Canon Explains Exposure

DanielpDanielp Registered Users Posts: 11 Big grins
edited November 26, 2013 in Tutorials
Canon has a website that helps beginners learn the basic things about exposure, aperture , shutter speed and even ISO

Very nice site and highly recommend for everybody!
http://www.canonoutsideofauto.ca/

Comments

  • slpollettslpollett Registered Users Posts: 1,219 Major grins
    edited April 17, 2013
    This explanation is very well done & perfect for a beginner. I've been trying to explain these concepts to my daughter only to get the eyes glazed over look back. This is put forth in a way that she understands perfectly.

    Thanks for sharing.

    Sherry
  • arodneyarodney Registered Users Posts: 2,005 Major grins
    edited April 19, 2013
    I sure hope they don't treat exposure for JPEG the same as raw. They are not the same!
    Andrew Rodney
    Author "Color Management for Photographers"
    http://www.digitaldog.net/
  • alaiosalaios Registered Users Posts: 668 Major grins
    edited November 24, 2013
    Hi can you explain this big difference?
    A
  • AndyAndy Registered Users Posts: 50,016 Major grins
    edited November 24, 2013
    arodney wrote: »
    I sure hope they don't treat exposure for JPEG the same as raw. They are not the same!

    It's a "for beginners" tutorial, Andrew. This is not a subject for beginners :D
  • arodneyarodney Registered Users Posts: 2,005 Major grins
    edited November 24, 2013
    arodney wrote: »
    I sure hope they don't treat exposure for JPEG the same as raw. They are not the same!

    Hi can you explain this big difference?

    Sure! Very similar to the old analog film days where we shot transparency and neg film which for ideal capture needed different treatments in terms of exposure. You'd never treat a B&W neg (Exposure + Processing) the same as a transparency. Raw data is vastly different than JPEG data in terms of expsorue, development and what both bring to the party. Raw is linear encoded. JPEG is gamma corrected and processed from the raw data inside the camera using it's proprietary processing. IOW, all these cameras produce a raw, not all but most provide that raw and/or the JPEG and if you expose a raw as you would a JPEG, you underexpose it big time! This piece should help visualize why and the differences:

    http://www.digitalphotopro.com/technique/camera-technique/exposing-for-raw.html

    As you can see in Figure 1, the linear raw data behaves quite differently from a rendered (encoded) JPEG. Think of the JPEG as a transparency where your fudge factor in terms of ideal exposure is rather small. Think of the raw as a neg where you have an ideal exposure too but is quite different from the ideal exposure for that raw data (ideal signal to noise ratio). Just like film (and JPEG), there is an ideal exposure in terms of best data and of course the role of the photographer to decide where to place the dynamic range of the scene on the captured data IF the scene range exceeds the camera's ability to capture it. Do you expose for shadow detail you wish to represent at the expense of highlights or do the opposite? It's really Photography 101! It's no different digital or analog in terms of ideal exposure once the photographer understands the difference in the media (film be it neg or transparency or digital with raw or JPEG). If the article mentioned fails to mention this and the camera has the ability to capture both raw and JPEG, the ariticle fails to properly educate even the beginner. Just as if someone wrote an article about film exposure for the beginner but never mentioned how to treat exposure and development of a 100 ISO transparency vs. a 1600 ISO color neg film!
    Andrew Rodney
    Author "Color Management for Photographers"
    http://www.digitaldog.net/
  • arodneyarodney Registered Users Posts: 2,005 Major grins
    edited November 24, 2013
    arodney wrote: »
    I sure hope they don't treat exposure for JPEG the same as raw. They are not the same!
    Andy wrote: »
    It's a "for beginners" tutorial, Andrew. This is not a subject for beginners :D

    Nonsense, it is a perfectly appropriate for any beginning photographer who's camera has a switch to hand off raw or JPEG as the Canon I see on the main article page should provide!. It's as I pointed out above, Photography 101. One small sentence in the entry level article could provide the necessary and salient points even for a beginner!

    "Exposure for raw and JPEG are not on parity...."

    If you expose your raw data as you would a JPEG, you're getting less than optimal exposure for that data, it is as simple as that.

    Might as well write an entry level article on exposure and film and simply state: exposure doesn't matter much, get close and push/pull the film in the lab. Dumb and bad advise unless for some reason, you had to expose that way and fix the issue later (far from ideal!).

    Stupid is as stupid does. Let's not treat beginning photographers as too dumb to understand fundamental photography in terms of media and exposure and development.
    Andrew Rodney
    Author "Color Management for Photographers"
    http://www.digitaldog.net/
  • arodneyarodney Registered Users Posts: 2,005 Major grins
    edited November 24, 2013
    From the Canon article:
    High ISO will cause grainyness so as a rule use the lowest ISO possible

    While it's for beginners, that's simply not the case (and it's a rare case that isn't correct with Canon sensors and processing!). Clearly illustrated here:
    http://digitaldog.net/files/100vs800iso.jpg

    The illustration begs the question, which of the two exposures has less noise? Clearly the capture with the higher ISO!

    Just because an article is aimed at beginners, no reason to write things that are technically wrong! The sentence from the Canon site about ISO is just incorrect. In fact, with Canon systems, the rule is quite clear: A higher ISO can and will have less noise IF the capture is exposed properly (ETTR) in this case for the raw data.
    Andrew Rodney
    Author "Color Management for Photographers"
    http://www.digitaldog.net/
  • alaiosalaios Registered Users Posts: 668 Major grins
    edited November 26, 2013
    Hi I read the external link you provided.. It looks too technical to me.. What is the advice I have to follow?
    A.
  • arodneyarodney Registered Users Posts: 2,005 Major grins
    edited November 26, 2013
    alaios wrote: »
    Hi I read the external link you provided.. It looks too technical to me.. What is the advice I have to follow?
    A.

    Film neg: Expose for the shadows, develop for the highlights.

    Raw: Expose for the highlights, develop for the highlights.
    Andrew Rodney
    Author "Color Management for Photographers"
    http://www.digitaldog.net/
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