What accessory do I need to par focal microscope camera in trinocular tube of stereo microscope ?

[jackieone]

In order to par focal a microscope camera, used with the trinocular port of a stereo zoom microscope, there needs to be some accessory in the trinocular tube to actually focus the camera.

Is this the piece? a 1x adapter - https://a.co/d/0f6A6tE

Or is this the piece? a 0.35x adapter - https://a.co/d/38QMfk2

There is also a 0.5 adapter - https://a.co/d/3cg1Lwu

Or is it something else? For example, just a focusing ring that fits into the trinocular tube.

(All these are just examples of what appears to be the accessory, none are singled out as better or worse than other items in the marketplace.)

This is the camera in question: Does not come with any focusing accessory - https://a.co/d/9HENJi0

Appreciate your advice.

[jackieone]

Perhaps rephrasing the question:

How to make digital camera (CMOS, USB 2.0, 5MP) parfocal with stereo zoom microscope, so when zoom feature is used, the camera stays in focus just like the binocular viewing eyepieces stay in focus, without constantly readjusting focus.

Camera did not come with a focus ring. Is a focus ring non-essential for this process?

Thank you.

[Topcode]

Assuming that those adapters are the right threads/attachment, they should work just fine for your purposes. I have that exact same 1x one (though bought from aliexpress) and it works really well.

[jackieone]

@Topcode - Thanks. Further question: The camera comes with a 0.5X adapter (a long tube), but for a stereo zoom microscope, can use with or without this tube, on the trinocular port. I'm guessing the 1X is "neutral", but putting a 0.5X focus ring in addition to the 0.5x camera attachment, is not needed, correct?

Appreciate your help. All I'm trying to accomplish is having the stereo zoom parfocal with the camera in the trinocular port to avoid constant re-focusing as the zoom feature is used.

[BramHuntingNematodes]

The reduction sizes are also important to match the image projected and the size of your sensor. If you have a very small sensor and use the 1x the image will be blurry. If you have a full size sensor and use too much reduction you will get a small circle of image but the rest will be black.

You can also use direct projection without any lenses if your sensor is big enough, but in all the setups I use a physical tube of a particular length at least is needed to obtain parfocality.

[jackieone]

@BramHuntingNematodes - Thanks for the heads up. The camera has a 1/2.5 sensor. (This one: https://a.co/d/cbE0qu4 )

Is that a small sensor? If so, what focus ring should be purchased in order to parfocal the stereo zoom microscope?

The options available are: to use the 0.5x tube with the camera, or just connect it without the reduction tube to the c-mount. If I do the direct connect, do I need a focus ring, and if so, what is the one to fit with the camera (I.e. 1x, 0.5x etc.)

If I use the 0.5x tube with the camera in the trinocular port, what size focusing ring should be purchased?

Thanks for your help.

[MichaelG.]

… The camera has a 1/2.5 sensor. (This one: https://a.co/d/cbE0qu4 )

Is that a small sensor?

.
This might help you put that into perspective, Jackie

https://en.wikipedia.org/wiki/Image_sen ... rSizes.svg

The history of sensor-sizing is rather ‘weird & wonderful’ !

MichaelG.

[bkt]

In order to par focal a microscope camera, used with the trinocular port of a stereo zoom microscope

The camera adapters you got are foreseen to fit into an eyepiece mount. Remove one eyepiece, plug your camera into, and see what you get out from your 0.5X adapter. And from the eyepiece adapter without optics inside, a 1X. You will quickly see the difference between 1x and 0.5X adapters or the images they produce.

The 1X, 0.65, 0.5 etc are used to adapt the image size to the camera sensor size. Most sensors are small, and need image reduction, for an acceptable field of view; without reduction, you would see only a partial image, a crop into. Full frame cameras have big sensors, they need 2x adapters.

On the trino photo port, you could basically fit an eyepiece mount. Then fit in there what you already own. If you set in there a basic c-mount adapter, without optics inside, you would be stucked to 1X (for approx one inch camera sensors).

Some solutions could be cheap, and this will depend of your microscope model and what you could need to adapt an eyepiece there. An example:

[jackieone]

@ but - Thanks for your response.

