Difference between revisions of "Help:Categories"

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In Camera-wiki, pages are indexed by Mediawiki categories, in order to help users find related information. Categories are listed at the foot of each page. For example, you will see "Category: Editing guidelines" at the foot of this page; or "Category: Japanese 35mm rangefinder" at the bottom of the [[Konica Auto S3]] article.
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Camera-wiki.org uses Mediawiki '''categories''', in order to help readers find related information. Categories are listed at the foot of each page. As examples, you will see "Category:Editing guidelines" at the foot of ''this'' page, and "Category:Japanese 35mm rangefinder" at the bottom of the [[Konica Auto S3]] article.
  
To discover more about what Mediawiki categories are and how to use them, you can try clicking on any category links you find in Camera-wiki, to see what happens; or you can explore the "Further reading" at the foot of this page; or both.  
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To discover more about what Mediawiki categories are and how to use them, you can try clicking on any category links you find in Camera-wiki.org and see what happens, or you can explore the "Further reading" at the foot of this page.  
  
Very briefly, however, [[Hasselblad 500 C/M]] is in both [[:Category: 6x6 SLR]] and [[:Category: Sweden]] (as well perhaps as other categories); clicking either will take you to a list of the articles in each category.<ref>Common sense may tell you that you should somehow be able to select ''both'' [[:Category: 6x6 SLR]] ''and'' [[:Category: Germany]] and thereby get a list of German 6&times;6 SLRs. This is known as "category intersections." However, the Mediawiki software unfortunately does not allow for this.</ref>
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==Basics==
  
Camera-wiki has its own policies of categorization. Before adding categories to a page (let alone creating a new category), please familiarize yourself with the relevant categories.  
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The [[Hasselblad 500 C/M]] is in [[:Category:6x6 SLR]], [[:Category:Sweden]] and [[:Category:Hasselblad]] (and perhaps in other categories too). Unless you have taken the option (in "Preferences") to change the "skin" (appearance) of Camera-Wiki.org, links to these will appear at the foot of the article. (With a different skin, they may instead appear at the top.) Clicking any of these links will take you to a list of other articles in the category.
  
You can do this in any of various ways. You can examine the categories to which a similar subject (camera, etc.) belongs; or you can browse a complete [[Special:Categories | alphabetical list ]] of categories (jump around in the alphabet via the search box). Categories are nested into subcategories; so beginning at [[:Category:Root category | the root category ]], you can explore outwards through branches of the category tree: From [[:Category:Countries]] on to [[:Category:Germany | Germany]] and then to [[:Category:German cameras | German cameras]] to [[:Category:German 6x6 | German 6x6]], and [[:Category:German 6x6 pseudo TLR | German 6x6 pseudo-TLR]] and finally to [[Pucky | the Ising Pucky]].
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(You may think that you should somehow be able to select ''both'' [[:Category:6x6 SLR]] ''and'' [[:Category:Sweden]] and thereby get a list of Swedish 6×6 SLRs. However, the Mediawiki software unfortunately does not allow for this.<ref>More strictly speaking, it does allow for this. However, it does so with bugs, and therefore this is not implemented here.</ref>)
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Camera-wiki.org has its own policies of categorization. Before adding categories to a page (let alone creating a new category), please familiarize yourself with the kinds of categories other articles use. You can do this in any of various ways. You can examine the categories to which a similar subject (camera, etc.) belongs; or you can browse a complete [[Special:Categories | alphabetical list]] of categories (jump around in the alphabet via the search box).
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Categories that only include one or two members are not particularly helpful; they should be avoided. You can open a [http://camera-wiki.org/index.php?title=Special:MostLinkedCategories&limit=700 list of Camera-wiki.org's most-used categories], then use your browser's "Find" function to discover what relevant categories are already being used. When you add a category to a page, the capitalization, spelling, etc. must exactly match the existing category.
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Categories are nested; so beginning at [[:Category:Contents]] (the most basic category of all), you can go via [[:Category:Articles]] to explore outwards through branches of the category tree: From [[:Category:Countries]] on to [[:Category:Germany]], to [[:Category:German cameras]], to [[:Category:German 6x6]], and to [[:Category:German 6x6 pseudo TLR]]; and finally to examples such as [[Pucky]].
  
