Thu 08-Dec-11 12:48 AM | edited Thu 08-Dec-11 02:12 AM by bclaff
The values for Field of View (FOV) come up frequently enough that I thought a list might be helpful. Remember that focal length is stated for infinity and most lenses decrease in focal length as you focus closer; so Your Mileage May Vary (YMMV). Also, this is a table of rectilinear values; fisheye field of view is a different beast.
Sun 22-Jan-12 06:59 PM | edited Sun 22-Jan-12 07:02 PM by jmmcg9
I am debating about renting a Nikon 24-70 f2.8 lens for an important event next week to use in place of my Tamron 28-75 f2.8. I also have a Nikon 50mm f1.4. I want the improved IQ of a Nikon lens. This got me thinking about Focal Length & Field of View. You're chart Is a great resource for understanding the range of FOV I would achieve from the 24-70 in comparison to the 50mm when standing in one spot. Thanks for sharing! Is there a resource that will tell me for a given field of view (ie subject size might be a better description), how far away a specific Focal Length lens would need to be placed? This would tell me how much I would have to "move my feet" with the 50mm to achieve the the same range. Ideally, this would be a calculator in the form of an iPhone app. Does such an animal exist?
It should be fairly simple to make an app to determine the lens-to-subject distance, inserting focal length, desired size of subject on frame and object size.
By remembering basic geometry, one finds that when working with a subject at distances much closer than to infinity, the size of a subject's image in the frame is proportional to to the lens to subject distance, simply because two similar triangles have the same angle.
JRP, Thanks for the feedback. That would be a great addition to one of the many DOF apps on the market. I ended up going with my Tamron 28-75 and saving money. The good news is I just sold the Tamron & replaced it with the Nikon 24-70 f2.8! That is one sweet lens! I still think that calculator would be useful to someone trying to decide on bringing a zoom or Primes.
Sun 02-Sep-12 11:58 AM | edited Sun 02-Sep-12 12:04 PM by jesse101
ok im a bit confused or maybe i am interpreting this chart incorrectly. But i cannot see where it shows a 50mm on a FX body equals to about 70mm on DX..or is this chart something totally different? my apologies ahead of time if i am asking something that should be particularly obvious.
this is my guess on interpreting the chart:
30 61.9 43.6 71.6 42.6 29.1 50.2
50.2 FX lens mounted on a DX body equates to 71.6? but then what about the focal length of 30?