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Messages - Meh

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586
EOS Bodies / Re: Does a Digital camera need SLR?
« on: October 26, 2011, 11:49:00 PM »
No matter how good or fast the contrast-detect algorithms can be run, it still has to guess at the direction of focus adjustment, move the focus element a little, measure again, rinse and repeat.  That physical process of the adjustment can't be overcome by faster processing.

Could it be helped by faster processing?  Take two measurements and extrapolate to the direction and magnitude of adjustment?  Maybe that's already being done.  I agree that even so, it will never be as fast as phase detect.  But maybe fast enough in some cases?  AF times and shutter lag on P&S cameras are growing shorter, albeit slowly.

Or is the answer to build a phase-detect autofocus system into the main imaging sensor?

No, bundles of light rays from opposite sides of the lens that would converge to a single point at the image plane if that point is in focus have to be separated and compared.  Here's a link to a little graphic demo I just found that shows it:  http://graphics.stanford.edu/courses/cs178/applets/autofocusPD.html

But then, Nikon claims to use phase-detection AF in their V1 mirrorless although they call it a "hybrid autofocus".  I'll look around and try to find an explanation of how they implemented it and if it has limitations compared to the typical phase-detect AF.

587
Lenses / Re: Lens Announcement [CR1]
« on: October 26, 2011, 03:44:45 PM »
If Canon release a 5D 3, 35L II and a 24-70 II then I'm going to be seriously broke!

Do you really need to buy all of he new things that come out?

I convince myself that I need the things I want.  It's a personal failing but one that I enjoy from time to time.

588
EOS Bodies / Re: Does a Digital camera need SLR?
« on: October 26, 2011, 11:59:44 AM »
* the gopro hero 2 has built-in heat-up function to avoid quick battery run-down at low temperatures; they could add something similar to an EVF if this is really an issue

Good point.  Unlike the rear LCD the EVF is physically small and recessed and I think behind another layer of glass with an air gap (not sure about that) so has some thermal separation from the environment therefore it wouldn't take much power to keep it at least at its minimum operating temp.  There are other pros and cons to EVFs though.

* contrast-detect AF is also getting better, give it five years to be just as good as phase-detect AF for everybody except sports shooters

If by "everybody except sports shooters" you mean anyone who doesn't need fast, predictive auto focus, and subject tracking then contrast detection AF is already as good as phase-detect AF and has some advantages.  But not sure I would agree that the segment of photographers benefiting from fast AF is so limited... shooting anything that moves from kids running around, people at weddings, photojournalism, sports, wildlife, street photography, etc. is much easier with phase-detection.  No matter how good or fast the contrast-detect algorithms can be run, it still has to guess at the direction of focus adjustment, move the focus element a little, measure again, rinse and repeat.  That physical process of the adjustment can't be overcome by faster processing.

589
EOS Bodies / Re: 1DX Review
« on: October 25, 2011, 11:49:25 PM »
Image noise goes up with higher ISO, fact of life.

Well that's one way of looking at it.

I would prefer to look at it as the noise being reasonably constant (within limits) but the signal being reduced due to the lower light levels available when you have to use higher ISO settings.  The end result is a lower signal to noise ratio (SNR) leading to a noisier image.   The post-capture ISO amplification applied gets you back to the correct image brightness, but as it boosts signal and noise equally, cannot do anything to correct the already impaired SNR, hence the noise that was there all along becomes relatively more visible.

Impaired SNR is the natural result an under-exposed sensor which of course is what you get if you use an ISO setting higher than base ISO.   The exposure meter may say you are not under-exposed, but that is because it is adjusted in advance to allow for the amount of post capture ISO amplification which is going to be applied later.  By going above base ISO you are effectively accepting under-exposure at the sensor.

I would therefore say that high ISO noise performance is a somewhat mythical concept, as in reality the performance at any ISO setting is largely dictated by the SNR ratio at base ISO.  The better this is to start with, then the better the results as you start losing signal due to low light levels. 

