There are many instances of using a camera as a measuring device for real world height, or maybe as a photon counter, or something else entirely...but all not being concerned with producing a photograph per se.

Where do these questions belong? Where can we drive that traffic?

Stack Overflow? Artificial Intelligence?

This question, Camera image in pixel to real image in meters size relation, fits the bill for being off topic, yet the OP was directed here from SO. Is this a branding problem?


3 Answers 3


I would think it depends on what, exactly is being measured. For using a camera to measure dimensions of an object, geometry would probably be the best place. For counting photons, physics would probably be the place.

In the end it should be based on the purpose of the exercise, not the tools used.


Forgive me as I'm not a regular here, but,

This question [...] fits the bill for being off topic

According to your help center guidance, this site is the place to ask about:

  • using photographic equipment

Perhaps I'm just missing it, but the OP would benefit from describing how the relevant question is off-topic. As it stands, I feel this question's relies on a faulty premise (that the question is about a camera being used as a tool for [non]-photography).

The asker of the relevant question is asking whether various camera parts and their parameters can be reliably used to determine the real-world size of the image or object based on the size of the resulting photograph. The experts on various camera parts, their parameters, and how they relate to the real world seem obviously congregated in one place... Photography.SE, the site for "professional, enthusiast and amateur photographers"

Consider this other well-received question, which is quite similar: Can we measure size of an object using EXIF data from a photo?. Is it off-topic?

Also consider the existence of tags such as , , and . Are these tags off-topic and needing burnination?

If the answer is yes, then there's some work to be done to ensure the site remains clean of any unwanted content (starting with discussions by this community in the first place on whether to keep those tags and questions or whether it ought to consider them off-topic). If the answer is no, then it seems the question referenced in the OP here is just fine.

  • 1
    is asking whether various camera parts and their parameters can be reliably used to determine the real-world size. He's really not though. He's asking for a formula to calculate real world size of an object from an image. He's not asking how to use photo equipment either. As for the tags, the question doesn't fit with image-processing's description, physics is a junk tag with no q's or description (and IMO, should be deleted), and calculations intent is photo formulas required to make an image, not analyze it. Though, I think this should be cleaned up too
    – OnBreak.
    Mar 7, 2019 at 22:30
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    It's off topic because the intent is not in the pursuit of creating a photograph. It cannot be grouped into any of our main target categories: photography, photographic processing or retouching, using photographic equipment, techniques and best practices, history of photography, photography in society improving an aspect of a photograph.
    – OnBreak.
    Mar 7, 2019 at 22:33
  • @hueco As someone who regularly works with photography specifically for the purpose of extracting information and data, I'm kind of at a loss as to why you feel such questions don't fit under "techniques and best practices" - Your current stance would dismiss about 90% of my photographic work as 'Not Photography' basically on the grounds that you don't seem to believe it is included under an umbrella label of photography. So you can hopefully imagine why some of us are confused here. Mar 7, 2019 at 23:19
  • @Hueco Are you suggesting that all questions here must be in the pursuit of creating a photograph to be on-topic?
    – TylerH
    Mar 8, 2019 at 15:19
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    @TylerH indeed, I am. Any knowledge that would help you become a better photographer is on topic. Back to the example - determining a formula to calculate real world measurements from images does not, in any way, help you become a better shooter.
    – OnBreak.
    Mar 8, 2019 at 16:50
  • @TheLuckless and TylerH - This is my opinion, and some others. If you'd like to start a meta about it specifically, then please do as I'd like to discuss it more as it's own question. But, in a nutshell, yes - my belief is that this site should answer any and all questions that would help one become a better photographer. I don't think machine vision fits into this definition.
    – OnBreak.
    Mar 8, 2019 at 16:52
  • @Hueco That position seems directly at odds with your recent activity: photo.stackexchange.com/a/101576/62895, photo.stackexchange.com/a/94242/62895, photo.stackexchange.com/a/98613/62895, photo.stackexchange.com/questions/98921/…, etc. None of these questions are in pursuit of creating a photograph, but were all very highly received by the community (and all answered by you in the last year or so).
    – TylerH
    Mar 8, 2019 at 17:13
  • @Hueco Now, this second position "help you become a better photographer" is an entirely different one from your first "help you take/make a better photograph", but some well-received questions here do neither, it seems. My point, ultimately, is that perhaps the answer to your question is "point them nowhere; answer their question, instead, because it's about photography or the tools used in the practice of photography".
    – TylerH
    Mar 8, 2019 at 17:15
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    @TylerH it's funny that you pick those examples. There's a few people on this site that feel that the business running side of photography should be off topic. But, via meta discussion, questions specific to running a photography business are, for now, on topic. Also, help you become a better photographer and help you take/make a better photograph are complementary statements. Both are still leading to what I said is explicitly on topic: the creation of a photograph
    – OnBreak.
    Mar 8, 2019 at 17:55

