Olympus ULWD M SPLAN 20 0.4 180 Infinity

[mjkzz]

I am getting this objective Olympus ULWD M SPLAN 20 0.4 180 Infinity shipped to me. I asked about working distance, the seller obviously does not know and told me the WD is 7CM (70mm), I was puzzled and thinking it could be a typo, maybe 7mm.

I looked up Olympus PDF, it seems they only have one (ULWD M SPLAN 0.4) in the document, and its WD is 11mm, am I reading the wrong document? I'd love WD of 11mm!!!

Second question is, it looks like I have to use tube lens, I have a Canon kit 18-200mm and I have 7 step down rings coming (82 - 58 ) and a 58mm to RMS adapter, so I am "good". But I thought I have seen a discussion about using infinity objective without tube lens somewhere, can I do that?

[Ichthyophthirius]

Second question is, it looks like I have to use tube lens

Strictly speaking you need a tube lens and compensating eyepieces (WHK visual or NFK for photography) with these objectives. http://www.alanwood.net/downloads/olymp ... ochure.pdf

[mjkzz]

Thanks Ichthyophthirius, and nuts, did I get the wrong type of objective? There goes 120USD.

[mjkzz]

Googling around and found the answer about this objective right here on this forum . . .

http://www.photomacrography.net/forum/v ... 73288bef13

[mjkzz]

Looks like we have CA issue with this objective. The subject is a used Misumi dovetail micro stage, made of copper (the yellow tint) and painted black, but the blue tint should not be there at all (or is it from my LED flashlight for focusing purpose?)

Here are setup info: Nikon D5200, 70-300 zoom lens set at 300mm and focus on infinity at f/5.6, single flash at 1/128 power level

[Pau]

It seems longitudinal CA, with achromat and Plan achros you can expect it (blue/yellow or green/magenta). The complemmentary colors don't focus at the same plane. Some stacking approaches will elliminate it almost completely.
In your example it's pretty visible because the contrast between dark and light zones is extreme, with more "normal" subjects it will be much less disturbing.

...made of copper (the yellow tint) and painted black, but the blue tint should not be there at all...

In fact I think that the yellow is also due to longitudinal CA.

[mjkzz]

Pau, I did this "high contrast" intentionally because I want to bring out CA issues. OK, I thought the yellow is from copper -- the surface of that micro stage is scratched pretty badly, so copper is exposed. But I take your words for it, it is due to CA. Thanks.

[mjkzz]

At first, I thought the glass is scratched because I could not remove some imperfections (dust particles). After cleaning it using lens clothe, no scratches. But it seems I can not get rid of dust particles, no matter how hard I clean it, they are always there, driving me nuts. Any special tools for objectives?