Diffuse & Uniform Dome Lights for Machine Vision - what is a dome light

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Photon quantities are also common. They are related to the radiometric quantities by the relationship Qp = hc/l where Qp is the energy of a photon at wavelength l , h is Planck’s constant and c is the velocity of light. At a wavelength of 1 mm, there are approximately 5×1018 photons per second in a watt. Conversely, also at 1 mm, 1 photon has an energy of 2×10–19 joules (watt-sec). Common units include sec–1-m–2-sr–1 for photon radiance.

The Fujifilm X-T50 is a mid-range 40MP APS-C mirrorless camera that has image stabilization, subject recognition AF and a host of high-res video features. We've put it to the test.

If you use the X3 in 4K single-lens mode (i.e. like a GoPro) they you could use it for handheld photos/video... although I agree that to get the full use of a 360 camera like the X3... a stick is important

I think I’m almost more upset that part of the 1EV gap is achieved by varying the ISO setting instead of the actual exposure. If at least it was an actual whole stop, the 9 shots would cover 8 stops + native dynamic range, but 1/5s to 1/134s as in my test is just 4.7 stops instead of 8.

Radiometry is the measurement of optical radiation, which is electromagnetic radiation within the frequency range between 3×1011 and 3×1016 Hz. This range corresponds to wavelengths between 0.01 and 1000 micrometres (m m), and includes the regions commonly called the ultraviolet, the visible and the infrared. Two out of many typical units encountered are watts/m2 and photons/sec-steradian.

Background: It all started over a century ago. An organization called the General Conference on Weights and Measures (CGPM) was formed by a diplomatic treaty called the Metre Convention. This treaty was signed in 1875 in Paris by representatives from 17 nations (including the USA). There are now 48 member nations. Also formed were the International Committee for Weights and Measures (CIPM) and the International Bureau of Weights and Measures (BIPM). The CIPM, along with a number of sub-committees, suggests modifications to the CGPM. In our arena, the subcommittee is the CCPR, Consultative Committee on Photometry and Radiometry. The BIPM is the physical facility responsible for dissemination of standards, the international metrology institute.

We know from the definition of the candela that there are 683 lumens per watt at a frequency of 540THz, which is 555 nm (in vacuum or air). This is the wavelength that corresponds to the maximum spectral responsivity of the human eye. The conversion from watts to lumens at any other wavelength involves the product of the power (watts) and the V(l) value at the wavelength of interest. As an example, we can compare laser pointers at 670 nm and 635 nm. At 670 nm, V(l) is 0.032 and a 5 mW laser has 0.005WŨ0.032Ũ683 lm/W = 0.11 lumens. At 635 nm, V(l) is 0.217 and a 5 mW laser has 0.005WŨ0.217Ũ683 lm/W = 0.74 lumens. The shorter wavelength (635 nm) laser pointer will create a spot that is almost 7 times as bright as the longer wavelength (670 nm) laser (assuming the same beam diameter).

Illuminance is another SI derived quantity which denotes luminous flux density . It has a special name, lux, and is lumens per square metre, or lm/m2. The symbol is Ev. Most light meters measure this quantity, as it is of great importance in illuminating engineering. The IESNA Lighting Handbook has some sixteen pages of recommended illuminances for various activities and locales, ranging from morgues to museums. Typical values range from 100 000 lx for direct sunlight to 20-50 lx for hospital corridors at night.

Me too. I just have one major problem with mine in that it automatically shuts down when trying to take video in cold weather. I bought it as an action body cam for skiing... same happened a month ago when I was riding my bike around after a hailstorm. Might have to upgrade since it’s been 4+ years.

Radiometric units can be divided into two conceptual areas: those having to do with power or energy, and those that are geometric in nature. The first two are:

Both plane angles and solid angles are dimensionless quantities, and they can lead to confusion when attempting dimensional analysis.

Edit: no, not for this purpose. I also got 9 raw files but all of them were taken at 1/25s ISO 324, at which settings the highlights were blown.)

where Xv is a luminous term, Xl is the corresponding spectral radiant term, and V(l) is the photopic spectral luminous efficiency function. For X, we can pair luminous flux (lm) and spectral power (W/nm), luminous intensity (cd) and spectral radiant intensity (W/sr-nm), illuminance (lx) and spectral irradiance (W/m2-nm), or luminance (cd/m2) and spectral radiance (W/m2-sr-nm). This equation represents a weighting, wavelength by wavelength, of the radiant spectral term by the visual response at that wavelength. The constant Km is a scaling factor, the maximum spectral luminous efficiency for photopic vision, 683 lm/W. The wavelength limits can be set to restrict the integration to only those wavelengths where the product of the spectral term Xl and V(l) is non-zero. Practically, this means we only need integrate from 360 to 830 nm, limits specified by the CIE V(l) table. Since this V(l) function is defined by a table of empirical values, it is best to do the integration numerically. Use of the Gaussian equation given above is only an approximation. I compared the Gaussian equation with the tabulated data using blackbody curves and found the differences to be less than 1% for temperatures between 1500K and >20000K. This result is acceptable for smooth curves, but don’t try it for narrow wavelength sources, like LEDs.

