Wikidata:Property proposal/aperture

aperture

Originally proposed at Wikidata:Property proposal/Generic

   Done: aperture (P7863) (Talk and documentation)

Description	aperture of the camera lens
Represents	aperture (Q6434802)
Data type	Quantity
Template parameter	en:template:Infobox photographic lens aperture
Domain	camera lens (Q192234)
Allowed values	A range with min and max value or a fixed value as both is possible.
Example 1	Canon EF 800mm f/5.6L IS USM (Q5033222) → 5.6
Example 2	Samyang 500mm f/8 (Q25038830) → 8.0
Example 3	Canon EF 1200 mm f/5.6 L USM (Q5033201) → 5.6 (applies to part (P518) "max aperture"); 32 → (applies to part (P518) → "min aperture")
Source	en:Aperture
Planned use	I like to add the aperture to the lenses, which has wiki data item.
Number of IDs in source	For Canon we have currently lens items, where it would make sense to add this aperture.

Motivation

I like to add this value to the photo lenses, which have an item in Wikidata. GodeNehler (talk) 17:06, 6 June 2019 (UTC)

Discussion

•  Support --Tinker Bell ★ ♥ 20:42, 8 June 2019 (UTC)
•  Support NMaia (talk) 10:18, 10 June 2019 (UTC)
•  Comment Make sure to distinguish this from Property:P6790 (f-number) or list it as a related property. Infomuse (talk) 03:32, 14 June 2019 (UTC)
•  Comment @Infomuse Thank you for the hint. As I am not a nativ speaker for english, and checking this issue again, I got the impression that 'f-number' might be the better Property, as 'aperture' seams to be the mechanic, but 'f-number' is the value, which I like to add. But in the Lens articles, like mentioned above, and in the template is the term 'aperture'. So I am not sure what is correct. The second issue: I have just add the 'f-number' to the Samyang 500mm f/8. There I got the warning 'Entities using the f-number property should be instances of photograph (or of a subclass of it), but Samyang 500mm f/8currently isn't.' From that I got the Impression that the 'f-number' is the real value, with which a picture is taken. So not absolutely clear for me. --GodeNehler (talk) 07:51, 15 June 2019 (UTC)
•  Comment After thinking about the issue, I got to the conclusion, that aperture is the correct term as aperture means the mechanical construct, which is correct for a lens. --GodeNehler (talk) 19:21, 20 June 2019 (UTC)
•  Comment A range is not sufficient because there are 2 different kinds of aperture ranges. First, some zoom lenses have different maximum apertures depending on the selected focal length (for example, w:en:Sony FE 28-70mm F3.5-5.6 OSS). Second, at a given focal length, a lens has a minimum and maximum possible aperture that the photographer can select. So we really need 4 numbers to characterize lens aperture ranges as commonly specified (min/max aperture when zoomed wide/tele). 2620:0:1000:3216:5413:4AF0:7532:8655 22:30, 21 June 2019 (UTC)
•  Comment The IP is right. This can be fixed with the possibility to add up to 4 values. Maybe there is a need to add infos like 'minimum aperture', 'maximum aperture' for prime lens, 'minimum aperture at maximum focal length', 'maximum aperture at maximum focal length', 'minimum aperture at minimum focal length', 'maximum aperture at minimum focal length' for zoom lenses and 'fixed aperture' e.g. for mirror lenses. --GodeNehler (talk) 16:38, 28 June 2019 (UTC)
•  Comment This proposal is not ready: clearly it should not have "Property" as datatype. A "Property" datatype means that the values of this property will be properties themselves. Please pick an appropriate datatype and add examples which are consistent with that choice. − Pintoch (talk) 21:06, 23 July 2019 (UTC)
• @Tinker Bell: Thanks for fixing the datatype - however, the examples don't have a "quantity" value right now - can you fix them to do that? Or perhaps GodeNehler can take care of this? Do you still think we need this property? The description also should be fixed (needs to be shorter, can't have wiki text or links). ArthurPSmith (talk) 16:55, 22 August 2019 (UTC)

I fixed the examples. But, I think there is, at least, two ways to store the data: for example, Canon EF 1200 mm f/5.6 L USM (Q5033201):

Storing each value in one statement

quantity 5.6 (qualifier applies to part (P518) "max aperture"); quantity 32 → (qualifier applies to part (P518) → "min aperture")

The other way, is calculating the average of maximum and minimum aperture, and storing it as the main value, and using upperBound and lowerBound to specify the range of aperture

quantity 18.8 (bound: 13.2)

The average is obtained doing $(5.6+32)/2=18.8$, the bound, $32-18.8=13.2$ and $18.8-5.6=13.2$. For fixed values, bound=0. We can obtain the minimum and maximum values adding or substracting 13.2 to the average. I know, it's a lot harder, but it allows using one statement for each range. --Tinker Bell ★ ♥ 03:34, 23 August 2019 (UTC)

Hi @Tinker Bell:,

I am little bit lost with the values 'quantity' and 'bound'. I can understand them mathematically. I would name it capability of a lens. But these values are really unusual for me. I have never seen them together with camera lenses. Quantity I understand somehow, bound not. I would neither put 'quantity' or 'bound' to a lens item, as these values are not common in photography. --GodeNehler (talk) 10:01, 5 October 2019 (UTC)

GodeNehler, «quantity» and «bound» are part of Wikidata terminology: «quantity» is the datatype of the value, and «bound» is an optional value that Wikidata allows you to specify for a quantity when you edit the statement. No one will write these words explicity, there aren't properties. 16:46, 5 October 2019 (UTC)

• @GodeNehler, Tinker Bell, NMaia, Infomuse, Pintoch, ArthurPSmith:  Done, see aperture (P7863). This was open for a while, but there were no outright opposes. I created it with datatype quantity and having qualifiers for minimum and maximum. Thanks, --DannyS712 (talk) 23:36, 24 January 2020 (UTC)