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Messages - Policar

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286
Lenses / Re: Photo lens - aperture vs resolving power....
« on: March 24, 2012, 12:51:16 PM »
There are charts for diffraction limits and how they relate to megapixels, but it's not cut and dry.  Since the airy disk fuzzes detail gradually (it doesn't either resolve or not resolve something, although the point at which you get to 0% mtf is calculable) and a bayer sensor doesn't really resolve its quoted resolution completely there probably will be a difference in detail between f2.8 and f5.6 on the 7D resulting from diffraction, but it would be imperceptible and only the very, very best lenses are diffraction-limited below f5.6 and chances are CA, curvature of field, depth of field, etc. will be much bigger issues than diffraction until you hit f11.

If you had perfect lenses and a 300 megapixel sensor (maybe even more than that) you'd be right, but that's assuming a lens that's way more perfect than any that actually exists.  Although I heard rumors (hype) the Leica Summilux cine lenses were diffraction-limited before f4, and it's possible Canon's super telephotos are, too, but then the sensor is still a limiting factor, and of course its light gathering ability is another concern (more noise or less sensitivity when you crop).

287
well I didn't understand ur point regarding less banding noise in 60D,T2i n T3i  than 7D .... can u explain this ...

In theory if you shoot low ISO raw and push it really far there will be more pattern noise in a 7D's shadows than in a Rebel's, if I understand correctly, which I might not.  It's a very trivial difference, doesn't matter at all in practice.

288
EOS Bodies - For Stills / Re: Something's up....
« on: March 21, 2012, 04:01:07 PM »
I ordered less than a minute after the camera went up for pre-order.  Had the first confirmation email of anyone I know of based on what's been posted online.

Card has not been charged.  Status remains "pending."  Really unhappy.

Yes, that sounds a bit odd.  Have you tried calling them and asking what is going on?

Maybe (just speculating here) they got a very large number of cameras - enough to fill all the preorders placed in the first few days - and are processing the orders in batches according to shipping methods, not in strict order# ... meaning the people with the slowest shipping get processed first ...

That's possible.  I ordered with the slowest shipping (free) but it's one day to me.  Maybe it's by geographical location.

289
EOS Bodies - For Stills / Something's up....
« on: March 21, 2012, 03:39:56 PM »
I ordered less than a minute after the camera went up for pre-order.  Had the first confirmation email of anyone I know of based on what's been posted online.

Card has not been charged.  Status remains "pending."  Really unhappy.

290
Same sensor, but the 7d has twice as many readout channels, I think?  In theory that could mean less skew and/or other advantages, but in my experience video from the 7d and t2i/t3i (never used a 60d) is indistinguishable.  If anything, I think I like the t2i's image more...probably because I own one.  But I couldn't tell the difference double blind if they were set the same and had the same lenses.  Video closely resembles the 5DII but in theory the smaller cameras have a little less resolution, a little more noise, and are inexplicably faster at a given ISO (not enough to cancel out noise)...plus obvious DOF differences.

The t2i and 60d will take cleaner stills since the fewer channels the less banding noise but the 7d is a killer still camera in terms of ergonomics and interface (minus the now sub par screen).  Very nice camera.

291
Software & Accessories / Re: Negative Printer for 35mm film
« on: March 19, 2012, 03:39:04 AM »
The Nikon scanners are really nice.  You can probably find a place that scans with them and scans affordably or buy one used online (though demand seems to outstrip supply atm). 

One thing I've noticed is that flatness matters a lot.  A lot of my slides had very soft corners with the Nikon 9000 but when I scanned with glass the results were much better and multipass matters a lot.  I found scanning film to be frustrating--the resolution is so much poorer (and grain so much worse) than digital and it's a lot of work.  But the colors look incredible, velvia looks so much better than any digital alternative to me.

292
1080i via hdmi is probably really 1080psf so with a little pulldown removal you're okay.