After sorting out some initial issues I managed to do a quick test about the AEB capabilities of this X3 camera.I regret to inform you that it is crippled. The AEB is done thru the HDR mode.The user doesn't have control of ISO, apparently it is fixed to ISO289 :(ISO289 is too high to capture light sources and highlights !User can pick the number of exposures (up to 9) and the EV increments between shots but even for 9 shots it is capped to 1EV gaps, or 2EV for 5 exposures, so never to exceeds 4EV plus and minus, 8EV in total.On top of that, in HDR mode, the resolution is limited to 18MP and it can not be saved in Raw format. :(

Insta360 has announced a new 360-degree action camera, the Insta360 X3. The X3 features new 48MP image sensors and a 2.29" touchscreen. Insta360 says it's 'the most powerful camera you can carry in your pocket.'

If a source is not isotropic, the relationship between candelas and lumens is empirical. A fundamental method used to determine the total flux (lumens) is to measure the luminous intensity (candelas) in many directions using a goniophotometer, and then numerically integrate over the entire sphere. Later on, we can use this “calibrated” lamp as a reference in an integrating sphere for routine measurements of luminous flux.

The X3 incorporates a six-axis gyroscope and utilizes Insta360's FlowState stabilization to keep your video stable. There's a 360-degree Horizon Lock that keeps the horizon level even when you completely rotate the camera.

If you want a compact camera that produces great quality photos without the hassle of changing lenses, there are plenty of choices available for every budget. Read on to find out which portable enthusiast compacts are our favorites.

This AEB is an undocumented function that probably came with a firmware update , back when the OneX was released I was looking for AEB.It would be safe to assume that the newer X3 will have it as well, hidden under the HDR function.Thanks for letting me know.I’d be buying one for sure now.Insta360 documentarion sucks. No user manual to download.

1 lambert = (1/p) cd/cm2 = (104/p) cd/m2 1 apostilb = (1/p) cd/m2 1 foot-lambert = (1/p) cd/ft2 = 3.426 cd/m2 1 millilambert = (10/p) cd/m2 1 skot = 1 milliblondel = (10-3/p) cd/m2

Lomography claims its new Lomo'Instant Wide Glass camera, which includes a ~35mm full-frame equivalent lens, is great for portraits and editorial shots.

I can choose the number of shots among 3, 5, 7, 9; as well as the EV gap among ±0.3, ±0.6, ±1.0; but it seems to count the ISO setting in the gap, so the range of actual focal plane exposures does not end up as wide as it would seem to imply. (In this test, shutter speeds varied between 1/5s and 1/134s.)

We don't usually test a product for ten years before reviewing it, but after a decade of using the Lowepro Photo Sport 300 AW II on an almost daily basis, Managing Editor Dale Baskin tells us why he loves this pack.

Or one that actually shows any evidence of the manufacturer caring about stills image quality as more than just an afterthought.

1EV steps as the largest option? Seriously? That's just a waste of storage space and bandwidth given that there's easily much more than 3EV dynamic range per shot. 2-3EV steps is far more useful/makes far more sense.

The current definition was adopted because of several reasons. First, the freezing point of platinum (ŧ 2042K) was tied to another base unit, the kelvin. If the best estimate of this point were changed, it would then impact the candela. The uncertainty of the thermodynamic temperature of this fixed point created an unacceptable uncertainty in the value of the candela. Second, the realization of the Pt blackbody was extraordinarily difficult; only a few were ever built. Third, if the temperature were slightly off, possibly because of temperature gradients or contamination, the freezing point might change or the temperature of the cavity might differ. The sensitivity of the candela to a slight change in temperature is significant. At a wavelength 555 nm, a change in temperature of only 1K results in a luminance change approaching 1%. Fourth, the relative spectral radiance of blackbody radiation changes drastically (some three orders of magnitude) over the visible range. Finally, recent advances in radiometry offered a host of new possibilities for the realization of the candela.

The abbreviation for the radian is rad. Since there are 2p radians in a circle, the conversion between degrees and radians is 1 rad = (180/p) degrees.

NOTE: Because of the limitations of HTML, a “clean” version of this document in format (without live links) is available. The PDF file is occasionally revised and corrected, the HTML file may not be. Click here to download the PDF file.

What’s the best camera for around $1500? These midrange cameras should have capable autofocus systems, lots of direct controls and the latest sensors offering great image quality. We recommend our favorite options.

Photato Why are 3 shots not enough? When I shoot for HDR I don't use more than 3. Even small sensor should be decent enough to have 10 stops in single shot, then add 2 EVs on both sides and you have your 14 stops.

Older X2 has AEB, so I assume X3 has it too. You'll need a bit complicated workflow to stitch all the bracketed images together, especially dng's, and combine them in equirectangular 2:1

The QooCam 8K has been out a long time and people do get amazing results, although they seem to have a number of issues (too many for me). It would seem someone should have done a more solid 8k model by now.Group:https://www.facebook.com/groups/1401187323381005Images:https://kuula.co/profile/murino69

I just hate bringing any kind of "stick" when I travel, which is almost mandatory for 360 cameras. With any other camera including the gopro you can just shoot handheld no problem.

