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Messages - neuroanatomist

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6166
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.

6167
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...

6168
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?

6169
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.

6170
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?

6171
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. 

6172
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?  ::)

6173
Personally, I find that a 3-stop and a 10-stop ND cover all my needs.  There are a lot of not-so-good variable ND filters out there, from an IQ standpoint.  The good ones are from Tiffen, Singh-Ray, and Schneider (B+W's parent compant).  I avoid variable NDs because I often want to use an ND with ultrawide lenses, and they're not optimal there (at wide focal lengths, you get a 'Maltese cross' artifact - an 'X' through the image - that gets worse the wider the AoV and the darker the setting).  But at 17mm on APS-C, you'd either not see it at all, or only at the very dark settings of a variND.

6174
Site Information / Re: Forum recommendations
« on: January 30, 2013, 12:05:00 PM »
For the login issue, instead of simply using the username/password boxes in the upper right, use the login link, and you can choose how long to stay logged in, or to always stay logged in.

Thanks - yes, that's where the options is, forgot to mention that, since I so rarely need to log in!

6175
Site Information / Re: Forum recommendations
« on: January 30, 2013, 11:47:26 AM »
When I log in, there's a checkbox to remain logged in - do you not see that?

Personally, I like the 'somebody posted while you were typing' as I find it often avoids me duplicating someone else's response.

In the past, the mods have gone through and reorganized the forums, combining some, splitting out others, ensuring there's only one topic per lens in the lens gallery, etc.  Perhaps some specific suggestions about what you think could be changed would help...

6176
EOS Bodies / Re: Canon 1DX ITR AF Feature
« on: January 29, 2013, 11:27:24 AM »
It's face-detection with phase AF.  I find that it works pretty for tracking a person moving through a group.  I have a Servo setting for 'people/events' and I use iTR for that, but not for my wildlife/birds setting.  Note that for iTR to work, you've got to be in 61-point auto selection more for the AF point selection.

6177
EOS Bodies / Re: Canon 1Dx Problem
« on: January 28, 2013, 12:40:29 PM »
FWIW, I have no issues with that combo.

6178
Consistent with my other recent experience, the IQ of the 5DIII makes up for the crop factor loss of 1.5 fold as the two centre crops were quite similar. The 7D was noisier, as expected. I usually use it at iso 320 or less. At great length extremes, the 7D does have an advantage but otherwise the FF is just as good for bird photography with the same lenses, and the closer you get to the target, the better it should be. It will be interesting to see when the 7D II comes out with more modern technology if it can overtake the 5DIII in the telephoto range,

^^ This is why I don't use my 7D anymore...  Add to that the case of the 600/4, where the FF 1D X will autofocus with a 2x TC for 1200mm focal length, compared to the 7D which needs f/5.6 for phase AF and therefore is limited to the 1.4x TC and a FF-equivalent of 1344mm - an effective 'crop factor benefit' of only 1.12x. 

6179
EOS Bodies / Re: Canon's Roadmap for 2013 [CR2]
« on: January 27, 2013, 10:38:36 AM »
Right now the sensor is the week part of the chain, but even so the system beats the competition for my needs.

+1

6180
EOS Bodies / Re: Canon's Roadmap for 2013 [CR2]
« on: January 27, 2013, 10:20:07 AM »
The problem is that I can pick up an Olympus E-M5 that beats the iq of any canon APS-c camera and they are supposed to be introducing an even better successor to the E-5 ..... Or I can go Panasonic......or I can go Sony..... Or I can go Nikon.... Canon is now positioned at the bottom of the APS-c world for iq and even micro four thirds is beating it.

From a DxO-minded, sensor-only viewpoint, sure.  But what's the lens selection like over there?  I think you know the answer, as a few posts later, you wish for a 400mm lens.

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