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Crop factor and DOF

mdpontin 17 6.0k Scotland
9 Apr 2007 12:34PM
Well I've certainly learned something from this thread. I've learned that I don't understand a word of it! Wink

Krakman 14 3.6k Scotland
9 Apr 2007 1:02PM

Quote:Did we decide that the crop factor doesn't affect DOF?

Crop factor has a similar effect on DoF to switching to a longer focal length with a full frame sensor. It doesn't affect the absolute depth of field of the image, but it does affect the way that we look at the image, so that for practical purposes there seems to be less depth of field.

So we perceive there to be shallower depth of field with a crop sensor, even though the relative sharpness of different elements of the image hasn't changed.

You get the same effective depth of field with a 75mm lens on a full frame sensor as you do with a 50mm lens on a 1.5x crop sensor.
spaceman 17 5.3k 3 Wales
9 Apr 2007 1:55PM
If a crop sensor makes the lens "longer" then you'll need to be further away from your subject - won't the added distance increase the DOF (and alter the perspective)?
Just Jas 19 26.3k 1 England
9 Apr 2007 2:11PM
However you argue this there is no doubt in my mind, from looking at the pictures, that I get more depth of field from my S602Z than I do from full frame, 7.8mm on S602Z and 35mm lens on full frame 35mm camera.

From the same position, viewpoint and effective lens angle of view and same size print.

User_Removed 15 4.9k England
9 Apr 2007 3:01PM
Yer but yer but yer, but yer, but yer but yer but?!!!!!!
If you take an image with any focal length, any crop sensor and blow the subject up to the same size each time........They'll all have the same DoF......theorectically!! BUT they won't appear so visually
Think that's right [;-D
Bryn_Jones 17 186 United Kingdom
10 Apr 2007 6:26PM
Maybe we need a technique page on this and then can someone translate that into stoopid for me!

Hell I just think more blurry small f number less blurry BIG f number, but always remembering that where that blur begins and ends you may have to adjust the f number so that you show everything you want to in focus or maybe a soft focus for some of it, depends on what you want to show.
certx 14 415 1 United States
11 Apr 2007 12:43PM

Quote:Maybe we need a technique page on this and then can someone translate that into stoopid for me!

I'll definitely second that notion!! Smile Perhaps we COULD get a technique page on it. How would we go about asking for one?

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