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Bobby Shore

7D resolution vs sony EX 3

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hey,

 

just curious, would the sensor size of the 7D have better resolving power than the sensor size of an EX 3? I guess in theory I'm thinking yeah (the same way 35mm resolves better than 16mm), but since both the 7D and the EX 3 shoot native 1080P HD, would the sensor size necessarily make that big of a difference?

 

I've tried researching, but haven't really found anything too concrete. Thanks in advance for any input.

 

bobby shore

www.bobbyshore.com

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The BBC allow the EX1/3 to be used on SD productions, the 5D is not considered acceptable to the BBC for SD Production.

 

hey,

 

just curious, would the sensor size of the 7D have better resolving power than the sensor size of an EX 3? I guess in theory I'm thinking yeah (the same way 35mm resolves better than 16mm), but since both the 7D and the EX 3 shoot native 1080P HD, would the sensor size necessarily make that big of a difference?

 

I've tried researching, but haven't really found anything too concrete. Thanks in advance for any input.

 

bobby shore

www.bobbyshore.com

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The BBC allow the EX1/3 to be used on SD productions, the 5D is not considered acceptable to the BBC for SD Production.

 

hey stephen,

 

thanks for the reply... for me it's more a question of whether or not the 7D could serve the shoot well for some of the wide shots we're planning. We're planning on finishing to film (which will probably be the next thread I start - EX 3 filmout), so I'm curious if the larger HD sensor would actually better resolve fine detail.

 

I've found some info for the EX at 1000 TV|/ph, but nada on the 7D.

 

bobby

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Depends on the type of film you're out to make. Do you need the shallower DoF of the 7D. Can you work within the limitations of the 7D and/or the EX3? Sensor size alone isn't really the way to compare cameras. A 7D might be great for run and gun documentary shooting where you want to hide your video camera, but on a narrative set the EX3 with it's "known" workflows and the fact that it's built like familiar video cameras (and hence can take their accessories easier) might be useful. Or maybe you need to shoot a 45 minute interview-- then you'd have to use the EX3. Or you're planning on just a series of short shots and you can get away with the 7D (which I think has a recording size limit). Or you are in some ugly locations and need to throw the backgrounds out of focus and need the DoF of the 7D.... so many variables. A little more information on the project and the aesthetics you're looking for would be helpful.

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I just bought a 7D and have been shooting with it for the past two days. It is soft at 1080 24P, certainly softer than the EX3. Playing it back on a 50" 1080P plasma HDTV via HDMI and on a 23" Cinema Display in Quicktime/FCP.

 

I think it would be acceptable downconverted to 720P, certainly all the 720P footage I've seen from the camera on Vimeo has looked sharp. The camera also does not have much dynamic range - it blows out quickly and clips hard in a nasty video-y way, and the noise floor is definitely there in the lower third of the histogram. I'd stay at 800 ISO or under and protect highlights, 1000 ISO is definitely pushing it. The 5D footage I've shot looks sharper with better dynamic range - it has a bigger sweet spot out of the box. Both cameras have some banding in out of focus areas. I was also not able to get rid of tv flicker even with a 1/60 shutter. Have not encountered any fluorescent flicker yet.

 

Frankly, I think the 7D is great for web and standard def distribution, but I'd hesitate to use it for anything going back to film and the big screen. We have to be realistic - for $1,700 you're still getting a lot of camera, and it's fun to shoot with. It is surprisingly difficult to focus (depends on your lenses, of course) and to keep the image stable in handheld. Keep in mind how big your final output will be and slow down your camera movements accordingly.

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The BBC allow the EX1/3 to be used on SD productions, the 5D is not considered acceptable to the BBC for SD Production.

 

I spoke with a man from Frontline PBS at the HD World convention a couple of weeks ago. He was talking about the 5dII and he said that they wouldn't recommend it to their field ops simply because it was tapeless. They aired footage from a 5dII because the stuff this freelancer in Afghanistan got was amazing, but they said they would stick with HDV or other non-tapless cameras. I'm assuming that would be the BBC's position on the 7D, unless they ruled the 5D2 fit for SD productions.

