Bob The Blob - An Extremely Large Amoeba - Video

[Pau]

There may be something wrong with the condenser though, as I only saw the oblique effect when I flipped that little lens up under the 40x objective, somewhat less on the 10x and not at all on the 4x.

Perhaps you have a mecanichal problem: dismount the condenser and inspect if the flip in lens does its complete travel. in any case, it's preferable to fine center the condenser with the auxiliary lens in and the 10X or 40X objective

Maybe it needs to be centered for each objective, cause I have noticed that when something is centered at 10x, then I flip the nose turret to 40x, the subject is not centered any more. Of course, I have no pointer to really be sure, but I always have to move the stage to recenter.

Try to proceed in reverse: center an object under the 40X and change to the 10X, is it still centered?. (little differences in centering are usual, but not big ones in a good scope).
If not, you have an issue with the objective centeterig. It can be due to the objective itself or more likely with the microscope nosepiece. If the nosepiece is removable, remove it, inspect its mounting mecanism and remount it. You can also try to switch the objectives positions in the nosepiece

[Mitch640]

The condenser look OK, other than that little lens have scratches on it. It does flip all the way out and in.

it's preferable to fine center the condenser with the auxiliary lens in and the 10X or 40X objective

This, I did not do, the auxiliary lens was flipped out of the light path when I centered it. I will try it in.

As for the nosepiece, it is resisting all my efforts to come off. I have even contacted Nikon USA and asked them. One of the techs contacted me yesterday and said the scope is so old they have no documentation for it and no one old enough there to remember how to take it off. LOL The center of the turret has a little cover that comes off easily, but it is full of grease and a bunch of tiny ball bearings. As a last resort, I may try taking it off that way, as behind the turret and in the light path, is a glass filter of some sort, with lot's of dust behind it, inside the end of the arm. No way to get to it that I can see, from the trinocular turret. The Nikon tech had no suggestions.

[Charles Krebs]

Mitch,

If you are reaching grease and ball bearings... stop! (Really... stop, and put it back together... )

If the nosepiece is meant to be removed by the user it is normally very obvious, straightforward, simple and fast.... no covers or screws to remove.

If your condenser has a "flip-out" top lens, that is meant to be moved out of the light path for very low power objectives only (typically 4X and less). You want it up in the light path for 10X and up. If you have it flipped out of the light path with a 10X or higher, then you can't fully illuminate the objective back aperture. In other words... even if you have the diaphragm of the condenser set to it's largest opening, it will be as if it were closed down far too much for decent image quality.

So keep that upper lens flipped up in the light path unless you are using the 4X. As Pau mentioned... align your condenser using the 10X or 40X (with the condenser flip lens up in the light path). If you are getting an "oblique" effect then something (most likely the condenser) is not centered properly. Run through the procedure in the instruction manual again with the 10X and condenser flip lens in place. (The misalignment could also be the light bulb, if it has user adjustments. Around the time this microscope was made, many manufacturers went to systems where the user could not adjust the position of the bulb. But if yours is adjustable there should be a clearly outlined procedure for doing so in the users manual).

You had mentioned earlier that you were setting the condenser aperture to about 70% of the objectives NA. This is good procedure (70-80% generally gives best compromise between resolution, contrast and DOF), but how are you doing this?... by the numbers on the condenser aperture, or by looking down the eyepiece tube? I recommend doing it by removing an eyepiece and peering down the tube. Look at the back of the objective and set the condenser diaphragm so that it appears as in this diaphragm:

[Mitch640]

Simply unbelievable. I can't thank you guys enough. It's like Santa dropped off a new scope last night. The condenser lens makes all the difference. I was not using it at all before, cause it just looked wrong. Also, I just centered it for 10x, then for 40x, and it needs adjustment for each one. As it turns out though, I was getting very close, by adjusting the iris to what I thought was 70% of the NA of each lens, and that was about the same as your technique of looking down the tube Charles.

I'm still getting green CA with that E 40x but I think that must be the glass itself. But wow, what a difference in the details, and everything is a lot brighter. I'll have to make up a slide and take some shots.

By the way, here is a link to some pages I put up with a growng number of images of the scope. I just added a bunch of pics of the condenser and mounting ring. Maybe they will help anyone else who has one of these old scopes.

http://www.flashbax.com/micro/nikon-fluophot.html

[Ferry]

I made this afternoon two pictures of the same amoeba (Saccamoeba spec.). One with the condenser closed and the other with the condenser open as seen on Charles drawing. No need to say which one is the best. You can clearly see the nucleus in the middle.






Succes!

Ferry

[Mitch640]

Yes, that's about what I saw when I figured out how to use mine. But now I am curious, what are those cubic and hex looking objects?

After seeing yours Ferry, maybe I have been beating myself up too much over that green cast I am getting. Is it just normal?

[Ferry]

Mitch,
Those are crystals.They can be characteristic for some species. Most amoebae contain crystals.

You get a color cast because your camera has an automatic white balance which functions well under normal conditions (landscapes, portraits etc.). But he has never heard of a microscope, so he gets confused with its white balance. You have to correct it manually with the camera setup or with software like photoshop. , as I did.

Ferry

[Mitch640]

Ah, OK, I thought I was the only one getting it. LOL Now I don't feel so bad.