitting outside of the sensor. They hit the blackened mirror box which does nothing but if the inside of the mirror box isn't well blacken it could cause fogging.
Nov 28, 2020 11:32:48 #
BebuLamar wrote:
More light goes thru the FF lens than APS-C lens but if using on the APS-C body more than half of the light hitting outside of the sensor. They hit the blackened mirror box which does nothing but if the inside of the mirror box isn't well blacken it could cause fogging.
I agree with the difference between a FF lens and APS-C lens, but I did refer to "a given lens" (singular) as in the FF lens in the discussion.
Fogging is a different anomaly and problem, but is related to the difference in the size of the circle of light transmitted into the camera body between a FF lens (larger circle) and an APS-C lens (smaller circle).
Nov 28, 2020 12:59:09 #
BebuLamar wrote:
More light goes thru the FF lens than APS-C lens but if using on the APS-C body more than half of the light hitting outside of the sensor. They hit the blackened mirror box which does nothing but if the inside of the mirror box isn't well blacken it could cause fogging.
And you do realize that the amount of light going through a FF lens with an ƒ/3.5 aperture and a APS-C Lens with an ƒ/3.5 aperture will be the same amount, just spread out over different size circles.
The glass will simply either concentrate it (smaller circle) or disperse it (wide circle).
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