Search found 165 matches

by Bushman.K
Fri Feb 05, 2016 2:24 pm
Forum: Frequently Asked Questions (FAQs)
Topic: FAQ: Assessment of empty magnification using GIMP
Replies: 13
Views: 10600

Rik, I did not recommend doing auto levels as a final step of the procedure - it is only an enhanced illustration of what that 1-pixel scale layer contains. Doing auto adjustment of levels only helps to see what is there, and user's next step is to think about what he sees. He makes a decision, if "...
by Bushman.K
Thu Feb 04, 2016 4:10 pm
Forum: Frequently Asked Questions (FAQs)
Topic: FAQ: Assessment of empty magnification using GIMP
Replies: 13
Views: 10600

Rik, It is not that kind of interpolation Malcolm was talking about, as I understand that. Or at least, it is the same interpolation every digital photo has, regardless of optical system, since almost every camera has Bayer pattern and so on. But, say, regular camera objective, brought too far from ...
by Bushman.K
Thu Feb 04, 2016 3:17 pm
Forum: Frequently Asked Questions (FAQs)
Topic: FAQ: Assessment of empty magnification using GIMP
Replies: 13
Views: 10600

Malcolm, Nature of digital photographic image, obtained using current technology, will always leave something in smallest scale level. I didn't tell anything about "clear-cut" image - it is completely impossible at least because there always be noise, different artifacts and so on. This method doesn...
by Bushman.K
Tue Feb 02, 2016 10:49 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Super-resolution from small sensors?
Replies: 15
Views: 4704

How about trying AutoStakkert! 2?
by Bushman.K
Tue Feb 02, 2016 9:47 am
Forum: Equipment Discussions
Topic: LED choice for video using microscope
Replies: 23
Views: 2567

To be more precise, in case of digital photography, only amount of photons converted into electrons by sensor channels does matter. Therefore, any weighted parameters, depending on human eye (luminous flux) or wavelength, are distorting the picture of situation.
by Bushman.K
Mon Feb 01, 2016 6:38 pm
Forum: Equipment Discussions
Topic: LED choice for video using microscope
Replies: 23
Views: 2567

In case of LEDs with their uneven spectrum, usage of term "color temperature" is a bit "forced". Also, luminous flux is a parameter, that is normalized to human eye. Therefore, these parameters are partially irrelevant to digital photography. When speaking about human vision, we need weighted parame...
by Bushman.K
Mon Feb 01, 2016 10:54 am
Forum: Equipment Discussions
Topic: LED choice for video using microscope
Replies: 23
Views: 2567

I am wondering if the article should be read with caution--the camera he used has a Bayer filter (2 green, 1 red, 1 blue in a block pattern). Cameras with different kinds of sensor designs (eg a stacked sensor such as Foveon) may not behave the same way. This article should not be taken as universa...
by Bushman.K
Mon Feb 01, 2016 10:51 am
Forum: Equipment Discussions
Topic: LED choice for video using microscope
Replies: 23
Views: 2567

Andy, I wouldn't be so sure about "14-bit processing" in general case - for example, it is well-known fact, that Panasonic GH3 and GH4 cameras have different sensor readout bit depth in the same mode to achieve higher speed on GH4. It's just up to manufacturer. So, that should be a subject of test t...
by Bushman.K
Sun Jan 31, 2016 8:21 pm
Forum: Equipment Discussions
Topic: LED choice for video using microscope
Replies: 23
Views: 2567

And here is an article on the same topic, but written from a bit different point of view - regular photography with daylight (high CRI and high color temperature light source). It gives certain illustrations of histograms without suppressed green and with it. In case of LEDs, we don't need to suppre...
by Bushman.K
Sun Jan 31, 2016 8:13 pm
Forum: Equipment Discussions
Topic: LED choice for video using microscope
Replies: 23
Views: 2567

Asha , that is exactly why I'm talking about the hidden issues of compensation. For example, here we can see an example of uneven spectral response of each channel of Sony CMOS sensor (see Figure 2). Same amount of photons, reached sensor surface, produces least signal in Blue channel, a bit larger...
by Bushman.K
Sun Jan 31, 2016 4:40 pm
Forum: Equipment Discussions
Topic: LED choice for video using microscope
Replies: 23
Views: 2567

Here is some small detail which is usually missed. Camera sensor channels have different quantum efficiency. Therefore, excess of light in certain spectral ranges can be compensated by lack of sensitivity and otherwise. So, higher CRI by itself works better for human eye, which has much wider dynami...
by Bushman.K
Sat Jan 30, 2016 3:16 pm
Forum: Equipment Discussions
Topic: LED choice for video using microscope
Replies: 23
Views: 2567

User zzffnn uses 40W Cree light, described in this topic to take videos of aquatic organisms and results seem to be quite successful.
by Bushman.K
Sat Jan 23, 2016 7:12 pm
Forum: Equipment Discussions
Topic: Bridgelux Vero 18 LED high CRI light
Replies: 22
Views: 5264

Several fresh examples of photos taken with this light: https://c2.staticflickr.com/2/1600/23920389894_bf2d93c3fa_c.jpg Tortula truncata moss https://c2.staticflickr.com/2/1666/24444844755_34d6f72d66_c.jpg Plagiomnium insigne moss https://c2.staticflickr.com/2/1534/23679219633_660873337b_c.jpg Plagi...
by Bushman.K
Fri Jan 22, 2016 11:41 am
Forum: Equipment Discussions
Topic: High CRI LED source?
Replies: 14
Views: 6170

Curiosity would cost at least $40 for a candelabra lamp and even more for more usable products. There is a chance for surprisingly good specs. But personally, I wouldn't invest more than ten bucks in testing, keeping in mind, how small that chance is.
by Bushman.K
Thu Jan 21, 2016 10:17 am
Forum: Equipment Discussions
Topic: High CRI LED source?
Replies: 14
Views: 6170

My statement could be "misleading" only in case when it's taken out of context. You can go to any major electronic components store such as Digikey and do a parametric search. Setting CRI 98 and CRI 98 (Typical) parameters as a requirement will narrow your results to LED Engin brand and 2700-3000K c...