Crop Factor, Low Light and Aperture with m4/3 lenses?

Started Jun 15, 2014 | Discussions thread
Fygaren Regular Member • Posts: 238
Re: Crop Factor, Low Light and Aperture with m4/3 lenses?

Fygaren wrote:

Fygaren wrote:

Another thing that hasn't been mentioned is that only the FoV is cropped, perspective compression and distortion remain unchanged as they are dependant on focal length. For 50mm on FF, you still need a 50mm on m43, you will just have to be a bit further back. Or you can remain the same distance using a 25mm, but the photos are ultimately different.

Perspective compression and distortion is ONLY dependant on distance to subject.

Cheers

The photos Ulric provided are surely substantial to the discussion, but the effect I refer to is not apparent. So there, I am confused. Here is a (better?) demonstration of what I meant:

http://filmmakeriq.com/wp-content/uploads/2012/05/focal-length.gif

The effect in the link is from different distanse to the subject.
If you would do the same using only one lens (cropping the picture as you move furter back to make it look like the subject is at the same distanse), the effect would be exactly the same using the same focal lenght on all pictures.

If focal lenght had anything to do with it, you would see fisheye effect on the tele end of compacts...

Cheers

Yes, cropping it will keep it the same but you lose resolution and detail. The pictures Ulric posted are at different focal lengths, the same as the link so I am not sure why the effect is not apparent. :? I'm just going by the exif data... are you saying that Ulric posted cropped photos rather than ones taken at different focal lengths, and different subject distances?

Ulric took 3 photos with different focal lenght from the same distance. As he crops the wider ones he simulates a camera with a different crop factor and shows that the compression is exactly the same with different focal and crop factors. If he had changed his distance to the subject as he changed focal lenght, he would have the same effect as you showed in your link.
So changing the focal lenght does not change compression, but changing distance to subject does.

Cheers

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