Fred

Yes, SNR is what matters most to what we see as image noise and you're absolutely right, ISO amplification happens after the sensor is exposed and amplifies the recorded signal at each pixel which includes the noise component... the camera doesn't know what the true signal was and how it was affected by the noise.  When shooting in low light the input signal is much lower so the SNR is in turn lower and the image looks noisy.

On the issue of thinking of noise as a constant, that depends what kind of noise we're talking about.  There is noise from the electronics (read noise) which is fairly constant and photon noise (aka shot noise) that is not constant.  Both contribute to the total noise (random variation) in the recorded signal.

Photon noise scales as the square root of input so the noise goes up with input signal in absolute terms (not constant) but is a smaller percentage of the input (higher SNR).   With very low light levels (dark shadows, night photos) photon noise can be significant.

Read noise is fairly constant for a given ISO setting and is in the range of around 2-20 electrons for most CMOS sensors.  Again, in dark scenes when the input signal is low (which is when we use higher ISO) the read noise becomes much more significant relative to the input signal (lower SNR) and we can see the noise in the dark areas of the image.

Even when we look at an image we can't "see" or know that a particular pixel (or any area in the image) was supposed to be say 500 photons but was recorded as 495 or 510.  What we see is the unnatural variation in adjacent pixels or groups of pixels that wasn't in the true input.  So say a group of 20 pixels were supposed to all be 500 photons but they were recorded due to noise anywhere from 470 to 530 we can see that variation and because it's random variation we know intuitively that the image isn't supposed to look that way and it's therefore noise.

590
EOS Bodies / Re: 1DX Review
« on: October 25, 2011, 10:56:35 PM »
@Chris_BC

Good points.  Given the slight drop in MP rather than an increase over the last generation FF sensor, the increase in standard ISO range, the fact that technology has progressed, and Canon's statements I would also hope for more than 1 stop increase.  My comment was meant more generally... that a full stop improvement over a predecessor body is a significant improvement.  Two or more stops would be even better of course.  As far as what body to compare to as the predecessor we could just as easily compare to the 1D4 since that was the most recent 1-series body but your point is still valid because the increase to 18MP FF from 16MP APS-H alone should result in improvements even if there were no other tech advancements.  How much improvement in noise and DR will "cut it" will depend on the user.

591
Lenses / Re: The price 300mm 2.8 IS--is just greed--maybe?
« on: October 25, 2011, 05:22:44 PM »
It's strange that there is such emotion on the pricing of things we want but can't justify the price.  It turns into a rant about corporate greed... there is such a thing as corporate greed but the pricing of products is an open and transparent thing and they aren't taking advantage, if you don't like the price don't buy.   What do you think the cost to produce any Apple product is... what's the markup on an iPhone... yet Apple and Steve Jobs are heroes.

There is so much to running any business far beyond just the cost to manufacture a product.  Who's to say what Canon spent on R&D to improve any given lens, re-tool the manufacturing process, etc.  Then there's marketing, distribution, overhead.

Even if Canon is making a killing on any particular product, so what?  If the market doesn't like the price and no one buys they will lower the price after a while.  Ultimately they're going to sell it for what the market will bear.  I wonder if the people who complain so much about corporate greed would sell their house for 20% less than market value because the business press reported widespread over-valuation in the housing market?

592
Lenses / Re: The price 300mm 2.8 IS--is just greed--maybe?
« on: October 25, 2011, 05:11:56 PM »
Time to "Occupy Canon?" :)

Nice one!  +1

593
EOS Bodies / Re: 1DX Review
« on: October 25, 2011, 01:08:50 PM »
Image noise goes up with higher ISO, fact of life.  Of course images at 51,200 are going to be noisy... but if those noisy images are usable, if only just barely, and you wouldn't have gotten the shot at lower ISO then it's a useful ISO setting.  I'm not saying it will be useful, have to wait and see what the real world images look like.  Even the marketing images Canon will show will be optimum and controlled situations.

Realistically, if the 1DX or any new body, gets even even a full stop of better ISO performance (i.e. ISO 3200 of the new body look as good as ISO1600 on its predecessor) then it's a significant improvement.  In general as technology matures, big advances from one generation to the next get harder to achieve.  If what Canon has claimed so far is even part way true they've made some significant improvements.  Whether worth the upgrade to any given user depends on their needs and preferences.

