If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#41
|
|||
|
|||
Finally a decent travel zoom from Fuji
On Thu, 25 Jul 2019 20:15:24 -0400, nospam
wrote: In article , Eric Stevens wrote: There is no such thing as an "equivalent" aperture. F4 is F4 both for a small sensor camera and a large sensor camera. for exposure, yes. for depth of field, no. Correct. But its got nothing to do with the size of the sensor. It occurs only as a result of the use of a shorter focal length lens. nope. it has everything to do with the size of the sensor, and the lens does not change. Are you discussing the use of the same lens on two different cameras? that doesn't matter. I thought that other people were discussing the effect of using a proportionally smaller (focal length and aperture dimensions) on two proprtionally different cameras. they might be, but again, that doesn't matter. Then what exactly are you talking about? |
#42
|
|||
|
|||
Finally a decent travel zoom from Fuji
In article , Alfred Molon wrote:
Sandman: just as the equivalent aperture is F6 (not F8, my bad) There is no such thing as an "equivalent" aperture. F4 is F4 both for a small sensor camera and a large sensor camera. Then there is no such thing as "equivalent" focal length, 16-80 mm is the focal length for the lens, regardless of what sensor you put under it. Sigh... -- Sandman |
#43
|
|||
|
|||
Finally a decent travel zoom from Fuji
In article , Eric Stevens
wrote: Then what exactly are you talking about? equivalency. do try to keep up. |
#44
|
|||
|
|||
Finally a decent travel zoom from Fuji
In article , Eric Stevens wrote:
Both physical factors of the lens are affected when comparing crop to full format. That's why a f4 m43 lens has the equivalent aperture of a f8 full format lens. Alfred Molon: Wrong again. An F4 lens is an F4 lens regardless of sensor size Sandman: No one has said otherwise. A 16-80mm lens is a 16-80mm lens also regardless of sensor size, but the *equivalent* focal length is 24-120mm, just as the equivalent aperture is F6 (not F8, my bad) Alfred Molon: , because the exposure is the same at F4 and 1/100s both on the small sensor camera and the large sensor camera. But if you shoot at F8, the exposure time will be 4x the exposure time at F4. Sandman: You're mixing exposure with equivalency. Exposure is light per unit area, a smaller sensor has fewer of those units, so the amount of total light is different, meaning that a crop sensor camera need to boost its signal to create an equal enough image. That's why crop sensors usually are said to have poorer ISO. Let's consider two cameras, identical except that one is half the size of the other. With the smaller camera, the focal length will be halved, the lens diameter will be halved. i.e. the f value will remain constant. With the smaller camera, the sensor area will be one quarter. So too will be the lens area. i.e. the amount of light entering the lens will be reduced by a factor of four. Exactly. -- Sandman |
#45
|
|||
|
|||
Finally a decent travel zoom from Fuji
On Fri, 26 Jul 2019 01:46:25 -0400, nospam
wrote: In article , Eric Stevens wrote: Then what exactly are you talking about? equivalency. do try to keep up. Equivalency of what between what? |
#46
|
|||
|
|||
Finally a decent travel zoom from Fuji
On 26 Jul 2019 06:02:44 GMT, Sandman wrote:
In article , Eric Stevens wrote: Both physical factors of the lens are affected when comparing crop to full format. That's why a f4 m43 lens has the equivalent aperture of a f8 full format lens. Alfred Molon: Wrong again. An F4 lens is an F4 lens regardless of sensor size Sandman: No one has said otherwise. A 16-80mm lens is a 16-80mm lens also regardless of sensor size, but the *equivalent* focal length is 24-120mm, just as the equivalent aperture is F6 (not F8, my bad) Alfred Molon: , because the exposure is the same at F4 and 1/100s both on the small sensor camera and the large sensor camera. But if you shoot at F8, the exposure time will be 4x the exposure time at F4. Sandman: You're mixing exposure with equivalency. Exposure is light per unit area, a smaller sensor has fewer of those units, so the amount of total light is different, meaning that a crop sensor camera need to boost its signal to create an equal enough image. That's why crop sensors usually are said to have poorer ISO. Let's consider two cameras, identical except that one is half the size of the other. With the smaller camera, the focal length will be halved, the lens diameter will be halved. i.e. the f value will remain constant. With the smaller camera, the sensor area will be one quarter. So too will be the lens area. i.e. the amount of light entering the lens will be reduced by a factor of four. Exactly. But you have snipped the next bit: "But so too is the sensor area to be covered by the light so that the intensity of the light falling on the sensor is the same in both cameras. In other words, when exposed at the same shutter speed and f value the quantity of light per unit area falling on the respective sensors will be the same. There is no need to calculate a different aperture." |
