Customer Rating: 
Summary: Not up to par
Comment: I was looking for a lightweight lens to use hunting, so after reading the other reviews, I gave this a try. It seemed to be pretty well made, however it has a couple of issues that I could not live with:
The first thing you notice when you look through it is how very small the depth-of-field (the distance between the closest object in focus and the farthest) is. With most optics, once you get past a certain range, pretty much everything is in focus. That is not the case with the Barska. You are always focusing. Even objects just a few feet apart way out in the distance require you to change the focus. This is very tiring.
The other big issue is it's relative brightness. A 40mm lens is fairly large, so I was expecting pretty good low-light use, however this is also not the case. It is pretty much unusable anywhere near dawn or dusk. I didn't get a chance to try it in heavy woods, however I expect it's performance would be similar.
Customer Rating: Summary: Great Telescope
Comment: Great Telescope. I took it to a football game and Wow. Get One. Great in the boat and for Bird watching.
Customer Rating: Summary: A big help
Comment: I am legally blind and my old monocular had broken from me treating it rough hiking in the woods and geocaching.
I came across this one which was a lot cheaper than the other one I had bought that didn't last as long as I felt it should. This one has worked out well for me so far. It's very clear and focuses pretty close too. I would recommend this to anyone with vision problems.
Customer Rating: Summary: Functional quality
Comment: OK, my take on the Barska Blueline 10x40 Close Focus Monocular. Semi-compact size, sturdy rubberized body, feels like build quality. The image is somewhat sharp, slightly color fringed, reasonably bright.
I guess I really hadn't considered the way a monocular operates. That a tubular 10x optic with a narrow field of view really has to be steadied with both hands to keep vertigo from setting in. Hmmm, kind of awkward, one hand ahead of the other on the barrel, elbows on the desk.
Which sets the thing at chest height, unless I want to sit on a paint can. In the chair, I'm hunching over on it, which tips my head forward, my eyeball squinting upward into the eyepiece. Neckstrain, eyestrain.
Now to focusing with that rotating eyepiece. Remember two hands holding it steady? Now you have just one. Which way to turn? Try one way and see what happens. About two full revolutions between the stops. No? Back the other way then. What's that? Your bird flew off already?
In conclusion, there's nothing wrong with this monocular. Works as claimed. If you need an optic mainly for positive ID on a bird or critter, fine.
But...if you are into your birds, would like a nice sharp image and good color, might enjoy some watching as well as just "spotting"...well, I'm springing for compact binoculars!
Customer Rating: Summary: Well made
Comment: This item seems to be well made. I am a professional photographer and I have been around quality optics for a long time. View is bright and crisp. Focusing is quick.
Only one small problem. The forward element seems to be a little loose.
