Thread: A bit more about optics

Lead params



Sharpness, contrast, brightness.
(acrylyc optic isn't good here).
...
There could be a lot of params, but actually you can't understand is it good or not for you before use it in real.
Because even so respectable words like "glass optic lenses", "aplanat", "CA correction", "full coated lenses"
- could be just misprint. And quality of lenses doesn't depend on this words.
Sharpness, contrast, brightness - you can't see this in product description.
So all you can do - see it in real or searching for reviews etc.
Don't forget that when you buy in a store, you can check for defect can compare etc.

All helpful you can see in description:
- magnification power
- field of view (rare)
- diameter of lenses\ocular (rare, frequently wrong)
- weight

And if you wear glasses (-D) working distanse (between lenses and object) is shorter.

Buying at a store



You should think about:
- are lenses clean or not?
because items at a showcase can be smeared with fingers of previous buyers (almost always actually)
- is there enought light?
- what to see?
-- distortion
see a ruler, something with scale or just a simple list from note
-- CA
metallic ruller, razor edge or something with strong contrast like black letters on white paper
also bright ligth is needed
-- sharpness
something with small details
you should pay attention to contrast of contours\edges of small objects (grains, fibers)
note list - try to see fibers
silicon carbide stone or dark hued (not white) aluminium oxide stone like Naniwa Chosera ~ 800jis (20mkm)
If you see every grain separated - it's a good loupe.
But in common you will see something looks like more a mosaic where edges of grains are guessed but not distinguishable.
-- brightness, contrast

!Don't forget that your eyes can get tired. So you need to make a rest about every 10 min. +\-

So typically:

metalic ruler:

CA, distorion
-- field of view (effective)

note paper

distortion, details (fibers)
colorization

Sharpening stone 800 jis grit


Sharpness - small details, contrast

More primers there photo samples from loupes - review [RUS]
or there photo samples from loupes - gallery

Photos



In reviews ou can see a different quality of photo examples from microscopes and oth.
But you should know that it's not so representative as you think.
Because the image depends on:
- quality of the microscope
- quality of the camera
like noise, blooming, camera inner image processing
- focal lenght of lenses of the camera
- dirt on the lenses
- light (quality, angle, brightness, side illumination, glare)
- motion blur
- focusing mistakes
- the optical axis of the microscope is'nt aligned with the optical axis of the camera
that leads to distortion, loss of sharpness, brightness

So if you have enough exp. and compare samples from one camera and under the same conditions - it could give you some information.

This is my own personal view, I hone a hell of a lot of razors, and I do not want to see more than my 10X Belomo Triplet shows me, I fail to see what you are looking for that a 10X can't already tell you.

My personal problem in sharpening is burr that less 20mkm. in size. You won't see it looking through 10x loupe.
And I want to see as many details as possible. Just because of curiosity.

I can sharp well without microscope.
I can sharp without loupe.
I can just live somewhere and not to share photos with anybody.
-- there is no practical reason to do that, right?
And the only answer that is right - is 42.

About current observation - it's just like short time hobby.
Like 's been said: Magnifier Acquisition Disorder.
or
Like: "Wow! Everybody use 10x loupes when I still use 50x microscope - something is missing".
Actually, it's not only one question, but a couple of dozen like:
This loupe is cheaper - what i actually paid for?
This loupe is quite expensive - is there something speciall? Just brand?
Loupe 10x - does it really help more than 50x microscope? In what cases?
...
So it's not about something practical and rational.
Just a way to spend time. That could give useful results.
Just wanted to collect everything that I've learned during last 10 years about sharpening.
Actually optics in sharpening is just a part of my conspectus.
------------

I will try to finish loupe and microscope review in this month.

In the end there are so many variables at play when discussing optics and taking photos of edges in addition to the problem of correctly interpreting what you think you are seeing as to make it a waste of time for most people using a straight razor. All you really need is a decent quality loupe and the gained ability to correctly interpret what you are seeing through the loupe.

Bob

Originally Posted by BobH

In the end there are so many variables at play when discussing optics and taking photos of edges

not so many, actually.
Light, angle, reflectors, camera settings, blade fixation, methods of magnification - that's all.
+\- details like "using this method you should think about side lightning and how to block it".

It's not so difficult to take a good photo. When you know how.
Yup, it takes a time. And it's a waste of time in some way...

But it's not what i'm trying to say..to do in this theme.
I mean, this time all I want is just to provide some information about optics.
And I don't want to start a holywar
or to persuade someone to join to my church of "50x microscope advantage witnesses".
It's like your loupe is enought for you - this theme will be useless, sorry.
You want to buy something good - there is(will be) enought info for make a good buy due to your chose params.
Nothing to read at the weekends? - You are welcome.
etc.

As a prime: Belomo 10x loupe isn't cheapest one. You can buy chinese microscope "50x" (usually it has about 20x power in real) for only $5 that will give you the same level of information about bevel condition or even higher.
So should I say that ch.microscope is better than Belomo? No.
Because if you have a task, then you have params how task should be done --- and there is no such a thing like absolete truth for anyone and anycase.
imho


PS:

Originally Posted by BobH

All you really need is a decent quality loupe

some of my friends tried to learn me to use loupe but I think my eyes just not sharp as their
20mkm burr isn't visible directly - just fuzzy allusion of it like vague sensation that something is wrong with the edge.
And you can't see: is it mistake at bevel setting stage or it's a burr(steel problems) or it's a micro-chipping -- you need additional time to check it.
Especially if your fingers not so sensitive to provide you good info from nail test.
Especially if you are testing a new hone.

Main problem is that after seeing this fuzzy allusion I start trying to see details and it loads my eyes heavily - don't like this feeling when you are almost see something but vision isn't clear or sharp enought.
For me 50x microscope a lot easier to use for burr control and oth.
For macro-control I don't need a loupe at all.

So, is a 10x loupe enought?
- Sure. But microscope is better. For me at least.

Originally Posted by Botanic

and there is no such a thing like absolete truth for anyone and anycase.
imho


PS:

So, is a 10x loupe enought?
- Sure. But microscope is better. For me at least.

Yes, absolutely there is more than one way to skin a cat as they say. You have to use a method that is suitable to yourself as everyone is different. It also depends on what your ultimate goal is. In my case it is a sharp edge that gives me a smooth and comfortable shave, gets the job done in other words. I'll grant you it may not be and likely is not the ne plus ultra of edges but works just fine for me. OTH if you want a ne plus ultra edge you will have a different view of the method and equipment required.

Bob

Like anything else there is what you need and what you would like to have and there is overkill. You could buy an SEM and have the ultimate in viewing informational overload. Really good optics can get very expensive and most neither want to spend the money or need to. You can spend a reasonable amount and get a great 10x magnifier which will show all you need to see. Of course if you want to see the microbes on the edge of your razor you can do that too.

So the question for most is how much do you need to see to maintain an edge?