Do we need both [neutral-density] and [neutral-density-filter]?

Question

At the moment there are 49 questions tagged with neutral-density, 34 with neutral-density-filter and 7 with both.

It doesn't look like we need both tags.

I don't know any use for the phrase "neutral density" besides that in the filters. There are neutral density filters for light sources to lower their power (if they cannot turned down lower), but they are also neutral density filters. Which suggests that only neutral-density-filter should stay.

But neutral-density is the more general term, so whatever else there is that has a neutral density, but is not a filter, would fit better into that tag. This tag has a tag wiki (which could be moved elsewhere). This suggests to keep only neutral-density.

Or should we keep both and make one a synonym to the other?

Answer 1

I think a tag synonym makes sense.

I'd say keep neutral-density-filter. If we kept neutral-density, then people would be tempted to tag questions with neutral-density and filter, which we're saying is probably redundant. Keeping filter in the tag would make that less tempting?

Answer 2

(Bit late to this party, but here's my 2p)

I think a filters category is useful in it's own right without a need for having filter repeated in the tags. I don't think the repetition would present a serious problem. But we should probably look at a wider tag review of all the similar tags...

• [polarizer] x 75
• [neutral-density] x 49
• [neutral-density-filter] x 34
• [nd-filter] x 9
• [graduated-filters] x 8
• [starbursts] x 5
• [skylight] x 3
• [close-up-filter] x 1

From this [neutral-density] would seem to be the more popular option and would be in line with the most commonly used of the filter tags.

There are probably a few more that I missed, but we're pretty inconsistent right now so it would be nice to fix it.

Answer 3

TL;DR: the tag should include the noun (i.e., [neutral-density-filter] or [nd-filter])

I believe tag ontologies should consist of nouns, not adjectives. For example, the camera-specific tags. Should we have [canon], [nikon], and a bunch of [1200d], [3ds], [d800], [d5100], etc.? Using (and ostensibly, sorting) those sub-tags is a bit more difficult than if they were [canon-1200d], [nikon-d800], etc. (albeit, slightly more annoying to type).

If the tags are economized on the repeated word such that we use [filters] and [neutral-density], then do we also have [graduated] that can be applied in conjunction with the ND tag? So if I want to see the questions about GND filters, I have to click on [graduated], which from a user interface perspective, seem kinda weird.

And of course, we should consider the [variable] ND filters. I'd have to click on the [variable] tag, which seems really weird. Just seeing a tag list, the word "variable" doesn't seem to belong to the concept of filters. It could apply to all sorts of other things, depending on my mindset when searching or browsing the taglist. But [variable-nd-filter] is clear and unambiguous. (BTW, the current [variable-nd] just sucks, IMO.)

As an aside, ontologies are hard. There are no absolute right or wrong ways to sort these kinds of things out. But on the margin, there are better and worse ways. Considering how tags are used, applied, presented, etc., on Stack Exchange, we can guide ourselves to less-suboptimal solutions. We can only apply 5 tags to posts. If we eliminate the common words in the tags, questions about variable ND filters or graduated ND filters would require 3 tags just to properly minimally tag it, leaving only 2 other tag slots for context. Thus, for the hypothetical "How can I use graduated ND filters to improve a panoramic landscape scene shot using HDR?" question (it doesn't exist, oh how I wish it did for this example), I need six tags: [filters], [graduated], [neutral-density], [panorama], [landscape], [hdr], but I can only apply 5. Which one gets the axe? But if we had [graduated-nd-filters], I would only require 4 tags, leaving me the luxury to apply [overtagged] or something more appropriate. =)

Answer 4

Weirdly, I can actually see a case for [neutral-density] and [neutral-density-filters] coexisting, and making a distinction. The neutral-density-filters tag being for physical lens ND filters, while neutral-density could capture ND gels for flash use and digital GND filters in post-processing, which are different subjects, but still fall under neutral density.

We'd have to edit the HELL out of the tag wikis, though and probably do a lot of tag cleanup and enforcing in the future. as this isn't exactly intuitive.