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20

Sounds a bit iffy to me... A card, by itself, DOESN'T have a fixed L*a*b* colour - that's a product of the reflectivity of the card at different wavelengths and the intensity and wavelength distribution of the illumination. In the dark, L* will be 0. Light it with a coloured light and your a*b* will change. Light it with a "white" light with a different ...


12

This frequently comes up in photographic reproduction jobs where one is trying to closely approximate some other object such as a painting antique drawing. This cannot be done with typical photographs even when adjusting them to a specific, matching, LAB color. Regular photographs increase color saturation and tailor contrast, boosting the midranges and ...


11

I think you've slightly misunderstood how the shutter works. Initially, the first shutter covers the sensor and the second does not. The first shutter then slides away to expose the sensor, and the second shutter follows it to cover the sensor again. The shutters always move at the same speed, regardless of the exposure time. For a short exposure, the ...


7

The example shot looks like it's suffering from two main issues. White balance is coming out very much on the blue side. When we think of 'sunny' we think of 'warm'. Humans equate orange with warm & blue with cold. It's over-exposed. The camera was presumably thinking the tree was the main subject & tried to deal with that. Unfortunately, cameras ...


7

Most DSLRs have shutter curtains that transit the face of the sensor in approximately 2-4 milliseconds. For any particular camera model, barring a mechanical malfunction, the transit time for each shutter curtain will always be the same, regardless of the exposure time. This is the case with shutter times anywhere from 1/8000 second, where the second curtain ...


4

Is this approach reasonable or am I missing something? You're making the mistaken assumption that consumer cameras, even those we call "pro-grade", intended for taking creative or documentary photographs are precise enough for what you are asking it to do. The EOS Rebel T5i is not a lab-grade instrument. Neither is the Canon EOS 1D X Mark II, the Nikon D5, ...


4

Lens bloom occurs due to light bending around a backlit object/subject. The distant trees are not backlit. Lens flare is caused by hard light directly hitting the lens elements, and looks different. The lens is in the shade. Increased contrast is the opposite of the issue here. Light does not have a resonance frequency as such. Objects have a resonance ...


3

It is still the same shutter, even in long exposure and pixels are not exposed simultaneously. However, the time difference (in relation to the total exposure time) becomes smaller as the exposure time increases. It might become insignificant depending on your requirements. If you cannot tolerate rolling shutter at all, you still have 2 options: use ...


3

You might be able to wrap the 100mm focusing distance around the object with mirrors.


3

You can mount a positive lens (convex) before the camera lens. Such a combination will allow close focusing. You can experiment using inexpensive reading glasses purchased from a drugstore. Yesterday I saw a display at my local dollar store. They were priced at $1.00. You can just hand hold them before your camera’s lens to test. The power of reading ...


3

Any converging lens will bring you closer to the target, you need to find a small magnifying glass or loupe (available online everywhere for a dollar or two). In fact, the conditions are equivalent to a human eye trying to focus at close distance. Test the lens by placing it between your eye and the subject, see if you can focus from 10-20mm. Small, good ...


3

This question is not so much about photography as it is about designing an experiment and the measurement of the experiment. I suggest doing what the Mythbusters do: build a measured board or sheet with distance marker lines or gridlines, as a "backdrop" right behind the ball. Another example, from Instructables.com


3

This is physically impossible. Without active amplification, the luminance of the image can not be more than the luminance of the subject. Otherwise you would be violating the second law of thermodynamics. If you try to focus the sun rays on a black body, it can get really hot, but not hotter than the surface of the sun itself. For a mathematical proof, read ...


2

Consider using a telescope-camera adapter. You can search your favorite auction site for "telescope camera adapter" along with the name of your camera or mount. Many come in two pieces. Telescope to T-mount. T-mount to camera mount. Here is a picture of a microscope adapter. It's the same concept, and works the same way.


2

You don't want a camera with a 2mm lens. you're not trying to use it like an eyepiece and get parallel light rays coming out of the back of the lens - you need something that will focus the image of the spectrum on the camera sensor. The normal way would be to use a standard microscope USB eyepiece camera without a lens, and adjust the focus of the ...


