Actually, this consensus about Photoshop exists in web development industry, where size does matter (as well as quality), especially in bulk amounts. When it's about compression or downsampling to screen resolution, Photoshop is not the proper tool (which doesn't mean people can't think it's accepta...

Indeed, there are many different techniques to fight banding on gradients. But in general case, Photoshop is not recommended for JPEG compression anyway. It has only a few settings. Free software such as GIMP or IrfanView (with Save for Web plugin) gives you better control over chroma subsampling an...

Okay, let me explain it one more time. Assume, we have one constant current driver and several LEDs. I'll use n variable for number of LEDs. Each LED has its nominal current I and nominal voltage U . To be able to vary number of LEDs, we need to connect them in series (plus lead of any next LED conn...

Chris, I understand your concerns about high voltage. But let me explain the options of this situation. Using constant current driver with LEDs connected in parallel makes voltage as low as single LED requires (about 30 Volts). But in the same time, if driver (or any other type of power supply) does...

Yes, this Mean Well driver seems to be good for your needs. I'd say, that six LEDs will be maximum number for it - seven is just a bit above its capabilities. But keep in mind, that six LEDs of this type are roughly equivalent to ~300Watt incandescent lamp. That's very large amount of light, suitabl...

While I don't know, which LED Lee is going to use, but from his posts here I've got these parameters (maybe, I'm misinterpreting it): Inom=350mA Unom=26.7V If that's correct, and there should be four LEDs, it's easy to find several models of LED drivers, suitable for this setup. Exelsys LXD42-0350SW...

All kinds of lab equipment can be more or less reliable. More expensive brands are usually better in terms of precision, thermal stability, quality of parts used there. For example, cheap capacitors can not stand high temperature, even if they are labeled as high temperature resistant. Sometimes, ch...

leekekhuan, there is at least one offer on eBay, Extech 382260 80W used power supply in good condition. If you are concerned about price, you can probably go for LED drivers instead of power supplies. They are way cheaper. You can drive LEDs in series and in parallel. In series, current should be eq...

Honestly, if I would be thinking about lab power supply, I'd try to look for used one in good condition. Starting from, say, Extech brand, which is from lower league, but it's better than "backyard team".

Technically, LEDs should be fed in constant current mode (and I don't know if this PSU actually supports it - it does have corresponding indicators, but operation manual doesn't tell how to set this mode). Here is some sort of review of Korad 3000-series PSU, just in case. http://www.eevblog.com/for...

Yes, 35W LED with collimator lens projects significant amount of infrared radiation onto the specimen. That's why I'm going to experiment with heat mirror. Theoretically, I can use flash, but for certain applications (shooting outdoor in really bad lighting conditions) I need continuous light. And n...

Another test.

Same setup with this light at 50mm distance from the specimen, 30 stack frames, light was on for about four seconds during each exposure. Temperature of specimen (piece of moss) increased by about 15-17ºC

Thank you. It was about 50-55mm far.

Example of stack, produced using this light.
Custom white balance (about 3100K), 1/320 exposure, 28 frames, no active cooling was used (light was on for short periods only).

Threntepohlia sp. algae

Another portion of test results. Light source was set at ~50mm distance from the object. To make light spot smaller, I put some noname aspherical plano-convex lens in front of it. (Its thickness is almost equal to its radius.) Used 58mm f5.6 lens with bellows to achieve 2-3x magnification. Sensitivi...