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Messages - kyamon

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16
EOS Bodies / Re: Beginning of a new Canon starting with 7D Mk II?
« on: June 27, 2013, 06:56:10 AM »
How much more technolgy should cameras have before they become "boring" because they do too much for you?

well, Canon can still go a VERY long ways from my current 7D until I would find more technology and capabilities "boring". Most of it is even invented already and would be dirt cheap to implement. :-)

e.g.
* twice the resolution AND 3 stops better DR at all ISOs - especially at ISO 100 and up to 25600 [=Nikon D800]
* Hybrid AF with contrast and phase-AF on image sensor ... working 10x faster and more accurate, especially in tracking moving objects 
* WIFI and GPS built in
* EX-RT radio wireless flash commander built in
* working Eye Control AF v2.0
* in-body IS working in tandem with IS lenses for a total effect of 5 or 6 stops stabilization
* invisible IR-laser AF illuminator built in
* fully functional and customizable Auto-ISO [Nikon D800]
* 2nd curtain sync for speedlights in wireless ETTL mode [Nikon]
* better batteries lasting 1000 shots ... between  -10 and +40 degrees celsius
* mirrorless FF body the size of a pack of cigarettes [Sony RX-1] with lens mount and EVF
* "Retina"-EVF [350 dpi +]
* a series of tiny hi-IQ, fixed focal pancake lenses between 20/2.8 and 75/2.8 IS [like 40/2.8]
* EF-S or EF-M 50-150mm f/2.8 IS in black and half the size of a 70-200/2.8 II :-)
* Canon cameras without any video capability - "for stills only" at a significant price discount -25% 
* ...

I could easily go on for 2 full pages ... without getting bored ... ever!

What kind of photography do you do that you need ALL these features...?

17
... I never quite understood why people say that FF and APS-C have different DoF (provided the same optics, aperture, and distance to the object are used).

Marketing through misinformation, obfuscation, leading and derogation.

DoF is related to angle of view and aperture. To get the same angle of view at the same distance from the subject, on FF you need a longer focal length (1.6x if we consider a Canon APSC) than on crop.

Then, because f/stops are related to focal length, if you keep the same aperture on both systems you'll see that on crop you end up with a narrower iris. This is why you have more DoF ;)

Provided you are comparing two photos that have the same framing. Which makes sense from a photographers point of view, I agree.
Basically all I had tried to point out in my previous posts was that this whole discussion is only because of different definitions. As some people said, this is all optics, and most of it has been known for almost 500 years. Wether we have dSLRs or not does not change any of this. But most of these statements about DoF or the required scaling of focal lengths on crop factors only make sense with very specific assumptions. The latter is only appropriate if you only look at an object at a particular distance - if you have a foreground and a background (assuming infinite depth of field here :) ) then the perspective will change, so the scaling factor does again not properly describe it.

18
... I never quite understood why people say that FF and APS-C have different DoF (provided the same optics, aperture, and distance to the object are used).

Marketing through misinformation, obfuscation, leading and derogation.

... then again, many people here seem to believe this too...


It's clear we have differing opinions, and clear to me who's correct. If you want to go on looking at single pixel output and compare different pictures to draw conclusions that are irrelevant for photographic images, you go right ahead. I'm done here.

This is not a matter of opinion, and you as a scientist in imaging know that. It is a matter of definition and standard. If you define DoF in purely optical terms then you have to define "focus" as a property that is independent of whatever sensor captures the image (and that sensor could be a human eye). As soon as you bring in the sensor you have to add further parameters to define for what conditions the DoF is compared. Once these parameters are defined, the case is clear again.

Things like cropping an image certainly don't change the DoF - it changes your framing and that is all. And for the same reason if you would take a FF sensor and cut out the centre part at the size of an APS-C sensor the DoF does not change - again, from a purely optical standpoint.

But that makes little sense from a photographers point of view, as has been pointed out previously...

19
Yes, I'm sure.  Go visit a DoF calculator (e.g., dofmaster.com), or verify it empirically as I've done.

But did you also look how the DoF calculator works? The only difference in the mathematical expressions that give you the DOF is the circle of confusion, which is a very ill-defined parameter anyways. They use a particular value for any sensor size, so by definition they have to get different DoF values for every sensor size.
But this only makes sense if you somehow take an image from the different sensors and look at them at the same size, and there are also certain requirements on pixel density, I would say. I don't think that the DoF calculator can be taken as an argument in this discussion - it just serves to give you an order of magnitude for some concept that is very hard to quantify.
Since you say you tested it empirically, however, I would be interested in seeing your data... Because I never quite understood why people say that FF and APS-C have different DoF (provided the same optics, aperture, and distance to the object are used).

