beginner - confusion about photo eyepiece, extension tubes etc...

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zzzxtreme
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beginner - confusion about photo eyepiece, extension tubes etc...

#1 Post by zzzxtreme » Wed Oct 04, 2017 11:48 am

hello good day. bought my first microscope.

objectives are plan achromats. the head is trinocular. it has a 23.2mm port on top

it comes with a "ccd linker" to connect the port to a cmount male. I'm able to attach my nikon 1 camera to it. but quality is not very good.

from what I read on the internet, I need a "photo eyepiece". some diagrams shows combination of photo eyepiece and a relay lens. So I'm a bit confused

I'm looking at Nikon TV Relay Lens 1x/16 which has a diameter of 23mm. I reckon it won't be much of a problem

what I'm confused about is how to attach that nikon tv lens to an m42 tube.

Image

the tube length is adjustable. any help/advice would be greatly appreciated.

also, I have an micro 4/3 camera. I'm ok with using either depending on how easy to set it up.

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Re: beginner - confusion about photo eyepiece, extension tubes etc...

#2 Post by zzffnn » Wed Oct 04, 2017 1:41 pm

It depends on which exact trinocular tube/head on which scope (brand/model), when you are not connecting with visual tube.

Can the length of trinocular tube be adjusted to focus with different eyepieces? Can you use a visual eyepiece there and get good image? Some trinocular tube can, some cannot. It depends, so it is hard for anyone to tell you exactly (unless they have your exact scope and exact trinocular tube).

If a visual eyepiece can produce good visual image on your trinocular tube, then simple connect the eyepeice with a 30mm lens, then onto your m4/3 camera. You can use lens step down/up rings (depending on exact connection diameters) or the adapter I mentioned previously.

You may or may not need that Nikon TV relay eyepiece. Either camera will work, but I think the m4/3 may be easier.

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Re: beginner - confusion about photo eyepiece, extension tubes etc...

#3 Post by zzzxtreme » Wed Oct 04, 2017 2:11 pm

Thanks mate. I'll try an eyepiece on top when I get home. There is ring to adjust height(focus). Ill take some photos

Great, i do have a good zoom lens capable at 14-54mm

Am I correct to assume the eyepiece magnification for eye and camera should be the same? So the image i see with my eye is same in the camera?

Your help is greatly appreciated

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Re: beginner - confusion about photo eyepiece, extension tubes etc...

#4 Post by zzffnn » Wed Oct 04, 2017 3:08 pm

No, magnification for eyes and cameras (sensors) may or may not be different, depending on your camera sensor size and lens focal length.

The exact match for afocal m4/3 camera is, again, m4/3 sensor, followed by 30mm camera lens, followed by 10x VISUAL eyepiece, 160mm tube, then 160TL objective. That exact combination gives your camera sensor about 85%-90% of your visual field. For an afocal m4/3 camera sensor, it is about as good as you can get. I use that exact combination myself. Afocal means camera lens over eyepiece, by the way.

Your zoom lens should be locked at 30mm.

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Re: beginner - confusion about photo eyepiece, extension tubes etc...

#5 Post by zzzxtreme » Wed Oct 04, 2017 3:17 pm

zzffnn wrote:No, magnification for eyes and cameras (sensors) may or may not be different, depending on your camera sensor size and lens focal length.

The exact match for afocal m4/3 camera is, again, m4/3 sensor, followed by 30mm camera lens, followed by 10x VISUAL eyepiece, 160mm tube, then 160TL objective. That exact combination gives your camera sensor about 85%-90% of your visual field. For an afocal m4/3 camera sensor, it is about as good as you can get. I use that exact combination myself. Afocal means camera lens over eyepiece, by the way.

Your zoom lens should be locked at 30mm.
thanks again. Is the tube clamped to the eyepiece ?

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Re: beginner - confusion about photo eyepiece, extension tubes etc...

#6 Post by zzffnn » Wed Oct 04, 2017 5:40 pm

What "tube" were you referring to?

The Amazon adapter (that connects camera lens to visual eyepiece) screws into front thread of camera lens, then clamps onto scope's eye tube. It does not clamp onto eyepiece in my case, on my Nikon scope. Once I remove camera and lens, I can leave the eyepiece and adapter there, and still view the eyepiece visually.

The "160mm tube" that I mentioned includes scope's mono/binocular/trinocular tube (if your trinocular tube length can be adjusted to 160mm; many relatively recent finite visual tubes are 160mm, except for some German brands like Leitz [who uses 170mm] and vintage ones).

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Re: beginner - confusion about photo eyepiece, extension tubes etc...

#7 Post by zzzxtreme » Wed Oct 04, 2017 6:56 pm

Ahhh thanks. Can't thank you enough

I did a quick test using macro lens on my 10x eyepiece. It seems to give me near 100% sensor coverage. Does this qualify as "afocal" method?

Image

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Re: beginner - confusion about photo eyepiece, extension tubes etc...

#8 Post by zzffnn » Thu Oct 05, 2017 12:19 am

Yours looks like afocal arrangement. 100% sensor coverage is not difficult though. What you want is, at each objective lens that is in use:

1) when subject is in sharp focus at visual eyepiece, it is also in sharp focus at camera sensor; and

2) when you see 10 ruler ticks at visual eyepiece, your camera sensor also sees around 8-10 ticks.

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Re: beginner - confusion about photo eyepiece, extension tubes etc...

#9 Post by zzzxtreme » Sun Oct 08, 2017 5:12 pm

that one is not 100% view. my bad. Initially I assume if there's no vignette, it means 100%. also last 2 days, I tried m43 camera with samyang fisheye. the lens is about few mm from the 20x eyepiece. switching on the m43 camera's digital teleconverter, I get a nice sharp circle. with 10x eyepiece, I get a very very small image.

just now before sleep, thought I'd give my nikon v1 another try with another lens. a 10mm lens just few mm from the 10x eyepiece. and I get 100% view of the eyepiece. So it's happy news for me. also works with the 20x eyepiece

handheld tests :

Image

Image

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Re: beginner - confusion about photo eyepiece, extension tubes etc...

#10 Post by zzffnn » Sun Oct 08, 2017 7:17 pm

Field of view and on-sensor magnification depends on your exact combination of sensor size, camera lens focal length and eyepiece magnification.

What works best for me is:
m4/3 sensor, followed by 30mm camera lens, followed by 10x VISUAL eyepiece, 160mm tube, then 160TL objective. That exact combination gives your camera sensor about 85%-90% of your visual field.

This combination also works well for 15x eyepiece, while keeping other parts the same. I don't know about other combinations.

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