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It's very hard to exactly evaluate exposure
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Oct 19, 2019 10:32:53   #
a6k Loc: Detroit & Sanibel
 
🙉

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Oct 19, 2019 11:11:50   #
wham121736 Loc: Long Island, New York
 
Exact is the devil to good enough!
I agree with Gene51.
a6k wrote:
To add to my first post, here is CaptureOne looking at the same picture but one is the JPG and the other is the .ARW (raw).

Notice that for the ARW the RGB numbers are a bit higher but the exposure evaluation is lower. The JPG's RGB numbers are slightly lower but the exposure evaluation is just above middle.

This may be a Sony thing or it may be a CaptureOne thing. Or both.

None of these differences are big enough to materially affect post processing but they do show how hard it is to be precise.

btw, the color readout is in the exact same position for both. The highest value on the exposure evaluation - the nearly vertical line on the right of the hump - is where the readout is, too. But the position of the readout does not affect the evaluation's graphic.
To add to my first post, here is CaptureOne lookin... (show quote)

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Oct 19, 2019 11:17:15   #
Fayle Loc: Seward, Alaska and Rionegro, Colombia
 
For proper exposure use your cameras histogram. It’s quite simple. For those that don’t know how to use it, there are plenty of online tutorials available.

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Oct 19, 2019 11:22:58   #
Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)
 
a6k wrote:
Gene, I thought you would know better than to say that. Why would anyone think that carefully learning about the equipment would preclude having fun and taking pictures? In fact, I have fun calibrating my gear so that when I'm where there is an opportunity to take pictures I will be more confident of getting what I intend to get. Try thinking about the alternative. Try to think about how you would use a camera that randomly varied the exposure by one full stop? That is the logical extension of what you are suggesting.

Bill, the only way to carefully measure what the sensor is doing is to control the light to which it is exposed. That is why I and some others use a monitor as a light source for tests like these. It's highly repeatable and can be used to test many different things without worrying about the haze in the sky or a cloud passing by, etc.
Gene, I thought you would know better than to say ... (show quote)


It's really not that involved. And there are several assumptions being made - a display rarely has consistent illumination across the entire screen, using a spot at the center of the brightest part of a screen image is somehow a valid way to evaluate exposure when clearly different tools provide slightly different results.

At the end of the day, what often matters most is what happens at the right edge of the histogram, where clipped channels can result in data loss, and irrevocably damaged images. And the threshold for data loss varies among different camera brands, and even across generations in the same camera brand. Older cameras are far less tolerant of overexposure than the new ones, and Fuji's tend to blow away the competition in this regard, often tolerating up to 3 stops of additional exposure over Canons and Nikons. What happens at the midpoint of tonal value is less important, especially if you are evaluating raw files. I do not agree with A6k's statement, " . . . there IS a standard for ISO for JPG but there is NOT one for raw . . ." or maybe I have no clue what he is getting at. Finally, measuring processed images, even they are processed by in-camera software is yet another uncontrolled variable.

The best way to evaluate exposure is to take a lot of pictures and look at them very critically. In my case, I expose for maximum detail in highlights, so that is how I evaluate exposure. Each camera is different, each ISO in a given camera is different. And I use camera meters, usually spot metering mode more as a tool to measure relative reflectances within a scene, not as an absolute EV, which for the way I shoot is less helpful. And I am not going to lose sleep over what amounts to less than 1/3 stop variations. Truth is, if you point your camera at a plain subject of even tonal value, and take 100 exposures you will find small amounts of variation - in the meter reading, shutter speed or aperture. There is no need for this level of analysis - it's far more productive to, as I stated originally, to go out and take pictures and not worry about this stuff. But if this floats a6k's and your boat, then I want to be the last person on the planet to try to dissuade you from such pursuits.

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Oct 19, 2019 11:56:22   #
Blair Shaw Jr Loc: Dunnellon,Florida
 
WOW....it must be something in the Water.......I'll find another topic to read cause this one is in the Weeds already and not going to go anywhere worth repeating or attempting to remember. I wish members would be more kind to one another in their differences of opinion. You're scaring the rest of us from trying to learn and reach a higher learning curve. Negative comments are an indication of pettiness & insecurity and some folks need a time-out.

Be KIND America to everything.....it matters greatly!

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Oct 19, 2019 14:01:14   #
TylerDurdensReel Loc: Fresno Ca.
 
CHG_CANON wrote:
Are you really supposed to get anything out of jibber jabber?



Speaking of "jibber jabber", have you no sense of irony?

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Oct 22, 2019 22:10:05   #
carl hervol Loc: jacksonville florida
 
dido

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Oct 27, 2019 00:29:53   #
anotherview Loc: California
 
"An Easy Way To Find Neutral Gray In A Photo With Photoshop":

https://www.photoshopessentials.com/photo-editing/neutral-gray/
a6k wrote:
To add to my first post, here is CaptureOne looking at the same picture but one is the JPG and the other is the .ARW (raw).

Notice that for the ARW the RGB numbers are a bit higher but the exposure evaluation is lower. The JPG's RGB numbers are slightly lower but the exposure evaluation is just above middle.

This may be a Sony thing or it may be a CaptureOne thing. Or both.

None of these differences are big enough to materially affect post processing but they do show how hard it is to be precise.

btw, the color readout is in the exact same position for both. The highest value on the exposure evaluation - the nearly vertical line on the right of the hump - is where the readout is, too. But the position of the readout does not affect the evaluation's graphic.
To add to my first post, here is CaptureOne lookin... (show quote)

Reply
Oct 27, 2019 04:50:51   #
Pablo8 Loc: Nottingham UK.
 
a6k wrote:
To add to my first post, here is CaptureOne looking at the same picture but one is the JPG and the other is the .ARW (raw).

Notice that for the ARW the RGB numbers are a bit higher but the exposure evaluation is lower. The JPG's RGB numbers are slightly lower but the exposure evaluation is just above middle.

This may be a Sony thing or it may be a CaptureOne thing. Or both.

None of these differences are big enough to materially affect post processing but they do show how hard it is to be precise.

btw, the color readout is in the exact same position for both. The highest value on the exposure evaluation - the nearly vertical line on the right of the hump - is where the readout is, too. But the position of the readout does not affect the evaluation's graphic.
To add to my first post, here is CaptureOne lookin... (show quote)


If it is so difficult, I suggest you take up knitting, or needlework, and relax.

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Oct 27, 2019 09:07:59   #
anotherview Loc: California
 
Ditto: "I wish members would be more kind to one another in their differences of opinion."
Blair Shaw Jr wrote:
WOW....it must be something in the Water.......I'll find another topic to read cause this one is in the Weeds already and not going to go anywhere worth repeating or attempting to remember. I wish members would be more kind to one another in their differences of opinion. You're scaring the rest of us from trying to learn and reach a higher learning curve. Negative comments are an indication of pettiness & insecurity and some folks need a time-out.

Be KIND America to everything.....it matters greatly!
WOW....it must be something in the Water.......I'l... (show quote)

Reply
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