20

Comparing particular frames is one way to do it, and possibly the most reasonable one from a photography point of view. But it is not the only one, and depending on the type of photography, the settings you have available, etc. it is also not necessarily what you need to know, is it?

No, it's not the only one...but I'd argue it's the most relevant and important one, for a photographer.  Wearing my microscopist hat, there are times (such as when imaging fluorescently-stained samples) where the pixel characteristics of an imaging sensor are more important (because the relevant portion of the sample covers a tiny fraction of the sensor, a few pixels wide in some cases).  But more often than not, when that's the case I don't use a planar imaging sensor, but rather a photomultiplier tube, with spatial information derived from rastered laser illumination.

Photographers generally acquire images...so comparing images is most appropriate. 

One could make a similar argument about the effect of sensor size on DoF.  We generally say that FF gives shallower DoF, and of course that's true when talking about identical framing where you're either using a longer lens or are closer to the subject.  But if you hold focal length and distance constant, you actually get shallower DoF with APS-C.  Of course, your head shot has now cut off the subject's hair and mouth to give you a nose-and-eyes portrait instead of a head shot.  Not a very useful point of view for most...

:) True (the last statement).

I have done my share of scientific imaging applications, and of course there the criteria are usually different, as are the technical requirements and/or constraints.

But I think this discussion is now really getting too far off-topic (among other things because I agree that there are many more things to a camera than the sensor, and that a good sensor far from makes a good photographer!). If we continue we should probably start a new thread and leave this one to figure out if the flagship actually is the ship carrying the flag, or if Canon was mistaken :)

21
As far as I understood it so far, the fact that in general FF cameras have lower noise is mainly due to the fact that the sensors are the most recent types that have been developed. I have no experience with most models that are out there, but I would think that newer crop sensors will give lower noise than older FF sensors - simply because they are newer. Any attempt to quantify high-ISO performance simply on size and MP-count alone don't work because no two sensors of different size are the same otherwise.

I am open to hearing that all I have just written is nonsense... But what I would really like to hear is what a real expert has to say. Someone who builds the sensors, or who does research in that field...


Check out the DxOMark ISO 'scores' (the highest ISO than meets a specific noise criterion, so the higher the number, the lower the camera noise).  For the newest Canon APS-C camera which they've tested, the T4i/650D, the score is ISO 722.   Compare that to the ISO score for the 5D (the original one): ISO 1368.  So the 8 year old FF camera with sensor tech that's also 8 years older has nearly a full stop better ISO performance than a very recent APS-C sensor.  By comparison, a modern FF sensor (the 5DIII) scores an ISO 2293, close to 2 stops better than its contemporary APS-C sensor.

Here's what one academic expert, Emil Martinec, has to say:

For comparing pixels on a patch of sensor of a given area, the normalizations given above are the appropriate ones. However, one is often interested in comparing the overall noise of the image coming from different sizes of sensors, so noise per area is less relevant that noise normalized to the image frame. Thus another metric for comparison is to consider the entire frame, and if comparing two different sensor formats (such as the 1D3 and 40D considered above), shoot with different focal lengths (say 130mm on the 40D and 160mm on the 1D3) so that the field of view is kept fixed. In the case of fixed framing, we should refer the noise characteristics not to a fixed spatial scale in microns, but rather to a fixed percentage of the frame height. An appropriate figure of merit is to divide the per pixel noise values by the frame height in pixels, again because the noise combines linearly in the number of pixels combined. The clear rule of thumb that emerges from such an exercise (not surprisingly) is that larger size sensor formats are less noisy than smaller size sensor formats. A simple example is the 40D relative to the 1D3; both are 10MP cameras, with 2592 pixels in the frame height, and so in this particular example the frame-referred noise levels are the same as the pixel-level noises, and these are lower (as measured in ADU) at all exposure levels and ISO's for the 1D3. The read noises are similar in photo-electron units, but the 1D3's bigger photosites capture more photons, hence have higher S/N ratio. Bigger sensors have higher S/N ratios, because bigger sensors collect more photons.