 
==Categories for articles on cameras==
 
==Categories for articles on cameras==
  
Categories aren't only used for articles on cameras, but because the overwhelming majority of articles in this wiki are on cameras we'll look at the categorization of such articles.
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Categories aren't only used for articles on cameras, but because the overwhelming majority of articles in Camera-wiki.org are on cameras we'll look at the categorization of such articles.
  
 
A page about a specific camera model should have the following categories:
 
A page about a specific camera model should have the following categories:
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The "country of origin" is normally that where the design was done: a camera planned in Japan and assembled in Malaysia is thus treated as having originated in Japan.
 
The "country of origin" is normally that where the design was done: a camera planned in Japan and assembled in Malaysia is thus treated as having originated in Japan.
  
Japan and Germany are special cases: the categories for the type of camera are prefaced by "Japanese" or "German". Thus although [[Hasselblad 500 C/M]] is in the pair
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Japan and Germany are special cases: A category "Japan" would include hundreds of pages—too many to be useful. Instead "Japanese" or "German" are used as qualifiers for other camera categories. While the Swedish [[Hasselblad 500 C/M]] is in included in the categories
* [[:Category: 6x6 SLR]]
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* [[:Category:6x6 SLR]]
* [[:Category: Sweden]]
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* [[:Category:Sweden]]
(as well as others),
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[[Minolta SR-1]] and [[Vitessa]] are respectively in  
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In contrast, the [[Minolta SR-1]] is included in
* [[:Category: Japanese 35mm SLR]]
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* [[:Category:Japanese 35mm SLR]]
* [[:Category: German 35mm rangefinder folding]]
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(as well as others).
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And the Voigtländer [[Vitessa]] is in
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* [[:Category:German 35mm rangefinder folding]]
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A page about a specific camera model may also be in the following categories:
 
A page about a specific camera model may also be in the following categories:
* a category for the lens mount (if applicable and if such a category seems helpful<ref>For widely known cameras with interchangeable lenses, it usually is helpful. By contrast, the Meopta [[Opema]] takes interchangeable screwmount (M38)<!-- Yes, M38; not M39 --> lenses. It does not share these with any other camera we have heard of; thus it is not helpful to create a category for its lens mount.</ref>)
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* a category for the lens mount (if applicable and if such a category seems helpful<ref>For widely known cameras with interchangeable lenses, it usually is helpful. By contrast, the Meopta [[Opema]] takes interchangeable screwmount (M38)<!-- Yes, M38; not M39 --> lenses. It is not known to share these with any other camera; thus it is not helpful to create a category for its lens mount.</ref>)
 
* a category for the camera maker (if such a category seems helpful<ref>Obviously Canon, Nikon, Zeiss, etc are helpful. But since the [[Ako folders]] are the only cameras known to have been sold (and perhaps made) by [[Ako Shōkai]], there's little point in creating an "Ako" category.</ref>)
 
* a category for the camera maker (if such a category seems helpful<ref>Obviously Canon, Nikon, Zeiss, etc are helpful. But since the [[Ako folders]] are the only cameras known to have been sold (and perhaps made) by [[Ako Shōkai]], there's little point in creating an "Ako" category.</ref>)
  
