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Messages - dlleno

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301
Great start!  I really hope that Mike the product expert can do more than just provide an SME presence on the forum to assist with understanding and using the equipment.  He needs to be able to influence or at least inform the individuals that can apply resources to address this issue, and not just talk about it.

302
EOS Bodies / Re: Possible positive 6D surprise? Should I wait?
« on: November 27, 2012, 12:00:45 PM »

I think it's fairly clear Canon had a specific type of photography/photographer in mind when they designed this system.  Namely people who don't shoot many fast moving subjects, but need to focus in all kinds of light.  Portrait and landscape are of course two that come to mind.  If you look at it from the perspective of that type of photographer, the -3EV center cross-type should be outstanding and clearly an upgrade from the 60D/650D, since the other points almost don't need to be there (even on the 5D3 the most precise points are in the center).  The sports/action/wildlife photographer is right to say this system is unlikely to be good for them - and get a 7D or 5D3.  I realize this isn't what a lot of people were hoping it would be, but for some this may be just what they needed (without the expense of the 5D3).
..

Some good points here.  6D looks to be very 40D like in that regard --  aimed at center-AF dominant work:  "grab focus;  then frame".  Whats interesting to me is that, while the -3EV center point on the 6D is attractive, to be sure, all the other points are +.5EV sensitive, which means the moment you pick a different focus point, the 5D3 clearly wins AF sensitivity by 2.5 stops . 

303
EOS Bodies / Re: Where the heck is the 70D or 7D mkII?
« on: November 09, 2012, 04:17:08 PM »
getting back to the original topic:  I suspect one reason we haven't heard more about the 7D2 is that Canon is trying to protect holiday sales, and may announce something soon into 2013.  They've telegraphed the big MP FF (to keep people from jumping to Nikon I suppose) but they have not telegraphed anything re:  the 7D2

304
EOS Bodies / Re: Where the heck is the 70D or 7D mkII?
« on: November 08, 2012, 06:43:16 PM »
on that topic, what if the FF 46mp monster and the new 7D2 crop sensor are based on the same process?

I bet it is :)

and the natives are restless for want of information!

305
EOS Bodies / Re: Where the heck is the 70D or 7D mkII?
« on: November 08, 2012, 06:13:26 PM »
... I have my doubts that Canon can get anything more out of the current 500nm process.  I suspect that any significant improvement in Canon's APS-C sensors would require a move to a newer process.
I have my doubts that we will see anything being announced before February or March next year, so we probably still have a while to wait before we see Canon play its hand.

What I suspect would be a likely approach from Canon is to move its APS-C sensors to a new process - possibly next year, while it carries on using the 500nm process for full frame for another 3 years or so, until the 1DX and 5DIII are replaced.  That would probably be done in order to achieve the required manufacturing costs.

That theory does square, in my opinion, with the fact that 7D2 rumors are quiet, while the 7D1 ages mercilessly, and yet Canon has already introduced a new crop sensor in the t4i.  What will be interesting to see, should this come to pass, is what IQ level can be acheived, how it compares with the current FF lineup, and what we might learn (by implication) regarding what Canon's future acheivements in future FF sensors.

on that topic, what if the FF 46mp monster and the new 7D2 crop sensor are based on the same process?

306
EOS Bodies - For Stills / Re: Would I benefit from going full frame?
« on: November 08, 2012, 04:15:44 PM »
my 17-40 on full frame is inferior to the EF-S 10-22 on crop.

My experience too. Is that what others have found, or did I have a bad copy or didn't spend enough time with the setup?

I'm thinking thats why God inspired Canon to invent the 16-35 II :D :D

on a related note:  with the recent introduction of the 24-70 F/4 L IS, at $350 more than the 24-105 f/4 L IS, I wonder if the latter is due for an update and price increase

307
To me the picture is a big deal because there arn't very many other ways to get such a dramatic capture.  Cost aside -- from requests to the pilot (lets go over there, no up higher, now over here.  try 500 more feet ... ahh thats it...) and strapping himself in dealing with the cold and the 1% keep rate, it all shows what one has to do to get shots like this. 

