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

Started Oct 1, 2013 | Discussions thread
gollywop Veteran Member • Posts: 8,284
Re: Pls show examples where increasing brightness in post better than increasing ISO.

Jeff wrote:

gollywop wrote:

Jeff wrote:

texinwien wrote:

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)

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

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.

Couldn't agree more. I've been experimenting a bit with the level settings for the blinkies. 5 and 250 may be unnecessarily conservative, but produce good files. 2 and 253

Anders W is probably right (as usual), but I just like how the controls work in A mode. Back wheel A, front wheel EC, and it's totally second nature. Flick the 2x2 control and then ISO is on the front wheel. I am using M mode more often, but A mode just feels more intuitive to me. Admittedly, this is a personal quirk.

Oly could really own this with a few more tweaks of their UI. They're pretty close now.

With the E-M5 and UniWB, I've found no need to adjust the histogram sensitivity at all. I keep it at 0, 255 and find it works splendidly. I believe Anders found the same thing using autoWB. The typical 1/3EV difference between UniWB and autoWB settings was made up by the fact that I adjust EC (or exposure) to "just under" blinkies, while Anders adjusted to "just showing" blinkies.

I tried Anders' method extensively while traveling this past spring, and I have to agree that it works just as well as the UniWB. I came back with 450 shots (not counting WhiBal readings) and absolutely none of them was problematic for exposure as assessed by RawDigger.

That's not to say I didn't have shots that were incorrect, but I was able to determine that situation immediately with the post-shot blinkies and retake as needed.

Many thanks. I'll be opening up the blinkie window.

I'm also intrigued by your comments regarding autoWB vs uniWB. Normally I use autoWB unless I'm in a tricky, bad lighting situation where I can set up a custom WB. What would be the advantages of uniWB?

It provides post-shot color histograms that are more nearly like the raw-data histograms.  This means that, for most situations, multipliers have not been applied to the B and R channels, allowing them to indicate higher R and B levels than in fact exist.  For most cases where G leads the way, this doesn't make too much difference.  But in cases where R or B lie further to the right, you can't be sure what's really happening using WB other than UniWB.

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