Question: Microscope Stay in Focus

[Kicker]

I am a Stone setter and recently purchased a Meiji EMZ-5. when i work with vice under microscope some time i have to tilt my vice, then the working distance is change around 5mm to 1cm, so i have to refocus the scope every time that i tilt the vice and back to normal position.
My question is: is there any microscope tay in focus when working distance changed or any adjustment on the Meiji EMZ-5 to make it tay in focus when working distance changed ?:thinking:
Thanks in advance.

 

[Donny]

Kicker,

This can be found in the Tips Archive.....Helped me a bunch!!!

Proper User Set-up for Stereozoom Binocular Microscopes

1. Set cross-line target on stage. Best results are achieved with 0.0006" cross-line reticle of
30 mm diameter. Focus and center cross-line image at highest magnification setting.
(If no glass cross-line is available try making your own cross-line with a very fine pen.) It
may become obvious to you that your eyes must strain in order to focus on the center of
the very fine cross-line. Continue with the rest of this procedure.

* This eye strain effect may be the cause of user complaints and can be corrected by a LASER alignment performed at ACC’s facility.

2. If your microscope has dual diopter adjusters (one on each eyepiece tube) they should
both be set at the zero mark or line. If there is only one diopter adjuster, please see line #3.

3. Focus at highest magnification using the stand focus knob. “Best focus” preference
should be given to the fixed eyepiece side (usually under the right eyepiece). Do not
move the stand focus knob from here on.

4. If you have a fixed eyepiece -- Looking through the fixed eyepiece side check focus of the cross-line target image at lowest zoom magnification setting. The fixed eyepiece image should still be clear. If not, the scope needs other adjustments.

5. Focus the other eyepiece also at lowest magnification using the adjustable diopter
collar under the eyepiece itself (usually under the left eyepiece). Again, do not use
the stand focus knob. If dual diopters are available - each eyepiece should be
adjusted for best focus individually. Using a jewelers screwdriver, now set each diopter
adjuster to its zero mark. This will ensure that you will always be able to quickly reset
your scope to your best parfocal setting very quickly and easily even if other people use it.

6. Scope should now stay focused when going from high to low magnification
as long as the stand focus was set at highest magnification, and eyepieces were
focused correctly (and matched) at lowest magnification setting.

7. Recheck by setting scope at highest magnification, focus image using the stand knob then go to the lowest magnification. Both images should be clear. Use this procedure before starting your work under the microscope at the beginning of each day or after someone else has adjusted your microscope.

** Once this procedure has been completed, the diopter adjuster(s) should not be moved.

Hope it works for you!!!

Donny

 

[Beathard]

This is a good explanation of how to setup a microscope, but it does not answer the question. I am also interested in the answer. The question is how to keep the piece in the focused area when tilting the block or how to increase the depth of field.

 

[airamp]

Hi All,

Well the problem you discribe is really two problems. I will asume you set up the scope properly (see Donny's post below).

First problem is that the scope is like a camera without the F stops. You cannot adjust the depth of field, but you can adjust the magnification.

So the lower the magnification the more depth of field you will have. (just the way the scope works).

The bigger problem, since you cannot adjust the depth of field in a scope (or buy a very very expensive scope) is the height of your vice and the work in the vise.

The higher the pivot point on the vise (higher the work) the easier it is to go outside the scopes depth of field. (5 inch ball, 6 inch ball's plus the jaws plus the work piece your pivot angle is very small to stay in focus since the depth of field is small.

I found that the only vise that stays in focus when tilting (or should I say the best vise) is a Ken Hurst designed Dovetail low profile vise.

I do have one and it is really amazing in that the ball part of the vise is almost 9 inches (8.6") and it was made so only about 1/3 of the ball is in the base.
( I hope that explains it well enough for you to picture it). The jaws are lower and therefore the pivot point is almost in the center of the ball.

Tilting this vise while in focus does not make the piece go out of focus. (I am sure you can get it out of focus (out of the depth of field with high mag. but you would have to tilt it quite a bit from what I have found.

Maybe you can make a bowling ball vise (seen in other posts) and cut the ball so you only use 1/3 of it to mount your clamping devise for your work??:thinking:

Or you can get in line for one of these great vises.

Ellis Sawyer is the shop that Ken was trying to help when he developed this vise and since the first run of them they have not been avalible as of yet.

My original post on the vise.
There is no comparison to the Hurst/Sayer Low profile Vise. (Now called the Dovetail vise).

