Exposing to the right

[unpopular]

anyway - OP here is the link I promised:

http://www.thephotoforum.com/forum/...262171-spot-metering-how-use.html#post2389739

The most important point is that "zero" does not mean "correct"

 

[WayneF]

anyway - OP here is the link I promised:

http://www.thephotoforum.com/forum/...262171-spot-metering-how-use.html#post2389739

The most important point is that "zero" does not mean "correct"

Right. Spot metering is an advanced technique, it is Anything But beginners point&shoot. Reflected meters can only strive for a middle gray result, because it is all the smart they have. Many typical scenes do have wide range and do average about middle gray, which is the only basis of the system. But if we are going to pick our own spot to meter, that spot better be near middle gray. It does not come out "accurate". It comes out middle gray (equivalent). A face probably should not be middle gray. It can still work if we know to compensate it about +1EV. But Spot metering is anything but a general concept.

 

[unpopular]

Well, yes. It will only be accurate if the exposure is "uncompensated", or exposed at ±0ev, that is "zeroed". There are a lot of decent references in nature for middle grey, green foliage, 45° from the horizon opposite the sun (at which point you may as well use Sunny 16). There are other reference concrete is typically +1ev, asphalt typically -2ev.

But really, I don't think looking at exposure this way is particularly useful. I think it's better to considering how the image is to be rendered, and this should be talked about early on if you're serious about photography. Maybe for the beginner this concept won't be fully developed, but it's important that exposure isn't seen as something that has only one correct answer for.

I really don't like the idea of a "proper exposure".

 

[apaflo]

Well, yes. It will only be accurate if the exposure is "uncompensated", or exposed at ±0ev, that is "zeroed". There are a lot of decent references in nature for middle grey, green foliage, 45° from the horizon opposite the sun (at which point you may as well use Sunny 16). There are other reference concrete is typically +1ev, asphalt typically -2ev.

But really, I don't think looking at exposure this way is particularly useful. I think it's better to considering how the image is to be rendered, and this should be talked about early on if you're serious about photography. Maybe for the beginner this concept won't be fully developed, but it's important that exposure isn't seen as something that has only one correct answer for.

I really don't like the idea of a "proper exposure".

Proper exposure is correct exposure, and that is an exposure that produces the image exactly as the photographer wants it!

Statements like "underexpose by 1 stop to get what you want" are contradictory. What it really means is that the light meter reading will over expose by 1 stop.

 

[vintagesnaps]

Why would zeroing out the meter give unexpected exposures? I've always used the meter to let me know if I'm getting a proper exposure, which to me means that I'm getting the proper amount of light coming in to the camera. How I get there is where shooting manual comes into it - I can adjust the aperture, or if I want to maintain a certain depth of field I can adjust the shutter speed, or vice versa, or some of both.

There might be situations where you'd want to adjust from what the meter is indicating, if the meter is fluctuating when the light is changeable (sun in and out) etc. When I'm shooting B&W film sometimes I bracket shots to make sure I have a negative that isn't too thin or too dense, but I have yet to figure out why people or websites say to always under or over expose.

When I'm shooting digitally (I'm a film photographer too) I usually shoot Raw and all manual and I don't get blinkys etc. so I go by what the meter indicates as to whether or not I'm getting the exposure I need, then adjust from there.

 

[sk66]

ETTR... I don't. Most of the time I don't have the chance to check the histogram and adjust/try again; and I would much rather protect highlights than clip them.

If you use the spot meter properly and have a good understanding of camera latitude then you will never, ever clip with ETTR. In fact, this is the main reason I use the technique. Clipping is only a risk if you arbitrarily increase exposure without paying attention to hilight placement.

Did you note that I said I generally don't have time to check the exposure/adjust right/try again?
And the ETTR technique also depends A LOT on the accuracy of your camera's histogram/blinkies... some lie quite badly (my D800 does).

 

[WayneF]

Did you note that I said I generally don't have time to check the exposure/adjust right/try again?
And the ETTR technique also depends A LOT on the accuracy of your camera's histogram/blinkies... some lie quite badly (my D800 does).

Blinkies: You are not watching the proper RGB histogram. Sounds like you may not understand about luminosity histograms. You need to read Two types of Histograms (it is short and very easy).

