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Messages - neuroanatomist

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6151
EOS Bodies / Re: making a case for that crop body camera
« on: February 02, 2013, 09:16:39 PM »
+1

The real 'case for that crop body camera' compared to FF is that it's cheaper than FF.  That's not a slam on crop bodies - affordability is very important in the real world!

6152
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 02, 2013, 09:06:40 PM »
@ LetTheRightLensIn - Changing the ISO has no direct effect on the amount of light that hits the sensor.  At ISO 400, enabling HTP does not result in a change in the amount of light hitting the sensor, no difference in the number of photons. Period. What the camera does is apply one stop less gain to the signal generated from those collected photons, then applies a tone curve to the jpg data to boost everything but the highlights back up that one stop. 

Suggesting that at ISO 400, HTP reduces the light hitting the sensor is not just misleading, it's plain wrong.  Neither aperture nor shutter speed are changed - and that's a damn good thing because aperture should be selected to give the desired DoF and shutter speed selected to control motion in the image as desired, and the camera shouldn't be changing those parameters if I don't want it to.  I disagree with your statement, "...if I want to do HTP myself what do I need to do? To get the exact same result I shoot at my selected ISO, keep my selected aperture and then I raise the shutter speed 1 stop faster."  What if you wanted motion blur of a fountain, but to preserve the highlights in the scene - would you sacrifice the motion blur you wanted, or stop down and change your DoF or lose sharpness to diffraction?  I would do what the camera does with HTP - underexpose by lowering ISO as many stops as needed, and if that took me to ISO 100, it would be time for an ND filter.

HTP has limitations, foremost being it's limited to one stop of 'highlight recovery'.  But if you understand the technical principles behind it, you can overcome those limitations to some extent, while still capturing the desired image in terms of DoF and motion control.

Like Mikael, you are confusing the actual collection of light by the photon wells of the sensor with what happens to the electronic information into which the energy of those photons is subsequently converted, and with the processing applied to the digitized form of that information even later in the image acquisition process. Those are discrete steps with their own characteristics, and if one is going to discuss the technical details of the image data generation, one should correctly describe and apply those details.  You can think of it as a semantic issue if you like, but there was no semantic confusion about providing an incorrect answer to simple yes/no questions - questions which you answered correctly but Mikael did not.

At the outset, everyone deserves respect, appreciation of cultural and linguistic differences, patience, and the benefit of the doubt. If, over time, someone consistently displays rude and insulting behavior (to the self-admitted point of being placed under strict regulations by the mods), makes no significant effort to contribute in anything but a negative manner, is repetitious and combative, and offers neither apology nor any redeeming characteristics, that person deserves to lose the respect of the community...as Mikael has certainly lost mine.

6153
Reviews / Re: Kirk Security Strap review
« on: February 02, 2013, 06:59:36 PM »
Makes perfect sense - thanks yet again!

6154
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 02, 2013, 06:41:41 PM »
no Im saying by exposure after 400 iso you have create a head room by 2 stops compare to 100iso
what is so difficult to understand Neuro! = exposure after 400 iso = halving the hitting lights twice compare to 100iso


Hypothetical example: I shoot jpg. I am taking a picture of a forest scene. I am in Av mode, and I set f/8 to obtain the desired DoF, and I chose ISO 400 to get a 1/100 s shutter speed at metered exposure to avoid camera shake, because I foolishly left my tripod at home. Please note, I couldn't care less about what exposure settings would be at ISO 100, 50, or 3200, that's tangential and irrelevant - I choose f/8 and ISO 400 for the reasons I stated.  I take a shot, look at the review image, and see blinking highlight alerts where I want detail of the sun-dappled forest floor. I've read that HTP can preserve my highlights.

If that scenario is confusing, I'll summarize - with HTP off, I set the camera in Av mode, f/8, ISO 400, and the metered exposure gave a 1/100 s shutter speed.

Answer these questions about what happens when I set HTP to Enable:

1) Does my selected aperture of f/8 change?
2) Does the camera-selected shutter speed of 1/100 s change?
3) Does the amount of light hitting the sensor change?