In order to convert a source with non-monochromatic spectral distribution to a luminous quantity, the situation is decidedly more complex. We must know the spectral nature of the source, because it is used in an equation of the form:

The solid angle is thus ratio of the spherical area to the square of the radius. The spherical area is a projection of the object of interest onto a unit sphere, and the solid angle is the surface area of that projection. If we divide the surface area of a sphere by the square of its radius, we find that there are 4p steradians of solid angle in a sphere. One hemisphere has 2p steradians.

The original OneX had RAW, but Insta360 didn't even bother to read the DNG spec and properly populate the color matrix metadata (lots of 360 camera manufacturers botch this).

Some other quantities (examples include spectral transmittance, spectral reflectance, spectral responsivity, etc.) vary with wavelength but are not used as derivative quantities. These quantities should not be integrated over wavelength; they are only weighting functions, to be included with the above derivative quantities. To distinguish them from the derivative quantities, they are denoted by a parenthetical wavelength, i.e. Â(l) or t(l).

The ratio of the radiant exitance (W/m2) to the radiance (W/m2-sr) of a lambertian surface is a factor of p and not 2p . We integrate radiance over a hemisphere, and find that the presence of the factor of cos(q) in the definition of radiance gives us this interesting result. It is not intuitive, as we know that there are 2p steradians in a hemisphere.

An Auto Exposure Bracketing function with the option of up to 7 exposures in Raw.They have no idea how useful this could be to create Spherical HDRI files for computer graphics and many other use cases.What a disappointment. :(

It is beyond irritating that a 360 camera like this doesn't have not even a basic Exposure Bracketing mode.A simple software function, which most normal cameras have !I own the X1 and have been waiting patiently for a AEB function ever since...

A few companies did this with semi-reasonably priced devices (TECHE, Labpano Pilot One, what was the name of that company that lasted maybe a year and was a spinoff of Ricoh or something?) where they had four sensors and instead of the circle being fit to the "narrow" dimension of a non-square sensor, it was fit to the "long" dimension.

We caught up with a few product managers and engineers at Adobe Max, and talked with them about the new features in the company's photo editing suite.

Papers published in recent issues of the NIST Journal of Research are available on the web in PDF format. Of particular interest is “The NIST Detector-Based Luminous Intensity Scale,” Vol. 101, page 109 (1996), which you can download now in PDF format.

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As far as I can tell, the One X2 has such a function (HDR & Night Shot). I would be surprised if the X3 doesn’t have it anymore.

The EOS R5 Mark II supercharges what the EOS R5 offered, boosted by a host of features shared with the flagship EOS R1. We've been shooting with it extensively to get a sense for what benefits those upgrades bring.

What’s the best camera for around $2000? This price point gives you access to some of the most all-round capable cameras available. Excellent image quality, powerful autofocus and great looking video are the least you can expect. We've picked the models that really stand out.

I received the X3 today, it took more than a week to arrive since these are being shipped from China. They won't tell you!I bought it through the Insta360 store. Taxes were included but Ilater the bank charged me after the fact a $13 foreign transaction fee !Unfortunately, there has been issues after issues.Currently I'm stuck in a loop.It won't let me use it, unless I register the device with them through the App.But I can't get to use the App until I upgrade the firmware.But I can't get to upgrade the firmware since it is failing when reaching 10%.And tech support is not online now. GrrrrThis sucks !!

More 5k complaints:https://www.dpreview.com/forums/post/66326653https://www.reddit.com/r/youtube/comments/w1973m/5k_2880p_option_removed_on_all_new_videos_since_1/https://www.reddit.com/r/gopro/comments/w88xkx/uploaded_a_video_shot_by_gopro_10_at_5k_to/https://www.reddit.com/r/gopro/comments/w2rrtg/hero10_5k_videos_uploaded_on_youtube_are_only/

Irradiance (a.k.a. flux density) is another SI derived unit and is measured in W/m2. Irradiance is power per unit area incident from all directions in a hemisphere onto a surface that coincides with the base of that hemisphere. A similar quantity is radiant exitance, which is power per unit area leaving a surface into a hemisphere whose base is that surface. The symbol for irradiance is E and the symbol for radiant exitance is M. Irradiance (or radiant exitance) is the derivative of power with respect to area, dF /dA. The integral of irradiance or radiant exitance over area is power.

The second class was designed to “simplify” characterization of light reflected from diffuse surfaces by including in the definitions the concept of a perfect diffuse reflector (lambertian, reflectance r = 1). If one unit of illuminance falls upon this hypothetical reflector, then 1 unit of luminance is reflected. The perfect diffuse reflector emits 1/p units of luminance per unit illuminance. If the reflectance is r, then the luminance is r times the illuminance. Consequently, these units all have a factor of (1/p) built in.

'With the X series, we are reinventing the point-and-shoot camera to make it easier for anyone to be a creator. X3 is built to help the next generation of creators take their creativity to new heights,' said JK Liu, founder of Insta360.