308
EOS Bodies / Re: Where the heck is the 70D or 7D mkII?
« on: November 08, 2012, 01:06:23 PM »
I would only disagree that the 6D IQ will surprise people...unless those people actually expect it to be much better than any other Canon sensor. Canon has not yet demonstrated an improved manufacturing process, so it is doubtful that the 6D sensor will be radically changed in any way.

true dat.  and extending this logic, one has to conclude that whatever sensor the 7D2 gets, it may be incrementally better than the 7D1 but still won't compare with 6D or 5D3.  I mean -- even if they could, its not likely that Canon would produce a crop body that would exceed the IQ of a more expensive FF body in the current line-up.  It wouldn't surprise me to see (in the 7D2) an increase in MP count, improvements to AF and perhaps even fps, and a measureable improvement to the ISO and noise performannce, but I guess I'm not expecting to be astonished by a market-disruptive IQ or DR.  is anyone else? 

someone in another thread (pardon the lack of reference) has already suggested that Canon has telgraphed their FF sensor offereings for the next 2-4 years or so, with the 1DX, 5D3, and 6D releases.  The big mp body is the unknown at this time, and I suspect this one to be optimized for DR and low ISO, expecially its first release I doubt it will match the ISO performance of the 5D3 for example.

but they have not telegrahped their crop sensors for 2013, and the silence of the 7D2 in this regard is defening.  I can only hope that the delays mean a new sensor and not a re-worked t4i sensor. 

309
EOS Bodies - For Stills / Re: 5D Mark III sensor cleaning noise (squeaks)
« on: November 06, 2012, 02:06:33 AM »
I have had two 5dIII (returned one) both made 2 high pitch noises when turning it on and off while it said it was cleaning so I would not worry about it. I am also one of those can can tell if a crt is on anywhere in the house. And those damn apple chargers for their laptops drive me crazy with their high pitch noise!

If you are hearing CRTs from NTSC Televisions, you know you can hear 15.7 KHz then :-D  Computer monitors generally run well above the threshold of human hearing. For example, a CRT capable of 1024 lines at a 60 Hz refresh rate runs at about 64KHz, which means in order for these devices  to be audible you would have to be hearing some subharmonic, which of course is quite possible. 

laptop chargers are a different animal.    Unlike the CRTs with flyback transformers, these are switching supplies running well above the audio range,   However, it is still not uncomon for these to produce some subharmonic mechanical vibration or even a real resonance in the audio range as a side-effect.  It wouldn't suprise me if these produce acoustic energy well below the upper threshhold of human hearing. 

310
EOS Bodies - For Stills / Re: 5D Mark III sensor cleaning noise (squeaks)
« on: November 01, 2012, 07:18:54 PM »
lol nice work TAF I hope your cats survive the experiment :D   indeed,  bypassing the natural low pass filter of the ear is comparitively uncharted waters.  Here's hoping something useful appears in time for Mt. Spokane!  :D

311
EOS Bodies / Re: 46.1mp Canon DSLR Previewed at PhotoPlus 2012? [CR1]
« on: November 01, 2012, 07:11:20 PM »
This might be off the wall for hard core students of Canon history who can predict what Canon will do -- but it will be interesting to see which of two paths Canon will take with this puppy.  Assuming this is a 5D style camera:

1.  further the specialization (and sale) of different bodies by preserving both a 5D and a high MP camera, optimizing each for their respective niches and preserving the sale of both, i.e. a 5D4 appears in addition to the 46mp body. 

