Comments on: The Basics of Camera Exposure Controls http://enticingthelight.com/2009/04/29/the-basics-of-camera-exposure-controls/?utm_source=rss&utm_medium=rss&utm_campaign=the-basics-of-camera-exposure-controls A Quest for Photographic Enlightenment Tue, 07 Feb 2012 16:47:04 +0000 hourly 1 http://wordpress.org/?v= By: Ivan Glisin http://enticingthelight.com/2009/04/29/the-basics-of-camera-exposure-controls/comment-page-1/#comment-798 Ivan Glisin Mon, 04 May 2009 04:56:10 +0000 http://enticingthelight.wordpress.com/?p=919#comment-798 Just a few small clarifications on aperture and absolute EV: I see in the table that EV 0 is used for f/1.0 which is only partially correct. EV 0 is by definition aperture of f/1.0 (as correctly stated) AND shutter speed of 1s (missing) at ISO 100 (missing). Relevant article: http://en.wikipedia.org/wiki/Exposure_value However, the article on Wikipedia is mentioning EV in the context of various camera settings that would result in the same exposure, then adding photometric exposure to the picture by using quite confusing definitions for non-engineers. But simply put, "photometric" EV 0 means that *subject brightness* is such that a photograph taken at f/1.0, 1s, and ISO 100 would result in a mid gray frame (or what camera manuals keep incorrectly calling "correct" exposure). Also worth noting is that there is a difference between EV (absolute EV) and +/-EV for exposure compensation (relative to established value by camera meter). For example, photometric EV 2 is not the same as +2 EV exposure compensation. Finally, f/1.0 is not only theoretical. Simply put, f = F/D, where F is the focal length and D the diameter of the lens. (This gets less obvious with retrofocus wide angle lenses, but f = F/D still applies although in a bit different way.) So, an F = 50mm lens with D = 50mm front element would be an f/1.0 lens, which really exists: Canon EF 50mm f/1.0 L USM. With D > F we would end up with an f/0.x lens. Is it possible? Why not! Check Canon 50mm f/0.95. I hope this further clarifies some points mentioned in the article. Just a few small clarifications on aperture and absolute EV:

I see in the table that EV 0 is used for f/1.0 which is only partially correct. EV 0 is by definition aperture of f/1.0 (as correctly stated) AND shutter speed of 1s (missing) at ISO 100 (missing).

Relevant article: http://en.wikipedia.org/wiki/Exposure_value

However, the article on Wikipedia is mentioning EV in the context of various camera settings that would result in the same exposure, then adding photometric exposure to the picture by using quite confusing definitions for non-engineers. But simply put, “photometric” EV 0 means that *subject brightness* is such that a photograph taken at f/1.0, 1s, and ISO 100 would result in a mid gray frame (or what camera manuals keep incorrectly calling “correct” exposure).

Also worth noting is that there is a difference between EV (absolute EV) and +/-EV for exposure compensation (relative to established value by camera meter). For example, photometric EV 2 is not the same as +2 EV exposure compensation.

Finally, f/1.0 is not only theoretical. Simply put, f = F/D, where F is the focal length and D the diameter of the lens. (This gets less obvious with retrofocus wide angle lenses, but f = F/D still applies although in a bit different way.) So, an F = 50mm lens with D = 50mm front element would be an f/1.0 lens, which really exists: Canon EF 50mm f/1.0 L USM. With D > F we would end up with an f/0.x lens. Is it possible? Why not! Check Canon 50mm f/0.95.

I hope this further clarifies some points mentioned in the article.

]]> By: image background clipping http://enticingthelight.com/2009/04/29/the-basics-of-camera-exposure-controls/comment-page-1/#comment-797 image background clipping Sat, 02 May 2009 04:10:29 +0000 http://enticingthelight.wordpress.com/?p=919#comment-797 Extremely informative article, well researched and clearly presented. I am thankful Peter Zack took the time to share this informative post. Regards, clipping path services Extremely informative article, well researched and clearly presented. I am thankful Peter Zack took the time to share this informative post.

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]]> By: Miserere http://enticingthelight.com/2009/04/29/the-basics-of-camera-exposure-controls/comment-page-1/#comment-796 Miserere Wed, 29 Apr 2009 13:55:48 +0000 http://enticingthelight.wordpress.com/?p=919#comment-796 Ro, I wrote a couple of articles (<a href="http://enticingthelight.wordpress.com/2008/12/24/achieve-the-exposure-you-want-part-1/" rel="nofollow">Part 1</a> and <a href="http://enticingthelight.wordpress.com/2009/01/08/achieve-the-exposure-you-want-part-2/" rel="nofollow">Part 2</a>) about achieving correct exposure more from an artistic point of view, but in this article Peter has addressed all the variables using a straightforward, down-to-earth approach, making it a valuable resource. Ro, I wrote a couple of articles (Part 1 and Part 2) about achieving correct exposure more from an artistic point of view, but in this article Peter has addressed all the variables using a straightforward, down-to-earth approach, making it a valuable resource.

]]> By: roentarre http://enticingthelight.com/2009/04/29/the-basics-of-camera-exposure-controls/comment-page-1/#comment-795 roentarre Wed, 29 Apr 2009 11:39:12 +0000 http://enticingthelight.wordpress.com/?p=919#comment-795 Peter, you have written a great article that I had been originally planning to do so. Now I think I would just better link people's questions to this particular post instead. Well written. I think I might have seen a similar article written from Miserere as well? Peter, you have written a great article that I had been originally planning to do so. Now I think I would just better link people’s questions to this particular post instead.

Well written.

I think I might have seen a similar article written from Miserere as well?

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