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The RF 24mm F1.4 L VCM and RF 50mm F1.4 L VCM are part of Canon's new 'hybrid' series of lenses designed to work with both EOS and Cinema EOS cameras.

Adobe's continued working on its Content Credentials system. We sat down with the head of the initiative to discuss new developments and its future.

The candela was formerly defined as the luminous intensity, in the perpendicular direction, of a surface of 1/600 000 square metre of a black body at the temperature of freezing platinum under a pressure of 101 325 newtons per square metre. This earlier definition was initially adopted in 1946 and later modified by the 13th CGPM (1967). It was abrogated in 1979 and replaced by the current definition.

The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540Ũ1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.

“One steradian (sr) is the solid angle that, having its vertex in the center of a sphere, cuts off an area on the surface of the sphere equal to that of a square with sides of length equal to the radius of the sphere.”

The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540×1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.

Photometry is the measurement of light, which is defined as electromagnetic radiation which is detectable by the human eye. It is thus restricted to the wavelength range from about 360 to 830 nanometers (nm; 1000 nm = 1 µm). Photometry is just like radiometry except that everything is weighted by the spectral response of the eye. Visual photometry uses the eye as a comparison detector, while physical photometry uses either optical radiation detectors constructed to mimic the spectral response of the eye, or spectroradiometry coupled with appropriate calculations to do the eye response weighting. Typical photometric units include lumens, lux, candelas, and a host of other bizarre ones.

Canon has announced the latest lens in its EOS VR System. It's intended to be an affordable way for social media content creators to experiment with new media formats.

Insta360 gap cam

'I just hate bringing any kind of "stick" when I travel, which is almost mandatory for 360 cameras. With any other camera including the gopro you can just shoot handheld no problem.'

What is agap cam

Just bought one online in the hopes it has AEB for photos.It is already #1 in Amazon in their category and B&H doesn't have them in-stock currently.Will clarify here since I couldn't find the AEB feature in any of the reviews nor the official documentation.

“The radian is the plane angle between two radii of a circle that cuts off on the circumference an arc equal in length to the radius.”

Energy is an SI derived unit, measured in joules (J). The recommended symbol for energy is Q. An acceptable alternate is W.

Adobe's Frame.io is now officially integrated with Lightroom, which could open up some new possibilities for photographers with supported cameras.

The Insta360 X3 is compatible with iOS and Android mobile devices. The mobile app includes AI technology to automatically select your best footage and apply edits. You can compile highlight videos and apply more than 30 special effects to your content. There's also a desktop version for improved controls and editing performance.

Rods: The rods are responsible for dark-adapted vision, with no color information and poor resolution when compared to the foveal cones. The dark-adapted relative spectral response of the eye is called the spectral luminous efficiency function for scotopic vision, V’(l). This is another empirical curve, adopted by the CIE in 1951. It is defined between 380 nm and 780 nm. The V’(l) curve has a peak of unity at 507 nm, and decreases to levels below 10–3 at about 380 and 645 nm. The 50% points are near 455 nm and 550 nm. This scotopic curve can also be fit with a Gaussian, although the fit is not quite as good as the photopic curve. My best fit is

Additional workflow features include BLE 5.0 Bluetooth, WiFi, a USB Type-C port for charging, and 48 kHz audio recording via stereo mics. The camera weighs 180g (6.35 oz.), and its dimensions (W x H x D) are 114 x 46 x 33.1 mm (4.5 x 1.8 x 1.3"). The new 2.29" touchscreen is covered with tempered glass and the camera includes four directional buttons so you can use the camera even while wearing gloves. The X3 includes a new, larger 1800mAh battery that can record 81 minutes of 5.7K/30p video. The camera's shutter speed range is 120s to 1/8000s and it includes +/- 4 EV of exposure compensation. The ISO range is 100-3200.

All you ever wanted to know about the SI is contained at BIPM and at NIST. Available publications (highly recommended) include:

3 exposures are not enough to create clean Radiance files for IBL, that is, image based illumination of 3D computer rendered scenes which normally need from 5 to 7 bracketed exposures at 2 EV intervals.This is a pretty standard requirement to create such files, is not my opinion.

Radiant intensity is another SI derived unit and is measured in W/sr. Intensity is power per unit solid angle. The symbol is I. Intensity is the derivative of power with respect to solid angle, dF /dw . The integral of radiant intensity over solid angle is power.

The theme for our November Editors' photo challenge is 'Fog'. Show us your favorite fog photos for a chance to be featured in our winners' gallery later this month. This challenge is open to photos taken at any time.

@spider-mario - I don't understand why in the world all of these 360 camera manufacturers insist on obscenely close bracket spacing. It's one of the many examples of the 360 industry being full of head-scratchingly dumb decisions, with capabilities inferior to what basic entry-level non-3D cameras have had for a decade or more.

I have to say I am a fan of insta360. Interestingly not because of its absolute IM quality, but its compact size. Besides of regular camera, I also need portable and 360 camera to shoot photo and video in special high speed situation, such as cycling event on car even on my EUC. I also have gopro fusion, which I think it has better image quality, a bit heavy though, however it is changing now.

