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Messages - Meh

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Lenses / Re: 24mm 1.4L II versus 35mm 1.4L - help!
« on: October 13, 2011, 12:25:48 AM »
Only bad advice retroactively :)  at the time the comment was posted to consider the Sigma 30mm f/1.4 the OP hadn't added the signature line or stated in the post that he was using a 5D2.

Sorry, but the signature was in the first post, which is the reason I didn't ask what body the OP was using (no way to provide meaningful advice on focal length choice without that information).

Well I guess I have to give you a hard time :) all in good fun of course.   The signature line wasn't in the original post (I looked for it at the time) and actually it couldn't have been because it was his 10th post exactly and the forum doesn't allow signature line until after the 10th post.   JR added his signature line a couple posts later and it retro got added to all his posts back to his very first.   However, he did mention the body and lenses he had in an earlier post in another thread so that must be where you remembered it from.... good memory!

EOS Bodies / Re: MP/ISO
« on: October 11, 2011, 10:35:42 PM »
Neuro, are you sure it's rigorously correct to say "smaller sensors have more noise regardless of pixel size" (I'm paraphrasing your statements somewhat), "smaller pixels have less sensitivity" (define 'sensitivity'), and that "reducing MP will not substantially reduce noise"?

Take a case of the same camera, same lens but test two sensors of different sizes but same design, same spatial resolution (pixel pitch/size).  The noise is the same, to say otherwise is suggesting that the noise in the centre of any given sensor is higher than that around the edges.  The same image (i.e. same composition) taken by a smaller sensor has to be enlarged more to get any given viewing size and the image will not look as good because there would be less resolution (assuming viewing size is large enough to see the difference) but that is not due to noise in the image... it is due to less resolution which is not the same thing.

Now consider two sensors, one larger than the other, with the same number of pixels.  Camera and lens are still the same.  The smaller sensor has more noise, but not because the "sensor is smaller" per the above but rather because the photosites are smaller and each collects less photons therefore the SNR is higher.   So again, compose each image the same, the frame from the smaller sensor is enlarged more to get the same viewing size but now each image has the same number of pixels.  The image from the smaller sensor has more noise because there is more variation (i.e. noise) from pixel to pixel.

So what about noise-reduction algorithms.  They work better the more information (resolution) there is to work with but megapixels are megapixels.  It doesn't matter whether the data (say 18MP) comes from a FF, APS-C, or smaller sensor.  The algorithms work on "data" and it's irrelevant whether that data came from a larger or smaller sensor.  Again, I'm taking the case here the same scene is imaged on the sensor regardless of size.  The NR algorithms work better but the image starts with more noise... the final image from the sensor with smaller photosites is still noisier and in addition has the NR softening so overall the image quality is worse.

In the case of P&S there is in fact another difference to consider.  The lens is not the same.  It is smaller, has a shorter focal length, smaller aperture (actual size), and usually lower quality than DSLR lenses which in most cases is a significant issue.  For any given f-ratio the aperture is in fact much smaller and that causes greater diffraction AND the higher spatial resolution of the sensor will pick that up to a greater degree.  This is offset somewhat because the image size at the focal plane is smaller but not entirely.  However, this is not "noise" in the context of what we're talking about and results in a general softening of the image rather than visible variation.

A good distinction to make here for folks who might not realise, is that the noise we see in any average to well-lit scene is primarily due to photon noise not due to the electronic noise (read noise) that most people think about when talking about noise.   Photon noise actually increases with increased brightness but only increases as the square root of the number of photons absorbed by the sensor so the SNR of brighter scenes is higher than darker scenes.   Read noise is relatively stable and does not increase with brightness (an exception is blooming but that is well controlled in modern sensors) therefore the SNR due to the read noise is really insignificant for reasonably bright scenes.  The fact that SNR (from photon and read noise) improves with the number of photons absorbed is a valid reason for "expose to the right" although I've read another reason that I don't believe is correct.

If any of the above isn't correct, what am I missing?

Lenses / Re: 24mm 1.4L II versus 35mm 1.4L - help!
« on: October 11, 2011, 10:09:03 PM »
Its all good as I am so passionate about my passion for photography and my equipment, that for better or for worst, I am already sold to Canon L lens...only a matter of time better I get a whole bunch more.   ;)

The 50mm and 85mm f/1.2L primes are out of my price league.  I am stuck with a lousy 16-35mm f/2.8L II and 70-200mm f/2.8L II ;)   And a Sigma 50mm f/1.4 that is OK.

Lenses / Re: 24mm 1.4L II versus 35mm 1.4L - help!
« on: October 11, 2011, 09:36:16 PM »
Otherwise I'd get the sigma 30 f1.4 Have you looked at that lens? It's a nice lens, half the price but not quite as bright as the canon, but still an awesome lens.

