If you have normal vision but need to see the detail on an LCD camera screen (the small detail really is too small for a normal human eye to see!) then these half spectacles are ideal, and they are 'half' so that you can see into the distance and see the screen at the same time.
Alternative item: if you wear prescription glasses, then at these strengths, you must get spectacles made especially for your eyes, see custom-made magnifying spectacles.
If you have normal vision, the magnification and working distances work like this:
4D, about 2X magnification, 7 inches working distance
This is the maximum strength you can buy (over the counter) as 'reading spectacles' if you have a prescription.
6D, about 2.5X magnification, 4 inches working distance
Good medium strength for camera work.
8D, about 3X magnification, 3 inches working distance
This is about the highest magnification possible with spectacles, and even at 3X you might struggle to use both eyes together, 3 inches is very close!
For digital cameras where the screen is very small (compared with a tablet or desktop monitor). You won't need spectacles for taking snapshots, but for landscape or portraiture work, with the camera on a tripod, you do need to see every detail.
You are on your way home from holiday, and on your camera are 500 shots, and the long plane journey is the ideal time to go through them and decide which to keep - but the screen is too small, you can't see the detail.
Q. What's the difference between these and 'over the counter' spectacles?
A. The maximum strength you can buy over the counter is 4D (2X magnification), these SPECS-LCD spectacles go up to 8D.
Q. I don't want spectacles for camera screens, I want some that are really powerful because my eye sight is just too poor to see very close-up. Can I use these?
A. No. If your eye sight is that bad you must get a prescription from your optician. Of course, there is nothing to stop you from getting head-mounted magnifier that sits over the top of your prescription spectacles.
Q. I can buy a large selection of powerful head-mounted magnifiers from you, so what's wrong with me using these spectacles to help my poor eyesight?
A. Two reasons. Firstly, it's unlikely that both your eyes are the same prescription, if you buy these, one side will be fuzzy. Secondly, the maximum strength for reading spectacles (that you can buy over the counter in the high street) is 4D - that's the law. But the law only applies to 'spectacles' not to 'magnifiers' - so you can use a 'magnifier' in addition to your prescription spectacles.
and what happens if each of my eyes is a different prescription and I buy over-the-counter spectacles in the high street?
A. One side will be fuzzy. Really. Ask you optician! That is why these super-powerful SPECS-LCD spectacles are only suitable for those that have normal eyesight.