I have one and it is just great.

Low profile so your microscope is lower (less neck strain).

Heavy so it can be used for H&C, Power tools or anything else you can think of....

As Steve said it stays in focus under the scope when you have to tilt it (like for undercutting a groove for a inlay). (This feature alone makes it stand out from all other vises).

It was designed by Ken Hurst and with the help of others to be the most universal vise around.

It has very smooth rotation and has a friction adjustment for setting drag of the rotation to your liking.

The adjustable jaws (from center) make it a positioning vise but personally the turntable under this vise works better than any positioning vise since you have a much larger range for off center.

In a dovetail (hardened and ground) will hold the jaws in position without any noticable ware for a few lifetimes.

For the price you cannot beat this vise for quality, versitility, stability, and being the best vise for working under a microscope.

I would buy it again in a heartbeat.

Just put one on order with Steve and he will let you know when it ships. Most of us had to wait 6-8 months for the first ones so a few weeks should be no big deal.

You would be glad you did..

Link to order and wait in line:

http://www.airgraver.com/Engraving_Blocks.htm

AirAmp

 

[Kicker]

I did setup my scope to stay in focus when the magnification changed but not the working distance changed, my question is how to setup the microscope to stay in focus when the working distance changed.

Kicker,

This can be found in the Tips Archive.....Helped me a bunch!!!

Proper User Set-up for Stereozoom Binocular Microscopes

1. Set cross-line target on stage. Best results are achieved with 0.0006" cross-line reticle of
30 mm diameter. Focus and center cross-line image at highest magnification setting.
(If no glass cross-line is available try making your own cross-line with a very fine pen.) It
may become obvious to you that your eyes must strain in order to focus on the center of
the very fine cross-line. Continue with the rest of this procedure.

* This eye strain effect may be the cause of user complaints and can be corrected by a LASER alignment performed at ACC’s facility.

2. If your microscope has dual diopter adjusters (one on each eyepiece tube) they should
both be set at the zero mark or line. If there is only one diopter adjuster, please see line #3.

3. Focus at highest magnification using the stand focus knob. “Best focusâ€￾ preference
should be given to the fixed eyepiece side (usually under the right eyepiece). Do not
move the stand focus knob from here on.

4. If you have a fixed eyepiece -- Looking through the fixed eyepiece side check focus of the cross-line target image at lowest zoom magnification setting. The fixed eyepiece image should still be clear. If not, the scope needs other adjustments.

5. Focus the other eyepiece also at lowest magnification using the adjustable diopter
collar under the eyepiece itself (usually under the left eyepiece). Again, do not use
the stand focus knob. If dual diopters are available - each eyepiece should be
adjusted for best focus individually. Using a jewelers screwdriver, now set each diopter
adjuster to its zero mark. This will ensure that you will always be able to quickly reset
your scope to your best parfocal setting very quickly and easily even if other people use it.

6. Scope should now stay focused when going from high to low magnification
as long as the stand focus was set at highest magnification, and eyepieces were
focused correctly (and matched) at lowest magnification setting.

7. Recheck by setting scope at highest magnification, focus image using the stand knob then go to the lowest magnification. Both images should be clear. Use this procedure before starting your work under the microscope at the beginning of each day or after someone else has adjusted your microscope.

** Once this procedure has been completed, the diopter adjuster(s) should not be moved.

Hope it works for you!!!

Donny

 

[Andrew Biggs]

Hi Kicker

I'm not sure that what you are asking is feasible.............and I could well be wrong

My understanding is that once you adjust the working distance by tipping the vice or raising and lowering it................then you have to adjust the scope to suit. Even at it's lowest magnification you will still have to eventually adjust the height and focus of the scope. If you have a very high magnification it just becomes more pronounced as your depth of field decreases. I use the Meiji EMZ 5 every day and in the beginning it can be a bit of a nuisance............but you do get used to it after a while and it just becomes second nature.

Airamp.....I don't see how the vice makes any difference. If you alter the working distance, no matter what the vice is, then you still have to alter the scope.

Cheers
Andrew

 

[Kicker]

Dear Andrew.
I use the GRS microblock for diamond setting and i tilt the block very often, when i tilt the block the working distance change a bit from 5mm to 1cm event more.

 

[airamp]

Andrew,


Changing the working distance you do have to refocus the scope but Tilting it at the work distance you are at is a different issue and can be corrected.

