Focal Length and Angle of View Illustrated

When it comes to angle of view, seeing is believing, so let's look at some example images:


Fisheye.  Probably a bad one to start with, since this is the only situation where focal length does NOT translate directly to angle of view.  A fisheye is as wide as you can go, in this case a 180 degree angle of view (when measured diagonally across the frame).  Still, it makes sense to start here since this is as wide-angle as you can get...

Ok now on to normal "rectilinear" lenses that won't distort the world like a fun house mirror!  I'm going to label these starting with the actual focal length of the lens, followed by the equivalent focal length for 35mm film that would produce the same angle of view.  Remember, 35mm film is still used as the "gold standard" when comparing angle of view (see the last post if you need a refresher).


10mm (equivalent to a 15mm focal length on a 35mm film camera).  This is about the widest you can go without a fisheye and is considered a "super-wide angle" lens.

12mm (equivalent to a 18mm focal length on a 35mm film camera).  Still "super wide-angle", but you can see we lost a lot of real estate in just two millimeters.  Compare the edges of this photo to the one above.

16mm (equivalent to a 24mm focal length on a 35mm film camera).  This is the end of the "super-wide angle" range.  Coincidentally, our cat Ping jumped up on the wall in the exact center of the frame.  You'll see her more later.

18mm (equivalent to a 28mm focal length on a 35mm film camera).  This was the beginning of the traditional wide-angle range before super wide-angle lenses were developed.

24mm (equivalent to a 35mm focal length on a 35mm film camera).  This is the end of the wide-angle range and the beginning of the "standard" or "normal" angles of view.

35mm (equivalent to a 50mm focal length on a 35mm film camera).  This is the middle of the standard / normal angles of view.

50mm (equivalent to a 75mm focal length on a 35mm film camera).  This is basically the end of the standard / normal angles of view and the beginning of the telephoto range.

70mm (equivalent to a 105mm focal length on a 35mm film camera).  This is in the beginning of the telephoto range, sometimes called a "short" telephoto.  Ping is really coming in handy at this point, good cat, please stay put!

105mm (equivalent to a 160mm focal length on a 35mm film camera).  We're starting to get pretty far into the telephoto range.  I am literally on the opposite end of the house from Ping.

135mm (equivalent to a 200mm focal length on a 35mm film camera).  This is the end of the traditional telephoto range and the starting point for "super telephoto".

200mm (equivalent to 300mm focal length on a 35mm film camera).  Ok, now we are in super telephoto land.  I also cannot BELIEVE Ping is still sitting there.

300mm (equivalent to 450mm focal length on a 35mm film camera).  This is the end of the road for me kiddies.  I can't afford a telephoto bigger than this.  They don't make amateur lenses longer than 300mm right now, and I have no intentions of spending $5000+ on a 400mm or longer telephoto lens!

THANKS FOR ALL YOUR HELP PING!!!  GOOD CAT!!!