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-   -   5DMkII 1080p Video Imatest MTF50 Resolution Testing Results (https://www.dvinfo.net/forum/canon-eos-full-frame-hd/228560-5dmkii-1080p-video-imatest-mtf50-resolution-testing-results.html)

Tom Roper April 23rd, 2009 12:13 AM

5DMkII 1080p Video Imatest MTF50 Resolution Testing Results
 
The test sample is my own 5DMkII body with V1.07 firmware, wearing a 50mm F1.4 prime lens, shooting an ISO12233 equivalent target in the center of the frame. Shooting the target from a tripod was 6.5 feet from the film plane. The camera settings were locked to the sweet spot of the lens, F/5.6, 1/50, ISO 400.

This is the same setup I have used to test my other video cameras that I have reported on at DVinfo. You can review those results as well, just search on my name and keyword "imatest".

Imatest is image testing software widely used for evaluating lenses and systems. Although the numbers are not comparable to other labs having their own established methods and procedures, they are comparable to my own as I have conducted the tests identically for the following video cameras systems:

Canon HV10
Canon XH-A1
Sony PMW-EX1
Canon 5DMkII

The test I performed was only for center resolution, MTF50, modulation transfer function, which reports the resolution at the point where contrast drops to 50%. The test normalizes the result to a standard 2-pixel sharpening radius, so that cameras with different levels of in-camera sharpening can be compared.

The 5DMkII has generated a lot of excitement for users, including me. Notable is the low light performance and potential for shallow depth of field opening many creative possibilities. Such videos have been amply demonstrated.

Unfortunately, it seems likely that more of that is owing to the talent of those users as the camera itself turned in rather pedestrian, underwhelming numbers. The 50mm F/1.4 prime is capable of out resolving the 21mp sensor at the center by a substantial margin, especially stopped down to F5.6, yet the limiting factor seems to be the Digic 4 processing which shoulders the task of downconverting the full frame sensor's native resolution to 1920x1080 in realtime.

In the end, the 1080/30p MTF50 results have the 5DMkII lagging behind all of the other HD/HDV video cams tested, the corrected horizontal resolution measuring just 623 lines, while the vertical a much more respectable 756 lines. For comparison, the Sony PMW-EX1 managed 931 horizontal lines, and an eye popping 1109 vertical lines.

5DMkII Horizontal

5DMkII Vertical

Nigel Barker April 23rd, 2009 07:32 AM

Quote:

Originally Posted by Tom Roper (Post 1126907)
The 5DMkII has generated a lot of excitement for users, including me. Notable is the low light performance and potential for shallow depth of field opening many creative possibilities. Such videos have been amply demonstrated.

Unfortunately, it seems likely that more of that is owing to the talent of those users as the camera itself turned in rather pedestrian, underwhelming numbers.

Do you think that your figures for the 5DII actually mean anything in real life? As an owner of both XH-A1s, an HV30 & 5DIIs I know which I think shoots the more detailed video.

How do you explain the difference between what your test measures & even the most casual recording on the 5DII by users without any talent? Perhaps some kind of optical illusion that fools us into thinking that the picture quality is better than it really is?

Yang Wen April 23rd, 2009 07:47 AM

Not to argue with how you conducted your test, but how does the HV10 even measure up to this? resolution-wise? A Day in Varanasi on Vimeo

I've got one and I know it doesn't... So I guess you can say I'm confused...

Daniel Jackson April 23rd, 2009 08:59 AM

Perhaps the 5d's sharpness with less lines is better than a less sharp image with more lines?

Wayne Avanson April 23rd, 2009 09:15 AM

I have to agree with the above. Tests are fine some but for me, I'm not interested. I just like the look of the footage.

Avey

Thomas Lowe April 23rd, 2009 09:26 AM

Can someone please sum up the results for me in layman's english?

Much thanks.

Jay Bloomfield April 23rd, 2009 09:33 AM

Quote:

Originally Posted by Tom Roper (Post 1126907)
The 50mm F/1.4 prime is capable of out resolving the 21mp sensor at the center by a substantial margin, especially stopped down to F5.6, yet the limiting factor seems to be the Digic 4 processing which shoulders the task of downconverting the full frame sensor's native resolution to 1920x1080 in realtime.

In the end, the 1080/30p MTF50 results have the 5DMkII lagging behind all of the other HD/HDV video cams tested, the corrected horizontal resolution measuring just 623 lines, while the vertical a much more respectable 756 lines. For comparison, the Sony PMW-EX1 managed 931 horizontal lines, and an eye popping 1109 vertical lines.

It doesn't surprise me that the true resolution of the 5D2 is somewhat lower that these other video cameras. But is the result really due to the Digic 4 downconverting? In the end, if you are working with imatest, you are working with a captured still image. It's also possible that the h.264 encoding done by the 5d2 causes the loss in resolution. Maybe that's what you meant by "Digic 4 processing".

An interesting experiment would be to check both 5D2 raw and JPEG still images (not the video captured to a still) at different resolutions and see what you get with imatest.

Chris Barcellos April 23rd, 2009 09:43 AM

However the camera does it, image wise, it appears to me to outshoot my HV20 and my FX1. Obviously unscientific. I don't know the tester, but something doesn't make sense here. I am getting the impression the the tester thinks the problem is with the processing of the image.

