Thread: A bit more about optics

I'm surprised at the amount of colour fringing/chromatic aberration in the Kenko example image. I think optics with good lens coatings are an aid in viewing the very edge of the blade.

Bob

Kenko doesn't have coating. And it's not a glass optic - acrylyc lenses.
Actually, chinese CN Scope (review) has coated glass lenses but it's still dark a bit. Darker than Mikko 30x (glass, no coating, a bit less magnification - just a bit).
And still uncomparable with peak 2008-50.

But _good_ lens coating definitely helps And a good optic with no CA(or very low) makes easier to view the edge.

Originally Posted by Botanic

Kenko doesn't have coating. And it's not a glass optic - acrylyc lenses.
Actually, chinese CN Scope (review) has coated glass lenses but it's still dark a bit. Darker than Mikko 30x (glass, no coating, a bit less magnification - just a bit).
And still uncomparable with peak 2008-50.

But _good_ lens coating definitely helps And a good optic with no CA(or very low) makes easier to view the edge.

Yup, the Kenko not having lens coatings would explain that. Using the right type of plastic in lens making is not necessarily a drawback consider some of the successful hybrid aspheric lenses that have been made. The "right" lens coatings should not necessarily make the lens any darker than a none coated lens if the right type of glass is used in the lens.

All in all a low powered loupe with the right type of glass in well ground lens elements with good lens coatings is about all you need for most honing purposes. Unfortunately the best of those are not inexpensive. You also get to the point of rapidly diminishing return on the money spent too as in if you can't see the difference in performance there is none and the extra cost is a waste.

Bob

Originally Posted by BobH

Using the right type of plastic in lens making is not necessarily a drawback consider some of the successful hybrid aspheric lenses that have been made.

yes. But I haven't met any good variants with PMMA optic if we are talknig about microscopes.
Kenko, Carson - it's just acceptable level, not more.
Noname chinese and near that(Kingmax, Bresser, ..) - are not better. Still sometimes acceptable (and also if you are a lucky one) but only for extra low money ways.

Loupes - that is another field.
Actually for 1000-2000 jis grit sharpening even chinese "30x" "triplet" with mud and pieces of paper in lences - is enought.
But if you want to save health of your eyes - it's better to think about something better, like Belomo.
And Eschenbach PMMA mobilux economy (official site)
Is near the same level.
For small details(<20mkm.), if you hate haziness and if you want to enjoy the process - Peak Steinheil would be better.
Schneider is the best but it's too expensive and it's overkill.
But if your sharpening frequency is about twice in a year and optic control takes about a couple of moments - it's not so important.

I have heard of lots of acquisition disorders: razors (RAD), soaps (SAD), hones (HAD), etc. but this is the first time I have known of people with MAD: Magnifier Acquisition Disorder. That might become the next big thing in straight razor shaving. The posts are quite interesting and informative.

Originally Posted by RayClem

....
MAD: Magnifier Acquisition Disorder.

and i think MAD is the best name for this, because prices aren't good
(see Swiss Axe Triplet Hawk link -- i wish to unseen this pokemon -- better to collect eschers).
...
Wait a minute..SAD? Sounds like a new hobby
mad sad had in all its manifestations

I love seeing magnified pictures of a straight razors edge as it get honed progressively on finer and finer grit stones. What’s the best magnifying system for that?

About chinese triplets
Chinese loupe named "triplet"(left) and normal triplet(right)


So it's not a 30x or 20x - it's about 10x.
and it's not a triplet in real - just a monocle system.
+ there is no CA correction like normal triplets have
+ no distortion correction