GH1 Sensor Size

Thomas Richter · May 7th, 2009, 02:26 PM

A few may remember me getting a bit overenthusiastic on the sensor size ;)

This video clip in the footage section compares Nikon D90 and GH1:
Comparison the GH1 and the D90 - Panasonic GH1 on Vimeo

I just took too screenshots and experimented until I could match the GH1 image to the Nikon D90 (slightly different angle of view, but check the flower pots in the image)

The GH1 image matches the D90 image best at 80% image width. In other words 1020 out of 1280 pixels. This means the sensor width is 80% of the D90's 23.6mm, which equates to (self-ironic drumroll): approx. 18.9 mm width (by 10.6 mm height in 16:9).

Not the 17.3mm by 13mm Panasonic states.

Why should anyone care? Well 18.9mm width is only around 10% away from the projected area in 35mm cinema film. Plus it means in 16:9 lenses become quite a bit wider horizontally. I hope to eventually rely on the 20mm pancake lens announced by Panasonic as a mild wideangle.

The GH1 may have codec limitations, but in terms of cinematic DOF I think it will be doing pretty well :D (as Phil Bloom has already illustrated).

Bill Koehler · May 7th, 2009, 08:13 PM

People may also remember my rather elaborate attempts to calculate it's dimensions.
Glad to know I'm wrong - it's larger than Panasonic's specs. indicate.

Illya Friedman · May 8th, 2009, 02:44 AM

When I first looked at the sensor I thought it looked slightly larger than what I read in the original specs. I never revisited it and didn't confirm, so I don't know for certain.

During NAB I did some quick calculations on a napkin, and came up with a 16 point-somethig% difference in HFOV between the GH1 and S35/APC, comparing same aspect ratio (16:9). That is 16% more telephoto on the GH1.

So to achieve a the same FOV as an 85mm lens on a 35mm camera you would use a 100mm lens on the GH1 (actuall 101mm- but close enough). I can find out definitively once I do some real testing, but it was kind of low priority for me at the moment.

Hope that helps,

I.

Illya Friedman
Hot Rod Cameras

Illya Friedman · May 8th, 2009, 02:54 AM

Quote:

Originally Posted by Thomas Richter

Why should anyone care? Well 18.9mm width is only around 10% away from the projected area in 35mm cinema film.

One more note- I worked my numbers from camera aperture not release print hypotenuse- I think the difference between aperture and release, is that release is about 5% or so smaller, to make room for the optical track, so the numbers sound pretty close to me.

It's slightly misleading to compare camera aperture to release projection hypotenuse, as this is a smaller number than S35 full aperture. If you want keep it apples to apples for HFOV, I recommend comparing camera full aperture to camera full aperture- and matching aspect ratio as closely as possible. As I mentioned, should be around 16 point something %.

I.

Illya Friedman
Hot Rod Cameras

May 7th, 2009, 02:26 PM	#1
Thomas Richter Regular Crew Join Date: Apr 2005 Location: Frankfurt, Germany Posts: 181	GH1 Sensor Size - larger than specs A few may remember me getting a bit overenthusiastic on the sensor size ;) This video clip in the footage section compares Nikon D90 and GH1: Comparison the GH1 and the D90 - Panasonic GH1 on Vimeo I just took too screenshots and experimented until I could match the GH1 image to the Nikon D90 (slightly different angle of view, but check the flower pots in the image) The GH1 image matches the D90 image best at 80% image width. In other words 1020 out of 1280 pixels. This means the sensor width is 80% of the D90's 23.6mm, which equates to (self-ironic drumroll): approx. 18.9 mm width (by 10.6 mm height in 16:9). Not the 17.3mm by 13mm Panasonic states. Why should anyone care? Well 18.9mm width is only around 10% away from the projected area in 35mm cinema film. Plus it means in 16:9 lenses become quite a bit wider horizontally. I hope to eventually rely on the 20mm pancake lens announced by Panasonic as a mild wideangle. The GH1 may have codec limitations, but in terms of cinematic DOF I think it will be doing pretty well :D (as Phil Bloom has already illustrated). Attached Thumbnails

May 7th, 2009, 08:13 PM	#2
Bill Koehler Major Player Join Date: May 2007 Location: Alpharetta, Georgia, USA Posts: 760	People may also remember my rather elaborate attempts to calculate it's dimensions. Glad to know I'm wrong - it's larger than Panasonic's specs. indicate.

May 8th, 2009, 02:44 AM	#3
Illya Friedman New Boot Join Date: Dec 2005 Posts: 14	When I first looked at the sensor I thought it looked slightly larger than what I read in the original specs. I never revisited it and didn't confirm, so I don't know for certain. During NAB I did some quick calculations on a napkin, and came up with a 16 point-somethig% difference in HFOV between the GH1 and S35/APC, comparing same aspect ratio (16:9). That is 16% more telephoto on the GH1. So to achieve a the same FOV as an 85mm lens on a 35mm camera you would use a 100mm lens on the GH1 (actuall 101mm- but close enough). I can find out definitively once I do some real testing, but it was kind of low priority for me at the moment. Hope that helps, I. Illya Friedman Hot Rod Cameras