As far as I understand this it is quite similar to what I wrote/asked, except that he specifically proposes a way to standardise the measurement. With the last sentence of what you quote he basically says that the noise generated in a single pixel is independent of its size (this was one of the questions I had asked), and thus the S/N gets better if the pixel collects more photons.
Comparing particular frames is one way to do it, and possibly the most reasonable one from a photography point of view. But it is not the only one, and depending on the type of photography, the settings you have available, etc. it is also not necessarily what you need to know, is it?

22
I am sorry to say this but honestly, I think bzzzz'ing each other is below the general level of maturity of this forum.

Now if you go back and read my post you will see that we probably agree regarding the framing. What I am saying is that the only difference between a crop sensor and a FF in most dSLR bodies is that the crop only collects a part of the image that makes it through the lens. Of course it collects less light than a FF sensor, but the additional light on the FF hits areas that simply don't exist in the crop sensor. The amount of light per unit surface is the same in both cases, because the image that is produced in the plane of the sensor depends on the lens and not on the sensor. Just that in one case you hold a large sensor in the beam path while in the other case you hold a small sensor in the same beam path.
It is as if you would take a movie projector and put a small projection wall at a given place. You don't get the full image, but what you get does not get any darker.

First: an APS-C sensor is smaller than a FF sensor, and thus a lower amount of light hits the total sensor surface. However, the framing is also different, and the image from the APS-C sensor has exactly the same size on the FF sensor because that is defined by the lens, not the sensor. Consequently, the amount of light per unit surface is the same on both sensors, and the noise performance can not depend on the sensor size.

BZZZZZT!

Worng.

The framing is the same only if you multiply the focal length by the ratio of the diagonals of the two lenses.

And the amount of light collected by the sensors is only the same if you perform a similar modification of the apertures.

To make the math simpler, let's start with a 100mm f/2 lens mounted to a 135 format ("full frame") camera. And we'll try to figure out what we need to get an equivalent image with a 4/3 camera, which has close enough to a 2x "crop factor" as makes no difference.

If you just mount the 100mm lens to the 4/3 camera, you'll only get the inner quarter of the image that you would have gotten on the 135 camera. On the 135 camera, you can get the exact same image by cropping out all but the inner quarter.

To match the field of view, we need to use a lens of half the focal length -- a 50mm lens. But what aperture?

The 100mm f/2 lens has a 100 / 2 = 50mm aperture. All the light headed to the lens that falls within that 50mm diameter circle makes its way to the sensor. To gather the same amount of light, we need a 50mm lens with a 50mm aperture. That means that our 4/3 camera needs a (50 / 50 = 1) 50mm f/1 lens to gather as much light as a 135 format camera with a 100mm f/2 lens. In both cases, both cameras are capturing all the light that falls onto a 50mm circle.

Because this is all simple geometry, it so happens that the depth of field, background blur, and the rest are also comparable.

But...even if everything else is equal, the larger format still retains a number of advantages, mostly because the image on the sensor doesn't need to be magnified as many times in absolute terms to print size. Imagine making a contact print with 8" x 10" film and comparing it with an 8" x 10" enlargement even from 4" x 5" film to understand why.

Cheers,

b&

23
Real photographers don't waste time on non photography related forum topics like this. Why don't you get out of the house and start honing your craft instead of talking about what really in the simplest sense is nothing that will help you take better pictures...

Agreed. But I think there is nothing wrong in trying to understand the gear you are using.

24
It appears that this discussion is taking off into a somewhat different direction than the OP had intended... But talking about noise performance on different (size) sensors is also interesting, even if a bit off-topic.
Now, I am not an expert in any of this, but reading the last few posts makes quite obvious that few, if any, of the last posters are, either. Just a few points/thoughts:

First: an APS-C sensor is smaller than a FF sensor, and thus a lower amount of light hits the total sensor surface. However, the framing is also different, and the image from the APS-C sensor has exactly the same size on the FF sensor because that is defined by the lens, not the sensor. Consequently, the amount of light per unit surface is the same on both sensors, and the noise performance can not depend on the sensor size.

