# Gaining the angle

An illustration on how equalling the relative, subjective framing from one format to another by way of altering distance to "see" the way that a lens looks according to a different format.

From the previous chart: Attempting to illustrate the basic concept of depth of field across formats. While mathematically the APS-C settings aren't completely accurate (due to variences in "APS-C" sensor sizes) it is a basic outline based on general crop factors, rounded to 1, 1.5 and 2x for Full 35mm frame, APS-C and Micro 4/3 formats respectively.

While we often hear that Full Frame offers shallower depth of field, it's not entirely true. That is only true if you are to use a focal length to frame a scene or subject with the same angle of view it would provide on a Full Frame, 35mm format sensor. From a fixed location, the smaller the format, with the same focal length and aperture setting, you will achieve a shallower depth of field. This can be handy if needing to shoot from a fixed location (ie: birding, sports, safari, trips to the zoo, etc) when wanting to achieve a shallower depth of field for subject isolation.

You can read more if you'd like on my blog here: Aperture, Focal Length, Sensor Size, Exposure and Depth of Field.

JonathanPosnerPhoto, Shahid Hameed, and 3 other people added this photo to their favorites.

1. i'm opening a mini studio and i use a 50mm in my Nikon D3100 this will be very usefull THANKS!!!

2. You might be interested in this blog post I wrote, which makes a related point.

eriksphotoblog.blogspot.com/2012/07/using-focal-length-to...

While the framing of the subject is the same in your three examples, the framing of the background is not. This is a useful fact, which can be leveraged to your advantage when trying to isolate the subject from the background.

3. Thanks Erik,

You're right. I tried to clarify this in the article by referring to it as "relative framing of the subject" when using these examples. To gain the same angle of view, the focal length needs to be altered based on format, but if using a fixed focal length where the format is the only variable, I wanted to show how the DOF was affected, and also to dispel exposure confusion as well as many of the "that 75mm f/1.8, is like a 150mm f/3.5 lens on full frame" comments which are only situationally true as well as being incorrect, or at the very least, incomplete statements.

Thanks for the link, I'll have a read.

cheers,
t

4. stunting shot

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