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Messages - neuroanatomist

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6181
Site Information / Re: Site issues, or my computer?
« on: February 01, 2013, 01:43:27 PM »
Working fine for me with Safari on a Mac and IE8 on a Win7 PC.

6182
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 01, 2013, 01:40:05 PM »
The new Photodo do not show any longer the old MTF tests manage by Lars Klellberg the founder of Photodo, since years back Photodo owns by a UK  company
Please start your own threads if you want to argue a point that does not directly apply to the threads you usually write into. Please do not hijack threads of others. Please stay on topic on other's threads. It is simple politeness. We are a community. Please help build it. We ALL share this great forum. Contribute. Life is about sharing. Not about who won an argument! >:(

I don't see the discussion of MTF curves as being off topic because:

1) The very impressive theoretical MTF curve of the new Nikon 800/5.6 was brought up on the first page, and

2) Once you've said, "Nikon just announced an 800mm f/5.6 VR lens that costs $18,000," really, how much more can you say that's actually 'on topic' besides, "Wow" or "Damn, that's expensive!"?!?

6183
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 01, 2013, 12:16:30 PM »
Therefore Photodos MTF tests where so valuable (world largest MTF tests collection) (today the magazine "Photo" in Sweden are alone  using Hasselblad MTF test equipment [/b]) and  to see if  a  lens have for example been improved or not regarding resolution. The Swedish magazine Foto are also testing new lenses from all manufactures and provide the readers with lens  MTF tests


Unfortunately, at least for Photodo, they have MTF measurements for only ~60 of their ~140 listed Canon lenses, and mostly for old ones, just a few of the current lenses have MTF data - e.g., none of the three 24-70mm lenses (but they do have MTF data for the long-discontinued 28-70L), the non-IS 70-200 lenses have data, but none of the three IS versions, etc.  But for the lenses that they happen to have tested, it's great that they have published those data!

As for Foto magazine, I wish I read Swedish.  :)

Roger's data are definitely useful. 

Reikan FoCal is also now publishing some aggregated sharpness and AF consistency data, but I'm still a bit skeptical about that, since the actual testing is in the hands of many users, not one, which has implicatations for standardization and consistency of results.

6184
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 01, 2013, 11:03:28 AM »
I felt cheated on learning that Canon publishes hypothetical MFT charts and does not actually test a sample lens.

Maybe.  But practically, it probably doesn't matter.  How are you going to use those MTF charts? 

  • If it's to compare one Canon lens to another, e.g. is the 135L sharper than the 28-135?, then the theoretical charts are fine.
  • If it's to compare a Canon lens to another manufacturer's lens, e.g. is the Canon 24-105L sharper than the Nikon 24-120?, they aren't valid, but that's ok because you can't easily Canon/Nikon lenses on the other manufacturer's bodies, so directly comparing those lenses via MTF curves isn't terribly useful.
  • If it's to compare your purchased copy of the lens to those MTF curves, unless you have the >$100K equipment to test bare lens resolution, neither theoretical nor empirical MTF data would be useful to you.

In fact, Canon quite likely does test some lenses empirically, as part of the QC process for setting up the manufacturing lines - they just don't publish those data.

6185
Blackrapid strap

Lowepro Toploader Pro 65 AW or 75 AW

6186
Lenses / Re: Help me choose between the two: 70-200 f2.8 IS or 17 TS-E?
« on: February 01, 2013, 10:17:47 AM »
I shouldn't buy them both.

I disagree.  You should buy them both.   :P

6187
EOS Bodies / Re: Canon Confirms 70D; Future of Semi-Pro DSLR is FF
« on: February 01, 2013, 10:16:45 AM »
PJ1974 - I think you're right, people often read between the lines and see something completely subjective.

+1 - when a corporate talking head makes statements like, "'That's something we're considering at the moment. From our semi-pro users there's still demand for APS-C but in the future, I think we will see an increase in the number of full-frame models,'" the 'in the future' part is very forward-looking, and it could be years before that becomes reality. 

IIRC, Canon stated several years ago that their goal was eventually move to all full frame sensors.  Eventually, as in 'some day' - we're still pretty far from that day, IMO.

This interview is nowhere close to a 'nail in the coffin' for a 7D Mark II - I think we'll see both a 70D and a 7D Mark II this year, and both will be APS-C.

