LWD Optosigma objectives.

Yawns · Post by **Yawns** » Wed Jan 22, 2020 1:10 pm

Does anyone have experience with these lenses? .. the price seems to be too good ... and I can't find any information / analysis / comment ...

searches here on the forum do not return anything except posts where Optosigma material is referred to ... stages ... nothing about the lenses.

https://europe.optosigma.com/long-worki ... -5177.html

Thank you.
António

RobertOToole · Post by **RobertOToole** » Wed Jan 22, 2020 9:53 pm

Yawns wrote:Does anyone have experience with these lenses? .. the price seems to be too good ... and I can't find any information / analysis / comment ...

searches here on the forum do not return anything except posts where Optosigma material is referred to ... stages ... nothing about the lenses.

https://europe.optosigma.com/long-worki ... -5177.html

Thank you.
António

Hi António,

I've looked at these before and cosmetically they look good but the lens datasheet only has a % transmission graph. Nothing about CAs other than "Chromatic aberration is corrected in the visible range (400 − 700nm)".

Thorlabs objectives are complete with graph axial color and lots of other data. You would think they would show how well they are corrected if had something to brag about, so judging by the price I would say they are not really APO corrected.

Hopefully someone with some first hand experience will post.

Best,

Robert

Chris S. · Post by **Chris S.** » Thu Jan 23, 2020 2:40 am

Note, too, that the numerical apertures are small for a couple of the lenses. The 20x has NA 0.30 (more normal for a 10x); the 50x has NA 0.42. As we know, lower NA means lower resolution.

--Chris S.

Yawns · Post by **Yawns** » Thu Jan 23, 2020 6:54 am

Thanks .. yes I am also suspicious .. even because I can't find any other references to the lenses .. I only saw them because I went to their website to check the specifications of a pair of goniometers and a rotation stage of the brand I bought on eBay.
Thank you

Yawns · Post by **Yawns** » Thu Jan 23, 2020 7:06 am

Chris S. wrote:Note, too, that the numerical apertures are small for a couple of the lenses. The 20x has NA 0.30 (more normal for a 10x); the 50x has NA 0.42. As we know, lower NA means lower resolution.

--Chris S.

I noticed that too, but I always thought it was a "normal" value for this type of long distance inspection lenses ...

Always puzzled me why Mitutoyo M plan APO have so low NA values ... well bellow Nikon or Olympus Fluorite lenses. Mitutoyo 10X 0.28 is below an FL, which usually has an NA of 30 ...

that part I thought it was " normal". The Optosigma 10x is 0.30 .. the Mitutoyo M plan is only 0.28...

Scarodactyl · Post by **Scarodactyl** » Thu Jan 23, 2020 7:21 am

Maybe rebranded Chinese mitutoyo clones?
Edit:it must be. Here is one from bolioptics. The picture is a little different and says 10x/.28 but the specs say .30 https://bolioptics.com/10x-infinity-cor ... nce-6-4mm/
The lowe NA variants are copies of the mititoyo super long working distance line which are not great for photography.
I wouldn't waste time on it.

lothman · Post by **lothman** » Thu Jan 23, 2020 7:33 am

Yawns wrote:
Always puzzled me why Mitutoyo M plan APO have so low NA values ... well bellow Nikon or Olympus Fluorite lenses. Mitutoyo 10X 0.28 is below an FL, which usually has an NA of 30 ...

Yes but look at the huge working distance of the Mitutoyos compared to other lenses. If you will keep NA but increase the working distance, the lens diameter has to become bigger, what makes lens usually much more expensive.

Providing a good working distance and somehow high NA makes the Mitutoyo well regarded for industrial use (where you have to measure in the bottom of a groove and there need high working distance). On a biological microscope you usually can keep the working distance very small and therefore have lens designs with high NA but small working distance.