And those who imagine that reflective meters always indicate the correct exposure are called beginners.

 

[Eagle74]

Why would zeroing out the meter give unexpected exposures? I've always used the meter to let me know if I'm getting a proper exposure, which to me means that I'm getting the proper amount of light coming in to the camera. How I get there is where shooting manual comes into it - I can adjust the aperture, or if I want to maintain a certain depth of field I can adjust the shutter speed, or vice versa, or some of both.

There might be situations where you'd want to adjust from what the meter is indicating, if the meter is fluctuating when the light is changeable (sun in and out) etc. When I'm shooting B&W film sometimes I bracket shots to make sure I have a negative that isn't too thin or too dense, but I have yet to figure out why people or websites say to always under or over expose.

When I'm shooting digitally (I'm a film photographer too) I usually shoot Raw and all manual and I don't get blinkys etc. so I go by what the meter indicates as to whether or not I'm getting the exposure I need, then adjust from there.

I'm just saying shooting in Manual in particular and zero'ing out the meter don't always give me what I am looking for. Example: shooting indoors using flash something white or reflective in close proximity to the flash get clipped. Another would be blowing out the light coming through a window because i use the subject focus point to meter off of. I know this isn't specific to manual mode. This is just my something I have to learn, keep in mind I'm pretty much a beginner, but I do like learning about this.

The main point of my question was if Exposing to the Right provided any kind of practical benefit if there is latitude in the histogram to move it right.

 

[sk66]

Did you note that I said I generally don't have time to check the exposure/adjust right/try again?
And the ETTR technique also depends A LOT on the accuracy of your camera's histogram/blinkies... some lie quite badly (my D800 does).

Blinkies: You are not watching the proper RGB histogram. Sounds like you may not understand about luminosity histograms. You need to read Two types of Histograms (it is short and very easy).

And those who imagine that reflective meters always indicate the correct exposure are called beginners.

Believe me, I understand histograms and blinkies. If you think the histograms (RGB or Luminance) or blinkies shown in the camera are accurate you would be mistaken. Quite possibly significantly. Even using a Uni-WB will only get you close... and I found it not worth the hassles.

 

[WayneF]

Did you note that I said I generally don't have time to check the exposure/adjust right/try again?
And the ETTR technique also depends A LOT on the accuracy of your camera's histogram/blinkies... some lie quite badly (my D800 does).

Blinkies: You are not watching the proper RGB histogram. Sounds like you may not understand about luminosity histograms. You need to read Two types of Histograms (it is short and very easy).

And those who imagine that reflective meters always indicate the correct exposure are called beginners.

Believe me, I understand histograms and blinkies. If you think the histograms (RGB or Luminance) or blinkies shown in the camera are accurate you would be mistaken. Quite possibly significantly. Even using a Uni-WB will only get you close... and I found it not worth the hassles.

I am still wondering if you do understand luminosity histograms.

The camera offers two histograms, the single one containing luminosity, which is a math abstraction of gray scale, which it isn't, which DOES NOT EVEN SHOW YOUR ACTUAL DATA ( but it is default unless you look further).

And the one showing the three Red, Green, Blue graphs, which is your real data.

The RGB histogram is NOT wrong (255 is NOT ambiguous). But yes, it is showing JPG with camera WB, when you may be using Raw with your own WB.

The single Luminosity graph is not even close to anything.

Try the link provided, it will make a huge difference for you. It is something we all have to know to get any use out of the histogram.

 

[Ysarex]

And the one showing the three Red, Green, Blue graphs, which is your real data.

The RGB histogram is NOT wrong (255 is NOT ambiguous). But yes, it is showing JPG with camera WB, when you may be using Raw with your own WB.

The Red Green Blue graphs are my real data, but it's showing JPEG? I thought the raw capture was my real data. So you're saying the RGB histogram is NOT wrong just that it's not my raw data which therefore must not be real data so the JPEG must be my real data. But if my raw data is my real data and the RGB histogram is showing JPEG then it must be wrong for my real data. Sounding very confused here.

