GH3 What's the real sensor size/ focal lenght lens difference between GH2 and GH3

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WielkiCzarnyAfgan

Member
Hey there. I have read many confuising opinions about GH2/GH3 sensor size difference which determines focal lenght crop factor. As we all know the GH2 crop factor is 2.0x ( for full frame ) and what's the factor for GH3? Heard that GH3 has about 10 or even 16% smaller sensor than GH2, what is true?
 
So if what's you saying is true, the 12-35mm on the GH2 is 11.4-33,25mm ( 22.8-66.5mm full frame ) and it is 12-35mm ( 24-70mm ) on the GH3 and AF100?

So the size difference is about 5.5% ?
 
WielkiCzarnyAfgan said:
So if what's you saying is true, the 12-35mm on the GH2 is 11.4-33,25mm ( 22.8-66.5mm full frame ) and it is 12-35mm ( 24-70mm ) on the GH3 and AF100?
Click to expand...

yes. That is the reason they went with the 12-35 as it gives the traditional 24-70 zoom which is common on a full frame. Most people just round the GH2 up to 2.0x crop to make the math easier. Either way it really is just a step back or forward to gain the same framing. IMHO people make too big of a deal of these crops. Full frame is the anomaly in the video world.
 
That 5% is really a non issue and in no way will affect the outcome of a shot. Take a look at the difference between 33mm and 35mm and you will see how silly it is to worry about the difference. In the real world it just is not an issue.
 
Ok, thanks. I was worrying because I've read many posts saying there is about 10% or even-16% smaller sensor in GH3. 5% is not a problem for me. Thanks a lot for reply
 
Thomas Smet said:
That 5% is really a non issue and in no way will affect the outcome of a shot. Take a look at the difference between 33mm and 35mm and you will see how silly it is to worry about the difference. In the real world it just is not an issue.
Click to expand...

Well, things get complicated in the wide end. It's the difference between 10 and 12mm that matters here. But you're right in some aspect, the more you go to tele, the less it matters.
 
WielkiCzarnyAfgan said:
Ok, thanks. I was worrying because I've read many posts saying there is about 10% or even-16% smaller sensor in GH3. 5% is not a problem for me. Thanks a lot for reply
Click to expand...

Take a look at BMCC footage which uses a smaller sensor than GH2/GH3....... Then you tell me if it's about sensor size........!!!........
 
Pietro Impagliazzo said:
Well, things get complicated in the wide end. It's the difference between 10 and 12mm that matters here. But you're right in some aspect, the more you go to tele, the less it matters.
Click to expand...

Percentage, not a 2mm difference no matter what. That is actually 11.4mm compared to 12mm not 10mm compared to 12mm. So yes 11.4mm is very close to 12mm. Sure it may be a larger difference visually on the wide end but I still stand by the difference being too small to really matter. Even at 12mm. If somebody is in a production environment where 12mm just isn't wide enough then 11.4mm also isn't going to be wide enough.

This crop thing really is splitting hairs.
 
WielkiCzarnyAfgan said:
Hey there. I have read many confuising opinions about GH2/GH3 sensor size difference which determines focal lenght crop factor. As we all know the GH2 crop factor is 2.0x ( for full frame ) and what's the factor for GH3? Heard that GH3 has about 10 or even 16% smaller sensor than GH2, what is true?
Click to expand...

Short answer: GH3's crop factor is 2.18X.

Long answer:

The confusion is probably due to lack of consistency. i.e. crop factor relative to what? I posted a graphic a while back that may help clarify things:

http://www.dvxuser.com/V6/attachment.php?attachmentid=21078&d=1285736508

So are we discussing crop factor relative to a photography frame? a 3:2 photography frame cropped to 16:9? an Academy motion picture frame cropped to 16:9? a Super 35 frame? Super 16?

But if we use the standard 3:2 35mm photography frame, yes, the GH2 has a 2X crop factor when shooting 4:3 and, because it uses a larger multi-aspect sensor (as shown in the graphic), it retains the same diagonal and thus 2X crop (relative to a full/uncropped 3:2 35mm photography frame) when shooting in 16:9 (and 3:2, but not 1:1). (Note: both the physical width and pixel dimension increase when shooting 16:9.) Whereas, while the GH3 also has a 2X crop when shooting 4:3, because it does not have a multi-aspect sensor, it does not retain the same diagonal (it gets shorter) and thus does not maintain the 2X crop (relative to a full/uncropped 3:2 35mm photography frame) when shooting in 16:9 (and 3:2). (Note: neither the physical width nor pixel dimension increases when shooting 16:9.) When shooting 16:9, the GH3's crop factor relative to a 3:2 photography frame is ~2.18.

And yes, when both cams are shooting 16:9, the GH2's multi-aspect sensor is ~18% larger than the GH3's sensor - Mark

P.S. the numbers:

standard 35mm photography frame 36mm x 24mm; diagonal ~43.2
standard 4/3 sensor: 17.3mm x 13mm; diagonal ~21.6 (Note: 43.2/21.6=2)

GH2's multi-aspect sensor when shooting 4:3--17.3mm x 13mm; diagonal ~21.6; resolution 4608 x 3456.
GH2's multi-aspect sensor when shooting 16:9--18.8mm x 10.6mm; diagonal ~21.6; resolution 4976 x 2800. (sensor area ~199 sq. mm)

GH3's sensor when shooting 4:3--17.3mm x 13mm; diagonal ~21.6; resolution 4608 x 3456.
GH3's sensor when shooting 16:9--17.3mm x 9.7mm; diagonal ~19.8; resolution 4608 x 2592. (sensor area ~167.8 sq mm)

199 sq. mm / 167.8 sq. mm = ~1.18 or 18% larger
 
One interesting fact is that 35mm on any camera I've used - GH1/AF100/7D/5D/F3 - is the sweetest spot. Even on my Canon 24-70 I often end up at 35mm.
 