For example, the [[Sony Alpha DSLR-A100]] would be in the following categories (as well perhaps as in others):
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For example, the [[Sony Alpha DSLR-A100]] would be in the following categories (as well as perhaps in others):
*[[:Category: Japanese digital SLR]]
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*[[:Category:Japanese digital SLR]]
*[[:Category: Sony|Alpha]] (this addition of "|Alpha" lists the camera at the correct place for "Alpha", not at that for "Sony Alpha")
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*[[:Category:Sony]] alphabetized under Alpha DSLR-A100<ref>Adding a pipe character to the markup, <nowiki>[[:Category: Sony|Alpha DSLR-A100]]</nowiki> lists the entry in the Sony index under the A's for "Alpha", not the S's for "Sony Alpha")</ref>
*[[:Category: Minolta AF mount]]
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*[[:Category:Minolta AF mount]]
*[[:Category: A|Alpha Dslr-A100]]
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*[[:Category:A]] (alphabetical listings)
*[[:Category: S]]
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*[[:Category:S]] (ditto)
  
 
and the [[Vitessa]] folder in the following:
 
and the [[Vitessa]] folder in the following:
* [[:Category: German 35mm rangefinder folding]]
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* [[:Category:German 35mm rangefinder folding]]
* [[:Category: Barn door]]
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* [[:Category:Barn door]]
* [[:Category: Voigtländer]]
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* [[:Category:Voigtländer]]
* [[:Category: V]]
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* [[:Category:V]]
  
These articles could imaginably be put in various other categories; for example, the former could be in "SLR cameras". However, the general rule is only to put a page in the most specific category, and not to put it in this category and also one or more parents of this category. So the Sony Alpha DSLR-A100 goes to "Category:Digital SLR" and is not listed under "Category:SLR".  
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These articles could imaginably be put in various other categories; for example, the former could be in "SLR cameras". However, the general rule is to '''put a page only in the most specific category''', and not to put it in any of the parents of this category. So the Sony Alpha DSLR-A100 goes into the category "Japanese digital SLR" and ''not'' also into any of categories "Japanese SLR", "Japanese digital", "Digital SLR", "Digital", or "Japanese cameras".  
  
(This general rule is sometimes broken; for example, cameras from the former East Germany are considered by most people as being German as well, so are listed both in the "Category:East Germany" and in the corresponding "German" category.)
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(This general rule is sometimes broken; for example, cameras from the former East Germany are considered by most people as being German as well, and so are listed both in the "Category:East Germany" and in the corresponding "German" category.)
  
 
==Creating new categories==
 
==Creating new categories==
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Please think very carefully before creating a new category. If you create one and you or others later decide that it is unsuitable or better renamed, a lot of work will be required.
 
Please think very carefully before creating a new category. If you create one and you or others later decide that it is unsuitable or better renamed, a lot of work will be required.
  
(This is in part because categories can't be renamed. To achieve the more-or-less equivalent of renaming a category, an administrator has to delete the category, and somebody creates a new category and edits the reference to it within each article.)
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This is in part because categories cannot be renamed. To achieve the more-or-less equivalent of renaming a category, it's necessary to (i) create the new category, (ii) change the link to the category within every article in the old category, and (iii) delete the old category. The second of these stages can be exhausting.
  
 
If in any doubt, propose the new category in one or more relevant talk pages and wait to see what reaction there is to your proposal. Be circumspect in creating even one new category.
 
If in any doubt, propose the new category in one or more relevant talk pages and wait to see what reaction there is to your proposal. Be circumspect in creating even one new category.
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Adding <nowiki>[[Category:Nikon]]</nowiki> to a page adds that page to the Nikon category.
 
Adding <nowiki>[[Category:Nikon]]</nowiki> to a page adds that page to the Nikon category.
  
By contrast, adding <nowiki>[[:Category:Nikon]]</nowiki> &mdash; note the extra colon at the start &mdash; to a page does not add that page to the Nikon category but instead provides a regular inline link to the Nikon category. This is something that's seldom done, except to discuss categories themselves (as within the page you're now reading).
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By contrast, adding <nowiki>[[:Category:Nikon]]</nowiki> &mdash; note the extra colon at the start &mdash; to a page does not add that page to the Nikon category but instead provides a regular inline link to the Nikon category. This is something that's seldom done, other than in order to discuss categories themselves (as within this very page).
  
