Considering building something from the wreckage of a Kodak 66
I'm making an ultra- long-range laser rangefinder as a personal project and need a very small spot size, and small FOV, for the reciever to reduce background light. I am using a small (40um) pinhole to limit the FOV of the receiver. Unfortunately (I believe) spherical aberration in the lens will increase the effective FOV of the system so I need to try to limit this.
I am a little horrified at how expensive aspheric lenses are so I'm hoping I can get away with an achromatic doublet. I don't really have the funds to try both given all the other bits I need. These are the two lenses I'm considering:
this aspheric,50mm diameter, 100mm FL, NA 0.24
this acrhomat, 50mm diameter, 200mm FL, NA 0.12
Note that the focal length is much larger in the achromatic lens, this is desirable as it reduces the FOV and increases SNR. There don't seem to be any aspheric lenses with similarly low numerical apertures. Given the rather low NA of the achromatic lens, would there really be much advantage to choosing the asphere? The Thorlabs application/performance info tabs seem to think that a very small spot size (3um) is achievable with a similar setup (10mm beam focused by 50mm FL lens to 3um spot, NA of 0.1). Could I also expect similar performance with the achromatic doublet, meaning spherical aberration is basically not relevant?
Edit. Another question. Edmond optics have a similar achromatic lens but it states the design wavelength is 587.6nm. My laser is 905nm. Would this have any impact on the spherical aberration, or other performance metrics of the lens?
Edit 2. See sketch of optical layout here
That is all. I will retire from my soap box for the evening.
Wow seems like only yesterday we were starting a flair post for you, u/ColorlessMurakami, but it's actually only been 29 since you started!
And already you are bleached no more as we colour you in a brilliant burnished Bronze for 100 Thank Yous and thank you for being so bighearted.
I'm not complaining, I personally love achromacy. But the 90's were vibrant and colourful, now everything is muted, gray, sterile and almost dystopian. Why is following this colour scheme associated with being more "modern" and why is it preferred by everyone?
Some examples: McDonald's, PlayStation logo Nickelodeon building
Hi there! My parents bought an HP OfficeJet Pro 6978 a couple years ago and I’m only just now using it to (try to) print decent quality images. Obviously the printer isn’t anything high quality for images, as the colors aren’t consistent. But they’re pretty easy to adjust- except for browns and blacks/greys. They are horrifically dull and dark. I’ve tried manually adjusting their brightness and saturation, but it doesn’t turn out anywhere close to the original colors. I am using a CMYK image/file and have printed from both my iPad Air (procreate and Google drive) and my PC (photoshop on an ASUS laptop/Windows 10). I’m trying to print out okay quality images for stickers, and those specific colors won’t look alright for the life of me. I’ve tried researching for similar issues and haven’t found any. I’ve also printed a quality report and there isn’t any issues.
https://ibb.co/pPNGmkG
Does anyone know how to delete/edit out the purple star halos that you get on photos when you use an achromatic refractor? How can I prevent them in the future using the same scope?
Four years ago I did an AMA here and since the community has grown I've opted to do another.
Basic information:
I have a retinal disorder called Achromatopsia, which is a disorder that has a variety of common features that usually affects all of us. For me those include total colorblindness, strong photosensitivity, and degenerative vision.
Achromatopsia is generally considered a genetic disorder however myself and about 400 other individuals present without the genetic component. Essentially this means that the cause of my disorder is unknown.
I'll spare the explanation of what rods and cones do since I'm confident everyone here is probably aware. Long story short, my cones don't work, and one of my ocular nerves doesn't seem to function properly.
Yes I can drive, as long as I wear special glasses that filter light. They're kind of like laser goggles in that they eliminate the shortest wavelengths of light.
I have never seen any color. My world exists in black, white, and shades of grey. As a side point, I can't distinguish any more than 30ish shades of grey.
The most common question I get asked is about traffic lights. Traffic lights are fine unless they don't have a background that lets me distinguish positions at night (the reflective backing). I don't generally drive at night because artificial lights from other cars and buildings can distort my vision.
Since this sub is rather slow paced I'll be checking occasionally over the next few days.
Ask Me almost (let's be reasonable) Anything!