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The International Photography Hall of Fame and Museum has announced its 2024 class of inductees, a group that includes photographers, visionaries and historians.

P.P.S. 5K:https://www.youtube.com/watch?v=oEIDZj8w0IMUploaded at 5k but only 4k:https://www.youtube.com/watch?v=oaLXg0QqN7Y

1-inch 360RS I got months ago provides great video quality! But it is on the heavy side - usable on 3m stick, a bit ... concerning.

Canon's newest, non-extending 70-200mm F2.8 L zoom for RF-mount includes features aimed at both photo and video shooters. It also works with Canon's RF-mount 1.4x and 2x teleconverters.

US travel/adventure brand Aether Apparel has made a photographer-friendly waxed field jacket in conjunction with Leica. Is that something we need?

We have other photometric units (boy, do we have some strange ones). Photometric quantities should be reported in SI units as given above. However, the literature is filled with now obsolete terminology and we must be able to interpret it. So here are a few terms that have been used in the past.

Isotropic implies a spherical source that radiates the same in all directions, i.e., the intensity (W/sr) is the same in all directions. We often hear about an “isotropic point source.” There can be no such thing; because the energy density would have to be infinite. But a small, uniform sphere comes very close. The best example is a globular tungsten lamp with a milky white diffuse envelope, as used in dressing room lighting. From our vantage point, a distant star can be considered an isotropic point source.

This week we're taking a look at another batch of accessories, including fun ways to control Photoshop and Lightroom, and some retro-looking gear for the X-M5.

5k7 for 360 video doesn't work brilliantly, especially if you want to crop non-spherical video from it. Is it a price-point issue?

The Color Vision Lab at UCSD has an impressive collection of the data files, including V(l), V’(l), and some of the newer ones that you need to do this kind of work.

With the new Loop Recording mode, you can also use the Insta360 X3 as a dashcam. It continuously records video in this mode but only saves a set duration of recent recordings based on your selected settings so that you won't fill up your storage with useless footage. Speaking of storage, the camera saves to a microSD card.

The process of combining AEB shots has been streamlined for years now.Photoshop has had this function where you can generate a HDRI 32 image in seconds.The emergence of these 360 cameras made it even easier and more so if they have a proper AEB function.One thing is missing though, and is Dolby Vision/HDR10 for video which is a must for 360, IMO

This topic is currently of great importance to me inasmuch as I have a commission to prepare an authoritative chapter on these issues for the forthcoming “Handbook of Optics III.”

There is nothing in the SI definitions of the base or derived units concerning the eye response, so we have some flexibility in the choice of the weighting function. We can use a different spectral luminous efficacy curve, perhaps one of the newer ones. We can also make use of the equivalent curve for scotopic (dark-adapted) vision for studies at lower light levels. This V‘(l) curve has its own constant K‘m, the maximum spectral luminous efficiency for scotopic vision. K‘m is 1700 lm/W at the peak wavelength for scotopic vision (507 nm) and this value was deliberately chosen such that the absolute value of the scotopic curve at 555 nm coincides with the photopic curve, at the value 683 lm/W. Some workers are referring to “scotopic lumens”, a term which should be discouraged because of the potential for misunderstanding. In the future, we can also expect to see spectral weighting to represent the mesopic region.

Circular Fish Eye lenses are generally made to project an image circle within the sensor, so you end up with a crop of the total pixels to begin with.The quality is not there yet, but is good enough for certain use cases. The quality is far from what a regular cameras do, but the functionality of these 360 cameras make up for it in spades.Insta360 sells hogher quality cams with with 6 lenses like the $5,000 Pro2.

Wow are you sure ?My OneX produces 3, but nine sounds like overkill. It gives you the option to chose the EV gap between shots up to 4ev but as I said, only 3 exposures. I’d be happy with 7.If this is the case, then I might actually buy the 1” sensor model.Although the X3 might be a better choice if the image quality is good enough.Thanks for sharing !

Rea, M., ed. “Lighting Handbook: Reference and Application,” 8th edition, Illuminating Engineering Society of North America (1993).

Leica has confirmed the 'Camera to Cloud' Frame.io integration system will be added to the SL3 this year, and to selected mirrorless cameras thereafter.

When the manufacturers say they've created a camera for 'creators' or vloggers, that doesn't mean they've turned their back on photographers.

I've found with my X2 that 5.7K 360 cropped down to 1080p 16:9 is "acceptable" quality in daylight... but it the versatility, convenience and flexibility of post-capture stabilization and camera angles often makes up for the fact - particular for action sports or family videos where you don't have time to setup something more involved.

Insta360 has announced the Ace Pro 2, its newest action camera and successor to its Ace Pro model. It includes features like 8K video, dual AI processors, longer battery life and up to 120 seconds of video pre-capture.

Photometric quantities are already the result of an integration over wavelength. It therefore makes no sense to speak of spectral luminance or the like.

Now this, X3! I bought one immediately. I never had X1 or X2 myself so here we go. Insta360 gets better and I hope it keeps going!