Adding <nowiki>[[Category:Nikon]]</nowiki> to a page on the Nikon F2 adds that article to the category's list with "Nikon F2" alphabetized under N. This is not what we want. Adding <nowiki>[[Category:Nikon|F2]]</nowiki> instead adds the article to the list alphabetized by "F2": better.
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Adding <nowiki>[[Category:Nikon]]</nowiki> to a page on the Nikon F2 adds that article to the category's list with "Nikon F2" alphabetized under N. This is not what we want. Adding <nowiki>[[Category:Nikon|F2]]</nowiki> &mdash; note the pipe character "|" &mdash; adds the article to the list alphabetized by "F2": better.
  
Adding <nowiki>[[Category:Nikon]]</nowiki> to a the main page discussing Nikon (the company) adds that article to the list alphabetized under the N's. Again, not so good. Adding <nowiki>[[Category:Nikon|*]]</nowiki> instead displays the article to the top of the list: better.
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Adding <nowiki>[[Category:Nikon]]</nowiki> to a the main page discussing Nikon (the company) adds that article to the list alphabetized under "N". Again, not so good. Adding <nowiki>[[Category:Nikon|*]]</nowiki> displays the article to the top of the list: better.
  
 
==In the absence of a conclusion==
 
==In the absence of a conclusion==
  
There are still many points to be discussed about categorization. Please think for yourself and post new ideas in the discussion page. You're asked above to be wary of creating new categories, but you can be as bold as you like in suggesting changes to categories.
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There are still many points to be discussed about categorization. Please think for yourself and post new ideas in [[Help talk:Categories|the discussion page]]. Although you're asked above to be wary of creating new categories, you can be as bold as you like in suggesting changes to categories.
  
 
==Notes==
 
==Notes==

Latest revision as of 07:13, 5 February 2012

Camera-wiki.org uses Mediawiki categories, in order to help readers find related information. Categories are listed at the foot of each page. As examples, you will see "Category:Editing guidelines" at the foot of this page, and "Category:Japanese 35mm rangefinder" at the bottom of the Konica Auto S3 article.

To discover more about what Mediawiki categories are and how to use them, you can try clicking on any category links you find in Camera-wiki.org and see what happens, or you can explore the "Further reading" at the foot of this page.

Basics

The Hasselblad 500 C/M is in Category:6x6 SLR, Category:Sweden and Category:Hasselblad (and perhaps in other categories too). Unless you have taken the option (in "Preferences") to change the "skin" (appearance) of Camera-Wiki.org, links to these will appear at the foot of the article. (With a different skin, they may instead appear at the top.) Clicking any of these links will take you to a list of other articles in the category.

(You may think that you should somehow be able to select both Category:6x6 SLR and Category:Sweden and thereby get a list of Swedish 6×6 SLRs. However, the Mediawiki software unfortunately does not allow for this.[1])

Camera-wiki.org has its own policies of categorization. Before adding categories to a page (let alone creating a new category), please familiarize yourself with the kinds of categories other articles use. You can do this in any of various ways. You can examine the categories to which a similar subject (camera, etc.) belongs; or you can browse a complete alphabetical list of categories (jump around in the alphabet via the search box).

Categories that only include one or two members are not particularly helpful; they should be avoided. You can open a list of Camera-wiki.org's most-used categories, then use your browser's "Find" function to discover what relevant categories are already being used. When you add a category to a page, the capitalization, spelling, etc. must exactly match the existing category.

Categories are nested; so beginning at Category:Contents (the most basic category of all), you can go via Category:Articles to explore outwards through branches of the category tree: From Category:Countries on to Category:Germany, to Category:German cameras, to Category:German 6x6, and to Category:German 6x6 pseudo TLR; and finally to examples such as Pucky.