In any event, the resulting image is what it is all about, and resolving power is not what this camera, in the video world, is about. The fullframe sensor provides a new depth of field perspective for the low budget film maker, and thats what it is all about. The image that astounds many but apparently fail the OP's test, is a big plus too!

Tom Roper April 23rd, 2009 09:56 AM

The resolution limits are fairly obvious in real world pictures that contain horizontal or vertically spaced lines near the extinction point, moire patterns appear. They can be observed from the live view lcd window of the 5DMkII.

The following pictures illustrate this. The first is a small 100% crop of an area of detail. The second picture is a .jpg screen grab from the native .mov file captured by the Zoombrowser utility. The third picture is the same as the first, except that it has been resized from the native 5616x3744 by the Canon Digital Photo Professional utility, to 1920x1080 to match the dimension of the movie screen capture. This image also contains the EXIF shooting information. What it compares, is the effectiveness of the digic 4 resampling (or h.264) to resampling of the same raw by DPP.

All three images were shot with the 50mm prime, aperture locked at F/5.6, shutter 1/160th, ISO 100.

Area of detail, 100% crop
Screen grab of .mov
Still photo resized to 1920x1080 by DPP, with EXIF info

Your browser window needs to display the above images at 100% magnification for proper viewing.

Yang Wen April 23rd, 2009 10:04 AM

But Tom - You are comparing a still frame from the 5D2's video against a down-sized image from the 5D2's original 21MP image. It's like comparing the resolution of a still from HD camera to downrezed 35mm film material. The result is would be obvious. To better make your point is to compare the 5D2's movie frame to a movie frame of the same scene shot the HV10.

Tom Roper April 23rd, 2009 10:26 AM

Okay. I understand. The pictured scene is from the parking lot at work. I'll bring the HV10 with me tomorrow, and the EX1, and redo the shots.

Dan Brockett April 23rd, 2009 11:40 AM

Hi Tom:

As an engineer, it is easy to quantify cameras based upon numbers, better numbers equal a higher quality image. But as an artist, all of this measurement goes out the window. I shoot with the HPX170 mostly because I own it. I own it because I really like the way it records images I have created. I have two clients who own the EX1 and when I shoot for them, I use their EX1s. The EX1, by measurement alone, easily outperforms the HPX170 with much higher resolution, there is no denying that Sony EX1 is a much more detailed, sharper and higher resolution camera.

But to my artistic eye, the Panasonic HPX170 looks better. It uses a better codec, has more color space sampling and the color, contrast, gamma curve and matrix are more filmic than the EX1. To me, the EX1 has that interlaced Discovery HD look even when shooting in progressive modes. It looks great, but it does not convey the same feel that the footage from the 170 does.

I wonder if we are experiencing the same with the 5D MKII? Most people, in an A/B blind test with the other cameras you mention, would find the picture on the 5D MKII better, more detailed and more filmic. Yet according to your measurements, the 5D MKII has fairly average resolution measurements. I think the take away is that we perceive overall picture quality much more based off of an emotional recognition of how an image looks than by sheer resolution and detail.

Interesting test and thanks for doing it.

Dan

Chris Barcellos April 23rd, 2009 11:46 AM

Quote:

Originally Posted by Tom Roper (Post 1128402)
The resolution limits are fairly obvious in real world pictures that contain horizontal or vertically spaced lines near the extinction point, moire patterns appear. They can be observed from the live view lcd window of the 5DMkII.
.

Interestingly, I experienced the moire effect in a recent shoot. It was occuring on tile roofs in back ground, with my zoom at wide angle (28mm), and f stop around 5.6. Everything was in pretty sharp focus, and the moire pattern showed up on the tile roofs in background. In other shots, with F 3.5 set, and zoomed in a bit closer to the subject, the background loses focuses, and moire disappears.

Tom Roper April 23rd, 2009 12:04 PM

Quote:

Originally Posted by Chris Barcellos (Post 1128753)
Interestingly, I experienced the moire effect in a recent shoot. It was occuring on tile roofs in back ground, with my zoom at wide angle (28mm), and f stop around 5.6. Everything was in pretty sharp focus, and the moire pattern showed up on the tile roofs in background. In other shots, with F 3.5 set, and zoomed in a bit closer to the subject, the background loses focuses, and moire disappears.

I absolutely agree, and also with what Dan said. The moire is not going to be apparent in a lot of the intended desirable situations, tighter shots, shallow depth of field etc.

The 5DMkii 1080/30p video grab frame from below for example, there would never be a problem with.

Best friend

favorite quote, "When a dog is a man's best friend, THAT dog has a problem."

Jay Bloomfield April 23rd, 2009 01:45 PM

There might be one other variable thrown in, when comparing various video cameras: the quality of the decoder. The Canon HV10 the Canon XH-A1 are HDV (1440 x 1080, 1.33 PAR) and use MPEG-2 compression, so they can be compared. The Sony PMW-EX1 also uses MPEG-2, but at a higher bitrate and at a full 1920 x 1080. The Canon 5DMkII uses h.264 (MPEG-4), so that throws another variable into the equation.

But that said, depending on the testing workflow, a given computer will have a specific decoder for that type of compression. The test might come out differently on different computers. It's not as big an issue (since decoders are pretty standardized), as some others in this type of testing, but it still needs to be considered.


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