6188
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 01, 2013, 09:53:41 AM »
Neuro:  Do not try to talk away your mistakes and that you  dont know its needs  a head room to create HTP


Do we really need to go over this again?  I have already pointed out your mistake, the incorrect extrapolation of the case of setting the camera to ISO 100 then enabling HTP while in an autoexposure mode (Av/Tv/P), where the camera will then change the exposure by adjusting the shutter speed or aperture one stop, to be a general explanation that the mechanism of HTP is for the camera to adjust the shutter speed or aperture by one stop, when if fact, that only occurs at ISO 100.  That's something that TheSuede clearly understood and explained very well, but you still seem unable to grasp.

Of course, headroom is needed to preserve the highlights. We agreed on the 'what' - your error concerned the 'how'.  My point was that HTP achieves the additional headroom by exposing at a one-stop lower ISO than is actually selected, not by reducing the exposure so that 'half the photons' hit the sensor as you repeatedly stated.

All of that was hashed out to the nth degree in the other thread, there's no point in restating those arguments - if you want to continue to argue your points, please go back to that thread.

As for MTF - read carefully what you wrote:

Page2 I wrote:
we dont know if this is estimated MTF, Canon and Nikon has a predilection to exhibit estimated MTF results  to impress

and then I wrote:
MTF tests from Nikon, Canon, Leitz, Zeiss , Hasselblad are real MTF tests and of the lens only


First, you state that Canon shows estimated MTF results.  Then you state that Canon's MTF curves are "real MTF tests".  Do you understand that your statements conflict with each other?  Canon shows MTF plots for their lenses (one for primes, two for zooms) - those data are either calculated/theoretical or they are real/empirical.  First you state it's the former (correct) then you state it's the latter (wrong).  Your statement about Canon having the equipment to actually measure MTF is irrelevant - fine, they can measure real MTF, but they do not show those data for their lenses, they show only theoretical data. 

It's obvious that we could go around and around about this just like we did with your 'half the photons' argument, and it's equally obvious that there's no point in doing so.  You know as well as I that Canon's published MTF curves are theoretical/calculated, and not 'real MTF tests' resulting from actual measurement of real lenses.  There is really no point in discussing it further, and therefore, I will not.

6189
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 01, 2013, 06:53:22 AM »
To all of you , then read the discussion again, and read Neuros answer.

By all means, people should read that thread and observe Mikael 'Half The Photons' Residal's staunch defense of his explanation that the general mechanism of HTP is that the camera reduces by half the amount of light hitting the sensor, his consistent refusal to admit that his 'explanation' applies only at ISO 100, his avoidance of specific questions from several posters to describe how HTP works at any other ISO setting than 100, etc.  Note how here in this thread, he reposts TheSuede's correct description of how HTP works, which matches what others in the thread were saying, but not his own flawed and incorrect explanation.

The answer is , I have been at Photokina since 30years back  as a member of the press every second year and discussed MTF, Lenses,Cameras, scanners with technical chiefs from Nikon, Olympus, Canon , Leica, you name it and I know they have own MTF equipments like Hasselblad

That's all you had to say, Mikael.  Why did you feel in necessary instead to lead off by insulting my knowledge and intelligence?

I can tell you people that I have got stringent regulations about my use of   language from CR,

Clearly, there's a reason for that.  Those regulations seem to have moderated your overt behavior somewhat (and even that seems to be backsliding), but not your general attitude.  Frankly, I find many of your posts to be rude and condescending.  I respect your 30 years experience as a photographer, but rather than using your experience and knowledge to help others here on these forums, you choose mainly to comment on Canon's poor sensor performance with regard to DR (you're correct about that, but really, most of us understand it already, so why do you keep beating that dead horse?), argue with people, insult others, and generally make these forums a more hostile place. 

6190
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 01, 2013, 06:31:00 AM »
Wondering why would Canon, Nikon would NOT measure actual lenses?
It's a numbers game. If they produce ten thousand lenses of a particular lens (I picked that number out of the air - I could be waaaaaaay out on that one...) and each MTF chart has at least eight squiggles, and each squiggle needs at least fifteen points (with zoom, double that - two charts...) that is a lot of points! So which point do you publish? Best? Worst? Average? Median? Mode? I guess simpler not to publish and statistically QA lenses assuring quality is as expected...

