GH2 Circle of confusion/shallow DOF the same for a GH2 at 25mm as a full frame at 50mm?

[nickn]

Suppose you have a full frame camera and a GH2 and that for simplicity sake the crop factor of the GH2 is 2. That is 50mm on the full frame is 25mm on the GH2.

Suppose you put a f1.8 lens on each one and focus each on the same subject at the same distance.

When the GH2 is at 25mm and the full frame is at 50mm, will the circles of confusion for both be the same? Will their backgrounds appear to be blown out/out of focus to identical degrees?

If not, why not? How will they appear different?

 

[Mezomorf]

No.

DOF with GH2 will be twice bigger
COC will be twice smaller for GH2

the answer to your question is COC because we use it to calculate DOF and COC it's different for different sensor sizes

 

[nickn]

Thanks for your reply

 

[TheDingo]

To match the DOF of a Full Frame sensor camera with a m4/3 sensor camera you have to use a lens with half the focal length of the Full Frame sensor camera, and you have to open up 2 f-stops.

So a 50mm lens at f/2.8 on a Full Frame sensor camera will have the same DOF as a 25mm lens at f/1.4 on a m4/3 sensor camera. ( assuming both cameras are shooting from the exact same position )

 

[J.F.R.]

To match the DOF of a Full Frame sensor camera with a m4/3 sensor camera you have to use a lens with half the focal length of the Full Frame sensor camera, and you have to open up 2 f-stops.

So a 50mm lens at f/2.8 on a Full Frame sensor camera will have the same DOF as a 25mm lens at f/1.4 on a m4/3 sensor camera. ( assuming both cameras are shooting from the exact same position )

Exactly, even then though I find F/1.4 on the GH2/3 still very shallow and honestly that's the fastest I would shoot. On MFT I honestly like it around F/2.0-3-5(most of my shots) with lighting of course.