Please, no hand-waving, no 'please read my earlier posts', no repeating what you've posted before, no referring to what may happen at some other ISO setting that I didn't select and don't care about - just answer those three, simple questions with a yes or a no.

 Answer : yes

Sorry, Mikael - it was a pass/fail test, and you have failed.  The answer to all three of those questions is "no".  In Av mode, f/8, ISO 400, enabling HTP does not change aperture or shutter speed, and therefore the amount of light hitting the sensor does not change. If anyone believes there a chance Mikael is right, feel free to set Av, f/8, ISO 400 then enable HTP and see if shutter speed or aperture change as a result.

Back in the other thread, I had come to the conclusion that this was semantics and your inappropriate extrapolation of what happens in the special case of ISO 100 in an autoexposure mode to a general explanation of how HTP works.

But...the fact that you answered "yes" to the above questions clearly demonstrates that you do not understand how HTP really works.  Despite repeated attempts by several people, including TheSuede, to provide an explanation which you could understand, you fail to grasp some details of the concept.  At this point, the only logical conclusion is that you are simply incapable of understanding the mechanism of HTP.  Not due to language, semantics, etc. - just a fundamental inability to comprehend this concept.  You are wrong, you don't get it, and apparently you never will, much less admit that you're wrong and/or incapable of understanding the concepts.

To paraphrase an earlier statement of yours, it's impossible to discuss this with someone who does not understand the basics - and that someone is you, Mikael.  For my part, this discussion is done.  Any further statements or questions from you on this matter will be ignored.

6155
Lenses / Re: 300 f4 + 1.4 TC v's 500 f4.5
« on: February 02, 2013, 04:40:30 PM »
The 500mm f/4.5L is an electronic manual focus lens, and AFAIK Canon no longer services that model. So, if the AF motor gives out (which happens on those lenses), you will be unable to focus the lens at all, leaving you with a $3000 rather heavy cricket bat.  I'd pass.

6156
EOS Bodies / Re: making a case for that crop body camera
« on: February 02, 2013, 03:27:09 PM »
How does using the best part of the lens help if I need to shoot at ISO 6400?   :-\

6157
Lenses / Re: Resistance to Larger Filter Size, Kills Great Lenses?
« on: February 02, 2013, 03:22:37 PM »
Actually, for something "well-known" I've never heard that.  Interesting information.  Personally, a 95mm filter size would not have impacted my decision in purchasing such a lens.

6158
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 02, 2013, 03:18:32 PM »
But what's to stop him from making a comeback with the familiar - "you do not understand" / "you have no clue" BS?

That would indicate to me that he found those three yes/no questions too difficult to answer…   ::)

6159
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 02, 2013, 03:05:51 PM »
have you noticed one thing, Mikael is quiet, with thoughtfulness , little bit of thinking he  probably understands now he is wrong

6160
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 02, 2013, 02:24:35 PM »
no Im saying by exposure after 400 iso you have create a head room by 2 stops compare to 100iso
what is so difficult to understand Neuro! = exposure after 400 iso = halving the hitting lights twice compare to 100iso


Hypothetical example: I shoot jpg. I am taking a picture of a forest scene. I am in Av mode, and I set f/8 to obtain the desired DoF, and I chose ISO 400 to get a 1/100 s shutter speed at metered exposure to avoid camera shake, because I foolishly left my tripod at home. Please note, I couldn't care less about what exposure settings would be at ISO 100, 50, or 3200, that's tangential and irrelevant - I choose f/8 and ISO 400 for the reasons I stated.  I take a shot, look at the review image, and see blinking highlight alerts where I want detail of the sun-dappled forest floor. I've read that HTP can preserve my highlights.

If that scenario is confusing, I'll summarize - with HTP off, I set the camera in Av mode, f/8, ISO 400, and the metered exposure gave a 1/100 s shutter speed.

