ID Mk2N - chimping and histogram inconsistency

Hi,

I shoot raw + small jpeg. When I chimp and check histogram I often see the image looking well exposed on the screen but the histo showing to the left. Where theres a person against a dark BG I don't like to increase exposure for fear of blowing the skin tones but I invariably find myself pushing up to a stop in ACR afterwards.

My question: does anyone else find that the jpeg displayed on the camera screen is inconsistent with the correct exposure? Do they appear more exposed on the screen than they should be?

Anybody???

Well, I have a mk2 and I consistantly underexpose by about 2/3 stop. My histogram is the same as yours with plenty of room to the left. If I move the exposure to get the histogram to the right the blinkies show up. I just live with it and adjust in PP. John

Thanks John,

I am away from cameras now for the weekend but I'll do some experimenting on the matter when I get back on Monday. I just finished a shoot of 600 soccer players in over 50 teams over the last three days, shot outside from 4pm through 7.30-8.30 pm each evening. I had a couple of monolights for daytime fill / darkness flash and I didn't feel like experimenting on such a shoot. I have no problems in m studio but with a dark BG outside at night I see inconsistencies. Luckily the shots take a little pushing in ACR well. Another reason to always shoot RAW regardless of the job. You just never know when that extra latitude will be needed.

None of the on-camera LCDs have the necessary dynamic range and viewing angle consistency to be a useful for exposures or white balance. They're not even good enough for sharpness. It seems to be a technology problem - at least at that size - combined with user interface design criteria. I'm sure they would rather you see something than just a black or white mess when the exposure is not right.

The histogram is far more useful and reliable but still not perfect. It tends to let you down when only a small amount of data is over-exposed.

In doing similar experimentation, I took identical shots with a 5D. One in sRGB and one in aRGB. Much to my surprise there were more blinkies in the Adobe RGB shot, which makes absolutely no sense to me. Anyone else do experimentation in this regard?

Are you using the RGB or the Brightness histogram. I think the brightness histogram is a little more accurate in indicating what the exposure actually is. Maybe it's just me.

Chimping and histogram inconsistency

The histogram is from the raw conversion to a jpeg thus the tonal curve affects the histogram like it or not.

I can not remember who it was that discovered that if you tweaked the tonal curve then uploaded it to the camera then shot raw and ignored the shot as settings you could get a near accurate histogram while shooting.

This will work on the 1D, 1Ds, 1DMKII, and 1DsMKII, I do not know if you can still upload a custom tonal curve on the "N"

Will T.

the histogram only serves as a quide to me.
after spending some time with some other really great photogs in Africa, and subsequent learnings since, I rely on a series of things. The histogram is but one part of the puzzle. Also the cameras act differently, the 1DsM2, 1DM2 and 20D all have their own hearts, and I need to know them. The P25 is entorely another beasty again.
Just my opinion.
Rob

"does anyone else find that the jpeg displayed on the camera screen is inconsistent with the correct exposure?"

If by "correct" you mean "exposed to the right" I'll agree. Near as I can tell, the metering system is biased to avoid blowing out highlights and that means leaving some room on the right unless you tweak it.

IMO, the LCD is okay for letting me know i didn't completely goof but that's about it.

Wow, I'm glad I went with my instincts and didn't allow the histo to move over to the right. I'd have terrible blown highlights if I did. As is it I have some shots that need bringing up a little but thanks to the superb lattitiude there's no problem for up to a stop. Some are even at 1.2 stops but still all under control.

My concern is that I had more blinking highlights in the small preview on the 5D. The histograms moved properly (more latitude in aRGB), but the fact that the blinkies indicated more blown pixels, is completely wrong if just the color space was changed. I will do some additional testing and report.

I rely on the histogram. Remember, the ambient light affects how bright or dark your pictures will look on the LCD. So if you set the LCD brightness to middle and go to a dark room to review, that same images will look brighter than if you go outside into the sun and view the same images. Unless you review the images on the LCD under constant ambient light (near impossible to do), you cannot rely on it for exposure, just for focus and composition.

So always use your histogram. A trick I use is to set the immediate review to include the histo. I have the "display" option set to the large picture. This way, after I shoot, the histo and the small image pops up so I can immediately see the histo. If it's good and then I want to review the composition, I press the display button and the large image comes up and I don't have to worry about if the picture looks too bright or dark, b/c I just saw the histo. It the instant review shows poor exposure, there is no need to press the display button. What needs to be done is to correct your settings and reshoot.

The LCD image is a jpeg version of the shot, so if you don't set it to neutral, the settings may affect your histo. I doubt the diff. would be hardly noticable though, but I do keep it the JPEG setting on neutral though. As for sRGB or aRGB making a difference in exposure, I'm not sure about that, but I've never experiemented wtih the shots to tell. But if you shoot RAW, that shouldn't really matter too much. Remember as well the hisot is of a JPEG version, you may have something a touch blown, but that should be recoverable in RAW.
Happy shootings.

The LCD is useful to make sure that you got the subject somewhere in the frame, but not really useful for assessing exposure; the histogram does tell you about exposure quite accurately.
I underexpose by 1/3rd stop all the time on my 1DMk2 and in really bright conditions will go to 2/3rds under to avoid blown highlights; a colleague uses 2/3rds under all the time though.

Here are a couple of good Digital Outback articles touching on these issues:

Histogram I Histogram II

Nill
~~
www.toulme.net

One of my pet peeves of the 5D and other prosumer Canon DSLRs is that the large review display does not show blown highlights, like the 1 Series does. I really miss it since I shoot both 5D and 1D2N. I cannot see why Canon Inc cannot make blinkies on the large image display an option on the xD and xxD cameras.

