20
votes
Raw photo for scientific purpose. How to set white reference to defined numeric L*a*b value?
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 ...
- 3,033
11
votes
Accepted
Raw photo for scientific purpose. How to set white reference to defined numeric L*a*b value?
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 ...
- 1,217
11
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Does a long exposure in DSLR camera have a similar effect to a global shutter?
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 ...
- 1,340
8
votes
Does a long exposure in DSLR camera have a similar effect to a global shutter?
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 ...
- 176k
7
votes
Why are mid-day images dull?
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 &...
- 23.4k
5
votes
What tiny lens to shorten the focus on a tiny camera?
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 ...
- 5,069
4
votes
Accepted
Why are mid-day images dull?
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. ...
- 18.8k
4
votes
How to optimize detection of brightness changes in an immovable object?
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 ...
- 176k
4
votes
What tiny lens to shorten the focus on a tiny camera?
You might be able to wrap the 100mm focusing distance around the object with mirrors.
- 8,544
4
votes
Accepted
What tiny lens to shorten the focus on a tiny camera?
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 ...
- 39.5k
3
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What tiny lens to shorten the focus on a tiny camera?
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 ...
- 1,153
3
votes
Does a long exposure in DSLR camera have a similar effect to a global shutter?
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 ...
- 5,069
3
votes
How to calculate the distance of an object in a photo?
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 ...
- 33.2k
2
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How to calculate the distance of an object in a photo?
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 ...
- 12.9k
2
votes
Calibrating monitor with lab spectrometer
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,...
- 5,602
2
votes
Does a long exposure in DSLR camera have a similar effect to a global shutter?
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 ...
- 121
2
votes
Does a long exposure in DSLR camera have a similar effect to a global shutter?
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 ...
- 9,739
2
votes
Color regrading/correction/calibration between photos for scientific color analysis using in-image palette
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 ...
- 133
2
votes
Accepted
Color regrading/correction/calibration between photos for scientific color analysis using in-image palette
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 ...
- 176k
2
votes
How Schlieren Photography can be done using mobile camera?
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 ...
- 5,069
2
votes
Organize photos for many overlapping projects
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:
...
- 2,330
1
vote
How to shoot in enclosed spaces with reflective surface without any reflection and have a good quality image
If they can be dyed:
Color them with with a dye that fluoresces in blue light.
Illuminate the wind tunnel with blue light (if blue LED strips are not available, put blue cellophane filters over the ...
- 2,651
1
vote
How to shoot in enclosed spaces with reflective surface without any reflection and have a good quality image
What you want is for the ceiling and walls to be white, and the lights to be installed on the floor with a baffle to keep them from shining directly onto the reflective sticky surface.
When ...
- 18.8k
1
vote
Color regrading/correction/calibration between photos for scientific color analysis using in-image palette
I think you need to define what your null hypothesis is, to help guide you on making a robust test (and think what may mess with the results)
I would suggest taking a bunch images with a printed scale ...
- 880
1
vote
Organize photos for many overlapping projects
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.
...
- 27k
1
vote
How to optimize detection of brightness changes in an immovable object?
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 ...
- 8,544
1
vote
How to get Canon 1200D quantum efficency plot?
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 ...
- 176k
1
vote
How can I connect a cheap digital camera to my 1960s spectrometers?
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 ...
- 27k
1
vote
Accepted
How can I connect a cheap digital camera to my 1960s spectrometers?
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 ...
- 3,033
1
vote
Accepted
What settings should I use on a webcam to get accurate light intensity measurements?
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 ...
- 3,912
Only top scored, non community-wiki answers of a minimum length are eligible