Video Accessories Misc
- Written by John E. Johnson, Jr.
- Published on 25 December 2008
On the Bench
Falloff in the wide angle lens setting showed negligible variation across the field of view. In fact, it was no more than about 0.1 f/stop variation in brightness consistency.
Video cameras seem to be getting better and better in this regard. I was used to seeing much more variation, particularly at wide angle settings. 0.1 f/stop is essentially no variation at all.
Canon is renown for their lenses, and maybe I should not be surprised.
At the longest telephoto setting, I got essentially the same results. This is really a very even response. You can expect your videos not to have any vignetting at all.
Here are the MTF50 sharpness (otimal resolution for viewing) test results for 1080i60 and 1080p30. Both were taken in the MXP mode (24 Mbps). The chromatic aberration results are in between each of the MTF50 graphs. The third MTF50 graph is from 1080p30 at 5 Mbps.
So, you can see the following: At 1080i60, the MTF50 sharpness value is 612 LW/PH (Line Widths per Picture Height), while at 1080p30, it is 559 LW/PH. The 1080p30 is also undersharpened, while the 1080i60 is essentially sharpened the right amount. So, it would seem that the 1080p30 video is not quite as sharp as the images at 1080i60 in terms of MTF50 which is the optimal sharpness for viewing (I duplicated the test to make sure). Chromatic aberration is also better with the 1080i60 images, although it may be an insignificant difference. Overall, chromatic aberration was about the same as other cameras in this price range, but much higher than the more expensive Sony PMW-EX1.
Now, in the third pair of graphs, taken at 1080p30 and at the lowest bitrate of 5 Mbps, the MTF50 value dropped to 433 LW/PH. So, it seems obvious that, all other things being equal, the higher the bitrate, the sharper the picture. The 5 Mbps image is also undersharpened by quite a bit, but even the corrected MTF50 value in the 5 Mbps graph which takes this undersharpening into account still does not bring the MTF50 value up to what it is at 24 Mbps. It could mean that trying to sharpen an image with such a low bitrate would introduce too many artifacts. The chromatic aberration is a bit higher as well.
Here is the Chroma DuMonde test pattern, which is a standard in the TV industry. It is very close to the original, with just a hint of oversaturation.
The gray scale is shown below, followed by the test results. Whites are not attenuated, so you may experience an occasional blown out highlight. The noise level is more than the Canon HG10 that we tested, but less than the Canon HV20.
The Q-60 color chart has the right tints, but is a bit underexposed.
The ColorChecker SG results are good. The top right corner of each color square is the way it should look, and the bottom right corner is the way the HF11 reproduced that color. Perhaps a little overexposed though.
The test where I measure the time it takes to go from a wide open aperture (lens is blocked) to closing down when exposed to a bright lamp indicated a longer time than I have seen in previous cameras I have tested. This may be due to the apparent higher sensitivity (you can take videos with very low ambient lighting).