External recording might be important to someone.  It certainly makes a difference if you're recording in log mode.  But it's the type of feature that seems more at home with higher end cameras and throwing too much (sound recorder, external video recorder, monitor, etc.) on a dSLR negates its greatest advantages (size, ergonomics, ease and speed of use).

Things that don't appear in specs (subjective look, resolution, skew, aliasing, etc.) are far more important to most users.  When someone starts worrying about clean hdmi out but not about the fuzzy images coming out of the 5DIII you have to wonder about their priorities.  Are there more interested in specs or IQ?


293
Do we have confirmation that the Mk III is binning pixels? Everything Canon has said implies that moiré is being removed by the DIGIC 5+ processor, and mentions nothing about binning.

Also, if the sensor is being binned, why is the maximum sensitivity of the movie mode lower than than that of stills mode? Binning should allow for higher ISO sensitivity, not lower.

The idea that it uses 3x3 pixel binning is based on some quote from a Canon spokesperson regarding the video in the 1DX, I believe.  I think he said something along the lines of "all pixels are being read out on the 1DX" and then someone said the 5DIII did something similar--and now for whatever reason everyone assumes it's 3x3 binning.

That said, canceling out aliasing in post is like virtually impossible without absolutely destroying resolution.  And the 5DII only skipped pixels in one axis it seems, probably binning them in the other.  So it's reasonable to conclude (or at least hope) its not 3x3 pixel skipping, which should be much worse....

This reasoning is still just a bit crazy.  Not just because the idea is based on quote regarding a different camera without a neat 1080p divisor res'ed sensor but moreso because the 5DIII's sensor doesn't divide into 1920X1080 neatly as the c300's does.  Bayer is 1:2:1 in terms of how R:G:B are represented.  Apply that to 5760X3840 and you have 1440X810 for two channels and 2880X1620 for the other.  Not 1080p at all.  If the c300 is doing what people label 2x2 pixel binning, it's getting true 1080p out of it.  If the 5DIII is doing the same process but 3x3, it's getting upscaled "810p" out of it.

294
EOS Bodies - For Video / Re: Real video samples from 5d Mark iii?
« on: March 16, 2012, 02:49:17 AM »
Here's another one that MIGHT be a 5D Mark III (it is only labelled as "Mark III"). Having looked at the 1920x1080 file, this one seems to show very nice resolution. It appears to be shot at a high frame rate, but the image is quite nice if you can get over the lack of stability by the camera operator. Rolling shutter still shows up, but of course it would when shot like this. The C300 footage looks dreamy to me, and the "Mark III" looks quite good, too.
https://vimeo.com/38536929

Thanks!  Well, he sold me on the c300...although it looks over sharpened in a way I'm not familiar with.  That I couldn't tell what was 5DII and 5DIII until I looked doesn't bode well, but the 5DIII's resolution isn't any worse and the rolling shutter is obviously improved.  Still looks like dSLR footage to me overall.  Really hard to conclude anything from that.

295
EOS Bodies - For Video / Re: 5D MkIII vs D800 for video
« on: March 09, 2012, 12:29:05 PM »
Unless you're doing extensive vfx or aren't very good at exposing (or need a really flat look for whatever reason), clean HDMI out is not that important...  And most of those external recorder devices are pains in the ass and/or big and expensive...  At that point, just get an FS100 (or F3 or C300).  Kind of defeats the point of a dSLR (small and cheap).  I'm sure someone out there needs this feature, but for most it's a just talking point.  A lot will depend on how the all intraframe codec performs; fwiw, the c300's codec is surprisingly great so you never know...

Specs don't mean much relative to how the footage performs subjectively and how it measures on test charts.  Specs are usually a best case scenario.  We don't have test charts, just a few clips online.  So far it seems like the 5DIII has less aliasing and skew and better low light abilities but the footage is really soft. When both cameras are released and further tested we'll know the full story.