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The video resolution of the Canon 7D (and most likely the 5DM2, too) is considerably less than the Sony EX1 & EX3.

 

See Barry Green's trumpet chart tests on DVXUser.com:

http://www.dvxuser.com/V6/showthread.php?t=186334

 

The Panasonic GH1 fared a tiny bit better than the 7D, but its video isn't nearly as good as the EX1/3:

http://www.dvxuser.com/V6/showthread.php?t=187165

 

However, it's interesting how -- despite these "DSLR" cam's relatively poor technical performance -- they are capable of producing fairly pleasant-looking HD video when handled appropriately. There are many examples of this available online.

 

But the chart tests don't lie: The actual video resolution of the 7D, GH1 & 5DM2 is quite low compared to most other HD video cams.

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I spoke with a man from Frontline PBS at the HD World convention a couple of weeks ago. He was talking about the 5dII and he said that they wouldn't recommend it to their field ops simply because it was tapeless. They aired footage from a 5dII because the stuff this freelancer in Afghanistan got was amazing, but they said they would stick with HDV or other non-tapless cameras. I'm assuming that would be the BBC's position on the 7D, unless they ruled the 5D2 fit for SD productions.

 

Hi,

 

The BBC don't accept the 5dMKII for SD broadcast due to aliasing. Alan Roberts who tests all cameras for the BBC wrote:-

 

'Yes, I have done formal tests on one and found out just what it does. 30Hz is a problem, but not the most significant one (the spectacular spatial aliasing, which makes it very difficult to compress well for broadcast at a sensible bit-rate). Canon have told me that the model they supplied for test was the version to be sold. So it gets a thumbs down for broadcast use'

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Update re: nasty video-y clipping.

 

I've started netting the back of all my primes to take the curse off the hard clip, and it's made a huge improvement in the look (while probably doing terrible things to "real resolution", but who cares about that!). The softening effect is in between a 1/8 and 1/4 BPM with nice halation and a creamy, more filmic texture. I'm curious what effect (if any) this will have on aliasing. Anyone know?

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What goes on with video engineers? It seems they think in terms of what we will compromise for when they design these widgets.

 

How many stream processors would it take to run the whole 5D or 7D sensor without compression at 24 fps? How many UDMA's at once to take the whole sensor in actual uncompressed bits with an internal clock to sync them all to when you dump the data to computer.

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Guest Matti Poutanen
Update re: nasty video-y clipping.

 

I've started netting the back of all my primes to take the curse off the hard clip, and it's made a huge improvement in the look (while probably doing terrible things to "real resolution", but who cares about that!). The softening effect is in between a 1/8 and 1/4 BPM with nice halation and a creamy, more filmic texture. I'm curious what effect (if any) this will have on aliasing. Anyone know?

 

What did you use for netting the lens?

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Thanks Stephen.

 

What did you use for netting the lens?

I use Berkshire Ultra Sheer nylons in Fantasy Black color. I did a lot of testing back in January for a 35mm shoot, and these were the ones I liked best. They looked great on the big screen in 35mm, and were surprisingly subtle. They cost around $7 a pair! Stretch it across the back element and attach it with some snot tape (3M Scotch ATG tape).

 

I did not test pure silk since I could not find any in my area, and it is super expensive online. The Berkshires give a 4 star cross pattern on highlights (which I could do without), and also create a rainbow diffraction around highlights (which I like). They do create a significant amount of halation.

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What goes on with video engineers? It seems they think in terms of what we will compromise for when they design these widgets.

 

How many stream processors would it take to run the whole 5D or 7D sensor without compression at 24 fps? How many UDMA's at once to take the whole sensor in actual uncompressed bits with an internal clock to sync them all to when you dump the data to computer.

 

I suspect the stills market wouldn't want to pay for these processors. The system seems to have been developed for photojournalists to provide video for the news web sites, which it does just fine.