Michael Tapes said:

One of my pet peeves of the 5D and other prosumer Canon DSLRs is that the large review display does not show blown highlights, like the 1 Series does. I really miss it since I shoot both 5D and 1D2N. I cannot see why Canon Inc cannot make blinkies on the large image display an option on the xD and xxD cameras.

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Blinkies are a 4k option ;-)

Are you sure about the bliking option on the 5D? Looking at dpreview shows the display blinking the highlights, atleast in the histogram display mode.
On the N it's an option you can turn on or off. I'm surprised 5D doesn't have this option.

I use the histogram and turn that feature off since I find it annoying when I'm checking composition. Plus what is blown in JPEG is not necessarily blown in RAW anyway.

Tom Yi said:

Are you sure about the blinking option on the 5D?

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Yes. You can see the blinking on the small preview with histogram, but the large preview can never show the blown highlights on the prosumer cameras. I also agree that they can be distracting, but surely an option for on/off on small display and independently for large display would be perfect.

Also, while I agree that measuring the blown highlights is not done on the RAW data, seeing them blink and knowing what that means can allow you to fine tune the raw exposure by allowing a learned amount of blown highlights shown on the camera. Also can provide a good warning when one gets so involved on the shoot and forgets that he is on manual exposure, like I sometimes do.

Alain Briot said:

Blinkies are a 4k option ;-)

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Yes, Alain, and that is the only reason that I hang onto my 1D2N :>).

If only an easy mirror lock-up and fully adjustable self timer were a $4k option! :>)

Michael Tapes said:

Yes, Alain, and that is the only reason that I hang onto my 1D2N :>).
If only an easy mirror lock-up and fully adjustable self timer were a $4k option! :>)

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That's a factory option only available by upgrading to the 1DsMk3 . . . maybe ;-)

What's "Chimping"?

What's "chimping?"

http://en.wikipedia.org/wiki/Chimping

http://www.sportsshooter.com/special_feature/chimping/

What's Chimping?

You now, I don't know either ~~~ :^)

The term chimping is you act like a chimp, just kidding
Chimping is when you take a picture over exposed, under exposed, right exposted you hope. In a nut shell you take a lot of pictures of one item and look for the best one.

The way I use the histogram is firstly to use it in RGB mode, faces are pretty much all red channel. Then I look for the whites, the whites should be pretty much as far right without clipping as possible, if your whites are not at least in the rightmost box of the histo then your faces are over 1 stop underexposed. So if you're shooting a guy in a suit and their isn't a peak (his shirt collar) in the middle to right of the rightmost box then I know that I'm under.

It used to annoy me that I couldn't see where in the histogram the faces were, I'm shooting weddings so the faces are crucial. But now if I can see where the white is on the histogram and to a lesser extent the blacks, then if the white is close to white (i.e. not middle grey) then the face will also be OK.

Oh, and never trust the screen, I have mine on the 5D turned down to second to darkest level and it's still a drop too bright. The problem is that a correct exposure for print is one where the facial values come close to starting to overexpose. If the face is not blinking on your screen then even if it looks washed out it is more likely to be a WB issue than a blown highlight. ACR is extremely good at recovering highlights using the exposure tool (minus exposure bring the picture back with brightness and twiddle contrast if necessary) so make sure that your whites are in that fifth box!

For truly accurate exposure based on the histogram you also need the WB to be as accurate as possible in camera. A photo with too warm a WB for the scene (canon are good at this!) will show blown highlights faster than one with a correct WB. The theory is simple, the red channel is the most sensitive to clipping and the warmer the photo the more red the more clipping. This actually might be the solution to MT's issue with his 5D, it gives a pretty warm WB, maybe the 1D mkII is more accurate or colder hence less flashing highlights on screen.

This is a reason why doing an in camera custom WB is still useful should you be able to for the job, I also advocate setting the parameters based on how you will be processing the photos. What do I mean? The preview on screen is based on the parameters right? If you process with X amount of contrast then shooting with the contrast on '0' or '-2' depending on camera, is going to give you a misleading preview and histogram. Yes the RAW file has far more control but setting the parameter to the minimum for all fields will give you a histogram that may show plenty room but when you load up the file in ACR with your usual settings for print, the file may show clipping or overexposure. Yes you can control it in ACR, no it is not ideal at all, especially when trying to keep as much ambient in a flash photo or fill flash. Shoot with the print in mind! If you didn't know that you flash was overexposing slightly then you won't know till you darken the picture in ACR thereby darkening the ambient and ruining your fill ratio.

Richard Rickard said:

The term chimping is you act like a chimp, just kidding
Chimping is when you take a picture over exposed, under exposed, right exposted you hope. In a nut shell you take a lot of pictures of one item and look for the best one.

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As far as I understand--chimping is just reviewing your pictures in the back LCD.

Hi, Diane,

As far as I understand--chimping is just reviewing your pictures in the back LCD.

Click to expand...

That's my understanding.

I think the metaphor arose from someone's obervation that some phtographers, while earnestly reviewing their shots on the camera's monitor screen (which is often, but not always, an LCD, and sometimes, but not always, the only LCD on the back of the camera), seemed to evoke the image of a chimpanzee excitedly looking at some shiny object.

For those who have not seen the video referenced above, take a look, it is hilarious

http://www.sportsshooter.com/special_feature/chimping/

harvey

Doug Kerr said:

Hi, Diane,



That's my understanding.

I think the metaphor arose from someone's obervation that some phtographers, while earnestly reviewing their shots on the camera's monitor screen (which is often, but not always, an LCD, and sometimes, but not always, the only LCD on the back of the camera), seemed to evoke the image of a chimpanzee excitedly looking at some shiny object.

Click to expand...

Yes, should have added that LOL---I've seen the video above before and it illustrates it pretty clearly--and IS funny..