I am preparing to teach a class to senior citizens on the basics of photography. Many of these people have no math skills and will not understand formulas. I need a graphic to show them how the f-stop numbers are related to focal length. I remember an illustration I saw many years ago where instead of showing head-on side-by-side views of diaphragms set to each f-stop (like almost all the illustrations I have found), it showed circles over layed on the centerline of an illustration of the lens to focal length distance to the film plane. E.g., f2.0 was illustrated with two circles each half the diameter of the focal length sided by side fitting the distance while f8.0, for example, had eight circles side by side on the line shown below. Each f-stop was shown in a series of separate similar drawings, one below the other on the same illustration.

I have spent hours with Google trying to find such an illustration without success. I do not have either the drafting skills or the software necessary to produce one myself. Could someone please direct me to a source for such an illustration or provide me one.

Thank you!

Well, since I am not a good photographer and do not claim to be anything more than an artist, what I have to say about this is not important and I'm sure will matter to no one at all, but being one of those seniors between the ages of 80 and 90, I think I know what will be fun for them and what will bore them to the point of wishing they were somewhere else. I not only FEEL what they feel, but I sometimes teach seniors to paint at Sr. Citizens Centers and Senior Sunday School classes at Churches. I show them they CAN do it and they are thrilled to see what they have done when it's over. Their attention span is not as long as middle aged people, so holding their attention long enough to learn much is not easy. Keep it simple. Teach them about the importance of good lighting first, then teach them simple stuff, like, not to have trees or poles coming out of heads or backs and make it FUN. Teach them when to fill the frame with a subject and when to back way off. Keep the wording simple, not words they will have to ask about. It's doubtful that they are out to sell photos. Just keep foremost in your mind that they want to have FUN making better pictures, not necessarily masterpieces. I'm sure that what I have said may do nothing for anyone but those seniors who are about to either have a great time or......

I am preparing to teach a class to senior citizens on the basics of photography. Many of these people have no math skills and will not understand formulas. I need a graphic to show them how the f-stop numbers are related to focal length. I remember an illustration I saw many years ago where instead of showing head-on side-by-side views of diaphragms set to each f-stop (like almost all the illustrations I have found), it showed circles over layed on the centerline of an illustration of the lens to focal length distance to the film plane. E.g., f2.0 was illustrated with two circles each half the diameter of the focal length sided by side fitting the distance while f8.0, for example, had eight circles side by side on the line shown below. Each f-stop was shown in a series of separate similar drawings, one below the other on the same illustration.

I have spent hours with Google trying to find such an illustration without success. I do not have either the drafting skills or the software necessary to produce one myself. Could someone please direct me to a source for such an illustration or provide me one.

Thank you!

I am preparing to teach a class to senior citizens on the basics of photography. Many of these people have no math skills and will not understand formulas. I need a graphic to show them how the f-stop numbers are related to focal length. I remember an illustration I saw many years ago where instead of showing head-on side-by-side views of diaphragms set to each f-stop (like almost all the illustrations I have found), it showed circles over layed on the centerline of an illustration of the lens to focal length distance to the film plane. E.g., f2.0 was illustrated with two circles each half the diameter of the focal length sided by side fitting the distance while f8.0, for example, had eight circles side by side on the line shown below. Each f-stop was shown in a series of separate similar drawings, one below the other on the same illustration.

I have spent hours with Google trying to find such an illustration without success. I do not have either the drafting skills or the software necessary to produce one myself. Could someone please direct me to a source for such an illustration or provide me one.

Thank you!

I am preparing to teach a class to senior citizens on the basics of photography. Many of these people have no math skills and will not understand formulas. I need a graphic to show them how the f-stop numbers are related to focal length. I remember an illustration I saw many years ago where instead of showing head-on side-by-side views of diaphragms set to each f-stop (like almost all the illustrations I have found), it showed circles over layed on the centerline of an illustration of the lens to focal length distance to the film plane. E.g., f2.0 was illustrated with two circles each half the diameter of the focal length sided by side fitting the distance while f8.0, for example, had eight circles side by side on the line shown below. Each f-stop was shown in a series of separate similar drawings, one below the other on the same illustration.

I have spent hours with Google trying to find such an illustration without success. I do not have either the drafting skills or the software necessary to produce one myself. Could someone please direct me to a source for such an illustration or provide me one.

Thank you!