DeCusatis, C., “Handbook of Applied Photometry.” AIP Press (1997). Authoritative, with pertinent chapters written by technical experts at BIPM, CIE and NIST. Skip chapter 4!

The comapny's bringing its latest chips to some of its most popular computers, and making its nano-texture display available on a laptop.

Most sources of optical radiation are spectrally dependent, and just radiance, intensity, etc. give no information about the distribution of these quantities over wavelength. Spectral quantities, like spectral radiance, spectral power, etc. are defined as the quotient of the quantity in an infinitesimal range of wavelength divided by that wavelength range. In other words, spectral quantities are derivative quantities, per unit wavelength, and have an additional (l –1) in their units. When integrated over wavelength they yield the total quantity. These spectral quantities are denoted by using a subscript l, e.g., Ll , El , Fl, and Il.

Thanks to the high-res image sensors, the camera records 5.7K 360-degree video with Active HDR and an Invisible Selfie Stick effect. As for still images, the camera captures 72MP and 18MP photos using its 6.7mm (35mm equivalent) F1.9 lens.

The International Commission on Weights and Measures (CGPM) has approved the use of the CIE V(l) and V‘(l) curves for determination of the value of photometric quantities of luminous sources.

The Fujifilm X-M5 is the company's latest APS-C mirrorless camera. Although it comes in at the budget end of the spectrum and is aimed at vloggers, it's built around the same X-Trans sensor as cameras like the X100V, X-T4, and X-Pro3.

Luminance should probably be included on the official list of derived SI quantities, but is not. It is analogous to radiance, differentiating the lumen with respect to both area and direction. It also has a special name, nit, and is cd/m2 or lm/m2-sr if you prefer. The symbol is Lv. It is most often used to characterize the “brightness ” of flat emitting or reflecting surfaces. A typical use would be the luminance of your laptop computer screen. They have between 100 and 250 nits, and the sunlight readable ones have more than 1000 nits. Typical CRT monitors have between 50 and 125 nits.

Power (a.k.a. radiant flux) is another SI derived unit. It is the derivative of energy with respect to time, dQ/dt, and the unit is the watt (W). The recommended symbol for power is F (the uppercase Greek letter phi). An acceptable alternate is P.

The value 683 lm/W was selected based upon the best measurements with existing platinum freezing point blackbodies. It has varied over time from 620 to nearly 700 lm/W, depending largely upon the assigned value of the freezing point of platinum. The value of 1/600 000 square metre was chosen to maintain consistency with prior standards. Note that neither the old nor the new definition say anything about the spectral response of the human eye. There are additional definitions that include the characteristics of the eye, but the base unit (candela) and those SI units derived from it are “eyeless.”

A lambertian sphere illuminated by a distant point source will display a radiance which is maximum at the surface where the local normal coincides with the incoming beam. The radiance will fall off with a cosine dependence to zero at the terminator. If the intensity (integrated radiance over area) is unity when viewing from the source, then the intensity when viewing from the side is 1/p . Think about this and consider whether or not our Moon is lambertian. I’ll have more to say about this at a later date in another place!

The first generation X1 is okay, but buggy - which is understandable, given the fact that high data rate dealing with panaroma in camera. X2 is quite good, portable with ok video quality, but still a bit behind the gopro. ONE is all right but still no big improve in video quality, and it is a bit heavy on a 3m stick.

Above $2500 cameras tend to become increasingly specialized, making it difficult to select a 'best' option. We case our eye over the options costing more than $2500 but less than $4000, to find the best all-rounder.

"5k7 for 360 video doesn't work brilliantly, especially if you want to crop non-spherical video from it. Is it a price-point issue?"

International organizations involved in the promulgation of SUN include the International Commission on Illumination (CIE), the International Union of Pure and Applied Physics (IUPAP), and the International Standards Organization (ISO). In the USA, the American National Standards Institute (ANSI) is the primary documentary (protocol) standards organization. Many other scientific and technical organizations publish recommendations concerning the use of SUN for their learned publications. Examples are the International Astronomical Union (IAU) and the American Institute of Physics (AIP).

Every Insta360 product since then has only talked about video capabilities when announced, making it nearly impossible to determine what photo capabilities have been added, if any. According to others, they still have nearly-useless exposure bracketing capabilities (for example, bracketing only at 1EV steps...). At least they save raw stills - so many 360 cameras do not and are JPEG-only!

Leica has announced the Q3 43, a variant of its full-frame fixed lens compact with a 43mm F2.0 normal lens. We've had the chance to use and test it, to produce an in-depth review.

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The symbol for solid angle is either w, the lowercase Greek letter omega, or W , the uppercase omega. I use w exclusively for solid angle, reserving W for the advanced concept of projected solid angle (w cosq ).

Also note that in the definition there is no specification for the spatial distribution of intensity. Luminous intensity, while often associated with an isotropic point source, is a valid specification for characterizing highly directional light sources such as spotlights and LEDs.

A faster sensor, improved autofocus and video see Nikon's third-gen mid-range full-framer go toe-to-toe against Canon's EOS R6 II and the Sony a7 IV. We feel its all-round ability lifts it to the top of the pile.

