Digiscoping with Kowa LER eyepiece

[Keith Glasscock]

I am trying to improve the quality of my videos by capturing mirage in the same way I see it through my spotting scope.

I have a spare KOWA TSN-1 with a newer model 25x LER (TE-17HD) eyepiece. I've given some of the typical phone digiscoping adapters a try, and they all hold the phone too close to the eyepiece to see through it. Attempts to use the rubber eyecup for support gave reasonable results, but the rubber won't stay put for very long - definitely not a good solution.

Any experience out there doing this successfully? I'm not afraid to spend money to do it, but would like to avoid having to purchase a new camera for this.

Thanks,
Keith

 

[NZ_Fclass]

Keith - although video is not my thing - I'm a stills photographer - I would suggest that a GoPro with the appropriate mount for the Kowa would be a good move.

 

[Turbulent Turtle]

I have been doing digiscoping with my Kowa 82SV and my Nikon D7500. There are essentially two ways of doing that. One is using a small adapter to take a picture of the eyepiece. The other, more sophisticated method is to use the larger photo adapter that replaces the lens on your camera and actually focuses the afocal image coming out of the eyepiece, onto the sensor in the camera. That's the method I use. The problem with that method is that you cannot use the LER eyepiece because it cannot be focused properly on the sensor with the photo adapter. I bought the 20-60X eyepiece and it works perfectly. I will post a link to some pictures and video I have digiscoped with that setup.

 

[Turbulent Turtle]

Here is a video I took some time back, showing trace via the setup I described above.
https://img.gg/59W7sLW

And some pictures from Lodi, I think, at high magnification on the 1000 yard line.

NIKON IMAGE SPACE

 

[Keith Glasscock]

@Turbulent Turtle
Thanks Denys!

The vignetting is problematic. What do you think the equivalent lens (in mm) would be to compare with a 20x-25x spotting scope image?

I know so little about optics, it's embarrassing...

 

[Turbulent Turtle]

Vignetting is not an issue. My camera's sensor is 20MP, I can easily crop the picture I want from it. In a DX format like my camera, a normal lens that gives the perspective of 1X is a 35mm lens. The issue is that the image is smaller than the DX sensor, which is why there is vignetting, so that introduces a crop factor, probably 2.0X. That would make a normal lens for that size image to be about a 17mm for a 1X. But this is all apparent stuff. So the equivalent at 20X would be 350mm. If you want in terms of a 35mm sensor, that would be a 1000mm lens, if my "math" is correct.

I'm not familiar with the TSN-1, but I did find a video that will give you some good information.

kowa tsn-1 spotting scope - Search Videos

www.bing.com

That method is the first one I described earlier and I have used that one to make the Trace video I linked to earlier. The demo video uses the 20-60X eyepiece I mentioned I have, but since you use the camera lens to look at the eyepiece, you can focus the lens to use that eyepiece. I believe I made my trace video with the 25mm LER lens.

That may be the simpler way for you.

Of course, if you use a smartphone, you will need to find out which adapter to use. Kowa has a wide array of such adapters.

 

[atblis]

It looks like a 1.25" eyepiece adapter is available for your scope. IMO, that's the better route using a digital eyepiece. You can select a sensor that's better suited for your purposes. Megapixels aren't everything. The Svbony SV305 does pretty well for what it costs. I believe it’s a Sony IMX290. Viewing can then be done on a laptop or tablet.