#47
|
|||
|
|||
Finally a decent travel zoom from Fuji
In article , Eric Stevens wrote:
Alfred Molon: , because the exposure is the same at F4 and 1/100s both on the small sensor camera and the large sensor camera. But if you shoot at F8, the exposure time will be 4x the exposure time at F4. Sandman: You're mixing exposure with equivalency. Exposure is light per unit area, a smaller sensor has fewer of those units, so the amount of total light is different, meaning that a crop sensor camera need to boost its signal to create an equal enough image. That's why crop sensors usually are said to have poorer ISO. Eric Stevens: Let's consider two cameras, identical except that one is half the size of the other. With the smaller camera, the focal length will be halved, the lens diameter will be halved. i.e. the f value will remain constant. With the smaller camera, the sensor area will be one quarter. So too will be the lens area. i.e. the amount of light entering the lens will be reduced by a factor of four. Sandman: Exactly. But you have snipped the next bit Because it shifted to exposure from equivalency. They're not the same thing. To create two equivalent images from two different sensors, you can't use the same exposure. http://www.josephjamesphotography.com/equivalence/#equivalence -- Sandman |
#48
|
|||
|
|||
Finally a decent travel zoom from Fuji
In article , Eric Stevens
wrote: Let's consider two cameras, identical except that one is half the size of the other. With the smaller camera, the focal length will be halved, the lens diameter will be halved. i.e. the f value will remain constant. With the smaller camera, the sensor area will be one quarter. So too will be the lens area. i.e. the amount of light entering the lens will be reduced by a factor of four. Exactly. But you have snipped the next bit: "But so too is the sensor area to be covered by the light so that the intensity of the light falling on the sensor is the same in both cameras. In other words, when exposed at the same shutter speed and f value the quantity of light per unit area falling on the respective sensors will be the same. There is no need to calculate a different aperture." but you have snipped the next bit: there is to obtain equivalent results. |
#49
|
|||
|
|||
Finally a decent travel zoom from Fuji
In article ,
Sandman wrote: Eric Stevens: Let's consider two cameras, identical except that one is half the size of the other. With the smaller camera, the focal length will be halved, the lens diameter will be halved. i.e. the f value will remain constant. With the smaller camera, the sensor area will be one quarter. So too will be the lens area. i.e. the amount of light entering the lens will be reduced by a factor of four. Sandman: Exactly. But you have snipped the next bit Because it shifted to exposure from equivalency. They're not the same thing. true To create two equivalent images from two different sensors, you can't use the same exposure. false |
#50
|
|||
|
|||
Finally a decent travel zoom from Fuji
On 26 Jul 2019 11:47:17 GMT, Sandman wrote:
In article , Eric Stevens wrote: Alfred Molon: , because the exposure is the same at F4 and 1/100s both on the small sensor camera and the large sensor camera. But if you shoot at F8, the exposure time will be 4x the exposure time at F4. Sandman: You're mixing exposure with equivalency. Exposure is light per unit area, a smaller sensor has fewer of those units, so the amount of total light is different, meaning that a crop sensor camera need to boost its signal to create an equal enough image. That's why crop sensors usually are said to have poorer ISO. Eric Stevens: Let's consider two cameras, identical except that one is half the size of the other. With the smaller camera, the focal length will be halved, the lens diameter will be halved. i.e. the f value will remain constant. With the smaller camera, the sensor area will be one quarter. So too will be the lens area. i.e. the amount of light entering the lens will be reduced by a factor of four. Sandman: Exactly. But you have snipped the next bit Because it shifted to exposure from equivalency. They're not the same thing. To create two equivalent images from two different sensors, you can't use the same exposure. http://www.josephjamesphotography.com/equivalence/#equivalence Aah! I get you. Most people focus on the exposure triangle. You have a different triangle in mind. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Finally, a decent P&S?? | Rich | Digital Photography | 25 | January 27th 08 08:33 PM |
Finally a decent bird shot | JimKramer | 35mm Photo Equipment | 1 | May 19th 07 01:28 AM |
Finally a decent bird shot | Paul Furman | 35mm Photo Equipment | 27 | May 18th 07 10:24 PM |
Finally a decent bird shot | Paul Furman | Digital SLR Cameras | 1 | May 15th 07 02:31 AM |
Why can I not get a decent picture with a fuji F610 | Trevor Davies | Digital Photography | 2 | December 7th 04 07:18 PM |