As someone who has worked for over a decade in the field of technical photography for science and engineering, my view would be that such questions would be totally on topic for a general Photography question and answer pool.

"Photography Stack Exchange is for professional, enthusiast and amateur photographers.

If you have a question about … techniques and best practices"

To me would suggest that a high level discussion on how to tackle the photographic element of data capture and management of the images produced would logically fit within the realm of this exchange as it is currently being branded.

  • Define the methodology and establish how photography can be used to achieve a goal, and then break things out into sub-problems/questions for other exchanges as needed after they're properly identified from the photographic standpoint.

Unless the community wants to rebrand itself as something along the lines of "Fine Art Photography", and clearly exclude everything that isn't focused on 'making pretty pictures', then encouraging a broad base of questions related to the photographic field is important to making this a useful resource that actually covers the breadth of the field it claims to:

"I want to use photography to do X" ... "Answer you can use Y and Z from Math and Physics, see [these questions/answers in] Math and Physics for further details on how to implement this" seems far more useful and constructive than "Not our department, go away".

This stance would also cover issues like discussions of custom equipment to achieve a photographic goal. - If I have equipment related issues to getting some specific photo I'm after, then this seems like the logical place to define what equipment is needed to do the job, how it should work, etc, but then specific questions on making that equipment would be directed elsewhere.

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    I don't think this is fair. The request is not to restrict to "fine art photography", but "photography at all". The questions aren't "how to use photography to achieve this goal". They are "how can I use camera equipment to achieve this goal" — if anything, photography just gets in the way, because the actual answer is inevitably that the design decisions in these tools are oriented toward making photographs and therefore in the real world the desired outcome is not actually easy. If you want to measure something remotely, get a laser distance meter, not a camera.
    – mattdm
    Mar 9, 2019 at 20:35
  • As someone actually working in a field using photography for this sort of thing, I can assure you that photography is very much the proper tool for data collection... A laser distance meter is only going to offer you one measurement in one dimension at a time. Try using one to take a thousand distinct measurements in 1/100,000th of a second... all the arguments against technical photography questions I've seen have basically boiled down to "I don't understand/agree with it, therefore it can't be photography" Mar 9, 2019 at 20:57
  • My argument is simply: if it's not about producing images with light, it's not photography.
    – mattdm
    Mar 9, 2019 at 21:02
  • And your argument kills any discussion of working with photos or with gear. Skimming your profile and applying the test of "Is this about producing images", would flag the majority of your own posts as being off topic. Mar 9, 2019 at 21:21
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    Let me refer to my comment from an earlier discussion about this "If it's 90% engineering and photometrics, that scares away people interested in composition, lighting, storytelling, etc. That doesn't mean there can't be highly-technical questions; I'd just like to see that within the frame, as it were."
    – mattdm
    Mar 9, 2019 at 22:23
  • Another example here. It's a fine question, but the level of precision they're asking for is not typical of consumer devices meant for making photographs. We can answer that fine, but... the answer is still gonna be disappointment.
    – mattdm
    Mar 11, 2019 at 16:59

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