Pls show examples where increasing brightness in post better than increasing ISO.

Started Oct 1, 2013 | Discussions thread
texinwien
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Re: Pls show examples where increasing brightness in post better than increasing ISO.
In reply to Jeff, Oct 2, 2013

Jeff wrote:

bobn2 wrote:

ultimitsu wrote:

bobn2 wrote:

So, mostly the metering is checking highlights. The easy technique is to set 2 1/2 or a bit more stops of EC and spot meter off the highlights (if your camera lets you use EC in M). On most camera there are a few ISO settings to be working with, and you know those pretty well anyway.

This sounds quite interesting, can you elaborate a bit on how it works? why 2.5 stops?

Your meter should be calibrated to centre when it gets 18% grey as the nominal exposure (10/ISO lux seconds). So, you need to miscalibrate it to regard 100% as nominal. According to ISO, the ratio of highlight to 18% is 78/10 = 7.8 = 2.96 stops (funny what these discussions can do - I see I miscalculated a long time ago, and have been giving my highlights a bit less than I could - dial in 3 stops). So, if the meter reads highlight and thinks it's 18% grey, it will give 3 stops less exposure than it should - so you correct that with EC, or recalibrating the meter (most will not let you recalibrate that far). In practice if you know how much headroom your camera has, you could dial in more than that.

(Just going back through my working, I realise where the extra half a stop came from, ISO leaves 1/2 stop for specular highlights over white - I must have taken it off somewhere along the line - 3 stops is better)

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Bob

This is more or less what I've learned to do when shooting in challenging light, but with a small twist.

My E-P5 allows me to adjust the level for shadow and highlight 'blinkies', which I've set at jpeg levels 5 and 250, respectively. In A priority, the rear control wheel adjusts aperture, and the front control wheel adjusts EC.

When taking a shot, exposure is set by keeping an eye on the blinkies while adjusting EC, and while monitoring everything else to be sure I'm not totally killing the shadows. EC will generally fall between -0.5 and -2.5, but the critical issue is watch where the highlights and shadows fall on the live histogram and, via the blinkies, on the image.

The resulting jpeg preview may look off (generally too dark) but this procedure will give me a good raw file for subsequent processing in LR. ISO is a tertiary consideration. I generally try to work at base ISO, but will increase ISO as necessary to keep the viewfinder and jpeg previews usable.

Here are some results http://www.flickr.com/photos/jck_photos/sets/72157635431417147/

It becomes second nature pretty quickly.

I started typing a similar reply, took a break, and here you've gone and done the work, yourself!

The live-view 'blinkies' overexposure indicators are a boon to ETTR raw photogs. Add sufficient controls (i.e. Olympus E-M5, E-P5, E-M1) and you have an ETTR dream machine.

I, too, started out in A mode, mostly, but since Anders W convinced me that there was little advantage to A or S over M when using the blinkies method of ETTR, I have switched, and stay in M 99% of the time.

What comes out are images that are usually within a (<1/3) fraction of a stop from optimal ETTR. As much light as possible collected without blowing any important highlights - consistently.

Since the E-M5 (and E-P5) sensor is not 100% ISO-invariant, I do switch between ISO 200, 400 and 800 (rarely 1600). My sincere hope is that the next generation of OM-D models will be truly ISO-invariant, so I can forget that useless (to me) throwback to ancient history and get on with making properly-exposed photographs - one less useless variable to have to keep in mind.

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