5DMkII 1080p Video Imatest MTF50 Resolution Testing Results

[Tom Roper]

It was threatening to rain so I worked fast, no special attention given to any of the cams, except careful focus.

Notes:

These pics are about 500KB ea. You have to view them in your browser at 100% so you don't alias them yourself. The 5DMkII pic I converted from PC-RGB to Studio RGB with Cineform. All snapshots were video grabs from Vegas except the setup shot and area of detail, both by the 5DMkII.

5DMkII - 50mm prime, shot at F/5.6
HV10 - shot at F/4.0
EX1 - shot at F/4.0

The setup
Area of detail and focus(from yesterday)
The 5DMkII
The HV10
The EX1

[Josh Dahlberg]

Thanks Tom.

Wish I had an EX1 to complement my 5D. These shots clearly bear out your numbers. Different tools for different purposes.

Josh

[Oleg Kalyan]

I think, that color latitude from 5d is much wider, there are more color generally, compared to Ex1 or any other HDV camera. I'd put Canon H1 with x16 lens second to it, A1 goes next, EX1 follows up, IMHO>>
I've shot with Ex1 many times already, my assistant owns it, we've tested different cameras side by side, shapness from 5d is just pleasing for a human eye shown on an HD panel,
EX1 produces "dry", flat picture, (subjective to our eyes off course), no matter how much we tried to get a good color from it..
(that's why they went with Canon cameras for a blockbuster Crank, I guess :) using Ex1 only for slow mo shooting 720 60p, I guess)

[Elizabeth Lowrey]

Unruly moire was the first negative I noted when I shot with the 5D in video mode: it was on shingles, brick facades, anything with patterned detail that was even partially in focus. Now my eyes immediately go to it, like the other night when I shot folks in a concert audience -- a very wide shot -- and the lady on the far left was wearing a shirt with horizontal stripes. The colored moire as the camera moved in relation to her was not a pretty sight.

On the other hand, the shots of the band and closeups of the crowd - lit only by the reflection from the stage lights - were incredible. It will have to do until I get my RED Scarlet later in the year.

[Nigel Barker]

Tom, thanks for posting those images. My wife & I spent a long time laying in bed looking at them very carefully (it is Saturday morning after all:-). They all look different & I guess that different 'looks' appeal to different people. The 5DII looks sharper but has crushed blacks & moire patterns but it has an overall 'glassy' shine & richer looking colours that made us think that the image is better. The EX1 may have a the more natural colour but the 5DII is 'punchier'.

Photos & videos are all an optical illusion anyway as they are only representations of real life. Whether the more detailed image fools the brain that it is more lifelike or whether it's the shiny sharpened image that the brain interprets as the more realistic is clearly open to debate & may simple be a matter of preference.

One possibility that should be considered is that as the image has been extracted from a video & processed differently for each different recording technology that we are not really comparing like with like. It is also a rather artificial test for a video camera as we are not looking at the video as these photos are still captures that nobody ordinarily would see.

Interesting nonetheless. I shall have to try a similar shoot out between a 5DII, a XH-A1 & a HV30 but processing the video in FCP.

[Tom Roper]

You bring up valid point about punchiness/color, that I think was mistake on my part for not addressing with the shots. Some time ago I had made adjustment of the HV10 to reduce it's contrast and saturation in relation to EX1. The HV10 only has coarse adjustments for this, but the default settings take on something of a "neon" appearance otherwise.

The 5DMkII was using the "Standard" picture style for the pics. I believe it would more closely align with the EX1/HV10 if I had selected the "Neutral" style. To be fair, the EX1 can be enhanced for a more vivid look either in-cam or in-post.

There is also a fair amount (not excessive) of sharpening that accompanies the 5d2 standard picture style, that you can see as a darkened halo outline around the hood/engine bonnet of the pictured vehicle.

I first noticed this when I ran the Imatest with sharpness at 3, it was reporting sharpness as 21% over the standard for a 2-pixel sharpening radius. I reran the test with sharpness at 0, and now it reported sharpness as 15% under, and that's what I posted for the Imatest screen cap in the first post of the topic. But it should be noted, Imatest returned the same MTF50 corrected numbers either way. In any case, 3 may be too much but 0 is not enough.

[Tom Roper]

Originally Posted by Elizabeth Lowrey

Unruly moire was the first negative I noted when I shot with the 5D in video mode: it was on shingles, brick facades, anything with patterned detail that was even partially in focus.

Daniel Browning mentioned this earlier as well, and unless there is a fix for it, the achille's heel.