Answer these questions about what happens when I set HTP to Enable:

1) Does my selected aperture of f/8 change?
2) Does the camera-selected shutter speed of 1/100 s change?
3) Does the amount of light hitting the sensor change?

Please, no hand-waving, no 'please read my earlier posts', no repeating what you've posted before, no referring to what may happen at some other ISO setting that I didn't select and don't care about - just answer those three, simple questions with a yes or a no.

6161
Lenses / Re: Considering Super Tele Options
« on: February 02, 2013, 01:38:10 PM »
With regard to field sports and wanting the 300 2.8 II, would that be on a full frame or your 7D?  Do you expect a 400 to be too long on a full frame to be used in that capacity?

On FF. Since getting the 1D X, the only times the 7D has been used are when I loaned it to someone as a backup camera for a wedding shoot, and to take a few comparison shots vs. the 1D X. Those comparison shots confirmed my belief (based on a more detailed 5DII vs. 7D comparison), that a 1D X image cropped to the FoV of the 7D has equivalent IQ (and better IQ at high ISO), so I'd only be giving up megapixels, and 7-8 MP meets my usual needs (up to 24x36" prints).  So, at this point, I see no need for my 7D.

6162
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 02, 2013, 01:04:25 PM »
are you for real?  then you have to adjust the time/f-stopt to the  metering of the subject or you are either over expose or under expose

Ahhh...now I finally understand. Mikael's cameras have infallible metering systems.  Snowscapes, fields of yellow flowers, black cats...in all cases, the metered exposure is perfect, so he can always let his camera make exposure decisions for him, so he can use ISO changes to adjust his aperture and shutter speed for him. That must be nice.

Some of you don't have a clue what discussion is about

2. 400 iso the head room is created by two stops , it means halving the hitting light twice to sensor

Indeed. You are stating now that at ISO 400, enabling HTP results in Half The Photons hitting the sensor, making it crystal clear that YOU (still) do not have a clue.

6163
Lenses / Re: Considering Super Tele Options
« on: February 02, 2013, 12:40:54 PM »
The 600 II is sharper than the 400 II + 1.4x, the 600 II + 1.4x is sharper that the 400 II + 2x, and the 600 II + 2x is 1200mm, still quite sharp, and will AF on the 5DIII after the firmware update due in April.

But...the 600mm is on the long side for sports.  I shoot birds/wildlife a lot, so for me the 600 II was the best choice.  If you shoot sports more than wildlife, the 400 may be better - it can be made longer with TCs. Do keep in mind there's an AF speed penalty with TCs - a 50% drop with a 1.4x and a 75% drop with a 2x.  If you plan to mostly use an extender, get a longer lens (the only current exception is the 600 II, since that plus the 1.4x beats the 800/5.6, and the 600 II + 2x beats the 800 + 1.4x).

Once my kids are old enough for field sports (2-3 years, I guess), I can see adding a 300/2.8 II to my kit.

6164
Lenses / Re: Need advice on telephoto zoom Lens
« on: February 02, 2013, 12:26:14 PM »
The 70-200/4L IS, 70-300L, and 100-400L are all excellent.  Your choice should be determined by whether you need 200mm, 300mm, or 400mm.

The 70-300 non-L seems to be listed on my local CL frequently, in the $300-350 range (higher sometimes, but I highly doubt those sell). 

6165
Reviews / Re: Kirk Security Strap review
« on: February 02, 2013, 10:15:28 AM »
I think you're talking about the dovetail on the bottom of the clamp when you refer to adding to the profile? I agree, that seems like a great feature. But, the 'lens plate' question I had is about using the clamp with an AS plate on a lens (tripod collar, like on a 100-400 or supertele), where the plate is oriented 90-deg relative to a camera body plate, and with no swivel on the clamp, that means the strap has to twist to accomodate that.

But - looking at it again, I'm asking a flawed question. Sorry for the confusion! The clamp is actually oriented to hold a collared lens plate on the axis of the strap.  It looks like with a camera plate, the natural hang would have the back of the camera facing your body - is that the case? 

Thanks again!

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