296
EOS Bodies / 8 channel readout
« on: March 05, 2012, 12:17:20 AM »
What does this mean?  The 5DII has four channels, 5DIII has 8, 1DX has 16.  How fast does each channel cycle?

It seems like the 5DIII can capture 6fps at full raster and that in each case a channel correlates with about 3fps.  Does that mean the 5DIII reads out 1/5th of the sensor at 30fps?

How can the camera avoid line skipping if the full sensor can only read out at 6fps?

297
Video & Movie / Re: I want a better quality video For the 5dm3
« on: March 04, 2012, 09:06:29 PM »
There's a HUGE market at the $3,000 price point among videographers and student filmmakers.  You can buy a couple lenses and have a usable kit under $4,000 or you can spend significantly more and develop something that's almost production-ready for music videos and shorts or as a b camera for a serious rig.  Canon would be foolish not to introduce an EF mount cinema camera in this price range, but for whatever reason it seems they want to start with expensive products and work their way down...

1080p/60fps would be nice, but is trivial compared with a reduction in aliasing and skew and a boost in actual resolution.


for the same reasons all other film-product competitors don't have equipment that cheap. Sony does have the fs100, which is at $5k, and you can now get canon/nikon mounts for it.. but there are still substantial limitations. The benefit though, even over the f3, is that you get 60fps@1080p.. the downside is the bitrate and color space, and only hdmi out, as well as the form factor and build quality. Enough people already complain about the fs100 in the professional video field.

You also have to remember.. sure, there is a huge market base for$ 3-4k as you say.. but there is an even BIGGER market base for $1-2k, or $300-500 - what's to stop them at 3-4grand if sheer volume of market sales was their intentions? I, for one, would love to save up for the c300 of f3, as the Arri Alexa is out of my price range.. and i'm simply happy and fortunate to have a professional option for less than 20 grand.. something that could provide me with a return income that costs about what a new Honda costs.

I suppose that's true.  PL mount cameras are allowed to be expensive since a decent kit of lenses or zooms starts around $30,000, though.  But for EF mount cameras, you can outfit one cheaply.  There's been a huge market in the $2,000-$5,000 range for a while (from the XL1 to the dvx to the hvx to the 5dII) of aspiring professionals.  Below that is, for better or worse, mostly dabblers, above that is pros.  If the 5DIII reads out like the C300 and produces decently sharp video it could very well be the next camera in this segment.

298
Cheers all. I'll see what I can do. Doubt I'll be able to slip in a CF card.

I had a private showing at Arri of the 1Dx and C300 days after they were announced, they wouldn't let us use cards then, so I doubt they would let me at a trade show.

I doubt I'll get any numbers from the reps, they tend to repeat what is in the marketing materials.

Video cropping, HDMI out, taking photos at high ISOs is my main area of interest. If there are no cards in the camera, it may be hard to view on screen as it will disappear after a few seconds.

Ask about video resolution vs the 5DII!  If the 5DIII is using a method similar to the c300 (full read out bayer sensor but no bayer interpolation or downscaling) and using a full raster read out it should be incredibly sharp.  If it's pixel binning then debayering or line skipping or something it could be softer than the 5DII.  Ask about resolution and sensor readout relative to the c300!

299
There's actually a pretty easy answer to this question.  But it takes a while to get there.

First, take into account that bayer sensors don't resolve the full resolution of the image you end up with.  They resolve about 70% in each axis to nearly 100% mtf, then alias a bit, then mtf drops to zero.  But with sharpening (since digital is so low noise) you can boost this up so it seems higher.  Remember, perceptual sharpness is most accurately represented by the measure of the area under the mtf curve--NOT where that curve hits extinction--and sharpening can bring areas of that curve over 100%.  This means 25 megapixels is really closer to 12 "perfect" megapixels, but in practice seems significantly sharper than that.