Joe

 

[apaflo]

If you think the histograms (RGB or Luminance) or blinkies shown in the camera are accurate you would be mistaken. Quite possibly significantly. Even using a Uni-WB will only get you close... and I found it not worth the hassles.

In fact the histograms are precisely accurate! They just aren't necessarily displaying what photographers want displayed. They are accurately showing exactly what is in the camera generated JPEG image, not what is in the RAW sensor data; nor is it what will be in a RGB image (JPEG, TIFF or whatever) generated with an external computer program. In particular White Balance, Brightness, and Contrast parameters will all drastically change how an histogram looks.

If you want to see an histogram that accurately displays what is in the RAW sensor data, in particular to use for ETTR or even just generally setting exposure, it is a fact that UniWB can be made as accurate 1/10th of an fstop. And yes that can be a hassle, given that you give up being able to use the in camera JPEG as a preview (don't use that JPEG to show Granny what she looks like, or you'll get tossed out the door!)

Commonly what is worth doing in many cases but not all, is adjusting the camera JPEG generator for low relatively contrast, and the using the brightness level to cause the histogram to be very close in terms of the exposure. It will usually be within 1/4 of a stop, and virtually always within 1/2 a stop. Hence adjusting it to be about 1/3 a stop high in brightness will provide a RAW file that never clips highlights and is always easily processed to provide nearly the maximum dynamic range the camera is capable of.

 

[WayneF]

The Red Green Blue graphs are my real data, but it's showing JPEG? I thought the raw capture was my real data. So you're saying the RGB histogram is NOT wrong just that it's not my raw data which therefore must not be real data so the JPEG must be my real data. But if my raw data is my real data and the RGB histogram is showing JPEG then it must be wrong for my real data. Sounding very confused here.

Joe

If you shoot Raw, you get Raw, and the only problem is, the rear LCD shows RGB, and cannot show Raw. Nor can our computer monitors show Raw. Our tools show RGB.

So Raw files include a small embedded JPG with the camera properties in it (WB, contrast, etc), to be shown on the rear LCD. And since Raw files are not RGB, my notion is the RGB histogram obviously comes from that JPG too.

Raw does not have gamma either, but gamma only changes the data between 0 and 255, and a quirk of exponents (anything to the power of 0 or 1 is 0 or 1) is that gamma cannot change 0 or 255 endpoints ( so no concern about gamma, it cannot induce clipping).

But WB can shift the dickens out of it, esp red and blue channels in opposite directions, and so WB can shift data to cause clipping. Raw could not care less about WB yet, but unless your JPG is ballpark WB, the histogram could be a bit different than what the final RGB produce later from Raw. Histogram shows that shifted JPG histogram.

Auto WB is fairly poor, but I use it with Raw, as a quicky way to see ballpark color on the rear LCD, to be unconcerned about clipping. It is halfway close, unimportant if it is exactly right or not.

 

[apaflo]

So Raw files include a small embedded JPG with the camera properties in it (WB, contrast, etc), to be shown on the rear LCD. And since Raw files are not RGB, my notion is the RGB histogram obviously comes from that JPG too.

The camera actually embeds a full sized JPEG in the RAW file, as well as a small version for preview on the LCD. If the mode is set to RAW only, the JPEG file is discarded, while if set to JPEG mode only it is the RAW file that is discarded.

The camera's histogram is from a full sized JPEG, generated using whatever parameters the camera has configured.

If the camera's mode produces a JPEG file, that histogram precisely represents that JPEG file. Likewise if a RAW file is produced by the camera and another JPEG is produced using an external RAW converter that can use the in camera configuration as a default (which perhaps is true only of the manufacturer's conversion software) then the in camera histogram will also accurately represent what is in that JPEG image.

Any JPEG, TIFF or RGB format image file produced from the original RAW file in any other way will not match the camera's histogram.

 

[WayneF]

The camera actually embeds a full sized JPEG in the RAW file, as well as a small version for preview on the LCD.

I cannot see inside the NEF file, but I don't see any evidence of that.

Here is NEF only, and NEF + Fine. On fixed tripod, on unchanged subject.

First line is NEF, followed by NEF + Fine. Second NEF is 106 KB larger (why, I don't know).

If the JPG is 30 MB, and if it is in there, why isn't the second NEF 30 MB larger?