28mm lens, square cropped, 6x6 approx equivalent?

[northeast16th]

I'll be shooting a 28mm lens on a 35mm camera, but I'm going to crop square, and I'm wondering if anyone knows the approximate angle of view as if you were shooting a 6x6 camera.

I'm thinking it's going to be about a 60mm on 6x6, but I'm no math genius. Just curious to find out because I'm familiar with what a 6x6 angle of view is, and it would be nice to know before I go off shooting.

 

[Matus]

This should be easy. 35mm square cropped is 24x24 mm. 6x6 is 56x56 so the conversion factor is 56/24 = 2.3 So the equivalent to 28 in 6x6 is about 65 mm.

 

[Godfrey]

Here's a field of view calculator:

http://www.mat.uc.pt/~rps/photos/angles.html

For 24x24 mm format with a 28mm lens, you have 46.4 x 46.4 degrees with diagonal 62.4 degrees. That is very similar FoV to a 6x6cm camera fitted with a 65mm lens.

The big difference, of course, is that you'll have a LOT more depth of field to work with compared to a 6x6 cm camera. Here's a sum up of the difference using DOFMaster:

----
6x6cm @ f/8 for 10 foot focus distance:

Depth of field
Near limit 7.97 ft
Far limit 13.4 ft
Total 5.43 ft

In front of subject 2.03 ft (37%)
Behind subject 3.41 ft (63%)

Hyperfocal distance 38.7 ft
Circle of confusion 0.045 mm

----
24x24mm @ f/8 for 10 foot focus distance:

Depth of field
Near limit 5.2 ft
Far limit 132.4 ft
Total 127.2 ft

In front of subject 4.8 ft (4%)
Behind subject 122.4 ft (96%)

Hyperfocal distance 10.8 ft
Circle of confusion 0.03 mm
----

Compared to the 6x6 camera, with your square 35mm camera you'll be able to achieve the same DoF at f/2.2 or so.

 

[Matus]

Godfrey, that is a nice summary. I would only add, that the difference on DOF would get even larger if the size of Circle of Confusion would be the taken same in both cases (what would translate into same enlargement factors if one were to print the images - the 6x6 image of course 2.3 times larger than the 35mm image)

I hope this does not sound confusing 🙂

 

[northeast16th]

awesome, thanks for the responses. the reason i'm going with 35mm is that I want everything in focus at midrange apertures, from about 8 feet to infinity, so this works out great. 65mm on 6x6 is a good focal length for what i'm doing.