Radiance is the last SI derived unit we need and is measured in W/m2-sr. Radiance is power per unit projected area per unit solid angle. The symbol is L. Radiance is the derivative of power with respect to solid angle and projected area, dF /dw dA cos(q) where q is the angle between the surface normal and the specified direction. The integral of radiance over area and solid angle is power.

I agree though that it seems there is some issue with achieving good 8K (I've been waiting since that Kodak Pixpro 8K prototype at the end of 2017). The QooCam has 8K... but it underperforms for 8K. my guess is that it is a processor/heat/price issue.

The SI was adopted by the CGPM in 1960. It currently consists of seven base units and a larger number of derived units. The base units are a choice of seven well-defined units which by convention are regarded as independent. The seven are: metre, kilogram, second, ampere, kelvin, mole and candela. The derived units are those formed by various combinations of the base units.

A great deal of confusion concerns the use and misuse of the term intensity. Some folks use it for W/sr, some use it for W/m2 and others use it for W/m2-sr. It is quite clearly defined in the SI system, in the definition of the base unit of luminous intensity, the candela. Some attempt to justify alternate uses by adding adjectives like field or optical (used for W/m2) or specific (used for W/m2-sr), but this practice only adds to the confusion. The underlying concept is (quantity per unit solid angle). For an extended discussion, I wrote a paper entitled “Getting Intense on Intensity” for Metrologia (official journal of the BIPM) and a letter to OSA’s “Optics and Photonics News”. A modified version is available on the web.

One other issue before we press on. Since the candela is now defined in terms of other SI derived quantities, there is really no need to retain it as an SI base quantity. It remains so for reasons of history and continuity.

Ten years ago today, we reviewed the Panasonic GH4, the camera that signaled the beginning of the 4K revolution in DSLR and mirrorless cameras.

You can capture 360-degree or standard single-lens content. Using the 360-degree feature, users can record 5.7K footage at 24/25/30 fps. You can also record 4K video at up to 60 fps. In the single lens mode, the resolution tops out at 4K (24/25/30 fps), although 3.6K, 2.7K and 1080p resolutions can be shot at up to 60 fps. Video modes include standard, Active HDR, Timelapse, TimeShift, Bullet Time and Loop Recording. Active HDR is possible thanks to the new 48MP image sensors and uses an algorithm to stabilize action footage and minimize ghosting while expanding the visible dynamic range of your footage. 360 Timelapse is available at up to 8K resolution. As for Bullet Time, it's a Matrix-like effect made possible by swinging the camera over your head in a circle. In this special mode, you can shoot at 4K/120p and 3K/180p.

Effective technical communication demands a system of symbols, units and nomenclature (SUN) that is reasonably consistent and that has widespread acceptance. Such a system is the International System of Units (SI). There is no area where words are more important than radiometry and photometry. Unfortunately, the Lewis Carroll quote seems to be the way things often work. This document is an attempt to provide necessary and correct to become conversant in this arena.

Like any good action camera, the X3 is rugged and durable. The camera is waterproof down to 10m (33') out of the box. You can also add optional accessories to increase its durability, including lens guards for users who enjoy action sports.

"One thing is missing though, and is Dolby Vision/HDR10 for video which is a must for 360, IMO" - There's little to no infrastructure for DV/HDR10 for stills as it is, let alone 360.

They are basically the same as the radiometric units except that they are weighted for the spectral response of the human eye and have funny names. A few additional units have been introduced to deal with the amount of light reflected from diffuse (matte) surfaces. The symbols used are identical to those radiometric units, except that a subscript “v ” is added to denote “visual. “The following chart compares them.

Energy is the integral over time of power, and is used for integrating detectors and pulsed sources. Power is used for non-integrating detectors and continuous sources. Even though we patronize the power utility, what we are actually buying is energy in watt-hours.

Insta360 X3 is available to order now via Insta360 and Amazon. The camera is $449.99. Additional accessories like the lens guards, a cold shoe, mic adapter and Quick Reader are also available now. For more information, visit Insta360.

There is so much misinformation and conceptual confusion regarding photometry and radiometry, particularly on the WWW by a host of “authorities”, it is high time someone got it straight. So here it is, with links to the responsible agencies.

We know that the eye does not see all wavelengths equally. The eye has two general classes of photosensors, cones and rods.

“American National Standard Nomenclature and Definitions for Illuminating Engineering” ANSI Standard ANSI/IESNA RP-16 96 (1996).

Projected area is defined as the rectilinear projection of a surface of any shape onto a plane normal to the unit vector. The differential form is dAproj = cos(ß) dA where ß is the angle between the local surface normal and the line of sight. We can integrate over the (perceptible) surface area to get

P.S. The Images link in my original post isn't anything to do with me, just someone who posts a lot of QooCam pictures somewhere easy to see...

Also there's the issue that YouTube seem to have stopped doing 5k and now only do 4k and 8k... Recent 5k videos I've uploaded only get processed to 4k, while older ones are still available in 5k (this affects GoPro Hero 9/10 and 5k7-ish 360 camera users the most).