Sorry, but that's bad advice. As indicated in the signature line and in a subsequent response, JR has a 5DII. The Sigma 30mm f/1.4 is a DC lens. While it will mount on a FF camera (unlike EF-S lenses), it has an image circle designed for APS-C that won't even come close to covering a FF sensor.

Only bad advice retroactively :)  at the time the comment was posted to consider the Sigma 30mm f/1.4 the OP hadn't added the signature line or stated in the post that he was using a 5D2.

Lenses / Re: 24mm 1.4L II versus 35mm 1.4L - help!
« on: October 11, 2011, 08:55:08 PM »
The question asked above about what camera you're using, FF or crop, is quite important.  The example images and advice from the other posters seems to be based on experience with a FF.

EOS Bodies / Re: Nikon D800 at 36mp, Will Canon Respond?
« on: October 04, 2011, 06:36:17 PM »
Nikon has to do something to stay ahead of the iPhone in the megapixel race...

Love it.  +1

EOS Bodies / Re: Nikon D800 at 36mp, Will Canon Respond?
« on: October 04, 2011, 11:23:30 AM »
I'm willing to bet it falls over on IQ

Maybe but don't be so sure.  Taking the new Sony sensor as an indication of what's possible the full well saturation is almost as high as some current FF sensors and they got the noise way down leading to very large DR.  A similar design used for a 30-40 MP FF sensor might just result in improved DR, ISO performance, etc. than what we have in FF sensors today.

As I'm digesting Nikon possibly releasing a 36 MP FF sensor, I'm considering Nikon's historical position that they would not sacrifice IQ for resolution.  So the question is have they caved to the MP race or has technology advanced to the point they can offer 36 MP without sacrificing IQ.  I suspect the latter is the case.

EOS Bodies / Re: Nikon D800 at 36mp, Will Canon Respond?
« on: October 04, 2011, 11:01:00 AM »
More MP?  Bring 'em on, especially for a FF camera.  Not so densly packed that diffraction starts to affect IQ at f/5.6, like the new 24 MP APS-C from Sony, but a 36 MP FF sensot would be just fine.

True but you'd still have the improved resolution wider than tha f-ratio limit and be no worse off narrower.  Besides you only start to resolve it at that limit... I think it's a few more stops before the improvement in sensor resolution is completely offset by resolving the diffraction and we can never do better than a diffraction limited optical system anyway.   Do you know of any paper that attempts to define a sensor spatial-resolution limit above which there is no value from the increased resolution?

Besides, that Sony sensor scaled up to FF would be about 60 MP and not likely we're getting anywhere near that with FF in the foreseeable future.

EOS Bodies / Re: Nikon D800 at 36mp, Will Canon Respond?
« on: October 04, 2011, 10:50:47 AM »
The big question is how the current lenses will hold up to a 36mp+ camera

How well do the current lenses hold up to a 16-18MP DX APS-C sensor? I think the proper way to look at this isn't that a marginal lens suddenly becomes a piece of junk if you exceed some resolution threshold but, rather, that you don't see all of the improvement theoretically made possible by a higher resolution sensor. There's always room for improvement in lens resolution but what will have to be foregone: having to use a prime instead a zoom, having to pay a lot more for the lens, having to carry around a heavier lens, etc?

Bob is correct.  The lens will continue to resolve what it always resolved and that will represent the resolution limit in the system (lens + sensor).  I recall reading somewhere on this forum that Canon's stated goal with the new lens designs was to resolve to 40MP in FF.  Does anyone know if that was an official statement from Canon?

EOS Bodies / Re: Opinion - What EOS Will Look Like by Photokina
« on: October 02, 2011, 10:29:45 PM »
Hard to kill because it is NOT a myth. is.  Smaller pixels have lower well capacities and lower read noise, implicitly, so there's no implicit reason for small pixels to have lower DR than large pixels.  That's why there's no rhyme or reason as to the DR among the range of pixel sizes, from 2 microns to over 8 microns.

A77, 3.89 micron pixels, 12.2 stops
5DII, 6.39 micron pixels, 11.2 stops
5D, 8.04 micron pixels, 10.8 stops

How can you say " there's no rhyme or reason" to something that is a measurable and quantifiable value.   There are also reasons, that are in fact very well understood, for the sources and amount of noise in any electronic circuit.

The three cameras you listed are all from very different generations, many years apart in fact.  That's a reason, technology improves over time.

