GH2 1:1 Crop Mode

[Bill Hollinger]

GH2, 100-300 EX Tele (1560 mm) video

GH2, 100-300, EX TELE setting, 24P on Vimeo

This is a H.264 file file, with no adjustments. I converted the MTS file to Apple ProRes HQ, and exported the H264 from FCP. Media info shows the MTS file bit rate as 21.3 kbps (the max rate shows as 21.7 kbps). I used the 24P(H) setting. I’ve included some video with focus shifting and image wobble to show the issues I encountered at this magnification, despite using a heavy Miller video tripod and Sachtler fluid head. The latter part of the video is at 300mm, which is the equivalent of a 1560mm lens on 35mm.

Bill

[Adrian Frearson]

Considering the extreme focal length, I think you did a pretty good job of keeping it under control. The image looks very clean.

[Les Wilson]

The bokeh is nice, not at all like a small chip camera, then again, what small chip camera and lens could even resolve 1500mm like that! Woot!

[James Chen]

Originally Posted by Daniel von Euw

The DoF of the 1080p crop is equal to a 1/2" sensor.
The DoF of the 720p crop is equal to a 1/3" sensor.


regards
Daniel

I believe this is incorrect, the 1:1 crop has absolutely no effect on depth of field. The sensor size itself isn't changing, nor is the flange distance changing to compensate and the circle of confusion remains the same. To my understanding, in the 1:1 crop mode, the three factors of depth of field (circle of confusion, aperture and subject distance) all remain the same. The circle of confusion for 4/3" is 0.015mm. Panavision rates a 2/3" chip CoC at 0.009mm. A 1/4" chip is about ~0.0025mm.

I'll put it another way, the 1:1 crop factor is the exact same as if you were able to take footage shot without the crop mode, go into Photoshop and crop the center of the image while maintaining resolution. Cropping in Photoshop would have absolutely no effect on depth of field. If it did, I would approach cinematography very differently.

[Rohan Dadswell]

A 50mm lens is a 50mm lens - the DoF doesn't change no matter what you put it on. Large sensor or small the DoF is the same (OK, there are very small differences) what changes is the Angle of View.

If you have a head shot with 50mm on the GH2 and then use the crop you will need a wider angle lens (about a 20mm) to get the same shot - which will have a deeper DoF. If you are using it to get the close up the DoF stays the same.

[Paulo Teixeira]

I have a lot of "full frame" and crop shots in here:

GH2 - ISO + tele conversion comparisons - Christmas Eve 2010 on Vimeo