Wow. I was very impressed with the Insta360 Air (I have a little fleet of them), and Insta360 seems to be tweaking things to be better all the time. This looks pretty compelling as a waterproof action camera.

Photopic (light adapted cone) vision is active for luminances greater than 3 cd/m2. Scotopic (dark-adapted rod) vision is active for luminances lower than 0.01 cd/m2. In between, both rods and cones contribute in varying amounts, and in this range the vision is called mesopic. There are currently efforts under way to characterize the composite spectral response in the mesopic range for vision research at intermediate luminance levels.

Cones: The cones are responsible for light-adapted vision; they respond to color and have high resolution in the central foveal region. The light-adapted relative spectral response of the eye is called the spectral luminous efficiency function for photopic vision, V(l). This empirical curve, first adopted by the International Commission on Illumination (CIE) in 1924, has a peak of unity at 555 nm, and decreases to levels below 10–5 at about 370 and 785 nm. The 50% points are near 510 nm and 610 nm, indicating that the curve is slightly skewed. The V(l) curve looks very much like a Gaussian function; in fact a Gaussian curve can easily be fit and is a good representation under some circumstances. I used a non-linear regression technique to obtain the following equation:

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More recent measurements have shown that the 1924 curve may not best represent typical human vision. It appears to underestimate the response at wavelengths shorter than 460 nm. Judd (1951), Vos (1978) and Stockman and Sharpe (1999) have made incremental advances in our knowledge of the photopic response.

The limitations of these dual sensor 360 cams is the lens, probably unlikely to get good IQ from small 180 deg lenses regardless of resolution . They could do quad sensors with narrower FOV but that would probably drive costs up.

The OneX and OneX2 HDR function create a finished tonemapped 8bit JPEG from 3 bracketed exposures, for which the user has little control, those are not true HDR images that keep the scene dynamic range.3 exposures are not enough to cover the 14 stops of Dynamic Range contained in certain scenes Which is a common ocurrence when capturing a 360 field of view.For true 32bit linear HDRI, you need 5 or 7 bracketed exposures separated by 2EV in Raw format.As I said, this is a simple software function that Insta360 should have in every camera they sell.I thought they might reserve this function for their top of the line models, but is absent in those as well. Grrrr !

The only real difference between radiometry and photometry is that radiometry includes the entire optical radiation spectrum, while photometry is limited to the visible spectrum as defined by the response of the eye. In my forty years of experience, photometry is more difficult to understand, primarily because of the arcane terminology, but is fairly easy to do, because of the limited wavelength range. Radiometry, on the other hand, is conceptually somewhat simpler, but is far more difficult to actually do.

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The lumen is an SI derived unit for luminous flux. The abbreviation is lm and the symbol is Fv. The lumen is derived from the candela and is the luminous flux emitted into unit solid angle (1 sr) by an isotropic point source having a luminous intensity of 1 candela. The lumen is the product of luminous intensity and solid angle, cd-sr. It is analogous to the unit of radiant flux (watt), differing only in the eye response weighting. If a light source is isotropic, the relationship between lumens and candelas is 1 cd = 4p lm. In other words, an isotropic source having a luminous intensity of 1 candela emits 4p lumens into space, which just happens to be 4p steradians. We can also state that 1 cd = 1 lm/sr, analogous to the equivalent radiometric definition.

We saw a lot of new things at Adobe Max 2024, and were able to demo some of the new features for Photoshop, Lightroom, Adobe Camera Raw, and more.

Lumens are what we get from the hardware store when we purchase a light bulb. We want a high number of lumens with a minimum of power consumption and a reasonable lifetime. Projection devices are also characterized by lumens to indicate how much luminous flux they can deliver to a screen.

Leica has announced it will make 250 platinum-plated film rangefinder kits to celebrate seven decades of its M-series cameras. Each will cost $22.995.

Plane angle and solid angle are two derived units in the SI system. The following definitions are taken from NIST SP811.

Now about converting from lumens to watts. The conversion from watts to lumens that we saw just above required that the spectral function Xl of the radiation be known over the spectral range from 360 to 830 nm, where V(l) is non-zero. Attempts to go in the other direction, from lumens to watts, are far more difficult. Since we are trying to back out a quantity that was weighted and placed inside of an integral, we must know the spectral function Xl of the radiation over the entire spectral range where the source emits, not just the visible. There are a few tricks which will have to wait for my forthcoming book chapter.

Why don't you like the stick for travel? Airline regulations/bulk? The latest shorter Insta360 stick is quite "handy" at 8.25 inches/22cm while extending to 27"/120cm. I find the stick makes it a lot easier dig the camera out my bag/backpack.

Lambertian refers to a flat radiating surface. It can be an active surface or a passive, reflective surface. Here the intensity falls off as the cosine of the observation angle with respect to the surface normal (Lambert’s law). The radiance (W/m2-sr) is independent of direction. A good example is a surface painted with a good “matte” or “flat” white paint. If it is uniformly illuminated, like from the sun, it appears equally bright from whatever direction you view it. Note that the flat radiating surface can be an elemental area of a curved surface.