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EOS Bodies - For Stills / Re: ISO 50
« on: January 23, 2013, 10:23:01 AM »
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Well Owl be.....whhoooo takes such great wildlife photos?Brilliant! both the comment and Gary's pet owl picture

My G.... You two Neuroanatomist and Rpt don't know the basic how a sensor works, collecting photons and if you are halving the time= go from 100 iso to 200 iso you are halving the amount of hitting light/photons on the sensor and the amount of read out electrons by half.Good night!
God night
Well, looks like Mikael stands by his Half The Photons theory. Choosing not to communicate on that statement is a communication in itself. Obviously he has a direct channel to the Photon God. So every time he sets his camera to HTP, his request for a reduction in photons is granted by that God...I have just done that both by text and by and illustration. Now its up to you and understandThat they gain a head room and a better reproduction of the high lights if they shoot JPG and don't know raw, under or over exposure, post processing etc .
no -- that is not the mechanism that is the benefit. how will you explain the HTP mechanism, the effect of exposure, and the number of photons striking the sensor.
I don't think you have, Mikael. Here is the question again: when the camera's ISO dial is set to something besides 100 (I mean it it is set to 160, 200, 400, or 800 or 1600, etc. etc.) how will you explain the HTT mechanism, the effect upon exposure and the number of photons striking the sensor?
My point from earlier, the explanation is 'right' in the same way a broken analog clock is 'right' twice a day.
ps: If anyone can tell me why it says Powershot G-15 below my name I would appreciate it. Went to edit my profile but could not find that....Try harder. More responses under your belt and you may see a "better" camera under your alias...
Maybe it's all the foreign languageIn my universe, Physics and Mathematics speak one language.

@rptI apologise. Whisky it is. And I prefer the smokiesQuoteScapes? You talk about land and sea scapes! Whiskey man! Whiskey!
If you go to Islay there is an abundance of all three. Work flew me over a couple of years ago, poisoned chalice in a way - beautiful place, but no real time to enjoy the views or the uisge beatha. Must try and get back.
And if it's Scotch then its 'Whisky'.

My two cents (and I am not disclosing the currency) is that to get a "true" ISO 100 if we need 14 bits, for a "true" ISO 50 we will need 15 bits. I am willing to bet that if you wait a bit longer, we will get native ISO 25 (how did I figure that? Well, 16 bits...). Now Einstein said time is relative so I guess the "bit" he was talking about was not a 0 or a 1...This thread just shows how much of us could really use a "True" ISO 50 in DSLR's. I'd like one canon and perhaps they will be the first with the new 1Dxs.
The problem is that there's no free lunch. A "true" ISO 50 would mean a lower base ISO, meaning that to achieve higher ISOs, even more amplification would be needed - meaning more high ISO noise. Usually, if ISO 100 is not low enough, one stop more is insufficient, at least in terms of shutter speed. The waterfall example posted earlier at ISO 50 and 5 s exposure required f/18 to get there - personally, I'd have preferred to shoot that at f/9 and ISO 100 with a 3-stop ND.
(Snip!)Dang! Silly me, I thought Mikael had found a way to set his Canon camera to HTP and control how the Sun streamed Photons towards his sensor!
What happens at higher ISOs (than 100) and with HTP is another story.
Since the actual aperture and shutter speed does not change when activating HTP, photometric exposure stays constant - i.e no loss of photons...
(Snip!)

Scapes? You talk about land and sea scapes! Whiskey man! Whiskey!This was taken at an impromptu demonstration against the British National Party.
Good visual on our fear, Paul. Collectively, we humans live in dread of "the other" and change and anything that seems to threaten our own security. Yet the irony is that our interdependence and change are our strengths and the fuel of our progress. You've endeared yourself to me with this little story, Paul.
I haven't been to Glasgow in 30 years, but I liked it when I was there. And Scotland has some of the best land and sea scapes I've seen anywhere. (Oh, and the best milk I've EVER had too!)

Yes Mikael, from my perspective you need to review you post on the first page where you mention this. You then say that results in half the charged electrons. That is not right. The same number of photons would be collected in the photo site irrespective if you has set HTP or not.Neuro wrote: Sorry, but you seem to be falling into the same trap and suffering from the same misconceptions as Mikael.
No it is about words, and what we mean.
And where is my earlier post?
HTP is nothing else than while the camera metering for 200iso the gain is smaller (around 100iso gain) and thereby we get a head room. ( I describe this as under exposure) because the camera metering after 200iso)
You get the same effect by under exposing 100iso 1 stop and later correct the raw file in the raw converter
In Jpg the camera lay a smoother contrast curve which make a smoother high light reproduction and also lift little bit in lower levels which make the noise little bit visible.
I hope I have make this message readable
Have a nice day
pardon my intrusion here Mikael, but the words and concepts you are using in the above is not under question. WHat is under question is the posts where you say that the HTP causes half the number of photons to reach the sensor.
This was taken at an impromptu demonstration against the British National Party.Wow! I did not know that about Glasgow! Great! More power to integrated societies.
I happened to be walking down Glasgow's main shopping area with my camera bag when my attention was taken by some ragtags and bobtails wearing hi-vis vests with the union jack flag on them.
Alarm bells rang and I hung around to see what developed, within 5 minutes there were civilians of all creeds, class, colour and age protesting against these anti-immigration loon-balls, to the point where Police were mobilised for their protection.
I love Glasgow. It has it's faults, but most of it's people are solid gold, and generally we stand up together against to people like this.
Glasgow was once one of the worlds busiest ports, our ships mobilised world trade, and brought impoverished hungry Irish and persecuted Jews to our city, enriching it's culture, fighting in our Army's, providing both brain and brawn to our industries. We have a history of acceptance, of refuge. And thats why we stand up to the BNP, when they attack the Eastern Europeans and Muslims who have made Glasgow their home in more recent years.
@Neuro:The ISO set determines the analog gain applied to the signal that resulted after photons are captured in the photo-site.
Neuro:QuoteIt's only half the photons if the aperture is set a stop narrower or the shutter speed is set a stop faster.
And not if ISO is reduced by a stop? Does the sensor not reject half the photons when it is 'asked' to be less sensitive?
Dont pounce on me, am learning here...
I can easily see that the amount of light reaching the sensor is a function of shutter/aperture combination. But am confused after that. I thought sensor reacts to the available light based on what ISO is set.
Thx...