To be sure I understand:

Trinocular port (C-mount) on stereo zoom microscope:

Using camera WITH the 0.5x tube, I would need a 0.5x focusing ring to achieve parfocality when "zoom" feature is used, so I do not have to constantly refocus

Using camera WITHOUT the 0.5x tube, would need a 1.0x focusing ring to achieve parfocality

Is that correct?

Again, thank you.

[bkt]

@jackieone

I told you to first plug your camera in place of an eyepiece, it is foreseen for this. And see the images, with your 0.5x adapter. That way:

Trinocular port (C-mount) on stereo zoom microscope:

We still don't know what your scope is... you shall take a picture or tell us what the exact model is.

I believe that other one comes with a camera port, with a basic empty tube top of it, were your camera could fit in directly also. You are maybe only missing that tube, for your own trino, were you could plug in your camera:

[bkt]

@jackieone additionally...

Trinocular port (C-mount) on stereo zoom microscope:

Add a picture of your trino head, and more details about its model. Will be helpfull.

You say your trino has a c-mount port? And according to your initial post, you intend to order an optic for a 38mm photo port, which won't fit to c-mount:

[jackieone]

Thanks for all the informative responses to this topic.

After quite a bit of browsing, and a few phone calls to various microscope vendors, this is what I discovered:

- The focusing adapter is "SZM CTV 1/2" and will work with a camera sensor of 1/2.5, and also with 1/2.3 (but 1/2.5 is recommended). That from the microscope manufacturer providing the adapter with the microscope. This call gave me the math, dividing 1 by the sensor size.

- The deceiving part about all this was the "1/2" on the adapter, where many other focusing adapters have "0.5" or "0.35" and I was not translating the "1/2" into 0.5...my lack of knowledge! I thought it was something completely different. The "CTV" part didn't help either, and one explanation I received from a vendor is that the adapter is only used to connect the microscope to an LCD or TV. OK, that was weird. I'm connecting to a laptop, so maybe that's the same thing? Who knows...

- Another vendor explained that this adapter can be used with a "max 1/2.3" camera sensor. Ok, got it. So, 2.3x is larger than 2.5x; so since 2.5 is smaller, it too will work with the adapter where 1/1.8x will not. Or, it will leave the outside of the picture with vignette.

- Yet another source, a website this time, says the 1/2 SZM adapter can work fine with sensors of 1/2.5x, 1/2.3x, 1/2.8x, 1/1.8x...which may be true but doesn't make sense if the math formula is to divide 1 by the sensor size, and if the answer is closer to 0.5, that will work with the adapter. So, doing the math in the same order: 0.4, 0.435, 0.357, 0.555. Which looks like the 1/2.3x and the 1/1.8x are closer than the 1/2.5x but for some reason the 1/2.5 is the best of all for that adapter. Still pondering that one.

Summary: I learned a lot, and that's a good thing.

Next step, attempt to parfocal the stereo zoom microscope camera now that I have the adapter/sensor problem solved...

[MichaelG.]

Thanks for all the informative responses to this topic.

After quite a bit of browsing, and a few phone calls to various microscope vendors, this is what I discovered:

- The focusing adapter is "SZM CTV 1/2" and will work with a camera sensor of 1/2.5, and also with 1/2.3 (but 1/2.5 is recommended). That from the microscope manufacturer providing the adapter with the microscope.

[…]
[…]

but for some reason the 1/2.5 is the best of all for that adapter. Still pondering that one.

.
You’re making good progress, Jackie
… The encouraging point is that 1/2.5 is the smallest of those sensors and it is the size of the one in your camera.

Have another look at the graphic I linked in post #7 … and then go to the Wikipedia page from which it comes
Ref. __ https://en.wikipedia.org/wiki/Image_sensor_format

MichaelG.

[jackieone]

@Michael G - I did take another look at the graphic, and yes, it makes a lot more sense now than earlier.

My brain is stubborn: 1/2.3 automatically looks like it should be smaller than 1/2.5 when just looking at the numbers, but the graphic does the trick. LOLZ!

Appreciate your insight and help!