GH2 ETC Crop Distance, What is the multiplication exactly?

memphishills

memphishills

Active member
Ok, so I love the ETC crop mode (makes every prime a 2 in 1) but I've read all kinds of different specs as to what the actual crop value of the ETC mode is. I've heard everything from 4.8 to 7.8x (all including initial GH2 2x crop).

Can someone tell me conclusively, with math and stuff, what the actually total crop will be to the lens, so I can calculate my lenses properly?

Thanks muchly!
 
The multiplication factor, to achieve a 35mm film equivalent focal length is 2x2.6= 5.2 . so a 50mm normal lens will become 260mm. This is the basic answer, but if you want to go into a bit more depth and perhaps confusion, you might be interested to know that the GH1+GH2 at the 16:9 ratio(not at 4:3) , actually have a larger sensor diagonal than "normal M4/3" sensor like the GF1 for instance because they have a multi-aspect sensor which means this:
4:3 - 4000x3000, diagonal 5000 pixels
16:9 - 4352x2448, diagonal 4994 pixels (essentially the same) . But it's important to realise that the 35mm film equivalent is 5.2x. If comparing to something like the canon 5D 2 which does not have a multi aspect sensor, when you shoot in its video mode which is 16:9 , the crop factor, as compared to the GH1/GH2 is more like 1.8x instead of 2x.
 
Just wanted to add something I forgot to mention which I think explains why you heard anything from 4.8x to 7.8x which depending on semantics, is all correct. You see the GH2 has two ETC crop modes , one for 1080p which is 2.6x and one for 720p which is 3.9, which is why it's important to specify which ETC mode you're talking about and I assumed before that you meant the ETC for the 1080p mode, so to sum up:
in 1080p, as compared to 35mm film, the multiplication factor is 5.2x
in 720p it's 2x3.9= 7.8
in 1080p, as compared to CANON 5D 2 16:9 video mode, the multiplication factor is more like 4.8x

hope this helps
 
Stefanos said:
Just wanted to add something I forgot to mention which I think explains why you heard anything from 4.8x to 7.8x which depending on semantics, is all correct. You see the GH2 has two ETC crop modes , one for 1080p which is 2.6x and one for 720p which is 3.9, which is why it's important to specify which ETC mode you're talking about and I assumed before that you meant the ETC for the 1080p mode, so to sum up:
in 1080p, as compared to 35mm film, the multiplication factor is 5.2x
in 720p it's 2x3.9= 7.8
in 1080p, as compared to CANON 5D 2 16:9 video mode, the multiplication factor is more like 4.8x

hope this helps
Click to expand...

Thank you, this was incredibly helpful and really well written! Thanks a bunch!
 
Actually the GH2 sensor in 16/9 mode, in horizontal angle of view, is more like a x1.9 factor from a full sensor, not a x2 (18,8mm versus 36mm).
 
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