Categories for articles on cameras

Categories aren't only used for articles on cameras, but because the overwhelming majority of articles in Camera-wiki.org are on cameras we'll look at the categorization of such articles.

A page about a specific camera model should have the following categories:

  • one or more categories for the type of camera
  • a category for the country of origin
  • one or two categories for the alphabetical index

The "country of origin" is normally that where the design was done: a camera planned in Japan and assembled in Malaysia is thus treated as having originated in Japan.

Japan and Germany are special cases: A category "Japan" would include hundreds of pages—too many to be useful. Instead "Japanese" or "German" are used as qualifiers for other camera categories. While the Swedish Hasselblad 500 C/M is in included in the categories

In contrast, the Minolta SR-1 is included in

And the Voigtländer Vitessa is in


A page about a specific camera model may also be in the following categories:

  • a category for the lens mount (if applicable and if such a category seems helpful[2])
  • a category for the camera maker (if such a category seems helpful[3])

For example, the Sony Alpha DSLR-A100 would be in the following categories (as well as perhaps in others):

and the Vitessa folder in the following:

These articles could imaginably be put in various other categories; for example, the former could be in "SLR cameras". However, the general rule is to put a page only in the most specific category, and not to put it in any of the parents of this category. So the Sony Alpha DSLR-A100 goes into the category "Japanese digital SLR" and not also into any of categories "Japanese SLR", "Japanese digital", "Digital SLR", "Digital", or "Japanese cameras".

(This general rule is sometimes broken; for example, cameras from the former East Germany are considered by most people as being German as well, and so are listed both in the "Category:East Germany" and in the corresponding "German" category.)

Creating new categories

Please think very carefully before creating a new category. If you create one and you or others later decide that it is unsuitable or better renamed, a lot of work will be required.

This is in part because categories cannot be renamed. To achieve the more-or-less equivalent of renaming a category, it's necessary to (i) create the new category, (ii) change the link to the category within every article in the old category, and (iii) delete the old category. The second of these stages can be exhausting.

If in any doubt, propose the new category in one or more relevant talk pages and wait to see what reaction there is to your proposal. Be circumspect in creating even one new category.

Markup

Add any category to, or very close to, the foot of the article.

Adding [[Category:Nikon]] to a page adds that page to the Nikon category.

By contrast, adding [[:Category:Nikon]] — note the extra colon at the start — to a page does not add that page to the Nikon category but instead provides a regular inline link to the Nikon category. This is something that's seldom done, other than in order to discuss categories themselves (as within this very page).

Adding [[Category:Nikon]] to a page on the Nikon F2 adds that article to the category's list with "Nikon F2" alphabetized under N. This is not what we want. Adding [[Category:Nikon|F2]] — note the pipe character "|" — adds the article to the list alphabetized by "F2": better.

Adding [[Category:Nikon]] to a the main page discussing Nikon (the company) adds that article to the list alphabetized under "N". Again, not so good. Adding [[Category:Nikon|*]] displays the article to the top of the list: better.

In the absence of a conclusion

There are still many points to be discussed about categorization. Please think for yourself and post new ideas in the discussion page. Although you're asked above to be wary of creating new categories, you can be as bold as you like in suggesting changes to categories.

Notes

  1. More strictly speaking, it does allow for this. However, it does so with bugs, and therefore this is not implemented here.
  2. For widely known cameras with interchangeable lenses, it usually is helpful. By contrast, the Meopta Opema takes interchangeable screwmount (M38) lenses. It is not known to share these with any other camera; thus it is not helpful to create a category for its lens mount.
  3. Obviously Canon, Nikon, Zeiss, etc are helpful. But since the Ako folders are the only cameras known to have been sold (and perhaps made) by Ako Shōkai, there's little point in creating an "Ako" category.
  4. Adding a pipe character to the markup, [[:Category: Sony|Alpha DSLR-A100]] lists the entry in the Sony index under the A's for "Alpha", not the S's for "Sony Alpha")

Further reading