2.  compete more directly in the D800 style market, but at a higher price -- , i.e. merge the 5D and high MP lines into one  camera that can play well at both 46mp and 21-ish. Use it for studio, landscape, location, wedding, lightweight sports and wildlife.    Odds are that the 46mp body won't appear until 5D4 time anyway :D

312
EOS Bodies - For Stills / Re: 5D Mark III sensor cleaning noise (squeaks)
« on: October 31, 2012, 07:20:27 PM »
Dude Mt. Spokane thats no good.  I've got industrial noise and age related losses that frustrate my wife,  but nothing like you or rush limbaugh.  these outside-the-box methods are awesome and still emerging, to be sure ,and I certainly hope you are able to find some relief or improvement! 

@ Tron/AdamJ  lol forgive my reversion back to the technical -- I'd say that if you can't hear it, and you're hearing is ok/normal for your age, , then that is good!  Best case is that a teen-aged girl can't hear the sensor cleaning routine :D  then you know that no parasitic resonances are happening in the camera!   


313
EOS Bodies - For Stills / Re: 5D Mark III sensor cleaning noise (squeaks)
« on: October 31, 2012, 02:32:57 PM »
definately lots we don't know about the abiity of humans to perceive or detect external stimulii of various sorts (especially at high energy levels) in ways that are perceived to be 'hearing'.   thats for sure --  total agreement there.  For example, the ability to detect the application of mechanical energy directly to parts of the body (like vibrating the skull at ultrasonic frequencies) is amusing, too.  Imagine the variance among individuals, i.e. size of the head, bone density, etc, etc.  and maybe those with 5D3s can try pressing their cameras bodies against their heads!

The physiology and mechanics of detecing low levels of true acoustic energy transmitted via air ("hearing") is relatively well understood though, and more closely applies to the phenomena of hearing the sensor being cleaned. 


this has been a cool thread, actually, an amusing departure from Dxo scores arguments :D 

314
EOS Bodies - For Stills / Re: 5D Mark III sensor cleaning noise (squeaks)
« on: October 31, 2012, 01:17:02 PM »
People can generally not hear ultrasonic tones, but they can dectect pulse trains at much higher than ultrasonic frequencies.  They sound like a chirp.
 
http://grouper.ieee.org/groups/scc28/sc4/Human%20Perception%20FINAL.pdf


This is a fascinating study, but it is not about detecting ultrasonic tones and doesn't really apply to the subject of ultrasonic hearing.  The study is about human sensitivity to and detection of pulsed radio frequency energy, an energy which consists of oscillating electric and magnetic fields that travel in free (empty) space without air.  This is the energy that, for example  lives in the Amateur radio bands, well above the FM broadcast band for example,  and well into the microwave region.  This is the type of energy that eminates from Television brodcast antennas, cell phone towers, cordless phones, your laptop's WiFi system, and microwave repeaters.  The study is not about ultrasonic "tones" and it is not about acoustic energy.

Acoustic energy (sound) consists of mechanical pressure waves and cannot be transmitted without a medium (such as air or water).  This type of mechanical energy requires an energy source of mechanical origin -- something, like a speaker cone, clapping hands, or Placido Domingo's vocal chords, has to move the air.   The energy used to clean the sensor is acoustic in nature -- this energy is vibrating the bejeebers out of somethign (the sensor) to shake dust loose.  In this sense, we can think of the sensor as a really high frequency tweeter that no one can hear.  In any case,  if the acoustic energy emitted by the camera  is within the set of frequencies to which your ears are sensitive, you will hear something but it won't be the 100Khz cleaning frequency itself.    The question is -- how can a sensor cleaning device operating at six times the upper threshhold of human hearing result in an audible sound? 

by far the best insight into what actually happens in sensor cleaning has been provided by TAF .  Very nice info sir!  TAF showed that the fundamental acoustic energy of the cleaning routine sweeps from 100KHz to 125HKz and back.  there is no way that any human being of natural orgins and abilities can hear this. The acoustic pressure waves reaching the ear just do not produce any response from the eardrum. no way.

of course, if you blast your head with a tremendous high-energy assult of air pressure waves at 100KHz, something is bound to happen internally (to your body)  that can be detected.  but this is not what is happening with the tiny little speaker we know as the sensor cleaning routine.  its a tiny little tweeter producing a very small amount of acoustic energy at frequencies that no one can hear.   

