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Considering a spotting scope for digiscoping - will vignetting be a problem? (1 Viewer)

Arthur Red Rod

Well-known member
Hello everyone,

I have been digibinning the birds around my house using a tripod set-up on the veranda for a couple years now. I am entertaining the idea of purchasing a spotting scope down the road for the same purposes out in the field.

My only reservation is the issue of vignetting. I have not dealt with this problem at all with binos, as the exit pupil is sufficiently large and I am forced to use digital zoom anyway. As such, I am quite ignorant on the optical principles behind vignetting and how to adjust for it.

As far as I understand it, even with a properly aligned set-up, vignetting can start to occur as you increase the zoom on the scope because the eye relief shortens and the phone progressively goes out of alignment. This was a suspicion I had in my head and some cheesy advertisements for the "Phone Scope" seem to confirm this.

The phone adapters I've been looking at seem to have no mechanism for adjusting eye-relief and frankly, I am concerned adjusting it at all will be too much of a pain to deal with compared to binos. Despite the obvious lack in magnification, I have grown quite fond of the digibinning set-up for its ease-of-use and could not see myself having the patience for something significantly more cumbersome.

Any insight into this matter would be greatly appreciated. Thank you in advance.


Well-known member
Hi Arthur,
Depending upon the spotting scope and eyepiece you purchase, and the camera/lens combination you wish to use you may need to deal with some amount of vignetting. Generally, an M43 camera requires a minimum of 20mm, while an APS-C camera needs ~30mm, and a FF camera ~40-45mm. A little bit of vignetting is actually good; it allows you to verify that you have correct focal plane alignment when that vignette circle is sharp with little-to-no chromatic aberration. Most of the time you can zoom the scope or camera to remove it, or just crop in post-processing. If you are using a smartphone you can zoom the view to remove the vignetting. Hope this helps!


Out Birding....
United States
Not sure if you are considering a camera or a phone .....or what type of scope. But vignetting is usually not that much of an issue, especially if done right. I use a camera with just a small digital zoom which allows me to take away vignetting from the start so I never have to worry about it. Check out this site for more information on digiscoping:


Well-known member
I generally find I need to zoom a little on my iphone to fill the picture, ie to avoid vignetting. It does depend on where you set the eye relief (to what extent the eyecup is screwed in or out) and also on the amount of zoom on the eyepiece. It’s well worth trying and you should be able to get some acceptable results, not least for video when the moving picture seems to detract from any image softness etc that might be noticed on a still. I use the Phoneskope which is a nice solid and lightweight solution, my experience with a couple of adjustable ones (ie Swarovski and opticron) was that they are bulky and less rigid. Also bear in mind if you position the phone in landscape mode, it will tend to twist the eyecup due to gravity and may also pull it downwards, affecting the focus. It’s still lots less hassle than connecting a scope to a camera and you have the advantage of the phone adjusting its own focus.

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