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hey,

 

just curious, would the sensor size of the 7D have better resolving power than the sensor size of an EX 3? I guess in theory I'm thinking yeah (the same way 35mm resolves better than 16mm), but since both the 7D and the EX 3 shoot native 1080P HD, would the sensor size necessarily make that big of a difference?

 

I've tried researching, but haven't really found anything too concrete. Thanks in advance for any input.

 

bobby shore

www.bobbyshore.com

 

 

Well, the larger sensor of the 7D (which is Super-35 in size I believe, i.e. APS-C, not FF35 like the 5D) would mean that a lens could have a lower MTF and still capture fine detail compared to a smaller sensor with a sharper lens. However, the 1080P recording is a limiting factor to some degree, not to mention that the way that the Canon still cameras create 1080P involves tricks like line skipping (and the OLPF was not really designed for this), not to mention the compression scheme used, so you aren't necessarily getting the maximum potential resolution from the sensor anyway. However, there will be a difference in Depth of Field between the 7D and the EX3 unless you compensate with the f-stop, and shallower-focused images often give the illusion of looking sharper because only the subject is in focus relative to a soft background.

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Well, the larger sensor of the 7D (which is Super-35 in size I believe, i.e. APS-C, not FF35 like the 5D) would mean that a lens could have a lower MTF and still capture fine detail compared to a smaller sensor with a sharper lens. However, the 1080P recording is a limiting factor to some degree, not to mention that the way that the Canon still cameras create 1080P involves tricks like line skipping (and the OLPF was not really designed for this), not to mention the compression scheme used, so you aren't necessarily getting the maximum potential resolution from the sensor anyway. However, there will be a difference in Depth of Field between the 7D and the EX3 unless you compensate with the f-stop, and shallower-focused images often give the illusion of looking sharper because only the subject is in focus relative to a soft background.

 

David, thanks the reply. I guess there's a lot more to consider than just the sensor size. I was able to filmout both footage from the EX 3 and 7D, but unfortunately it couldn't be a side by side comparison. If I can swing it, I figure the best way to actually answer this question would be matching wides blown-up to film. If I can get production on board, I'll post the results.

 

@ everyone else - thanks for all the info and advice, much appreciated.

 

bobby

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The Canon vDSLRs are not 1080p cameras, period. Maybe 720p, but even then you are subject to horrendous aliasing if you point it at the wrong subject.

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PBS’s Frontline, one of the most beautifully shot and edited documentary programs on television, produced segments for it latest show Obama’s War with the Canon 5DmkII. One of the DP’s, Danfung Dennis , shot the opening sequence with a custom rig that allowed it to be attached to a steadicam rig.

 

Frontline Shoots Doc with Canon 5DmkII

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Are they less 1080P cameras than previous HD cams that shot 1440P with 2/3 inch sensors?

 

The Canon vDSLRs are not 1080p cameras, period. Maybe 720p, but even then you are subject to horrendous aliasing if you point it at the wrong subject.

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Are they less 1080P cameras than previous HD cams that shot 1440P with 2/3 inch sensors?

The DSLR cams produce "HD" video with about 600 lines resolution or so, plus lots of aliasing. Links to test charts are here:

http://www.cinematography.com/index.php?sh...st&p=304072

 

I wouldn't be surprised if the live SDI output of my Sony DSR-450WSL (a SD cam with three 1MP 2/3" CCDs) would be higher res when properly up-converted to 1080p compared to what's produced by the current crop of "HD" DSLRs.

 

Doesn't mean DSLRs can't produce useful HD video. But they aren't as truly hi res as most "traditional" HD video cams, including some relatively inexpensive ones, or even some SD cams.

 

See also:

http://www.dvxuser.com/V6/showthread.php?t=187503

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The DSLR cams produce "HD" video with about 600 lines resolution or so, plus lots of aliasing. Links to test charts are here:

http://www.cinematography.com/index.php?sh...st&p=304072

 

I wouldn't be surprised if the live SDI output of my Sony DSR-450WSL (a SD cam with three 1MP 2/3" CCDs) would be higher res when properly up-converted to 1080p compared to what's produced by the current crop of "HD" DSLRs.

