If it's not very thick, I wouldn't bother. I assume you are aware that having it tempered is likely a code requirement for such an application in your locality.

1/2" is around the point at which you might begin noticing. Maybe you can get a small sample and see if it makes any difference in that location. The direction that light hits it from and the properties and color of what is on the other side are likely to be bigger factors than just the glass thickness.

I mentioned tempered only because many people aren't aware of such requirements, and it will add further to the cost.

I thought it was worth it for all my shower doors. I used expensive white and light colored tile and didn't want to see "green" tile when looking into the showers.

Regular glass will be very green when looking at the edges. Low iron glass will be clear with a light blue hue. Get the low iron glass if green bothers you. Personally I got it for one shower but have regular glass in areas where I wanted the green look.

Personally fro me, and I work with glass everyday, inside your house you will have many things competing for the eye and many colors more than likely. I think I would save the money and use it elsewhere. At 2x the price I would not use it.

What finish and color is the wall behind it going to be?

The glass in question will be the railing for my stairs. The location of the stairs is such that you will only see the glass from a sharp angle, either at the bottom looking up at the glass or at the top looking down. There's really no way to look straight through the glass.

There is nothing interesting to see on either side of the glass, just the brown wood floors and gray walls in the stairway. I don't care if the colors aren't true.

What I'm worried about is, when you are looking at the glass at a sharp angle, if you will see a band of green glass rather than seeing what is on the other side of the glass.

Picture tinted windows on a car. When you look directly at them you can see through them more clearly. But if you look at a sharp angle, you just see the tint and don't clearly see through to the other side (depending on how dark the tint is). This is what I worry about -- as you approach and enter the stairs, will regular 1/2" glass look like a translucent wall of green or will it still be clear? (I know the edges will be green, I'm not talking about that.)

I don't want to spend more for the low iron but in the big scheme of things it's not a ton of money so I can justify it if it will make a difference.

"What I'm worried about is, when you are looking at the glass at a sharp angle, if you will see a band of green glass rather than seeing what is on the other side of the glass."

Yes, you will see a back of green in my opinion.

And will the low iron glass be transparent from this sharp angle or am I just trading green tint for blue tint with the low iron?

Thank you for calling it an acute angle. My teacher was right when she said that learning these things would help in the real world. And all this time I thought she was being obtuse.