15x - 30x Eyepieces for Stereo Microscope

[krame]

I just received my first stereo microscope (Nikon SMZ-1B) from one of our board members here, and I have a question about increasing the magnification. I currently have 10x eyepieces which gives me 8x-35x.

Is there any way to increase magnification other than swapping eyepieces? There are no additional objectives to screw onto the base?

If the above is true, then what are your thoughts and feeling on increased power oculars? I assume that there are drawbacks with higher mag like narrower focal plane, smaller FOV, decreased resolution, and need for more light.

When I dabbled in photography, the general rule of thumb I followed was never to duplicate your zoom ranges, following this ideal would put me at 30x eyepieces. After looking online, there are not a lot of 30x x 23.3mm lenses out there, so I'm assuming that there is a reason for that. Are non brand name 30x eyepieces going to be absolute trash? 25x eyepieces seem to be the upper limit of those sold by Amscope and Omax...any thoughts or experience on those?

The impetus behind this came from looking at an unopened flower buds and there were purple dots in the folds where the flower would open and I really wanted to get a better look. While I know that there will always be something smaller, I think these dots were still too big to fall under a compound microscope.

Thanks everyone!

[Scarodactyl]

You can get a 2x objective to screw onto the base. They have I think a 48mm thread and there are many third party compatible objectives that work. I tried a third party 2x once, a cheap 25 dollar example from Amazon, and was surprised at how well it worked. Olympus also used the same thread for objectoves on their stereos at one point so there is likely some compatibility there too.

15x or 20x eyepieces can be handy for tweaking the zoom range for a particular task, but thevlimits you mentioned above apply.

[krame]

That's great! I think a 2x objective would be perfect.

I tried searching for 2x objective and I didn't get anything obvious. Is it also called a Barlow lens?

[MicroBob]

Hi,
stereo microscopes generally work best in the magnification range you already have. The numeric aperture of stereo microscope objectives is on the low side in most cases so stronger eyepieces don't offer more resoultion. But there are exceptions: My Leitz Großfeld TS stereo microscope has a 1x objective with n.a. 0,05 anc could easily support a 20x eyepiece.
Typically the n.a. of zoom stereos increases with the magnification but not as much as needed. So a 2x lens will probably be worth a moderate invest but not more.

Bob

[krame]

Thanks!

[Scarodactyl]

They're sometimes called barlow lenses or auxiliary lenses.
I think this is one I used though I imagine most are similar and they can likely be found cheaper https://www.ebay.com/itm/KP-2X-Auxiliar ... 2638359059

[MicroBob]

Auxiliary lenses change the free working distance, e.g. a 2x halves it. The plus side is: At least theoretically the numeric aperture is doubled. So at full zoom setting the auxiliary lens has more potential than the stronger eyepieces. For my Olympus (the nuclear reactor design) I have both 0,5x and 2x lenses and rarely use them.

[apochronaut]

Eyepieces of between 5X and 15X usually can be relied on to fulfill an objective's peak potential. Magnifications above 15X and sometimes including 15X exist as special purpose eyepieces and the main usefulness of them is to maintain working distance, while bumping the magnification. Maintaining the same eyepiece design as those of lower power though, is not practical for the designer because loss of field, loss of eye relief , loss of contrast and loss of brightness are the tradeoffs, even if they do not override the potential magnification peak of the objective. In order for high power eyepieces to not make it seem as though you are losing an enormous level of quality, they need to be made to a different standard and or technical parameters, than those of a lower power and therefore a premium is usually added to their value. In some systems special eyepiece optics can be 2 -4X the price of the standard eyepieces. If high power eyepieces are either added to a low priced package as an attractive accessory, or exist as an extra accessory at a price that doesn't seem out of line, then they are almost for sure bound to be useless. Starting campfires is one option for them.

[krame]

Starting campfires is one option for them.

That would have been useful information yesterday. I had a bear of a time starting charcoal for my grill.