Distance between phone and eyepiece (1 Viewer)

[mbb]

Considering trying to make my own DIY digiscoping adapter for my smartphone (and maybe afterwards camera), I’ve found quite a bit of information and examples online, but I didn’t find clear info and explanation about the ideal distance between the glass of the scope’s eyepiece and the lens of the (smartphone’s) camera.

Is it really always better to have both as close together as possible or can it be too close (apart of course from the risk of both lens touching eachother causing scratches)?
Should you ideally consider an optimal distance based on both optics and how do you define that?

I’m mainly wondering because all commercial smartphone adapter ranges seem to differentiate between eyepieces and smartphones only regarding their diameter and width/length, to have a good fit/grip, while for our direct eye placement using a telescope, the distance (/eye relief) is an important parameter. There is some apparent contradiction here that I cannot fully elucidate. |>|

 

[mbb]

Mhh. I’ve just realised that maybe this should have been posted in the forum «*digiscoping adapters*» instead of «*mobile/iphone digiscoping*», as it also applies to adapters for regular cameras (not from smartphones).
Is there a way of shifting this thread there? (Not wanting to create duplicates.)

 

[Hauksen]

Hi mbb,

Considering trying to make my own DIY digiscoping adapter for my smartphone (and maybe afterwards camera), I’ve found quite a bit of information and examples online, but I didn’t find clear info and explanation about the ideal distance between the glass of the scope’s eyepiece and the lens of the (smartphone’s) camera.

I believe this value is determined by the "eye relief" distance you can find in the technical specifications of your scope.

It varies with magnification, if you're using a zoom eyepiece.

You can rig up a simple cardboard tube to cross-check the technical data, hand-holding the phone camera against the tube.

I've designed adapters for 3D printing, and found that the eye relief distance doesn't have to be matched exactly for a good picture.

(My fixed adapters that only fit a single phone/scope combination worked great, but the semi-adjustable one left a bit to be desired.)

You can find my (free and open source) designs here:

https://www.thingiverse.com/groups/bird-watching/things

A pretty good adjustable one designed by other community members can be found here:

https://www.thingiverse.com/thing:3813595

(Use the search term "OpenOcular" to find more variants ... the one I linked has a bracket for the bottom of the phone, which the original design lacks.)

Regards,

Henning

 

[mbb]

Hi Henning,

Thank you for the info and links! I didn't know about those 3D-printed projects. This might be the time to pick up on making 3D-models again and go for my first 3D-printing. This might just be the excuse I needed for that |=)|
I was looking for another approach, attaching a ring to some phone-cover I'd buy, like in many other DIY-solutions, but I'll also consider this new option. With 3D-printing it might actually be easier to get the 'ideal' distance between lens and eyepiece (if I'm sure of the distance I need).