Are 35 & 50 too close together?

Truman Prevatt wrote:

Snap Happy wrote:

The Ghost of Caravaggio wrote:

Snap Happy wrote:

...Here's the problem: 35 & 50 feel too close together for me. So do I:

Most photographers do not "feel" these two angles of view be too close together.

The angles of view for the Fujinon 35/2 and 50/2 lenses are 44.2° and 31.7° respectively.

For about 70 years 55mm and 75mm lenses 135 format (24 x 36 mm media and sensors) have angle-of-views of ~43° and ~32° for 50mm and 75mm lenses respectively. A lot of people spent money for both lenses, so empirically they are not too close.

The" feel" off a lens depends entirely on how far one stands from the subject(s). Here I use the word feel to describe an image's perspective[1]. One can make identical images with the 35 and 50 mm lenses just by moving closer or further from the subject(s).

If the photographer never has practical restrictions for where they can stand (the subject-to-lens distance), they only need one prime lens. Otherwise, different focal lengths provide composition versatility. If the these lenses "feel too close together" for you, chances are you subconsciously move closer (or further) from your subject(s) to achieve the image perspective you prefer.

1. "Perspective is conventionally defined as the size of objects in the frame. I am unfamiliar with a different definition, but am always willing to learn new things. The relative size of multiple objects does not change when cameras with different sensor sizes or focal lengths have identical subject to lens distances. Instead objects closer to the camera appear larger as the the lens to subject distance decreases." Roger Hicks

Yep, I get it perspective entirely depends on the camera position relative to the scene - not focal length as some people wrongly believe.

Not quite true. Run a little experiment. Hang a rectangle with 2 by 3 aspect ratio. Take two laser pointers and cross them and tape them together so that there is a 44 deg angle between the two lasers. Turn them on and walk find a point from the paper the the lasers are exactly at opposite edges of the paper and notice on a far wall where the laser spot is and mark it. Do the same with the angle at 31 degrees. Lets put some numbers in.

Say the long edge (the one that is the edge for the lasers is x feet - say one for arguments sake. The for lens of a field of view of a the x feet will define the edge of the field of view at a distance of d = x/(2*tan(a/2)). Now for a way y feet (y>x) away the laser spots will be separated by the same relationship. That is once the set up is set for two different angles of view and the distance for the rectangle is set so that it fills the angle of view of the sensor at a distance greater the distance between the two points of one will be given by that second distance (say a wall) and and the angle of view of the sensor. The ratio of the distances of the two different angles of view is given by tan(a1/2)/tan(a2/2).

You could also see this if you had a flash light with a variable been pattern. Set the beam pattern on narrow and shine it until it just illuminates to the corners. Look at the spill over onto the wall of the beam Now change the pattern to wide and move forward until the beam just covers the corners of the rectangle and check the beam pattern - it is bigger.

A lens projects all rays in the cone defined by the angle of view on to the sensor. While the distant for a given size rectangle to fill the sensor at that field of view will vary with the field of view. Past that object the there are rays within the angle of view of the wider lens that are outside the cone from the narrower field of view of the lens. So the perspective is not the same. Axial magnification also changes with the focal length which defines the angle of view.

However, I do feel that 16, 35 & 50 don't make for the most versatile 3 prime set for my use case.

Like all feelings, they are personal to the individual. Others may choose to share them or empathise with them.

Or not 😎

I literally need to go into a darkened room to think about that

In the mean time, I re-found an article by Thom Hogan I meant to link in this post:

https://www.dslrbodies.com/lenses/lens-articles/choosing-lenses/choosing-a-simple-prime-kit.html