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Author Topic: Expose to the left...........  (Read 19177 times)

barryfitzgerald

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Expose to the left...........
« on: March 16, 2007, 10:32:03 pm »

This should at last kill off the idea that digital is like slide!



We know shadows are held well on digital esp a 6mp one..



hold highlights expose to the left...get the most out of you latitude! Though being fair I could have lost more highlights and got away with pulling them back

Nice area..connor pass, dingle, co. kerry, ireland.
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larsrc

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Expose to the left...........
« Reply #1 on: April 25, 2007, 07:37:44 am »

Quote
This should at last kill off the idea that digital is like slide!



We know shadows are held well on digital esp a 6mp one..



hold highlights expose to the left...get the most out of you latitude! Though being fair I could have lost more highlights and got away with pulling them back

Nice area..connor pass, dingle, co. kerry, ireland.
[a href=\"index.php?act=findpost&pid=107117\"][{POST_SNAPBACK}][/a]

What in your opinion did you gain from not exposing one stop "to the right"?  Obviously, you would never want to blow any highlights, but is there a point to leaving the entire stop stop empty?

-Lars
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ckimmerle

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Expose to the left...........
« Reply #2 on: April 25, 2007, 09:25:06 pm »

Barry,

There is a very good reason for exposing to the right rather than the left. There is more data to work with. The way you have exposed your image, you've actually LOST quite a lot of data and probably have fairly noisy shadows.

If you have not yet seen the LL article, check it out. It's written far better than I can explain in a forum.

http://www.luminous-landscape.com/tutorial...ose-right.shtml

Nice image, btw.

Chuck
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Jonathan Wienke

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Expose to the left...........
« Reply #3 on: April 29, 2007, 09:49:53 am »

If you'd increased exposure 2/3 of a stop, your shadows would have better tonality and be less noisy, and you wouldn't have lost any highlight detail. You haven't proved anything other than that shooting RAW allows more latitude for correcting exposure errors, but we already knew that.
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BJL

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Expose to the left...........
« Reply #4 on: April 30, 2007, 10:01:28 am »

Maybe Barry's main point is that DSLR's have far more shadow latitude (and more usable latitude overall) than slide film, contradicting the claims that DSLR sensors are only about equal to or slightly better than slide film for latitude and ability to handle scenes of high subject brightness range.

I suspect that those comparisons are based on highlight handling only, ignoring very different placement of mid-tones within the response curve, due in turn to digital having no shoulder at all above the linear section.

My guess is that

- Standard film exposure places midtones roughly in the middle of the linear section, or places mid-tones at about 18% of the level at the top of the linear section (three stops down), with shoulder beyond that.
Thus when technological progress increases DR, the extra usable range is spread both above and below the mid-tones.

- Standard digital exposure places midtones at about 18% of a highlight limit, but with DSLRs leaving some headroom above in raw: the base-ISO speed definition is based on placing midtones at about 18/170 of the maximum, leaving 70% headroom above 100% diffuse reflectivity if the metered level does in fact correspond to 18% reflectivity. Probably JPEG conversion discards that 70% headroom, placing midtones at about 18% of maximum JPEG level: hence the roughly one stop of highlight headroom typically present in raw files.
Thus as technological progress increases DR, the extra usable range all gets added to the levels below the mid-tones, rather than the extra stops being spread both above and below the mid-tones. (Fuji SR is an exception.)

In some sense, standard digital metering already follows a basic version of the expose to the right idea, but assuming a standard three stops of so between midtones and highlights.
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bjanes

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Expose to the left...........
« Reply #5 on: April 30, 2007, 10:22:21 am »

Quote
Barry,

There is a very good reason for exposing to the right rather than the left. There is more data to work with. The way you have exposed your image, you've actually LOST quite a lot of data and probably have fairly noisy shadows.

If you have not yet seen the LL article, check it out. It's written far better than I can explain in a forum.

http://www.luminous-landscape.com/tutorial...ose-right.shtml

Nice image, btw.

Chuck
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I agree 100% with the responses from Chuck and Jonathan. The shot is underexposed and the fact that some correction was possible proves nothing and I do not understand the OP's point. He should read Michael's essay on exposing to the right.
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barryfitzgerald

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Expose to the left...........
« Reply #6 on: April 30, 2007, 10:43:21 am »

Quote
I agree 100% with the responses from Chuck and Jonathan. The shot is underexposed and the fact that some correction was possible proves nothing and I do not understand the OP's point. He should read Michael's essay on exposing to the right.
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Lol...........

I have read it..and it makes sense to reduce noise. Yes. (in some cases)

My post was aimed at one thing....destruction of this "digital is like slide film" myth.....it most def is not.

