GH1 16:9 lenses wider than stated!

T

Tameside

Well-known member
The GH1 uses a 4:3 frame as we all know and a 2x crop as c/w 35mm frame. Reality is that lenses are stated for that format, however, GH1 uses a multi-aspect sensor, essentially bigger in 3:2 and 16:9 and not much off an APS-C sensor in 16:9 format.

If you quickly run through the images you will see the lenses are far wider in 16:9 and this carries over to video. By simple calculation the lenses are actually about 9%wider than there stated focal length for 4:3. eg the 20mm is actually a 18mm aprox or 36mm c/w 35mm frame and the 14-140 actually starts at about 25.5mm! obviously this has the effect on the tele too, which means its really a 255mm as well.

I think this is correct but welcome any disagreement.
 
As a side note on this, you wouldn't happen to know the sensor size in mm for each aspect ratio (4:3, 3:2 and 16:9)? As I've been using the GH-1 for stitching/ 3d tracking using 3:2 format (to get less distortion at the edges than 16:9 as you're using the central part of the sensor, and the need to stick in a sensor size (or film back) is important.

And linking back to your point, what is the multiplier for focal length that you've arrived at for each aspect ratio?


thanks

mike.c
 
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pixel pitch is 4.3microM in 4:3 according to;

pixel pitch is 4.3microM in 4:3 according to;

http://www.dxomark.com/index.php/eng/Image-Quality-Database/Panasonic/Lumix-DMC-GH1#

Which seems to equate in 4:3 to 13mmx17.3, so the width in 16:9 is actually 19mm(Update Pana say 4.36) APS-C are 22.3mm for the Canon 7d, 1.6 crop. ie about 17.5%larger and knowwhere near bigger than the marketeers will have you believe.

Therefore probably easier to think of it as a 1.8 x crop. in 16:9!

Therefore a 14mm lense*1.8 = 25mm. Therefore the new 14mm pancake f2.5 looks interesting. Also, the zoom is actually a 25-250mm! the 7-14 is actually a 12.5mm -25mm too, very wide for sure. The Olympus option as a 9mm looks possibly a better compromise as is actually a 16mm lens wide open and 32mm full tele.

Overall not much in it really between aps-c, especially Canon, Sony are slightly larger sensors, 1.5 crop, but really!

Please feel free to correct my maths am no mathematician.
 
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Whats really interesting is the pixel size

Whats really interesting is the pixel size

the 7d/550d are actually 4.2microns and the GH1 are 4.36microns , so the pixels in the GH1 are larger than the 7D, it has more obviously than the GH1 but the size is the same and the crop is 1.8 vs 1.6 in 16:9. People should be aware of all of this, add in that iso800 on the GH1 is more like iso1600 on the Canon's.

http://www.dxomark.com/index.php/eng/Image-Quality-Database/Compare-cameras/(appareil1)/337%7C0/(appareil2)/350%7C0/(appareil3)/329%7C0/(onglet)/0/(brand)/Panasonic/(brand2)/Canon/(brand3)/Canon

and the sum is there aint much in it really between all of them and probably in some respects the GH1 is ahead.
 
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Man, this is the kind of stuff that I should have figured out long ago...

Yes, it does appear that the sensor size is a lot closer, and therefore the FOV and DOF a lot closer, between the GH1 and the 7D than was previously thought.

The "1.0" vs. "1.6" vs. "2.0" crop numbers are for still photography, based on a 1.5:1 aspect ratio, and are not directly applicable to film and the 16:9 aspect ratio.

If we dispense with the old notion of the still photography "crop factor" and instead use the 35mm motion picture film frame as the "1.0" gold standard, and ignore 4:3 but instead use them for 1.85:1 extractions, and use the GH1's actual sensor size instead of the standard u4/3 size, then it shapes up like this:

35mm cinema film: 22mm x 11.9, for a diagonal of 25mm.
Canon 7D/T2i: 22.3mm x 12.05, for a diagonal of 25.3mm.
GH1: 18.9 x 10.22, for a diagonal of 21.5mm.

Based on these numbers, we could define a new (and probably far more useful) "Cinema Crop Factor". The 7D and T2i have a Cinema Crop Factor of basically 1.0. The GH1's Cinema Crop Factor would be 1.18.

So let's forget the whole "2.0" and "1.6" and all that, and let's deal with reality here. The movies, as shot on 35mm film, have a Cinema Crop Factor of 1.0, and so does the 7D and T2i. The Gh1 has a Cinema Crop Factor of less than 1.2. The 5D has a Cinema Crop Factor of 0.62.
 
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Kholi said:
ARG! Hunter Richards and I were saying this SO long ago! Nobody listened to us. LOL
Click to expand...

Well sometimes genius has to wait for the rest of humanity to catch up.

You think Einstein's work was immediately accessible to the masses?

I think not!

:laugh:
 
I knew it was talked about, but I didn't know if it was ever actually quantified.

I think the CCF of 1.18 makes it understandable and approachable and dispels all the confusion. I had always thought of it as a CCF of 1.3, based on the generally-accepted "Crop Factor" numbers that are published, but ... it's almost half as cropped as I thought!
 
Glad you both agree.

Glad you both agree.

I think its useful for a new std like you say Barry, I dont think anybody is making much compromise whatever they choose Kholi.

If we can fix that mud, and you'd think Pana would want to more than anything else, then the GH1 is a great option for sure.
 
I want to either get a GH-1 or 5D. But, hoping GH-2 comes around sooner than later. Would like to skip Pulldown and all of that, and at least have a video tap.
 
eye-fi x2?

eye-fi x2?

Does anybody know if you can read the eye-fi card m2ts files as its being written? this could be a wireless tap;-) and possibly more useful as maybe multiple devices can view the files?
 
Tameside said:
Does anybody know if you can read the eye-fi card m2ts files as its being written? this could be a wireless tap;-) and possibly more useful as maybe multiple devices can view the files?
Click to expand...

No, I already answered it some time ago.
Eye-Fi internal construction do not allow such low level operation.
 
OK thanks

OK thanks

Thats a pity? so when you create this add-hoc network between the laptop and the camera is it only to allow an upload of files from the camera? it doesnt make it a wireless disc that can be read-written to-from?
 
Tameside said:
Thats a pity? so when you create this add-hoc network between the laptop and the camera is it only to allow an upload of files from the camera? it doesnt make it a wireless disc that can be read-written to-from?
Click to expand...

No, company that make it mirror wireless disk will be very succesfull.
And they have all knowledge from Eye-Fi (as they use general components and some Chinese factory to do assembly).
 
Canon, aps-c in 1080 may be 1.7x even

Canon, aps-c in 1080 may be 1.7x even

Havent done the maths completely here, but because the sensor is 3:2 in design it effectivel crops top and bottom off to create the 16:9, but it may crop in further on width too, certainly if I use the same maths for sensor width as the GH1, using pixel pitch of Canon with smaller pixels gives us 21.7mm, just 2.7mm larger than the GH1 and smaller pixels to boot. It may be that the aliasing in APS-C is because of the extra scaling from 3:2 to 16:9 where as the GH1 is doing this natively. In any event, I wouldnt be surpised if the crop in 1080 for the Canon's and other APSC moves up a notch. Certainly the difference is very minimal.
 
Could someone please kindly post up the mm size and diagonal pitch for each of the GH-1 aspect ratios (1:1, 3:2, 4:3, 16:9) with the focal length multipliers while they have their head in the problem, and the maths at hand.

A simple list that becomes a reference for all.


ta very much

mike
 
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