xkaes

23-Jan-2018, 17:01

I know I am wading into the swamp. But I've done that since I was a kid, so no amount of MUUUUDDDD will bother me. I've seen it all.

Several people on several board have basically asked a simple question. Admittedly, they asked it in several ways which has just made matters worse -- trying to figure out what they mean.

The question is "Is there a SIMPLE way to determine the amount to adjust the f-stop of a lens if - If - IF you know the magnification?"

First, this question is IF you know the magnification, so there is no need to respond by telling us how to determine the magnification.

Second, this question is how much to adjust the aperture -- not a calculation about how to adjust a SPECIFIC f-stop. In short, +1/3 f, or +2 3/4 f, etc.

Here is a real number chart of how much you need to adjust the f-stop based on the magnification.

173998

You might want to print this out for your use on a sheet of paper or a business card.

It seems like a pretty smooth curve, but when I try to compute the formula for the line/curve the best I can do is a cubic formula.

173999

It's close, but not as close as I would like.

There has to be a better formula to compute f-stop adjustment based on magnification.

Is there one?

Let's stick to this simple question, OK?????

IF I KNOW THE MAGNIFICATION, HOW DO I DETERMINE THE AMOUNT TO ADJUST THE f-STOP????

Several people on several board have basically asked a simple question. Admittedly, they asked it in several ways which has just made matters worse -- trying to figure out what they mean.

The question is "Is there a SIMPLE way to determine the amount to adjust the f-stop of a lens if - If - IF you know the magnification?"

First, this question is IF you know the magnification, so there is no need to respond by telling us how to determine the magnification.

Second, this question is how much to adjust the aperture -- not a calculation about how to adjust a SPECIFIC f-stop. In short, +1/3 f, or +2 3/4 f, etc.

Here is a real number chart of how much you need to adjust the f-stop based on the magnification.

173998

You might want to print this out for your use on a sheet of paper or a business card.

It seems like a pretty smooth curve, but when I try to compute the formula for the line/curve the best I can do is a cubic formula.

173999

It's close, but not as close as I would like.

There has to be a better formula to compute f-stop adjustment based on magnification.

Is there one?

Let's stick to this simple question, OK?????

IF I KNOW THE MAGNIFICATION, HOW DO I DETERMINE THE AMOUNT TO ADJUST THE f-STOP????