The proof.......well just go take slides like that....see what happens. In the bin!

As for the image..yes I could have exposed better..and used the highlight region more..and brought it back a bit. Very true. As it is, the IQ has suffered, gone too far on this.

But I still say expose for highlights with jpeg shooting.....that makes a world of sense.....BJL was correct in working out what my intentions were. Either that or get a ND graduated filter.....
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bjanes

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Expose to the left...........
« Reply #7 on: April 30, 2007, 01:55:11 pm »

Quote
But I still say expose for highlights with jpeg shooting.....that makes a world of sense.....BJL was correct in working out what my intentions were. Either that or get a ND graduated filter.....
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Barry,

I don't know what you are laughing out loud about, since we may have the last laugh, because you did not expose for the highlights as indicated by your histogram, where there is no image information toward the right. I think we all know that the digital image is not the same as transparency film, since digital has a far greater dynamic range. However, with both the exposure is mainly for the highlights

Of course, exposure to the right is meant mainly for raw shooting, but the same concepts may also apply to JPEGs, since Lightroom and ACR 4.0 can apply the same adjustments to JPEGs as to the raw file. However, with the JPEG you are working with only eight bits of data rather than the 12 found in most raw files (256 rather than 4096 levels). If the dynamic range of the scene exceeds that of the camera even with exposure to the right, you need your ND graduated filters or HDR from multiple exposures. Again, what is your point? Your exposure would be incorrect for both digital and film transparency.
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alainbriot

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Expose to the left...........
« Reply #8 on: April 30, 2007, 03:37:07 pm »

Quote
My post was aimed at one thing....destruction of this "digital is like slide film" myth.....
[a href=\"index.php?act=findpost&pid=114989\"][{POST_SNAPBACK}][/a]

I don't think many of us here doubt that digital captures, properly exposed, are better than transparencies...
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barryfitzgerald

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Expose to the left...........
« Reply #9 on: April 30, 2007, 03:48:50 pm »

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Barry,

I don't know what you are laughing out loud about, since we may have the last laugh, because you did not expose for the highlights as indicated by your histogram, where there is no image information toward the right. I think we all know that the digital image is not the same as transparency film, since digital has a far greater dynamic range. However, with both the exposure is mainly for the highlights

Of course, exposure to the right is meant mainly for raw shooting, but the same concepts may also apply to JPEGs, since Lightroom and ACR 4.0 can apply the same adjustments to JPEGs as to the raw file. However, with the JPEG you are working with only eight bits of data rather than the 12 found in most raw files (256 rather than 4096 levels). If the dynamic range of the scene exceeds that of the camera even with exposure to the right, you need your ND graduated filters or HDR from multiple exposures. Again, what is your point? Your exposure would be incorrect for both digital and film transparency.
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Hmm not exactly sure I was laughing!

I didnt expose for the highlights..yet the sky is exposed for? Ok....maybe I am missing something here!

I am not questioning expose to the right..in some situations its a good thing to do. However a histogram isnt life or death, many scenes do not display so called perfect hisograms.

Here is a jpeg example of increasing your DR with a shot.

Original



Corrected and sepia toned:



All that was required was a lift in the shadow areas.

As you can see the DR or the scene was greater than I was able to capture..as I didnt have a ND grad..I had to adjust my exposure to suit, in this particular case, I did wish to keep the highlight areas. Had I done a normal exposure..they would have been washed out.

So expose to the right isnt always ideal for everything...

And I shouldn't have to say this to a fellow photographer, but there is no such thing as correct exposure..only the effect you want.
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digitaldog

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Expose to the left...........
« Reply #10 on: April 30, 2007, 03:53:22 pm »

On our recent Amazon trip, I noticed a lot of users setting their cameras to minus a stop. This of course goes against everything we've heard about exposing to the right. I've done some initial tests that you can examine and post your impressions. Forgive the copy and paste but here's an email I sent this morning to Michael and Jay (Maisel) about this.

Quote
I’ve started some testing I think you two might be interested in based on our conversations on the Amazon trip. On my iDisk I have a folder called Expose to the Right for you guys to download if willing. There are three DNGs and three rendered images.

The two original DNGs are of a exposure target metered using the Sekonic unit. The “normal” exposure is F16 @ 200th. I also shot various brackets, the lightest being F16 at 1/50th which is in the folder discussed. In Lightroom it looks blown out and way too light. I made a virtual copy and clicked on the Exposure button in Quick Develop twice (the one that is more course that looks like this <<). This seems to bring the exposure very close to the normal. Its not exact but as close as I can get without resorting to sliders.

