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CROP FACTOR: Sensor Size vs Focal Length ▶︎ Why Does One Change?

Photo Moment - August 31, 2018

Have you ever wondered what “crop factor” is, or why a 50mm lens on your APSC or Micro Four Thirds sensor camera isn't really a 50mm lens? This video answers and explains this relationship.

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I hope that covers everything you wanted to know, (or didn't know you wanted to know). If you still happen to have any questions, feel free to ask them here!

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•• Panasonic Lumix 14mm f/2.5 ••

•• Canon EF 14mm f/2.8L II USM Lens ••
Great explanation and examples, thank you
Nice video. One of the few video's that makes it clear that crop cameras don't change the focal length. For those interested in crop vs full frame test look in YouTube for "Pentax K1 Full Frame vs Crop modes Test"
my mind was blown when you talked about the definition of a telephoto lens
haha awesome
Hi PhotoJoseph

To get same size photo with aps-c sensor as in 50 mm lens with full frame camera , we need to take ~35mm apps-c lens
Correct. APS-C is usually about a 1.5x or 1.6x crop. Different manufacturers have different implementations.
Which lens would you consider to be the best overall for the GH5 in a studio setup with two people talking in front of it plus occasional product reviews?
The 12-60 is a great all purpose lens, and it’s on sale now, too!
PhotoJoseph Thanks so much! I’ll use your link to purchase.
Nicely done!
Hi Joseph, regarding the gh5, when attaching a manual lens to a gh5 the camera asks for the focal length to be chosen, my understanding is this is for the stabilisation to work correctly with that focal length, correct? If so, what would you need to select as the focal length of say a Helios 58-2 with a .71 speedbooster as an adapter? The effective focal length of the Helios without the speedbooster is 116mm on the gh5 but is 82mm with the speedbooster, so do I choose 58,116 or 82? Thanks, apologies if there is an error in calculations
Yeah that can be confusing. Yes it’s for stabilization. Enter the actual focal length, not effective. The LUMIX doesn’t care about “full frame equivalent”. So it’s Helios x 0.71 that you enter. So that’s 58x0.71=41.
So what do we think will happen to Panasonic's 4/3 line up after they release their full frame.
Will they slow down development for 4/3rds and go all in for full frame, or can both systems get equal support?
So g-d tired of listening to "YouTube experts" ( cough, pretty boy and pretty wife, you-know-who, cough) giving these long explanations that throw BASIC OPTICS and PHYSICS out the door!?!?! 😣
This was the most simple and realistic point about: field-of-view and ability to capture data in a digital camera.
Yes the marketing has become the "alternative facts" to how a lens and sensor work.
Just stop the madness. 🙄🤓😎
Amazing explanation. Keep all of this up, in this sort of detail. Onwards to 100k Subscribers!
Good explanation. But what I think is needed is a follow up video on a more practical issue - how does this affect aperture and iso at identical shutter speeds when using different sized sensored cameras.
Different conversation for another video.
The best explenation sensor size in yt, realy:) from A to Z!!!
Great explanation Joseph! Thank you for that!
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