I wouldn't think so, I don't thing anyone is suggesting that they QC every lens that rolls off the line with a full MTF curve test.  However, Zeiss does publish real, empirical MTF curves for their production lenses, whereas Canon and Nikon choose to publish idealized MTF charts.  That choice is likely a marketing decision - it makes their lenses look better (but does Zeiss test a whole bunch of lenses, then publish the best curve?  Most likely).  In the end, it probably does not matter...but I'd prefer to see real data from a real lens, rather than (not-real) ideal data which a real lens may never match.

6191
Third Party Manufacturers / Re: Canon may be expensive but...
« on: January 31, 2013, 09:39:11 PM »
This smells head -room over all, you didn't know how a sensor works, no cameras)


Actually, you were the one in error in the thread to which you're referring, and ultimately, you admitted it.  We actually agreed on most points in that thread, though - so if I do not understand how a sensor works, then neither do you.

Regardless, the point about MTF measurement really isn't worth arguing over.  Sleep well...

6192
Third Party Manufacturers / Re: Canon may be expensive but...
« on: January 31, 2013, 08:04:55 PM »
I have already answer that, go back to page 2, BUT Canon, Leitz , Hasselblad Nikon  etc  has real MTF equipments and measuring of the lenses  , not to be mixed by Photozone and others "MTF" tests .
There is no problem to measure a Canon lens at Hasselblad MTF lab in Gothenburg and compare that to others

I do not see an answer.  Are you saying that the MTF curves published on Canon's (and Nikon's) websites represent real, empirically measured data?

I wrote
we dont know if this is estimated MTF, Canon and Nikon has a predilection to exhibit estimated MTF results  to impress
Which means estimating, calculating
And please, if you are going deliberately misunderstand me, keep going.

Ahhh...but we do know. Canon's published MTF curves are calculated/theoretical, not empirically measured. 

You have two possibly conflicting statements above - "Canon, Leitz , Hasselblad Nikon  etc  has real MTF equipments and measuring of the lenses," vs. "Canon and Nikon has a predilection to exhibit estimated MTF."  Certainly it's possible that Canon has the instrumentation to empirically measure lens MTF (as Zeiss does, for example), and yet chooses to not show those data for their lenses.  What is your evidence that Canon has such instrumentation?

6193
Set high prices for lenses, lose sales to competitors, profits go down, what a surprise.

NOT.

Well, thanks for that uninformed opinion.  Did you actually read the linked presentation materials?  Perhaps if you had, you'd have noticed that while Canon lost revenue and profits fell in some business segments, and sales of PowerShot cameras were down, their sales in the dSLR and lens category was actually up 14% in FY12.  Are you surprised now?  ::)

You mean that if Canon sold even more DSLR lenses, it's bottom line wouldn't have improved? That's even more surprising.

It's not surprising at all. Canon is a moderately diversified business, and in particular, the office (copiers) and industrial (lithography) segments are tied tightly to the global economy.

6194
Third Party Manufacturers / Re: Canon may be expensive but...
« on: January 31, 2013, 03:18:29 PM »
I have already answer that, go back to page 2, BUT Canon, Leitz , Hasselblad Nikon  etc  has real MTF equipments and measuring of the lenses  , not to be mixed by Photozone and others "MTF" tests .
There is no problem to measure a Canon lens at Hasselblad MTF lab in Gothenburg and compare that to others

I do not see an answer.  Are you saying that the MTF curves published on Canon's (and Nikon's) websites represent real, empirically measured data?

6195
Third Party Manufacturers / Re: Canon may be expensive but...
« on: January 31, 2013, 09:27:51 AM »
MTF tests from Nikon, Canon, Leitz, Zeiss , Hasselblad are real MTF tests and of the lens only

Actually, most of those published MTF curves are not real MTF tests, i.e. the manufacturers are not actually measuring the resolution of a real lens.  Canon's and Nikon's published MTF curves are theoretical MTFs (as are Sigma's, Tamron's, etc.) - they are calculated curves, generated by a computer algorithm based on the optical design of the lens.  AFAIK, Zeiss is the only lens manufacturer that published MTF curves that are empirically measured on a real production lens (not sure about Hasselblad). 

Since neither Canon nor Nikon make public their algorithms for generation of theoretical MTF curves from the lens design, it's not really valid to compare them to one another, nor to Zeiss' real measurements.  Comparing within a brand is fine. 

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