Search found 2488 matches

by mawyatt
Tue Jun 30, 2015 6:49 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: My new high-power home-made "Focussing lights"
Replies: 13
Views: 3256

Mike - thanks for the analysis. I have vague recollections of that from the dim and distant past! Joy - some resonance (;)) there. I've found I've volunteered at a local school to help a biology teacher take on 13 year old girls with an electronics course. The tech stuff I can handle, there are boo...
by mawyatt
Tue Jun 30, 2015 6:44 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: My new high-power home-made "Focussing lights"
Replies: 13
Views: 3256

Thanks for all the technical info - I will keep it in mind for my next upgrade. Just for fun, I call myself a BSc Electrical Engineering Second Year (Failed) - way back in 1966 when LASERS were a gimmick no-one knew what to do with ! Joyful I am not far behind, got out of HS in 66. We used slide ru...
by mawyatt
Mon Jun 29, 2015 4:58 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: My new high-power home-made "Focussing lights"
Replies: 13
Views: 3256

Chris, Bipolar transistors are noted for this, the ratio of collector to base current called beta increases with temperature, it's called thermal runaway and is destructive if not limited. Most semiconductor junctions have a negative temperature coefficient, which as you indicated causes the LED On ...
by mawyatt
Mon Jun 29, 2015 6:38 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: My new high-power home-made "Focussing lights"
Replies: 13
Views: 3256

Re: My new high-power home-made "Focussing lights"

Very nice setup. Being an electrical engineer (IC designer) but not an LED expert, I would think the LED would operate better (safer and with less variation) when operated under constant current conditions rather than constant or somewhat constant voltage condition. An LED is basically a semiconduct...
by mawyatt
Sat Jun 06, 2015 3:14 pm
Forum: Equipment Discussions
Topic: APO-COMPONON 4.0/45 Fixed f4 Direct from Schneider for $250
Replies: 20
Views: 4279

Bob, These are very nice indeed. I am not familiar with this lens, so please excuse my questions. How do you think the sharpness & contrast would hold up from 2 to 6X, or higher, compared to the Mit inf. objectives? I think it might be nice to be able to control the magnification by moving the APO-C...
by mawyatt
Fri Jun 05, 2015 3:56 pm
Forum: Equipment Discussions
Topic: May I please get some help locating the parts for a 10x rig?
Replies: 20
Views: 4105

Saw some dudes building rigs that look like the price of sports cars, got a feeling despite my current technical understanding of how to build my own rails and whatnot that it'll be happening with the help of some engineering savvy friends. Just getting started LOL[/quote] Yeah I got bit by the Pors...
by mawyatt
Fri May 08, 2015 6:49 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: RW Hard Drive Head
Replies: 1
Views: 1042

RW Hard Drive Head

Following Steve's superb subject and images of the hard drive internals (see link below) I thought I might give this a try if I could find a scrap hard drive. We were physically destroying (grinding up platters) many of our older hard drives from our in-house computer network system, so I grabbed a ...
by mawyatt
Mon Apr 20, 2015 4:29 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Drill Chuck Key
Replies: 4
Views: 1137

Great shot Mike. That's a cool subject, makes one look around the house and shop for interesting things!!

Mike
by mawyatt
Wed Apr 15, 2015 10:50 am
Forum: Frequently Asked Questions (FAQs)
Topic: FAQ: What factors affect the speed of Zerene Stacker?
Replies: 3
Views: 6468

Rik,

I'll try some of these suggestions when I get home tonight. This is beginning to make me wonder if 32GB of DRAM is sufficient.

Thanks for the help,

Mike
by mawyatt
Wed Apr 15, 2015 8:35 am
Forum: Frequently Asked Questions (FAQs)
Topic: FAQ: What factors affect the speed of Zerene Stacker?
Replies: 3
Views: 6468

FAQ: What factors affect the speed of Zerene Stacker?

Rik, Chris, I am sure this has been answered somewhere but I couldn't find it, so my apology in advance. Does the hard drive R/W speed and latency have much to do with the overall speed of large number of stacks (200~500) with large individual TIFF images (110MB)? For example, how much improvement s...
by mawyatt
Tue Apr 14, 2015 8:35 am
Forum: Equipment Discussions
Topic: shutter cable on stackshot
Replies: 21
Views: 3491

Chris, I got a schematic from Cognisys that has a SBD diode in the switch. This was required to emulate the half press function on the D800 I recall. Cognisys sold me the diode (HP) and I got a cheap remote and wired the phono plug and diode into the switch. This was almost 3 years ago, so the D800 ...
by mawyatt
Tue Apr 14, 2015 7:39 am
Forum: Equipment Discussions
Topic: shutter cable on stackshot
Replies: 21
Views: 3491

It would seem to be much cheaper to get a "Chinese" remote shutter release and a standard connector from a local shop? You would need to solder a couple of wires.. This is what I did, I got a remote switch and wired in the RCA Phono Plug. For the D800 you will need to add a SBD diode. Check with St...
by mawyatt
Tue Apr 14, 2015 6:44 am
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Third-party Li-ion circuit board
Replies: 8
Views: 1211

Usually NiCd batteries are not soldered, they are spot welded. The spots are small and sometimes multiple with cooldown time in between. The stainless steel doesn't like to accept solder. and the batteries don't like the heat. Agree, but these NiCd batteries had the spot welded tabs but the other e...
by mawyatt
Mon Apr 13, 2015 5:08 pm
Forum: Technical and Studio Photography -- Macro and Close-up
Topic: Third-party Li-ion circuit board
Replies: 8
Views: 1211

Re: Third-party Li-ion circuit board

Mike, Many years ago I ran across a lot of NiCad batteries that had leaked due to overheating the terminals. Surprisingly, the best soldering method utilizes a large iron with lots of thermal mass to heat the terminal quickly. This keeps the heat from propagating into the battery terminal and breaki...
by mawyatt
Mon Apr 13, 2015 3:53 pm
Forum: Photography Through the Microscope
Topic: Intel Pentium I microprocessor
Replies: 6
Views: 2252

Re: Intel Pentium

Benjamin D, A metallurgical scope uses axial (epi-) illumination, so the light is coming down through the objective and then the image is returned back up through the objective to the eyepiece and/or camera. Even though a microprocessor may appear flat, it actually has some depth because the circui...