Has Anyone Used This Size Loupe -Extra Large Fold Away Loupe

I use a 10x loupe for coins though not as big. It takes a little getting used to holding the loupe close to the eye and adjusting the distance to the coin to get into focus. 10x is powerful enough to see errors and the condition of the coin surface. Just for general view a 3x to 5x would work. But being able to spot errors is a good thing, finding an error might make a coin more valuable.

I also have a bigger lens 3x magnifier for reading, especially the small print on medicine bottles. It's nice to have both 3x and 10x.

I use something like this--a linen tester. It folds up so there's flexibility in how the lens can be used...

https://www.amazon.com/Carson-Linen...f_B0011X4722

I use a 20x loupe of the type pictured for examining the internal flaws in gemstones. It has a very narrow depth of field, and is very difficult to examine the surface of coins, but with an acquired skill, it can be done. Very useful in examining the surface texture of suspected fake coins.

I also use a 10x eye loupe of the same standard power that third party graders use. It has a much wider depth of field. I use this separately, but in conjunction with 4X normal design twin lens glasses, which provide for easy binocular vision. I use these in combination for grading coins for myself.

I find that point source light is much easier, rather than flood lighting. Direct sunlight is by far and away the best for coin grading, but care is needed to avoid shadows.

My favourite is a Belomo Triplet 10x. More expensive than your 'Quality Brand' but in my opinion, well worth the extra cost.