I just received my Super Yoter 25mm scope the other day and was thinking of getting a flip up cover for it, so
the current one isn't just flopping around.
Will a flip up one impede the image at all?

Sure. I use a Butler Creek cap on my Nox18. Doesn't impede anything in terms of image.

No, flip covers are included factory accessories with some higher end thermals. You are supposed to NUC with the cover down.

There you are Apec! Where you been buddy?

Let's see a pic of that attack dog!

Ordered a butler creek one yesterday, so hopefully it fits.

The Yoter I had didn’t matter.  You could manually do it (and you hear an internal shutter cover the sensor… that click noise) or you can do it with the cap.

I bought a Butler Creek for my Hogster.  It fits via a rubber sleave that slides over the objective lens.  Its not quite strong enough so when I try to flip it open, the whole thing slides off.  I may have to go with a tighter one.  No biggie.

Had same issue w a Butler Creek. Run a thin ring of quality electrical tape around the circumference of the lens (if feasible) which often tightens up the tolerance of the diameter. Worth a shot right?

So the Butler Creek flip up cover I bought fits nice and tight.
Here's a pic of the package for others if they want one that works.
Attached File

Making a proper pinhole is not much harder than making a bad one.

A proper pinhole is a perfectly round hole in a very thin substrate. This eliminates reflections from the sides of the hole, which cause image degrading effects that are wildly enhanced in NV applications. Many tutorials for making a good pinhole are available in online photography forums - the only change being that the NV user might want a relatively larger pinhole. Search "pinhole photography"

Simply punch a significantly larger hole on the lens cap you are using and adhere the real pinhole sheet behind it. Make sure you punch the pinhole and then clean off the dimple and any "raggedness" of the round pinhole. And blacken the pinhole material without getting the blackening agent in the hole.

No sense in using a poor pinhole that reflects light into the objective optics to bounce around and diminish the SNR figure you paid so dearly for. Not even for daylight practice use when the sun is out there, off axis, pretty often. Especially when it is so easy to do it right. Experimenting with various hole sizes is a breeze.

While it would be possible to cut a tapered hole in a lens cover, it is real hard to get the hole round and free of ALL jagged edges. Easier to use a thin metal sheet and stick it to the plastic.

Pinholes must be in very thin material, which is why peep sights have that V shaped taper on the side away from the eye, or have pinholes in thin metal shaded and strengthened by a much larger, thicker cylinder on the side away from the eye. If your peep sights are the other way around, then the optical engineer and the mechanical engineer didn't consult during the firearm design phase, or the aftermarket peep sight manufacturer needs to read some books.