From: Wilba on
Paul Furman wrote:
> Wilba wrote:
>> Paul Furman wrote:
>>>
>>> An interesting related issue I don't understand is how the exposure
>>> slider works in Lightroom or ACR. I don't know how to duplicate that
>>> effect in photoshop with curves, levels, etc. Those all do like you
>>> describe, moving the middle parts of the histogram but there isn't an
>>> easy way I can see to shift the whole exposure. Hmm, the middle slider
>>> on levels comes close but still doesn't match the effect.
>>
>> Image | Adjustments | Exposure... ?
>
> Hmph, CS1 doesn't have that.

Bummer.


From: Wilba on
Porte Rouge wrote:
>
>>> I think he meant the increments on the controls are arbitrary(1/3,
>>> 1/2, or 1 stop for each click on the dials.
>>
>> But that does happen to be *exactly* where the term "stop" came
>> from.
>
> I'll let you and Alan figure out where "stop" came from.
>
> The amount of change in exposure per click on the dials on my DSLR
> is arbitrary, I choose how much I want.

Right. And those increments have nothing to do with what I was talking
about - you get that, don't you? :- )


From: Mike Russell on
> Paul Furman wrote:
[re Image | Adjustments | Exposure... ]
>> Hmph, CS1 doesn't have that.

Here's something similar that will work on most versions of PS
http://www.anntorrence.com/blog/2008/02/multiply-and-screen-to-adjust.html

--
Mike Russell - http://www.curvemeister.com
From: Paul Furman on
Mike Russell wrote:
>> Paul Furman wrote:
> [re Image | Adjustments | Exposure... ]
>>> Hmph, CS1 doesn't have that.
>
> Here's something similar that will work on most versions of PS
> http://www.anntorrence.com/blog/2008/02/multiply-and-screen-to-adjust.html

Wow, thanks! Interesting how he duplicated the effect with curves and
that looks a lot like a gamma adjustment. Seems like it incorporates the
linear-data conversion to adjusted-for-human-perception idea (if that
makes sense).

"Multiply/Screen"
-storing that away for future use...

Fascinating to overlay those two files in PS & scroll through the layer
modes. Pick one from the drop-down then use the up/down arrow keys to
browse.

--
Paul Furman
www.edgehill.net
www.baynatives.com

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From: Paul Furman on
Wilba wrote:
>
> "Stop" is used to mean "equivalent to an f-stop", but that's not what it
> literally means. In that case it's a misnomer, like "shutter speed" for what
> is actually shutter duration, "post-mortem" for autopsy, point-blank range,
> 10-speed bike, ...
>
>> Whether aperture, shutter speed, filters, light levels (control of flash
>> or constant lighting by any means) it's a "stop" (or fraction thereof).
>
> How do you "stop down" a shutter speed or ISO?

Or even worse, how do you "stop up" a camera?

:-)

--
Paul Furman
www.edgehill.net
www.baynatives.com

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