 

Doesn't mean DSLRs can't produce useful HD video. But they aren't as truly hi res as most "traditional" HD video cams, including some relatively inexpensive ones, or even some SD cams.

 

See also:

http://www.dvxuser.com/V6/showthread.php?t=187503

 

hey peter, thanks for the link to the barry green article, was really informative.

 

bobby

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That is an interesting article, but what is more interesting about it is that none of the points made in it are anything new. Digital video has always used smoke and mirror tricks to hide aliasing, chromatic aberration, and banding. Digital video has long used edge sharpening and contrast to make an image appear sharper than it really is. The points made in the article apply to pretty much all digital video formats in one way or another.

 

HD and SD use entirely different sample rates, bit rates, chroma sampling, and color space. I seriously doubt the Sony DSR-450WSL can equal the 5D, because its recording less information in every way.

 

Its a interesting article but I wouldn't call it the final word on HDSLR shooting. There will be more tests that will reveal more information.

 

 

The DSLR cams produce "HD" video with about 600 lines resolution or so, plus lots of aliasing. Links to test charts are here:

http://www.cinematography.com/index.php?sh...st&p=304072

 

I wouldn't be surprised if the live SDI output of my Sony DSR-450WSL (a SD cam with three 1MP 2/3" CCDs) would be higher res when properly up-converted to 1080p compared to what's produced by the current crop of "HD" DSLRs.

 

Doesn't mean DSLRs can't produce useful HD video. But they aren't as truly hi res as most "traditional" HD video cams, including some relatively inexpensive ones, or even some SD cams.

 

See also:

http://www.dvxuser.com/V6/showthread.php?t=187503

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... HD and SD use entirely different sample rates, bit rates, chroma sampling, and color space. I seriously doubt the Sony DSR-450WSL can equal the 5D, because its recording less information in every way. ...

 

Hi Tenolian: I may be misunderstanding Sony's resolution specs for the DSR-450WSL, but they say it's capable of "850 TV lines (4:3 mode), 800 TV lines (16:9 mode)":

http://pro.sony.com/bbsc/ssr/cat-broadcast...duct-DSR450WSL/

 

Sony's SDI output option installed in the DSR-450WSL outputs "live" (not from tape) uncompressed 10-bit 4:2:2 SD video in 24p, 30p or 60i.

 

I believe the current DSLRs record highly-compressed (<50 megabits/sec.) 8-bit 4:2:0 24p, 25p, 30p, 50p or 60p (depending on the model) 1080 onto SD/CF cards. Their relatively lo-fi "live" video outputs (if available) are not intended or typically suitable for program recording.

 

And although Barry Green doesn't get the final word on DSLR HD video quality, in addition to the article & tests referenced above, he also says: "Problem is, if you eliminate all the aliasing [in DSLR HD video], you're going to be left with only the true resolved detail that these cameras can provide, and that's not much more more than standard-def. It is the presence of aliasing that makes these cameras look sharp at all. ..." There's more:

http://www.dvxuser.com/V6/showpost.php?p=1...mp;postcount=23

 

It would be very interesting to take the live SDI output of a DSR-450WSL (fitted with an HD 2/3" lens) and properly up-convert it to 1080p using a Teranex Mini or AJA KiPro system, and then compare the resulting HD video to what is recorded to SD/CF cards by the 5DM2, 1DM4, 7D and GH1.

 

Of course, my idea is silly, too, considering the vast cost difference of these two piles of gear. But it would be a fun comparison, and depending on the subject(s) of the test video, enlightening to me at least! :)

 

All the best,

 

- Peter

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The numbers between HD and SD don't correlate that way. 4:2:2 and 4:2:0 don't mean the same thing between SD and HD because HD is sampling (at least) twice as much information, and recording a higher data rate.

 

Plus there are a lot of questions about the authors methodology for shooting the resolution chart. He didn't give any information about his method or what lens he used. He very likely could have used a better lens that could have resolved more detail.

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