Search found 2488 matches

by mawyatt
Wed Mar 25, 2020 1:42 pm
Forum: Equipment Discussions
Topic: Building an LED light/flash
Replies: 92
Views: 7764

...We did a quick "hands on" test here that required 1.6 seconds exposure of a 220 lumen LED illumination for proper exposure, so for a 10ms exposure would require 35200 lumens... Hi Mike, How are you measuring lumens ? Hi Saul, This is from the specification on the light, then somewhat confirmed b...
by mawyatt
Wed Mar 25, 2020 7:58 am
Forum: Equipment Discussions
Topic: Building an LED light/flash
Replies: 92
Views: 7764

I think there are a lot of LED lights on the market are like this, no flickering even for high frame rate. Just be aware that some of the LED lights are over rated (like they use 60W LED but claim 100W, or 100W LEDs but claim 200W -- this is the funny part, they claim the extra power is due to refl...
by mawyatt
Tue Mar 24, 2020 7:19 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Sample density needed to resolve Rayleigh features
Replies: 40
Views: 5777

wpl. Disclaimer, I'm not a Signal Processing expert, nor Math expert. Just another quick look at the beginning of this and equation 7.2 seems like nothing more than the Discrete Inverse Fourier Transform of function f(ndelta), not sure why this is attributed to Shannon tho? Which seems strange becau...
by mawyatt
Mon Mar 23, 2020 4:56 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Sample density needed to resolve Rayleigh features
Replies: 40
Views: 5777

wpm,

Thanks for the link.

Just took a quick look at this.

What first struck me is that I believe the 1st equation 7.1 is incorrect, the Fourier transform equation has omitted the time domain function f(t) within the integral!!

I'll spend more time on it later.

Best,
by mawyatt
Sun Mar 22, 2020 12:04 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Sample density needed to resolve Rayleigh features
Replies: 40
Views: 5777

In our discussions here I would think black as a lack of photons, as pure black as no detectable photons. Not necessarily. Any levels of energy are OK as long as the receiver can differentiate them and knows the encoding/modulation rule used by the transmitter. Moreover, it can even be the other wa...
by mawyatt
Sun Mar 22, 2020 5:15 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Sample density needed to resolve Rayleigh features
Replies: 40
Views: 5777

A certain amount of information destined to a specific pixel is scattered over its neighboring pixels What I am having trouble with is the use of "information" where most physicists would say "energy". The energy in itself is not information, but it can carry information. Usually, the information i...
by mawyatt
Sat Mar 21, 2020 6:58 am
Forum: Equipment Discussions
Topic: shared reference silicon wafer for comparisons
Replies: 139
Views: 15013

Lothar,

Just received the surprise package in the mail.

Thanks so much!!

Best,

Mike
by mawyatt
Fri Mar 20, 2020 11:15 am
Forum: Equipment Discussions
Topic: Thorlabs ITL200 as tube lens&setup for Coolscan 8000ED l
Replies: 15
Views: 2292

Have you considered using a Z mount to 42 or 52mm adapter rather than the Nikon FTZ, then the F mount to SM2 (or 42 or 52mm) adapter? I don't use the FTZ for this type of macro use, but prefer the direct Z to 42 or 52mm adapters. However I don't have the really nice Thorlabs tube set, use the Weamc...
by mawyatt
Fri Mar 20, 2020 11:02 am
Forum: Equipment Discussions
Topic: Thorlabs ITL200 as tube lens&setup for Coolscan 8000ED l
Replies: 15
Views: 2292

I was pleasantly surprised at the little vignetting the Wemacro Lens Kit exhibited on my Nikon FF camera. This lens kit is based on 42mm tubes and has internal flocking. I think the exact post that you're referring to is this one: https://www.photomacrography.net/forum/viewtopic.php?p=255697#255697...
by mawyatt
Fri Mar 20, 2020 10:12 am
Forum: Equipment Discussions
Topic: Thorlabs ITL200 as tube lens&setup for Coolscan 8000ED l
Replies: 15
Views: 2292

Heads up for Canon shooters: Canon EF to SM2 adapter is likely going to appear on RAF camera inventory soon. For those using full frame that should eliminate vignetting, which M42 or T2 could cause. The flange distance should be identical to EF->M42 + Thorlabs M42->SM2. JKT, I was pleasantly surpri...
by mawyatt
Fri Mar 20, 2020 8:57 am
Forum: Equipment Discussions
Topic: Thorlabs ITL200 as tube lens&setup for Coolscan 8000ED l
Replies: 15
Views: 2292

You need adaptor for the ITL200 which has some oddball M38 threading: https://www.thorlabs.com/thorproduct.cfm?partnumber=SM2A20 For Mitutoyo, you can use Thorlabs SM2 > SM1 then SM1 > M26x0.706 That's what I use. https://www.thorlabs.com/thorproduct.cfm?partnumber=SM2A6 https://www.thorlabs.com/th...
by mawyatt
Thu Mar 19, 2020 8:37 am
Forum: Equipment Discussions
Topic: My new 1:1-1:4 LED studio rig
Replies: 5
Views: 4390

Nice setup and arrangement, seems easy access to things and to make adjustments. Really like the beautiful woodwork, miss the very old masterfully crafted wooden boxes that held precision instruments and devices. Now everything is plastic, or metal which works well but just doesn't have that special...
by mawyatt
Wed Mar 18, 2020 9:02 am
Forum: Equipment Discussions
Topic: Building an LED light/flash
Replies: 92
Views: 7764

The heatsink is cool and looks like a car engine manifold, hot rod LED COB!! Fans are usually a problem, here's a Godox 150watt 16,000 lumen Video Light where the fan is reported as too loud, so it's vibrating something. https://www.bhphotovideo.com/c/product/1342001-REG/godox_sl150w_5600k_150w_led....
by mawyatt
Wed Mar 18, 2020 8:50 am
Forum: Equipment Discussions
Topic: Dimmable LED/flash microscope illuminator
Replies: 23
Views: 8248

Saul, Another excellent combination of LED and Flash. As we've shown on another thread an LED, or LED COB simply can't compete with the Xeon flash tube in terms of short high energy optical bursts helpful for "freezing" vibration effects. 1ms seems about the limit for practical LED use, but you've s...
by mawyatt
Wed Mar 18, 2020 8:13 am
Forum: Equipment Discussions
Topic: Fast LED Strobe for Macro
Replies: 45
Views: 5707

Just did a quick "hands on" test for some "concrete" evidence regarding LEDs for flash use. The setup is a Nikon D850 at base ISO with Mitutoyo 5X and a single 220 lumen LED (IKEA LED) undiffused as the light source. Proper exposure required ~1.6 second shutter, so this would equal a LED with 1.6*22...