Daniel stated that the 5DMkII samples every 3rd line. I've been thinking about that ever since. More than just a processing limitation, it could be physical limitation to manage heating of the cmos sensor. While the Imatest reports the resolution numbers as low on the horizontal, the vertical is actually above the average.

[Evan Donn]

I think it's important to remember that perceived sharpness/resolution is relative to the content of the image - i.e. could you tell the difference in sharpness between any of these cameras when filming a flatly lit white wall? I think several aspects of the 5D's default image rendition contribute to greater perceived detail than is clearly present in objective measurements like these.

First off it shoots a fairly high-contrast image, even with contrast turned down in the image settings, and higher contrast tends to emphasize edges better than low contrast. Under similar conditions I also find the 5D to almost always produce less noise than my XHA1, which results in a very 'smooth' looking image - I believe this is also a function of the h.264 encoding which tends to smooth out noise in low-detail areas of the image more than MPEG2 does. This again increases the perceived contrast between sharp lines and the surrounding areas of low detail - so detailed areas and hard edges look 'sharper' than their measured resolution would suggest. This effect is further enhanced in shots which take advantage of the ability to achieve shallow depth of field - soft focus elements in the image make the focused areas appear sharper than they may really be.

All if which only goes to reiterate what so many people have said so far - the camera shoots an image which is more appealing than the other cameras for a lot of people. If that's you, it doesn't matter how the camera performs in these tests.

[Jon Fairhurst]

Originally Posted by Tom Roper

Daniel Browning mentioned this earlier as well, and unless there is a fix for it, the achille's heel.

The solution is a softening filter. My tests show that a Tiffen Soft/fx1 works well on an 85mm lens. I plan to get an fx2 for my 50mm lens and an fx3 for the 24mm...

The filter you choose is a compromise. A less aggressive filter will not remove all of the moire. A more aggressive filter will soften your edges. Unfortunately, there are no optical brickwall filters, so don't expect perfect resolution and anti-aliasing.

[Peer Landa]

Originally Posted by Jon Fairhurst

The solution is a softening filter. [...] The filter you choose is a compromise. A less aggressive filter will not remove all of the moire. A more aggressive filter will soften your edges.

This is also my thinking -- a filter would be the best solution of keeping the balance between a sharp image and getting rid of the moire.

-- peer

[Charles W. Hull]

Originally Posted by Peer Landa

This is also my thinking -- a filter would be the best solution of keeping the balance between a sharp image and getting rid of the moire.

Here is an off the wall thought. Is there any chance that a 5DMkII class of sensor could eventually be set up for 4K video? This might lessen the compromise between sharpness and moire.

[Jon Fairhurst]

Originally Posted by Charles W. Hull

Here is an off the wall thought. Is there any chance that a 5DMkII class of sensor could eventually be set up for 4K video? This might lessen the compromise between sharpness and moire.

Ideally, we'd be able to read out the whole sensor for each frame, which is what RED does. Unfortunately, the 5D MkII sensor/system isn't fast enough to do this. Even when skipping every third line, it takes 75% of a frame interval to read the data.

So, yeah, it could read out all the data, but no faster than 13.3 frames per second. Rolling shutter artifacts at that rate would make this a flubber cam!

[John Woods]

All:

I have spent an hour or two looking over the messages on this thread and another dvinfo alias discussion on this camera. My conclusion is that by subsampling vertically on the sensor pixels, rather than averaging over them, to get down to 1080 lines, the camera designer has given up the main line of defense against the aliasing that has been sometimes seen. While it is true that defocusing the lens and/or adding in an optical anti-aliasing filter will help alleviate the problem, unfortunately there is no real substitute for the above mentioned decision to sample the sensor output without a vertical average first. As some of you have mentioned, this may well have been done because the hardware read speed (sensor+computer) would not permit the vertical average together with a video frame rate output.

John Woods

[Jon Fairhurst]

Originally Posted by John Woods

While it is true that defocusing the lens and/or adding in an optical anti-aliasing filter will help alleviate the problem, unfortunately there is no real substitute for the above mentioned decision to sample the sensor output without a vertical average first.

Actually, the optical solution can totally remove the aliasing, but because we can't get a brickwall optical filter, you will lose some detail. In theory, we can get the same results as any camera with a native 1080 vertical line sensor.

It would have been awesome had they been able to sample the whole sensor though. Not only could we get high resolution without aliasing (given a powerful digital filter), we could have gotten three times the light sensitivity(!)

[John Woods]

You forget about the fill-factor. For this camera, in video mode, it just ins't there. So the vertical sampling is much harder to account for with a practical anti-alias filter.

John