Look at the comparison of the two at 100% and notice the huge difference in noise (Jay, this makes the image appear sharper but its not what we want). Note too these were shot at ISO 1600! I have a set shot at 100 which I will also work on. I’ve enclosed a screen capture in case you just want to look at the results quickly without working with the DNG’s or large rendered TIFFs.

Feel free to pass this on to anyone you wish. I want to make sure I didn’t do anything wrong (still feeling the effects of the Malarone).

I think this illustrates a few important points. One is that exposing to the right in this case provides far less noise and better data. Lightroom has plenty of capability to normalize the over exposed appearing image. This doesn’t address Jay’s issue with the camera LCD! The double click on the exposure in Quick Develop or a saved preset for import of images exposed this way would ‘fix’ the over exposed appearance as files are imported. So that’s an easy fix. The LCD is another issue.

Comments?

You can find the DNGs at other files at:

My public iDisk:

Thedigitaldog

Name (lower case) public
Password (lower case) public

Public folder Password is "public" (note the first letter is NOT capitalized).

To go there via a web browser, use this URL:

http://idisk.mac.com/thedigitaldog-Public

Andrew

Michael of course on our trip shot to the right and used LR to normalize (his term) the images which I suspect is really the way to go. I have other brackets I want to test and I want to try other ISO's but if you examine the DNG's using your own raw processor, I'd be interested if you see similar results.
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bjanes

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Expose to the left...........
« Reply #11 on: April 30, 2007, 05:41:43 pm »

Quote
Hmm not exactly sure I was laughing!

I didnt expose for the highlights..yet the sky is exposed for? Ok....maybe I am missing something here!

I am not questioning expose to the right..in some situations its a good thing to do. However a histogram isnt life or death, many scenes do not display so called perfect hisograms.

Here is a jpeg example of increasing your DR with a shot.

All that was required was a lift in the shadow areas.
[{POST_SNAPBACK}][/a]

Barry,

With a high dynamic range situation, I would never attempt to raise the quarter tones from a JPEG, because you are working with an 8 bit image, which has relatively few levels in the shadows and you may encounter posterization or poor tonal gradation. It would be much better to work with the full tonality of the camera, either in Camera Raw or from a 16 bit file in Photoshop. See this discussion on [a href=\"http://www.normankoren.com/digital_tonality.html]Norman Koren's [/url] site. As Bruce Fraser pointed out in his camera raw books, it is better to darken a digital image than lighten it. With darkening, you are taking data from an information rich area and transferring it, whereas with lightening you are taking data from an information poor area.

The overall shape of the histogram is not crucial, and it will reflect the distribution of tones in the scene. A high key subject will have values predominately on the right and the converse will be true for a low key scenes. The most important information in the histogram is at the two extremes, where the effects of highlight and shadow clipping will be apparent.

Quote
As you can see the DR or the scene was greater than I was able to capture..as I didnt have a ND grad... I had to adjust my exposure to suit, in this particular case, I did wish to keep the highlight areas. Had I done a normal exposure..they would have been washed out.

[a href=\"index.php?act=findpost&pid=115041\"][{POST_SNAPBACK}][/a]

Unlike film, the digital sensor has no knee or shoulder and is linear throughout its range. If you place the highlights just short of clipping, they will have full tonality and will not be washed out or damaged in any way. If you do accidentally overexpose slightly, ACR's highlight recovery often will rescue the situation, but I do not recommend overexposure.

Quote
So expose to the right isnt always ideal for everything...

And I shouldn't have to say this to a fellow photographer, but there is no such thing as correct exposure..only the effect you want.
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Thanks for your respect to a fellow photographer, but I submit that with a scene that occupies the full dynamic range of the camera, there is only one correct exposure: the exposure that does not clip either the highlights or shadows. If the dynamic range of the scene is greater than that of the camera, as indicated by clipped shadows and highlights on the histogram (assuming that it is accurate), then you can expose for the most important part of the image, highlights or shadows.

If the scene occupies less than the dynamic range of the camera, as indicated by free space at both extremes of the histogram, they you have some latitude. With negative film you would expose for the shadows. With raw digital, it is best to expose to the right. If this places the mid tones too far to the right, you can take care of this in ACR. If you expose to the left, and there is no clipping, you can also take care of this in PP, but you will lose tones and have excessive shadow noise.

That's is my opinion, but I see that we have Digidog and possibly some other heavys entering into the discussion, and it could get interesting.

BTW, I like your pictures  

Bill
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jjj

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Expose to the left...........
« Reply #12 on: April 30, 2007, 08:21:39 pm »

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BTW, I like your pictures
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Hard to tell as iDisk refuses entry to Opera, even thoughl Opera works fine on sites that need IE or FF work. Rant rant.
Imagine trying to open a image with PS and being told you had to use MS Paint.
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