Second: Noise comes from the physical, chemical, and electrical properties of the sensor - or of each individual pixel, to be more specific. A photon hitting a section in the CMOS-chip promotes an electron to the conduction band, thus leading to a measurable current. Occasionally some other effect leads to current, producing dark counts. The current that is collected from the chip needs to be amplified, and the degree of amplification is set (in a camera) by the ISO speed. The amount of dark counts remains the same, but if pictures are taken in low light then the ratio between dark counts and "real counts" gets worse. Since the amplification process does not distinguish between the two types of currents, high ISO leads to more noise. The number of dark counts can either be constant for any single pixel, or a constant of the surface. I personally don't know which one it is, but they lead to different results if we then compare different sensors.

If we have a constant number of dark counts per pixel, then obviously we get lower noise in low-MP sensors of a given size) since there the amount of photons hitting each pixel is larger (as the pixels are larger), and the ratio of good/bad electrons is better. In the extreme case of one single pixel we would have the lowest absolute rate of dark counts, and thus the highest IQ (OK, the term "image" becomes questionable here...)...
On the other hand, if the rate of dark counts is a function of the total surface (and does not depend on the number of "cuts", or pixels, we make into that surface), then the number of MP will not matter. We then get lower dark count rates per pixel for higher MP, but the summed rate is still the same.

As far as I understood it so far, the fact that in general FF cameras have lower noise is mainly due to the fact that the sensors are the most recent types that have been developed. I have no experience with most models that are out there, but I would think that newer crop sensors will give lower noise than older FF sensors - simply because they are newer. Any attempt to quantify high-ISO performance simply on size and MP-count alone don't work because no two sensors of different size are the same otherwise.

I am open to hearing that all I have just written is nonsense... But what I would really like to hear is what a real expert has to say. Someone who builds the sensors, or who does research in that field...

25
Lenses / Re: I have just lost confidence with Canon Rumors & B&H
« on: April 17, 2013, 10:51:27 AM »
I think im a pretty nice guy. But what a tongue lashing she got. But i enjoyed it.

 :D
Best reply so far...

26
Lenses / Re: I have just lost confidence with Canon Rumors & B&H
« on: April 17, 2013, 07:04:49 AM »
It seems to me that the OP was under the impression that Canon Rumors was some magic blog that financed itself from thin air and colourful pixels, and could thus operate completely independently from the rest of the (economic) world. Too bad it is not. But on the other hand, CR makes no secret that BH is financially involved in this undertaking - there are ads all over the site, and every review or article has a link to the according site from B&H. It is pretty clear what is happening here, isn't it?

Is that a problem? No, of course not. The blog is about Canon (rumors), not about Canon distributors and sales companies. The support from BH does not lead to any bias at all, since BH is not the only place selling Canon, and it is also selling things other than Canon. And I don't think CR ever claimed that the deals you are getting at BH are the best you can get. And most of the times that is probably also not the case - you will always find someone on eBay or Craigslist who sells you an 800 mm lens for $1200, supposedly in perfect condition. BH will not do that, I hope, nor is CR claiming that BH is the only place to buy. People who do buy there know why they do so, I presume (being in Europe I have no experience), and might even be willing to pay a few bucks extra because at BH they seem to know what they are getting. If you want the absolute cheapest you have to do the research yourself.

 As many others said before, you got a better price, be happy. Maybe some moderator blocked your post because he had not yet had his morning coffee, maybe he accidentally clicked the wrong button, maybe you were using indecent language, whatever. The fact is that you have it here now, and that you seem to have idealised expectations from our world, where - unfortunately or not - money plays a certain role and is necessary to run businesses.

27
Software & Accessories / Re: Pixma Pro 9000 II prints are dark
« on: April 09, 2013, 08:13:09 PM »

OEM inks are not as trumped up as you think they are. Epson and Canon make it seem so because it's in their interests to protect the HUGE margins they make on it.


This is certainly true - after all, they have to pay for the printers that they give away basically for free...

It actually depends what your definition of great prints are. In my opinion, what you're getting is already great - in comparison to what most people not using LR/Photoshop, icc profiles, and professional home printers.

But it seems what you want is the peak of Mt. Everest, which means you do have to invest time and money to reach. Nothing comes easy my friend, such is the bitch called Color Management. So I say take the plunge, get a spectro. Best investment you'll ever make.

No... Mt. Whitney would be good enough. Or Mont Blanc, since it is around the corner from here ;)
Maybe you are right and I should look into spectrometers...