Adalbert · Post by **Adalbert** » Thu Jan 23, 2020 7:37 am

Hello everybody,
I have Mitty 10x / 0.28 and Lu Plan 10x / 0.30
Lu Plan produces more CA than Mitty !
BR, ADi

Scarodactyl · Post by **Scarodactyl** » Thu Jan 23, 2020 7:52 am

Lu is a nikon plan fluor, right? It should be less corrected than an apo.

Adalbert · Post by **Adalbert** » Thu Jan 23, 2020 7:56 am

Hello Scarodactyl,
Yes, all my lenses from NIKON (Lu Plan 5x, 10x, 20x) produce much more CA than Mitties

BR, ADi

RobertOToole · Post by **RobertOToole** » Thu Jan 23, 2020 10:03 am

Adalbert wrote:Hello Scarodactyl,
Yes, all my lenses from NIKON (Lu Plan 5x, 10x, 20x) produce much more CA than Mitties
BR, ADi

Just FYI if anyone is curious:

Nikon LU Plan 10X vs Nikon CFI Plan Achromat 10x 0.25 vs
Mitutoyo M Plan Apo 10X 0.28 vs Nikon 10x 0.20 MM:

https://www.closeuphotography.com/10x-lens-test

Also

Mitutoyo M Plan Apo 5X/0.14 vs Nikon CFI LU Plan Fluor 5X/0.15 vs Mitutoyo M Plan Apo 7.5X/0.21 Objective @ 5x vs others:

https://www.closeuphotography.com/5x-lens-test

Adalbert · Post by **Adalbert** » Thu Jan 23, 2020 10:26 am

Hello Robert,

I would recommend the Lu Plans if someone wants to learn how to remove the CA from the stacks :-)

Some years ago they were extremely cheap, so I made some good bargains but I had to learn how to manage the problem of the CA

BTW, but since I have had the Mitties I have been using only Mitties :-)

BR, ADi

RobertOToole · Post by **RobertOToole** » Thu Jan 23, 2020 2:05 pm

Adalbert wrote:Hello Robert,

I would recommend the Lu Plans if someone wants to learn how to remove the CA from the stacks :-)

Some years ago they were extremely cheap, so I made some good bargains but I had to learn how to manage the problem of the CA

BTW, but since I have had the Mitties I have been using only Mitties :-)

BR, ADi

This is the same case here ADi, I usually reach for the Mitutoyo in most cases, they are sharp, well balanced with a good image circle.

I only wish I knew then, what I know now about Mitutoyo, I would have saved myself a ton of money and time.

I have too many Nikon objectives sitting here with a layer of dust on them

This is why I decided to create my site and I'm really glad I did, even though it has taken lots of time.

Best,

Robert

Scarodactyl · Post by **Scarodactyl** » Thu Jan 23, 2020 3:11 pm

Does nikon make a lwd apo series? I'd figure they would have to but I bet they cost a lot more than a mitutoyo. Again it's pretty clear a nonapo isn't likely to beat out an apo (of equivalent tier and vintage anyway) on ca. My normal nikon 20x apo is extremely well corrected as far as I can tell, but that must be easier without the constraint of a long working distance.

RobertOToole · Post by **RobertOToole** » Thu Jan 23, 2020 3:46 pm

Scarodactyl wrote:Does nikon make a lwd apo series? I'd figure they would have to but I bet they cost a lot more than a mitutoyo. Again it's pretty clear a nonapo isn't likely to beat out an apo (of equivalent tier and vintage anyway) on ca. My normal nikon 20x apo is extremely well corrected as far as I can tell, but that must be easier without the constraint of a long working distance.

As far as I am aware, there are no APO ELWD or SLWD, the longer the WD the less corrected for CAs generally speaking. MM objectives have super WD but the they are also the least corrected for CAs.

You are pretty much right on objectives and APO labels but that's not the case with consumer and industrial lenses, some non-APOs are much better corrected for CAs vs APO labeled lenses, like the Tominons or Noritsu lenses are good examples of well corrected without an APO label.

Best,

Robert

LWD Optosigma objectives.

LWD Optosigma objectives.

Re: LWD Optosigma objectives.