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Update: These are spectrometer adaptors. It has CCD inside so fall under photography of wavelength.

Is there any instruments in photography which has similar adaptors?

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assembled

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to be threaded to this 42mm male thread:

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Sets. I'm just asking about the right most ring (see above)

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Jtl
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  • What are those rings for? If you're asking about lens mounts, there are two 42mm mounts in common use. One is M42. The other is T-mount. – xiota Oct 11 '19 at 23:29
  • The ring on the far right looks like a Series VI filter holder ring. https://en.m.wikipedia.org/wiki/Photographic_filter#Series_filters – Mike Sowsun Oct 11 '19 at 23:42
  • please see edited post for detailed pics of each and assembled. The measurements were not in the series filters VI. Know which other accessories are similar to them? – Jtl Oct 12 '19 at 00:40
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    I'm voting to close this question as off-topic because spectrometry is not "photography of wavelengths". This isn't to be snippy — it's off topic because it's not I the expertise of the actual field of photography. – mattdm Oct 12 '19 at 02:16
  • I should have mentioned just "Photography". I was just asking if anyone recognize these adaptors used in photography too. – Jtl Oct 12 '19 at 02:53
  • "Is there any instruments in photography which has similar adaptors?" – All adapters look the same. All 42mm threaded tubes look the same. Have you tried Google? – xiota Oct 12 '19 at 03:27
  • Yes, but all of them has additional male thread besides the 42mm female thread. So I'm asking what kind of thread where there is only 42mm female thread without the male thread in it. – Jtl Oct 12 '19 at 03:29
  • What are you trying to accomplish? – xiota Oct 12 '19 at 03:40
  • I want to buy extra mounting ring because the supplier doesn't sell any extra. – Jtl Oct 12 '19 at 03:45
  • The best place to look for exotic thread adapters tends to be wherever astronomical equipment (telescopes etc.) are offered... though the prices can be astronomical too. – rackandboneman Oct 12 '19 at 20:16
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    Is your question "are these adapters used in spectroscopy also used for photography, potentially providing a cheaper way to get them"? – mattdm Oct 13 '19 at 00:12
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    It's been a month, but the point of @mattdm 's question is, perhaps the question you think you're asking, isn't really the base question at hand. I'm referring to the XY problem. – scottbb Nov 20 '19 at 03:49

1 Answers1

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I'm not sure if I understand specifically what question you are asking... but am willing to take two guesses.

  1. If you are asking how to attach these to a modern camera ... then it would be possible to do so provided these use T-threads. You can get an adapter called a "t-ring" which will have the t-threads or M42 threads on the front (so they adapters can thread on) and will have your camera model's bayonet type mount (e.g. Canon, Nikon, Sony, etc.) on the back-side so it will attach to the camera body.
  2. Another possibility is that you are asking if there are other adapters to do spectroscopy with a modern photographic camera. This gets a more nuanced answer.

Spectroscopy should not normally be done (unless it's for fun) with a modern color camera for two reasons (but I'll provide some info in a moment that will let you do this anyway).

  • In order for the spectra to be analyzed the camera should not be filtering the wavelengths of light being projected onto the sensor. But modern cameras do this. They have an internal filter that is meant to try to imitate the sensitivity of the human eye so that the colors you see in your photos will resemble the colors your eye saw when you took the photo. Human eyes are not equally sensitive across the spectrum. We are most sensitive to green (somewhere around 550nm) and a little less sensitive to blues (e.g. around 450nm) and much less sensitive to reds (around 650nm). Also we aren't very good at seeing UV or IR so the filters try to cut those wavelengths completely out.
  • A color camera has a color-filter-array (CFA) installed (usually a Bayer Matrix) and each of these filters further limits light sensitivity.

This means that if you use a normal digital camera for spectroscopy you will not get very accurate information. You would ideally want to use an unfiltered monochrome sensor camera (these are usually specialty cameras -- not made by the common brands familiar to most photographers).

But ... if you want to have a bit of fun, RSpec-Astro.com sells diffraction gratings, spacers, and software that would allow you to do spectroscopy using an ordinary color camera and a Windows PC.

I occasionally do spectroscopy demonstrations for students using special gas tubes (e.g. a tube filled with hydrogen gas... or a tube filled with neon gas, etc.) so students can see that the light is made up of specific wavelengths depending on the atoms involved. For hydrogen, the hydrogen-alpha wavelength is the most dominant wavelength in real life (~656nm) but if you do this with a normal color camera (with factory internal filters) you'll find the Ha wavelength is fairly weak and the H-beta wavelength appears to be stronger. The filtering of the camera gives a false impression of the relative strength of the various emission lines.

Tim Campbell
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  • what thread is this exactly? https://imagizer.imageshack.com/img922/8361/u5Lp2G.jpg Is it M42? I guess that's all I have to know.. because I don't know what kind of thread is it. – Jtl Oct 13 '19 at 00:22
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    @Jtl you'll need to measure the thread pitch. Both T-thread and M42 are 42mm diameter, but M42 has a 1mm thread pitch whereas T-thread has a .75mm thread pitch. See: https://en.wikipedia.org/wiki/T-mount – Tim Campbell Oct 13 '19 at 14:50
  • I measured thread pitch of 1.3mm, what kind of thread is that? – Jtl Oct 13 '19 at 23:20