Since tilting the work changes the working distance is the question and since you cannot increase the depth of field in the scope when you tilt it the vise correction is the only solution.

To stay in the depth of field with a tilt and without changing the working distance can only be corrected with the vise.

What is happening with the Hurst vise is that the center of rotation is at the workpiece so moving it by tilting the vise does not actually move the working distance and depth of field. It just tilts in the plane (X,Y,Z axis stays in the workpiece). So you are really not moving the working distance just tilting it at the origin not a radius from the center point.


In other words the work moves in the pivot plane not 2 to 3 inches below the work which creates more work movement outside of the pivot plane.

Low profile vices are made to work under microscopes for that reason.. you are effectively trying to tilt the work at the center of rotation (focus) of the scope to keep it in the focus plane and working distance of the lens.

The Hurst vise does work like this and that is why refocusing is a lot less than other types of vises. Ken Hurst is a Master Engraver as you know and this design was his idea after over 40 (maybe 60?? sorry Ken) years of experence and it really does work.

If you work with 3d cad programs you will see what I am talking about. The closer the working plane is to the rotation (and tilting plane) the less the work moves and the focus distance changes only a little. Further away the work is from the origin, the greater distance it moves and goes out of focus.

Bottom line is to try to stay in the magnification range of your microscope and keep the work at the origin of the holding device so tilting doen't make you refocus the scope every time you tilt it (low profile vise with origin of rotation and tilt the same as the origin of the workpiece).

AirAmp

 

[Donny]

Kicker,

I think Andrew is right. IF you are setting a gem AND you are focused AND magnAfied to the point where the gem you are setting is filling your field of view, or even half of it, then you change the level(altitude, distance of gem to lens) then YES you will have to refocus each time. But a microblock on a turn table(lazy susan) and using your fine focus knob shouldn't slow you down too much.

Did you use a optivisor or loop prior to the Meiji? Most of the jewlery folks I know use a Optivisor with a #10 lens or glasses with these really cool lenses attached.

I am sorry I couldn't be more helpful.

Donny

 

[DakotaDocMartin]

Short answer: No

Not until someone invents the auto-focus microscope.

 

[airamp]

Besides the low profile fudge factor to decrease the effects of change of work distance when tilting the vise.
(post below).
A USB autofocus microscope camera might help but you have to adapt to engraving off a computer screen.

AirAmp

 

[Beathard]

The problem with the camera is it is 2D not 3D.

 

[airamp]

True but you might have a depth of field adjustment (F stops) 2.5 D??

 

[Andrew Biggs]

Hi Kicker

It seems that a lot of stone setters like using the micro block for holding their work.

You can buy "Step risers" from GRS that may solve (or not) your problem. They are a set of rings that sit at the base of the vise so you can easily raise the vise in increments of about half an inch. I saw them in action at the Basel show earlier this year and they worked really well. It may be faster than raising and lowering the scope all the time.

You can see them here

Cheers
Andrew

 

[Sam]

Unfortunately a microscope can't have it both ways, which is being bright AND having a great DOF. As magnification increases the laws of optics dictate thinner and thinner DOF. A smaller aperture creates greater DOF at the cost of brightness. About the only thing I could suggest is zooming out and working with less magnification which will give you greater DOF, but I wouldn't want to do that myself.

Make sure you've correctly done the microscope setup procedure or each time you zoom the focus will drift, complicating things even more. It amazes me how often I see microscope users that are not familiar with this critically important procedure.

 

[Marcus Hunt]

It's a pain in the butt and a problem I struggle with daily. Its often a case of tilt, adjust, tilt, adjust all day long!

 

[Dave London]

Humm
Well as Airamp has stated the low profile dovetail vice works when tilted . Stop by an I will prove it

 

[Kicker]

Dear Donny.
yes, most of the times i use Megaview optivisor for my diamond setting, i use Meiji for micropave set only.

 

[Kicker]

Andrew.
I like to use microblock to hold my workpiece under the microscope for under 3 pointers but from 5 pointers and up most of the time i use Megaview optivisor with GRS benchmate

 

[Kicker]

Ps Andrew.
I do use the step riser for microblock but that not the problem because when i low or rise the block i only focus onece untill my workpiece finish, the problem is when i tilt the block, sometimes for 1 workpiece i have to tilt it maybe 10 - 100 times and i have to refocus everytime i tilted it. so most of the time i set my scope at low magnification for less refocus.