BitMaestro said:
Short answer: GH3's crop factor is 2.18X.

P.S. the numbers:

standard 35mm photography frame 36mm x 24mm; diagonal ~43.2
standard 4/3 sensor: 17.3mm x 13mm; diagonal ~21.6 (Note: 43.2/21.6=2)

GH2's multi-aspect sensor when shooting 4:3--17.3mm x 13mm; diagonal ~21.6; resolution 4608 x 3456.
GH2's multi-aspect sensor when shooting 16:9--18.8mm x 10.6mm; diagonal ~21.6; resolution 4976 x 2800. (sensor area ~199 sq. mm)

GH3's sensor when shooting 4:3--17.3mm x 13mm; diagonal ~21.6; resolution 4608 x 3456.
GH3's sensor when shooting 16:9--17.3mm x 9.7mm; diagonal ~19.8; resolution 4608 x 2592. (sensor area ~167.8 sq mm)

199 sq. mm / 167.8 sq. mm = ~1.18 or 18% larger
Click to expand...

In photography we are often more concerned with linear resolution than area - i.e, Micro 4/3 is called a 2x crop (linear), not a 4x crop (area).
So we're talking about a 8% larger sensor size on the GH3 in linear terms.

In practice it may not be a huge deal for most, but it's actually good news for those of us who are using adapted 2/3" B4 lenses and others like c-mount lenses that vignette. Those lenses can be soft or dark in the corners and by cropping by 7 or 8 percent we'll be shaving off some of the offending corners and edges. This is a definite positive for me since I use, buy and sell so many B4 lenses.
 
So the GH3's sensor size when shooting video is actually 18% smaller than the sensor of the GH2? That's a pretty big difference... 2.18x crop factor is almost as 'small' as the BMCC... Not that you cannot create beautiful images with it (as can be seen from the BMCC footage), but didnt think the difference was that big...
 
If you are talking about calculating the diagonal. In terms of horizontal it is only 8%.

While I understand where the 18% number is coming from it doesn't exactly paint the full picture of what is going to happen. Different numbers with different meanings and typically a diagonal measurement is not one people will think about in the field. Knowing the width is about 8% tighter makes more sense in the field.

This still means a 12mm will basically act like a 13mm.


BitMaestro said:
Short answer: GH3's crop factor is 2.18X.

Long answer:

The confusion is probably due to lack of consistency. i.e. crop factor relative to what? I posted a graphic a while back that may help clarify things:

http://www.dvxuser.com/V6/attachment.php?attachmentid=21078&d=1285736508

So are we discussing crop factor relative to a photography frame? a 3:2 photography frame cropped to 16:9? an Academy motion picture frame cropped to 16:9? a Super 35 frame? Super 16?

But if we use the standard 3:2 35mm photography frame, yes, the GH2 has a 2X crop factor when shooting 4:3 and, because it uses a larger multi-aspect sensor (as shown in the graphic), it retains the same diagonal and thus 2X crop (relative to a full/uncropped 3:2 35mm photography frame) when shooting in 16:9 (and 3:2, but not 1:1). (Note: both the physical width and pixel dimension increase when shooting 16:9.) Whereas, while the GH3 also has a 2X crop when shooting 4:3, because it does not have a multi-aspect sensor, it does not retain the same diagonal (it gets shorter) and thus does not maintain the 2X crop (relative to a full/uncropped 3:2 35mm photography frame) when shooting in 16:9 (and 3:2). (Note: neither the physical width nor pixel dimension increases when shooting 16:9.) When shooting 16:9, the GH3's crop factor relative to a 3:2 photography frame is ~2.18.

And yes, when both cams are shooting 16:9, the GH2's multi-aspect sensor is ~18% larger than the GH3's sensor - Mark

P.S. the numbers:

standard 35mm photography frame 36mm x 24mm; diagonal ~43.2
standard 4/3 sensor: 17.3mm x 13mm; diagonal ~21.6 (Note: 43.2/21.6=2)

GH2's multi-aspect sensor when shooting 4:3--17.3mm x 13mm; diagonal ~21.6; resolution 4608 x 3456.
GH2's multi-aspect sensor when shooting 16:9--18.8mm x 10.6mm; diagonal ~21.6; resolution 4976 x 2800. (sensor area ~199 sq. mm)

GH3's sensor when shooting 4:3--17.3mm x 13mm; diagonal ~21.6; resolution 4608 x 3456.
GH3's sensor when shooting 16:9--17.3mm x 9.7mm; diagonal ~19.8; resolution 4608 x 2592. (sensor area ~167.8 sq mm)

199 sq. mm / 167.8 sq. mm = ~1.18 or 18% larger
Click to expand...
 
Ok so basicly the sensor is 18% smaller, but the width is only 8% smaller making the effictive crop factor 2.0x?
 
Stab said:
2.18x crop factor is almost as 'small' as the BMCC... Not that you cannot create beautiful images with it (as can be seen from the BMCC footage), but didnt think the difference was that big...
Click to expand...
The GH3 is almost exactly halfway between the BMC and the GH2 in sensor size.
 
In my view there's no point in comparing just horizontal (or vertical) frame sizes. The only numbers that matter are the diagonal, since that is what crop size is referring to, and total frame area, since that is one of the factors that affects low-light capabilities. Horizontal or vertical sizes have no meaning by themselves, only as a means to calculate the other two numbers.
 
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