What's this scale?

[iconoclastica]

I am slowly turning my Labophot into a customized Optophot. Now I note a difference in the carrier mechanism of the stage, that I don't find explained in the manual(s). Moving with the focusing, there's a scale (R-DIC-T) and above that an arrow and a dot on the other side. A screw allows for adjusment.

What it seems to do is adjusting the stage position to the parfocal distance. Indeed I have wondered when trying an Olympus objective on the Labophot, why I couldn't lessen the distance, albeit it definitely prevented ramming an 100x objective through the slide. I suppose the letters relate to transmissive, DIC, and reflective. However, they are way too low to position the stage there. The arrow is about correct - in fact I have it now even a tid more conservative (not yet so in the photo below).

How is this scale supposed to be used?

Wim

[apochronaut]

It the calibration look more related to transmitted D.I.C. or reflected DIC, rather than transmitted, D.I.C. or reflected. Possibly to get the correct distance to the rear focal plane of the objectives, a parameter upon which D.I.C. is based.

[iconoclastica]

All DIC-related, could be. But how would that work, does the DIC-unit sit between the turret and the frame, thus lowering the objectives by some 20mm?

It's briefly mentioned in the version two manual that the dot should be aligned with the arrow/triangle. Seemingy, the Optiphot is a 1/2 hybrid in itself. The frame is version 1.

[zzffnn]

I moved from Labophot 2 to Optiphot 1. I don't know exactly why (don't have manual that explains it), but Apochronaut 's comment makes sense to me.

I am using 33mm parfocal LOMO objectives on my Optiphot. I use long M4 and M4 nuts to raise us my stage 12mm:
http://www.photomacrography.net/forum/v ... o&start=15

Condenser can be raised up with some DIY adaptation too.

[PeteM]

The top mark is for normal 160mm brightfield and 210mm brightfiled/darkfiled (but not DIC) use with an accessory lamp head.

The "R" mark drops the stage down to allow the insertion of Reflected DIC prisms.

The "T" mark drops the even stage further to allow the insertion of a normal DIC slider attachment for Transmitted light. That attachment attaches like a nosepiece, and then the nosepiece to it.

As Fan notes, the Optiphot's adjustable stage can be set above the normal mark; to let you use short objectives (such as the Lomo water immersion types).

[iconoclastica]

It is as I surmised, the DIC unit comes between the frame and the turret. This adds some 2cm that the stage should be lowered.

(photo from photomacrography.net)

It's unlikely that I'll ever do DIC, but I do like to know the function of all the buttons

thanks,

Wim

[iconoclastica]

The top mark is for normal 160mm brightfield and 210mm brightfiled/darkfiled (but not DIC) use with an accessory lamp head.

The "R" mark drops the stage down to allow the insertion of Reflected DIC prisms.

The "T" mark drops the even stage further to allow the insertion of a normal DIC slider attachment for Transmitted light. That attachment attaches like a nosepiece, and then the nosepiece to it.

As Fan notes, the Optiphot's adjustable stage can be set above the normal mark; to let you use short objectives (such as the Lomo water immersion types).

Sorry, I didn't see see your conribution before I posted my last.

I tried to move the stage up but just a little above the engraved marks it becomes unstable. It can't be raised 14mm to accomodate 33mm. At least, this one it can't.

Wim

[zzffnn]

Wim,

I added M4 nuts and switched to longer M4 screw to raise up the stage. That does not require any change to stage holder and will work on Optiphot 1 and Labophot 2. You would understand, if you read the thread that I linked to.

Best,
Fan

[iconoclastica]

That was clear from the beginning, Fan. It seems I misunderstood Pete.

Wim

[PeteM]

That was clear from the beginning, Fan. It seems I misunderstood Pete.

Wim

Problem was my cryptic response. As Fan said, you can use spacers to get close. Then, the adjustable stage lets you get exactly where you need to be for various short barrel objectives.