what is far more likely, as TAF has rightly pointed out, is that there is some sympathetic or natural mechanical resonance that occurs within the camera structure itself -- much like the vibrations you hear from your dashboard when driving on certain roads...  The structures themselves are responding at some subharmonic (a sub multiple of the 100KHz fundamental) that is within the range of human hearing.  Note that if this sub-harmonic were present naturally in the sensor cleaning function itself you would hear a high-pitched tone that would sweep up and then back down, perhaps at the 7th or even 8th subharmonic (something between 12Khz and 18 KHz) The fact that no one has reported hearing a smooth frequency sweep is clear evidence to me that TAF is right --  there are fixed frequency mechanical resonances in the camera that will respond, some more than others, when the cleaning "sweep" reaches the right point in its sweep.  Note that if there are two or more natural structural resonances within the camera, then you will hear two or more distinct tones or perhaps they will sound like chirps.  in any case, you are not hearing the sensor cleaning function, you are hearing an artifact or side-effect of it.

what is clear to me , based on the above, is that  (1) there is  a very wide variation from camera to camera structural resonances, and owner to owner hearing abilities,  with respect to what is actually heard during the cleaning routine, and (2) human hearing cannot possibly be used to measure the presence of or effectiveness of the cleaning routine because the cleaning routine itself cannot be heard!. If you hear something, then your ears are sensitive to whatever frequencies your camera's internal structures are vibrating at.  Thats about it :D .  Moreover, when you compare your audible results with someone else, then you are not comparing your respective cleaning systems, you are comparing your own hearing sensitivies and the natural structural resonances present in your respective camera bodies :D

315
EOS Bodies - For Stills / Re: 5D Mark III sensor cleaning noise (squeaks)
« on: October 30, 2012, 08:42:32 PM »
I just took some measurements, and my 5D3 sensor cleaning 'sound' is a series of two smooth frequency sweeps from 100 kHz up to about 125 kHz and back down.

So I would conclude you are hearing some structure in the camera vibrating, and not the actual signal.

indeed, given this data,  it is probably sympathetic resonance.  so the sweeps themselves -- is this a single tone sweep or what is the bandwidth of the signal that sweeps through 100KHz to 125KHz?  I take it you were measuring with a wide band audio spectrum analyzer, measuring actual acoustic energy? 

the "vibrating structure" theory aligns well with the 'shifting chirp' experience as well -- the structure exhibits a natural harmonic resonance at two distinct frequencies as the source sweeps through its range.

Quote
As an aside, although very few people can hear much beyond 20 kHz in free space, almost everyone can hear to ~40 kHz if the sound is directly coupled to their head ie: via bone conduction.  Dukane makes acoustic devices used to find the 'black boxes' from crashed aircraft underwater that ping at 37 kHz, and if one is held behind the ear, I've never met anyone who couldn't hear it loud and painfully clearly.  And it isn't just the pop of the pulse, you 'hear' the tone.

fascinating.  If he sound energy demonstrably above 20KHz is experienced and detected by a  human subject of natural abilities and origins, then it is either a sub harmonic, or it is not detected by the auditory nerve via exitation of the eardrum,  which is of course the basis of the "20Hz - 20 KHz" range of human hearing.  Conduction via bone structures is an entirely different mode of detection, which could include sub-harmonic exitation of those bone structures or even the eardrum itself,  which in this case would easily fall within the auditory range anyway.  Also -- sub or supersonic energy can easily be detected, or "felt" even when it is not heard tonally, especially if one's skull is subjected to such a direct mechanical assult :D

Incidently -- on the other end of the sonic spectrum, the lowest fundamental frequency of the largest pipe organ is 8 Hz, which is present on only a few organs in the world.  Such a pipe is there not because anyone can hear it,  but because they can feel it. 

now then, everyone go out and hold your 5D3 up to your skull during the cleaning routine and tell us what you hear!

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