Btw, where you write "implicitly" in your comment I will assume you meant to say "inherently".   I will also grant you that a lower noise floor allows for higher DR for a given maximum signal and that is because DR is the ratio of the largest signal to the lowest signal that can be recorded.   So yes, in a case where the noise floor reduction is proportionally larger than a decrease in the max signal (due to the smaller photosites) then DR would go up.

You might also read my comments again and notice that I identified the Sony A77 sensor as having achieved a notable increase in the full well capacity which is done by increasing the size of the photosite which is the surface area of that is sensitive to the photons.  The size values you are quoting are the pixel pitches which is not the same thing...  there are gaps between the photosites due primarily to the electronics that sit beside each photosite.  It would seem Sony has found a way to increase the size of the photosite possibly by reducing the size of the other electronics... with more area available for the photosite they can be made larger so that each can collect more photons.

Historically, larger pixel sensors have had higher read noise than contemporary smaller pixel sensors.  Read noise is actually made up of a number of noise sources in the electronics but not all of them scale with pixel size.   It has also been historically the case that the read noise at low ISO was higher than at high ISO and this was related to the noise sources that scale with the fullness of the wells (at high ISO settings the wells are not filling up) and the way the amplifiers work.   CMOS sensor technology has advanced read noise has come down which improves DR.  Again, the Sony sensor in the A77 is notable because the read noise has come down at all ISO levels and in fact it's a significant improvement at low ISO such that the read noise is remarkably consistent from low to high ISO.   If this can be implemented for a FF sensor with larger pixels (higher maximum signal) we should see a big bump in DR!!!

I'm happy to discuss further if you or anyone has any facts or examples about this but please don't just write back "yeah... it is".

EOS Bodies / Re: A Loose Roadmap [CR1]
« on: October 02, 2011, 04:05:08 PM »
While it might be unusual for Canon to release 3 bodies in 12 months, these are unusual times.

2008: 1000D, 50D, 5D2
2009: 500D, 7D, 1D4

So, it's NOT unusual for Canon to release 3 bodies in 12 months. Not in the least. :)

And if you ignore calendar years, they've actually announced 4 DSLRs in a 12 month period - the 1000D, 50D, 5D2 and 500D were within 12 months of each other.

My comment was referring to the original post that said it was unusual and to be fair to that post, I took it to mean 'enthusiast and above' bodies.  So say, 7D and above.  Below that, the bodies are on a fairly fixed annual update schedule I think.  But perhaps I misunderstood what was meant by that.

To further explain my point "these are unusual times" my thinking is that 60D and above are all due or overdue to be updated now or within 12 months which may not have occurred in the past, anyone know for sure?  So based on coincidence of timing and combined with pressure from Sony at the enthusiast level, Canon (and possibly Nikon also) will want to refresh everything.  Maybe I just want that to be true so looking for reasons to believe it :)

I don't believe they have any mandate to stick to a certain cycle.  They will decide based on availability of new sensor technology (which is here now as we've seen with the latest Sony sensors), DigicV now in manufacturing, and market forces.

My prediction is that all 60D and above will be updated within 12 months along with something new such as another model in between or maybe medium format at the top end.  Something is coming, I can feel it :)

EOS Bodies / Re: A Loose Roadmap [CR1]
« on: October 01, 2011, 07:06:48 PM »
Is their next-gen sensor too hard to get right?

They really don't need to do a lot with the 5D to make it a killer dslr. But people are expecting a digic V when really a IV with a few more megapixels  and faster autufocus may be the magic bullet.

But breaking that news to Joe Consumer....

Why would a Digic4 be preferable (a magic bullet) over a Digic5, am I misunderstanding your comment?  Higher resolution and improved autofocus is almost a given, but then I can't understand the suggestion to keep Digic4.

EOS Bodies / Re: A Loose Roadmap [CR1]
« on: October 01, 2011, 04:12:02 PM »
@Canon Rumors - don't stress yourself over such idiots, the site is good and if he wouldn't want to visit it he wouldn't even be on the forum.

Go bi*ch somewhere else please.

I think the 7D is very, very likely next year, so is the 5D Mark II. But indeed, 3 in a year would be a bit unusual, so that may leave the 1Ds Mark IV for this year, but almost definitely before the Olympics. When might the Rebels come out then, if early 2012 is 1Ds, middle is 5D, then 7D. It truly is a mistery, but these cameras are coming, that's the most important part  ;D

I second that whole-heartedly.  No need to beat up on CR Guy for doing what the site is all about.  Now if CR Guy doesn't do his job and posts crap but rates it CR3 then have at him :)

While it might be unusual for Canon to release 3 bodies in 12 months, these are unusual times.  1Ds4 is long overdue, 5D3 is due, and within 12 months 7D2 will be on deck.  Combine that with competitive pressure from Nikon and Sony and I don't think it would outlandish to think we might see all three bodies... 1D (merged), 5D3, and 7D2 all between now and Photokina!