Other than a non Canon employee getting to touch the 1DX and tell us about that, there's nothing new in the Engaget review but still worth the read and a quick look at the product shots.

594
EOS Bodies / Re: Feedback on 1D X from 1-series users?
« on: October 24, 2011, 10:28:39 PM »
But to start a thread that assigns qualifications for contributors based on who can afford high end equipment from those who can't -- which is what this individual did -- is elitist and discriminatory.

English is not my native language, so maybe I'm missing something, but I just hear someone (neuroanatomist) saying, hey, we heard the crowd and they're in title to their layman opinion, but I like hear what the experts (as far as 1D or 1Ds) are thinking about the new tool.  That’s not “elitist and discriminatory” where I live.

This issue that drew complaints was not the request for comments from 1-series owners/users.  That was a great topic that neuro started.  The part that drew complaints was the Camry analogy that implied (although probably not what neuro intended, he has since said it was an attempt at humour) that most of the members commenting on the 1DX up to that point had never used a 1-series body and probably wouldn't ever buy a 1DX because they couldn't afford it even if they wanted to.  It came across as elitist because everyone knows neuro can afford a 1DX and will be getting one as soon as it's available.  Most of us will just stare dreamily at it in the window until the kids are done college (or drop out and we liquidate their college fund).

It was an attempt at humour and we've all said things that came out wrong or were interpreted in ways that were not intended.  Neuro's comments and all the sharing of knowledge from testing lenses, micro-adjusting every lens and sharing his experience, and proving us wrong with tack sharp images from lenses we complain about are valuable contributions to the forum.  So he has lot's of credit stored up to be forgiven for the odd failed humour... even Seinfeld bombed every now and then.  :)

And thanks to all the 1-series users who have contributed their comments.  Appreciated by everyone I'm sure.

595
EOS Bodies / Re: Feedback on 1D X from 1-series users?
« on: October 23, 2011, 09:50:23 PM »
So far, we've heard a lot of feedback, mainly complaints, from people who are not currently using 1-series bodies, and don't seriously plan to get one.  Sort of like people who say, "I was going to buy a Ferrari California, but now I'm not since they didn't put a V12 in it," and then just keep on driving their Toyota Camry, or at the most take out a 5-year loan on a newer model of the same car.


Nice elitist attitude.
So I guess Camry owners can't have opinions with regard to how the new Ferrari will effect their next Camry?
This IS an opinion message board, remember?
[ok, lets hear your real snappy comeback...)

Yes you can - there are enough threads on this site to cover that. The OP asked specifically for those who already have one of the Pro bodies. If you check his sig. he does not and is therefore asking from those that do.

Sorry, don't do snappy at 2am  :D

Well... neuro did ask for those opinions along with a smattering of a slam against those expressing opinions that may not intend to buy one.  He could have left out the whole Ferrari/Camry thing of course it would be less fun if he did.   Neuro gets some credit since we all know he's in the camp of those not currently using a 1 series as well as being in the camp of those that may in fact buy a 1DX.  I am in both those camps as well but for me not likely a 2012 purchase unless the retail price turns out to be below $6k which is doubtful.

So neuro, in your analogy was the Camry equivalent to any particular level of body or would even a 5D/5D2 be included.   Or maybe you were only taking a shot at people who talk like they want one but can't actually afford it?   Sorry, you may not have meant it but your comments come across a little elitist.  You might get credit for your honest viewpoints and credible statements about buying the 1DX as soon as it's available but you're also on record as stating that any piece of gear you want is "only X number of hours of consulting work" to you.

Great idea though to ask for more 1D users to weigh in.


596
Canon General / Re: Birders don't use Canons?
« on: October 20, 2011, 11:03:35 PM »
One thing I bet makes us all laugh is the photo editing software on cop shows or spy shows. I like how they will bring up a totally blurred image and type a couple of keys and suddenly the image creates data that was not there and suddenly the image looks great. Or when they magically hit a single key and the editing software turns an object around or creates a face that is behind a post or tree or something.

apparently they have access to the Adobe de-blurring tool!  http://tv.adobe.com/watch/max-2011-sneak-peeks/max-2011-sneak-peek-image-deblurring/ ... I still can't believe this is real, but Adobe seems to be pretty serious about it.