Take fuji velvia 50, the sharpest color film; it has 100% mtf up until the equivalent of 4-6 megapixels, I think, (not going to bother to look up numbers, could be more or less), then hits extinction at about 25 megapixels.  And my scans back this up.

Depending on how you measure (mtf going under 100; mtf reaching extinction; area under mtf curve), you'd get something like 4, 12, or 25 megapixels from 35mm slides is my guess.  I'd put APS-C digital on par with 35mm film but much faster and full frame digital on par with 645 or 6x7 but faster, just personally.  I prefer 6x7 chromes to full frame digital, but once printed they look pretty similar to me!

But film also has a LOT more grain.  Taking SNR into account, film takes a huge hit...

Fwiw, black and white is even sharper and c41 is generally less sharp but not bad at all!

But film, shot properly, still looks better!  Love the colors and highlight roll off.

300
EOS Bodies / Re: Videographers happy with 5D Mark III?
« on: March 03, 2012, 11:51:28 AM »
Did anyone notice that 5D3 native image resolution is exactly 1920*3 x 1280*3 (5760x3840). It is 3x3 pixel binning for video.

I've been wondering why no one has mentioned this when discussing Canon's supposedly odd 22.3MP resolution choice. This also seems to be a much overlooked factor when assessing moire and rolling shutter improvements.

The resolution certainly seems like a strange choice; it must have to do with video....

However, 1920X1080 bayer pattern (3x3 pixel binning) isn't that sharp.  The F3 has a 3+ megapixel sensor and the Alexa a 4+ megapixel sensor to achieve a sharp 1080p image.  In theory, bayer sensors can resolve about 70% of their stated resolution (not even taking aliasing into account)--so you need almost four megapixels to get a really crisp 1080p image.  And this puts the 5DIII's 1080p mode at closer to 720p, about what the previous cameras have resolved.  So that's disappointing.

The latitude, decrease in moire, decrease in skew (fingers crossed), and great looking colors still count for something, though.

So... disappointed because it's not up to par with the Alexa? I would say while it's nothing to gush at we shouldn't be disappointed because it's not competing with cameras that are about 10x the price.

It's not just the Alexa...virtually every decent video-specific 1080p capable camcorder records at a higher resolution than bayer 1080p and scales down--because bayer sensors aren't that sharp at a per-pixel level.  Even models in the few hundred dollar range oversample.  It just seems strange that the sensor would be designed around video resolution, when the video resolution it's designed around produces a fuzzy image.   A weird compromise in general, though if the recording were done with 2:1 binning and then scaled down from there...that could look incredible.

And seriously, don't start the "not as good as x" debate.  The Alexa may have better resolution, but it also has way less skew than any other CMOS-based camera, a great codec, more latitude than anything else, and awesome highlight rendition with a smooth bloomy look.  Even the c300 isn't as good.  DSLRs aren't close.  Meanwhile, the fs100 (which uses the f3 sensor) is only 33% more expensive than the 5DIII and has a properly implemented super35 bayer sensor.  But it's a dedicated video camera, so again a somewhat unfair comparison.

Then again, the 5DII apparently debayers from 5616x1053.  Which means the 5DIII will have LESS resolution.  Overall, the 5DIII should have 30% LESS resolution than the 5DII if this pixel binning stuff is true.

I get that the 5DIII isn't a video camera.  It's just odd that the sensor's resolution was apparently chosen to improve video quality when a multiple of 1080p shouldn't help things one bit.  I suppose maybe this is a limitation of the digic5 chip--it can't debayer, downscale, and compress that fast...who knows.  Certainly the 5DIII video samples have less aliasing than the 1DX samples, which is a great start.

And that said...a reduction in aliasing is a huge and substantive improvement relative to the introduction of 1080/60p, so I applaud Canon for that (the Alexa and Red didn't do this to start because it's no one's priority--you all really use slow motion that much?! rent a phantom already....).  This might still be a nice camera for video.  Looks amazing for stills.


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