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doc:appunti:hardware:canon_s120 [2019/03/22 10:25] – [Safety Shift] niccolodoc:appunti:hardware:canon_s120 [2020/10/31 07:33] (current) – [Exif Tags] niccolo
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 ^ Exif.CanonCs.AFPoint  | Auto-Focus frame setting. Exiv2 library is incomplete or misleading, here it is the true meaning of values:\\ ''(0)'' => **None** (Manual Focus)\\ ''(16390)'' => **Face AiAF**\\ ''Manual AF point selection'' => **1-point**  | ^ Exif.CanonCs.AFPoint  | Auto-Focus frame setting. Exiv2 library is incomplete or misleading, here it is the true meaning of values:\\ ''(0)'' => **None** (Manual Focus)\\ ''(16390)'' => **Face AiAF**\\ ''Manual AF point selection'' => **1-point**  |
 ^ Exif.CanonSi.SubjectDistance  | Subject distance, as per manual focus or Auto-Focus. The number seems to be the **distance in cm**, where **infinity** is reported as **6553**.   | ^ Exif.CanonSi.SubjectDistance  | Subject distance, as per manual focus or Auto-Focus. The number seems to be the **distance in cm**, where **infinity** is reported as **6553**.   |
 +^ Exif.CanonSi.0x0014  | According to Exiftool source code, this should be **FocusDistanceLower**, where the //SubjectDistance// is actually the **FocusDistanceUpper**. It is supposed that the camera knowns not the actual subject distance, but just two distances where the focus point is in between.  |
 ^ Exif.Canon.0x0027  | This multi-byte tag contains, among others, **Dynamic Range Correction** and **Shadow Correct** settings. Byte 4 (counting from zero) is a bitwise representation, under investigation.\\ Byte 16 is the Dynamic Range Correction:\\ 0 => **Off**\\ 1 => **Auto**\\ 200 => **200%**\\ 400 => **400%**  | ^ Exif.Canon.0x0027  | This multi-byte tag contains, among others, **Dynamic Range Correction** and **Shadow Correct** settings. Byte 4 (counting from zero) is a bitwise representation, under investigation.\\ Byte 16 is the Dynamic Range Correction:\\ 0 => **Off**\\ 1 => **Auto**\\ 200 => **200%**\\ 400 => **400%**  |
 ^  ISO Speed  ^^ ^  ISO Speed  ^^
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 **Safety Shift** is an option that interferes with manual settings in **Tv** and **Av** modes. **Safety Shift** is an option that interferes with manual settings in **Tv** and **Av** modes.
  
-Pressing the **shutter button halfway** will show the aperture value or the shutter speed **selected automatically to obtain a standard exposure**, if such exposure cannot be obtained, the value is displayed in **orange color**. But if **Safety Shift** is enabled, the manually selected value (aperture or speed) will be corrected and disaplyed on the screen. To enable this option, press the **%%[MENU]%%** button and search the **%%[Safety Shift]%%** into the //camera tab//.+Pressing the **shutter button halfway** will show the aperture value or the shutter speed **selected automatically to obtain a standard exposure**, if such exposure cannot be obtained, the value is displayed in **orange color**. But if **Safety Shift** is enabled, the manually selected value (aperture or speed) will be corrected and displayed on the screen. To enable this option, press the **%%[MENU]%%** button and search the **%%[Safety Shift]%%** into the //camera tab//. 
 + 
 +===== Neutral Density Filter ===== 
 + 
 +In photography, a **neutral-density filter** is a filter that **reduces the intensity of all colors of light** equally. The purpose of a neutral-density filter is to **reduce the amount of light** entering the lens, **allowing combinations** of aperture and exposure time that would otherwise produce overexposed pictures. 
 + 
 +For example you can use it to allow an **high aperture value** and get a **lower depth of field**. 
 + 
 +====== Python Script Download ====== 
 + 
 +Here it is a Python script to decode Exif metadata from photos taken by the Canon PowerShow S120: **{{.:canon_s120:canon-metadata.txt|canon-metadata}}**. 
 + 
 +====== Web References ====== 
 + 
 +  * **[[https://www.exiv2.org/tags-canon.html|Exiv2 - Canon MakerNote Tags]]** 
 +  * **[[https://www.dpreview.com/forums/post/35260903|Wow.... focus distance reported in EXIF???]]** 
 +  * **[[https://photo.stackexchange.com/questions/105977/what-is-focus-distance-lower-upper-and-how-is-it-different-from-depth-of-field|What is “focus distance lower/upper” and how is it different from depth of field?]]** 
 +  * **[[https://www.dpreview.com/forums/post/51962463|Distance in EXIF]]**
doc/appunti/hardware/canon_s120.1553250351.txt.gz · Last modified: 2019/03/22 10:25 by niccolo