MicrobeHunter.com Microscopy Forum

Hello, I am new to this forum and not very knowledgeable about microscopes but would like to ask a question. I purchased an Olympus SD30 stereo microscope for $20 that seems to be in good condition but is missing the objective. I contacted the local Olympus Rep who advised that, although the SD30 is obsolete they could supply an objective and an extension sleeve from their current range of products that would work. The cost would be about 250 USD. I was wondering if anyone could suggest a less expensive alternative. The thread is 1 7/8” (or 48 mm)x 0.75 mm pitch. I would like the objective to be either 0.5x or 0.7x. I have looked on eBay and can see much less expensive objectives that would fit the microscope but I am not able to determine if they would actually work properly on this microscope. I would be grateful for any advice about choosing a lens.
Thanks.
JCF5

There are 48mm objectives out of China that are very inexpensive. I have bought a couple of 2x ones for my nikon smz1s and found them to be of surprisingly acceptable, even pleasing quality. A reducing lens should be even less demanding n specs.

Thanks Scarodactyl, much appreciated. So is that to say that, quality aside, the specifications of 48 mm thread and 0.5x will be enough parameters to find a suitable objective? There are no other dimensional considerations?

I checked the one I just bought, and it looks to be 48mm with a .75 thread. That should work fine. I dunno if there will be variation in working distance from system to system but probably not a big deal. There's one up now on the cheap, he shipped my 2x fast in like new condition.
https://rover.ebay.com/rover/0/0/0?mpre ... 3205935916
Worth making an offer, and you won't be out much if it doesn't work for some reason.

Thanks for those details. I think that sounds like a good plan. Cheers.

If you buy used, look carefully for deformed female threads at the specimen side. They will stop you from screwing on filters and such.

A good camera store that cleans and services lenses can pound out the deformations with a hammer and wooden chisel. (Professional photographers drop the occasional lens.) Alternatively, I found a really good auto body shop guy can make things right, once you convince them that the lens is fairly stout and you can pound on it a little.

Scarodactyl wrote:I checked the one I just bought, and it looks to be 48mm with a .75 thread. That should work fine. I dunno if there will be variation in working distance from system to system but probably not a big deal. There's one up now on the cheap, he shipped my 2x fast in like new condition.
https://rover.ebay.com/rover/0/0/0?mpre ... 3205935916....

I bought a low cost 0.5X barlow lens just like that. I wish I knew its archetype.

I found an Olympus 110AL0.5X, another 48/0.75mm lens, gives somewhat more working distance and less magnification.

JCF5 wrote:Thanks for those details. I think that sounds like a good plan. Cheers.

I forgot to ask. Do you seek the microscope's main objective or are you after an auxiliary objective, such as these, to screw on to it?

Hi John. Thanks for the advice so far. I am just after the main objective.

This is not a CMO stereo, so it is just an aux lens.

jfiresto wrote: I bought a low cost 0.5X barlow lens just like that. I wish I knew its archetype..

Yeah, hard to be sure given how many olympus and nikon lookalikes there are out there. I actually rather liked one of the nikonalikes I tried, pondering getting one used.

Scarodactyl wrote:This is not a CMO stereo, so it is just an aux lens....

Ah yes, reading about the missing objective confused me a little, as I thought the microscope was incomplete. It is a Greenough design, however, so it can have its main, built-in objectives, plural, yet not have the accessory, auxiliary objective the OP is after.

Sorry, I realise I was confused about the terminology. After reading John’s last post I can see that it is the auxiliary lens I am after. I have looked on EBay and see a good selection.