A7RII in Crop mode DOF

Started Jul 28, 2019 | Discussions thread
sjazz
sjazz Contributing Member • Posts: 660
Re: A7RII in Crop mode DOF
1

Pixel Pooper wrote:

sjazz wrote:

Pixel Pooper wrote:

These 2 statements are contradictory because when you crop an image you change the FF equivalent focal length, so you also change the DOF.

Following your statement I will do an experiment. I have a 8x10" print that I'm going to crop with scissors. I will let you know if either the focal length or DOF changed

This is a red herring, because as stated numerous times in this thread, the reduced DOF is caused by the extra enlargement required to display the crop at the same size as the uncropped image.

When you crop a print with scissors you don't enlarge it, but you can get the same effect if you hold the cropped print closer to your face so it subtends the same angle in your vision as the uncropped print.

Also, it it the equivalent focal length that changes, not the actual focal length.

You are assuming a couple of things that I'm not. Extra enlargement and holding the print closer to my face. If you don't move anything, taking a photo on a FF camera set to APS-C mode will be the same as cropping in post.

Now, if you enlarge, zoom, move or use a camera with APS-C sensor, then results are how you mentioned.

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j.a.

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