There are a few algorithms that can sharpen images but most likely this is just an implementation of a Richardson-Lucy Deconvolution.   Already available for free in RawTherapee.  It works best for simple camera movements that caused the blur... it's less effective or non-effective for complex or multiple movements (for example camera shake + lateral movement).

597
EOS Bodies / Re: The EOS 1D X Sensor Demystified...
« on: October 20, 2011, 10:24:32 PM »
Larger pixels giving more Dynamic Range is not a myth just an oversimplified statement because there is more to it than just pixel size.  It is true when those other things are equal.  DR is the ratio of the largest signal to the lowest signal that can be measured .  That ratio can be expressed as a simple ratio, stops/EV, or dB.

The maximum signal is the most electrons that can be stored in the photosite (one electron is release for each photon absorbed).  This is also referred to as saturation value or full-well capacity.  Note that it's the size of the photosite that matters... the area of each pixel that is sensitive to light which in the past I believe has been as low as 30% but in recent years was up to about 50%.  This is called the fill-factor 

The lowest signal is taken as the noise floor.. which is the read noise at whatever ISO your using.  Most CMOS sensors up until the most recent generation actually had higher read noise at ISO 100 but the Sony sensor used in the D7000 greatly improved on this and the read noise is fairly constant with ISO settings.

The Sony also has much higher full-well capacity even though the pixels are smaller.  This is most likely because they were able to increase the fill-factor... i.e.  a higher percentage of the pixel area is used for the photosite.  In other words, even though the pixels are smaller the photosites are larger (higher max signal).  Combined with the lower read-noise at ISO 100 (lower noise floor) the ratio of largest to smaller signal is much larger giving the very high 13.9 stops of DR.

Hopefully, we'll see these advances in the 1DX sensor as well but there are many other tradeoffs in designing a sensor to optimize for speed, heat, minimizing blooming (current leakage), etc. that the Sony sensor may have sacrificed... I don't know that's the case just stating the possibility.




598
EOS Bodies / Re: What's Next?
« on: October 19, 2011, 10:57:55 PM »
I thought that the 200-400 1.4X was a reality?

Yes, I am confused too. It's a lens that was announced some time ago, just that the release date is delayed (much like what happened with the 8-15 fisheye).

What I want to see: 24-70 f/2.8L with better optics and 14-24 f/2.8L

What I personally wish to have: FF with pentamirror or mirrorless. Just want to have a cheap, low weight Rebel type FF camera. :) That's just me.

I believe the 200-400 was announced to be "in development" and as yet not an officially announced product.

599
EOS Bodies / Re: What's Next?
« on: October 19, 2011, 04:22:08 PM »
I have been waiting to transition into DSLR filmmaking.  My holding out for the 5DmkIII is over...  I will get the 7D and some better glass while I wait for mkIII.  Then sell back the 7D.

At least wait until Nov 3rd. It's only 2 weeks away. Trust me as someone who has shot a lot of DSLR video the last few years. The moire and alias and soft video image can drive you crazy. It was good when it came out 3 years ago, but now compared to Sony and Panasonic, it's very dated.

Just give it 2 weeks before you buy. I think something good will come.

It may not change your mind about DSLR film making, since the alternatives are prohibitively expensive, but check out the 3-part series "The Great Camera Shootout 2011" at www.zacuto.com

The third in the series shows the motion artifacts that DSLRs are prone to due to the rolling shutter of CMOS sensors.  It will be interesting to see if what Canon announces on Nov 3rd will address this issue and if they announce something affordable for indie film makers or only cameras to compete with RED.

600
EOS Bodies / Re: What's Next?
« on: October 19, 2011, 04:05:15 PM »
Common 14-24 lens!

+1. I think we're the biggest fans of this idea.

I must be missing something. The 14-24 is a common lens?
Nikon makes one, but does anyone else?

I think it was mean to say "come on 14-24 lens" ?

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