2

I would print a straight vertical line and attach it to a turntable set to 45rpm. IF you set up the camera so that the frame covers the centre to the edge of where the record goes you can then measure the effect by the bend in the straight line, and compare different cameras even if the focal length changes.


2

Your best bet to accurately determine the distance is to simply and directly use a regular measuring tape. Then there is no question about it. But if you know your cameras sensor size (size in both mm and pixels), and if you know its lens focal length (these are relatively difficult questions to find out for most small cameras), then there is a calculator ...


2

The straightforward method is to use the software unless you're a glutton for punishment and have lots of free time on your hands. :-) There's much more to monitor behavior than just the full-on red, green and blue response in isolation. A monitor's picture controls don't give you enough control to correct for what is often nonlinear behavior across all ...


2

Since you have a scientific background (I hope?) I'll use mathematics to describe why what you're saying is impossible. A camera only has 3 color filters--red, green, and blue. Obviously those three words are qualitative and not quantitative at all, but what is important that all color is multiplied by the spectral transmission function of those RGB filters ...


2

My question then is this: how should I best go about using an in-picture color palette to "match" colors between photographs? Any workflows I should look into or avoid? What other factors might I not be aware of that I should take into consideration for "scientific" color analysis? You'll probably never get the precision you need for ...


2

Yes, and you can even do schlieren photography using old and poor mobile phone camera. It's not rocket science, yet it requires some equipment not normally found in a typical houshold (or even professional photographic studio), unless you are the amateur astronomer. The key ingredient is spherical mirror, which can be obtained from a cheap newtonian ...


2

CMOS pixels are reset and then gather the cumulative charge from the light they receive until they are read & reset again. The CMOS is usually reset, the shutter process takes place (front curtain, delay, then rear curtain) and then values are read. Because of the mechanical process, there will always be a short period during the shutter opening/...


2

For the purpose you describe: Yes, all pixels are exposed simultaneously; they work independently, in parallel. Even for the short periods of time at start and finish, they're still all working together - but the shutter will need some time to get out of the way completely. So if a short event were to happen during the long exposure, what you will get is a ...


2

First step should be to conduct a detailed review of the data to establish solid project expectations so you can make these sort of decisions with confidence. Key thing we're looking to answer is: How much overlap can an image have between sub-projects? How much 'meta data' do we want to embed in the file structure vs an external storage/library file? How ...


1

Consider using hard links in multiple folders with different methods of organization, as xenoid comments. That way, you can use whatever method is most convenient to find the images you want. Organized by Date/location. YYYYMMDD (City, ST) Location - Description/YYYYMMDD-HHMMSS Description.jpg Organized by Taxonomy, as Stan ponders. Organized by Project. ...


1

I essentially abuse the camera as a photon counter. Keep in mind that you are using a consumer grade camera, not a measurement device. My main interest is to capture small changes in brightness or colour of the light diffracted by the object by comparing subsequent pictures. [...] My biggest concern is that the resulting exposure time is about ⅛ s If you ...


1

I've had good luck with molded plastic aspherical lens. Edmund Optics is an excellent source: https://www.edmundoptics.com/f/Precision-Molded-Aspheric-Lenses/14752/ They have lenses as small as 1 mm diameter although there are more options around 5 to 6mm.


1

Canon is not in the habit of releasing such information. The source of the data reflected in the chart at your link was measured by someone else. If you notice, in the lower right corner is the following text: Canon data © Christian Bull There are a few well known sources for independent measurements of camera sensor quantum efficiency. But most of them ...


1

So long as they're fixed it shouldn't matter very much, except for gamma correction which should probably (there are always edge cases) be set to 1. Gain and brightness should probably be low to reduce the dark count. You must fix the exposure time. If that's not an option the experiment won't work. Having done exactly this I'd urge you to calibrate (which ...


1

I would use a flash. The intensity of a flash and the extremely short light duration are unbeatable for sharp macro images. However what you want is GOOD flash illumination. What I have used in the past is a box made of white foam core board with a translucent window on one side and an off camera flash fired into the window on high power (although even half ...


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