Third Party Lenses (Sigma, Tamron, etc.) / Re: Sigma 50mm f/1.4
« on: September 30, 2011, 09:51:55 PM »
I just shot a wedding and I only used the Sigma 50mm 1.4 and a canon 17-40 L, the Sigma is a fantastic lens, sharp and fast ,its the second wedding that I have done using this lens, its well worth the 500 bucks

Assuming you were using AF, approximately what % of your shots were properly focused?  I've had good experience with my copy but most of the reviews of this lens cited low hit rate with autofocus.

EOS Bodies / Re: Opinion - What EOS Will Look Like by Photokina
« on: September 30, 2011, 07:45:49 PM »
My understanding is that the read noise in almost all modern CCD and CMOS image sensors is about as low as it's going to get but there may still be a little improvement to be had (e.g. the 1D4 sensor and the latest Sony sensors in Nikon D7000 and Sony A77) so we'll almost certainly see this in the all the next Canon sensors.

Plenty of room for improvement between the 7D and D7000, especially at low ISO.

What do you mean by "plenty"?  We're talking about read noise at low ISO right?  Look at the info you linked to... 7D read noise is 8.6 electrons and the D7000 is 3.1 electrons.  So the difference is 5.5 electrons.  So there is a little room for improvement which as I said we've now seen in the latest Sony sensors.  By the math, this is a a little over 1 stop of DR.

However, the increase in DR due to the lower read noise is being offset by increasing resolution (smaller pixels) so overall we might see at most another stop of DR in the next 7D but maybe not.

No, this is a myth (hard as hell to kill, too).  Smaller pixels don't make poorer DR inherently.

So, 7D and G12 both have 11.2 stops of DR at base ISO, but the G12's pixels are 4.4 times smaller.

Hard to kill because it is NOT a myth.  First let me point out that the G12 sensor is a CCD and the 7D sensor is CMOS so not apples to apples.  CCD are much simpler and the photosites can be made larger for any given resolution (more specifically "pixel pitch" or pixels per unit area on the sensor).  This is one of the big advantages of CCD.  The other advantage of CCD is that they have lower read noise (actually did have but CMOS has caught up in the last few years which you see in the Sony sensor data in your link) .  The combination of larger photosites and lower read noise gives much higher DR than CMOS.  When the industry first started to move to CMOS it was because of expected lower costs but that turned out not to be true at first but did come down over time (CCD has come down in cost as well but not as much).  CMOS has now caught up to CCD in read noise but not in photosite size.  The photosites are smaller with CMOS because there are more electronics required on the sensor itself and in fact take up about half the surface of the sensor.  CCDs don't have as much electronics on the sensor and the photosites can be made larger for a given resolution.

DR is better with larger photosites.  The larger the photosite the more electrons (converted/released from absorbed photons) can be collected so that the saturation level (the largest number of electrons that bucket can hold) is higher.  Look at the links you provided... the saturation levels are higher in the 7D and even higher in the D7000.  The D7000 has the highest saturation level and low read noise and therefore has the highest DR.

We can also see that the Sony sensor has much higher saturation levels than the 7D with about the same resolution and sensor size.  So we can conclude that the latest Sony designs have increased the size of the photosites (i.e. each photosite can hold more electrons).  I'm not aware of any proprietary/patented breakthrough from Sony so I think it's just the next evolution in the CMOS designs and we'll see it in the next Canon sensors as well but I'm guessing.

A good example of the progress in CCD sensors is to look at the data for the G10 compared to G11.  Canon wanted to make a the sensor better so they reduced the pixel pitch but also increased the photosite size which is evident from the large increase in saturation levels.  Also they got the noise down and the result is going from 9.3 stops DR in the G10 to 11.2 stops in the G11.  I'd like to see the sensor data for the new CMOS sensor in the S100.

f/8 autofocus is possible but what's left to differentiate the 7D2 from the 1D4/5?

The 1-series has a built in portrait grip, a bigger battery, is built like a tank, has better weather sealing, has UI designed to be used with gloves on, has a larger sensor, produces faster frame rates, and has longer shutter life.

I meant my answer as a bit of joke but it didn't come out that way I guess.  Of course there is a lot to differentiate the 1D4.  And with the latest processing speeds and new sensors the 1D5 will probably be FF because they will be able to get 10 fps from a high resolution sensor.  I do agree that if the for any sports oriented camera (1D4, 7D, and successors) AF performance is key and will always be an area for improvement.

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