28
Software & Accessories / Re: Pixma Pro 9000 II prints are dark
« on: April 09, 2013, 07:38:39 PM »
I really find it unbelievable that this is not a solved problem.

As I indicated in my first post on this thread, it is a solved problem. It's just that the solution isn't obvious and requires equipment and skills.

Here's super over-simplified instructions to how to solve the problem:

  • Buy a spectrophotometer such as the i1 Pro or the Color Munki.
  • Use said spectrophotometer to calibrate and profile your display.
  • Again use said spectrophotometer to profile every combination of printer / ink / paper you use.
  • Learn what to do with all those ICC profiles you've created. That includes things like soft proofing -- and there's a lot more to soft proofing than ticking a box in Photoshop. Much more. And that's just one small piece of the puzzle....
  • For bonus points, use better software than that X-Rite ships with their instruments. They make some very good but very expensive profiling software that shouldn't be too hard to use. ArgyllCMS produces superlative quality and is free, but it's command-line only. There are other options, too.

I assure you, that's "all" you need to do to solve your problems within the physical limits of the various pieces of hardware. Problem is, it's not an easy solution....

Cheers,

b&

OK, I have calmed down a bit by now :)

I know that there is a way to get prints look the way they should. I know there are people (professionals) who are skilled enough to get these systems to work properly.

What I meant was that I find it weird that there is no simple solution to get this to work at home, for amateurs who can not invest the time and money to go through the entire recipe you described (command-line is not even the issue, I would not have a problem with that...). My thought when I purchased that printer was that it is a way to get around the randomness of large-scale commercial photo-printing companies. I thought that if I get a printer, use that company's own ink, quality paper, and established software I would get a system that is close to plug-and-play. But that is far from the truth... That is what annoyed me, and that is what I meant by "unsolved problem".

Granted, if I want to make the best possible espresso in my own kitchen I can not just get a professional espresso-machine. I also have to learn which beans to buy, how to grind them, how much of them to use, how much pressure to apply, etc. But since we are dealing essentially with chemistry and computers in the case of photo-printing, I thought that things would be sufficiently well standardised and controlled to make the procedure simple. I think if I would take to photos with different cameras of the same type, using the same settings, I would get identical pictures - or is that not the case? That is what I also expect from printing.

Essentially what this all means is that for any non-professional (or for me, at least) it is simply impossible to get great prints without investing a lot more money and a lot more time. Both of which I am able to invest only to a certain extent. It just looks like I have to reduce my expectations, and that frustrates me.

29
Software & Accessories / Re: Pixma Pro 9000 II prints are dark
« on: April 09, 2013, 05:22:42 PM »
this is really frustrating... I am close to giving up and just try to avoid in the future to print dark photos. And otherwise use PS to print...

I really find it unbelievable that this is not a solved problem. The fact that two programs from the same company produce different output on the same setup is miserable. These are computers, after all. They may not always do what we want, but they are pretty good at doing the same thing over and over again. So all we need is a reasonable way to calibrate. Once. And then it should work...

Or is it all just so sensitive that nothing is reproducible? Does a tiny change in the composition of the ink change everything? Does the temperature of my room change? Or is it only the amount of coffee I had before sitting down at my desk...?

(as a side-note... I am a scientist and do experimental work. I know that things never work the first time around. But then someone works to understand what is going on and improves it, and ultimately something functioning results. In this case the fact that Canon, Ilford, and Adobe (or all the others) do not manage to produce a proper system together is outrageous. And it is not like this is a new problem in any way... OK, I am frustrated and will stop my rant here ;) )

30
Lenses / Re: Is there any chance this is legit?
« on: April 09, 2013, 03:27:16 PM »
Just write to him - he will tell you that he is out of town at the moment and that you should wire him the money. He will then (maybe?) send you the lens (or probably "object") as soon as possible. If you tell him that you want to see the lens before sending him the money you will see how he reacts.

Might be legit, might be fake. You don't lose by contacting him... If you actually meet and talk with him about the lens you will immediately know if he knows something about photography. Then again, the lens might still be stolen, even if he is a photographer...

Photo jargon is all over the web, and bad english proves nothing. But I would think that such a lens might be registered with CPS, so ask him for the serial number and contact CPS. If he does not give you the S/N, drop it. Otherwise who knows....

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