The Histogram learning Curve

[Ian Colley]

Hi, hopefully I have posted this in the correct forum. In the last few weeks I have been trying to rely on the histogram to try and achieve the correct exposure, or at least get it as close as I can. Normally I just rely on the highlight blinkies or the quality of the image on the LCD, to tell me I have it wrong and adjust shutter speed accordingly, but I miss a lot of opportunities.

I have Art's book and also read regularly on the web that after a quick histogram check I adjusted the exposure by X. It sounds easy but I must admit I struggle, but practice makes perfect, I hope.

On the attached image I have included the histogram from Bridge. I used my wife's Canon 400d - RAW, 1/50 f/8 AV +0.33 ISO400 with a kit lens EF75-300 F/4.5.6. Normally I shoot an Olympus.

The image has slight level adjustment and sharpening and some minor cloning in the top and bottom left corners, 90% of original, other than that straight from camera. I can post the original if required.

My question, have I exposed correctly, if yes or no, what should I be looking for in the histogram to confirm the correct exposure?

[Nonda Surratt]

Ian,

This is nice, the bg the exposure and the focus look pretty right on target to me,nice, nice and nice again! Would wish for a bit more canvas under the tail.

I love that in you face look, face on, of the bird too!

[Alfred Forns]

Ian is difficult to see the very right side of the histogram but the idea is to have it all the way to the right without going over

In this case it looks like you can open up more There is a lot of room to the right The hight of those spikes tell you how much of a single tone you have and the width the tonal range

Regarding the blinkies you are correct in part. For some ducks and other birds with a small white patch it would be the best way to check Histogram looks right but you do have blinkies A couple of them I would not bother In the conversion they will be taken care I know on the Canon cameras is very difficult to see the end of the histogram With Nikon we are lucky in that the histogram is bright yellow with a red box

One of the reason we want to nail the histogram the first time is for one of a kind encounters You can always make an image and check to get it perfect Sometimes there is no time Working and with a little time you will be able to judge the light and come close

Fully agree with Nonda's critique ....... you owe us one tail !!!!!:)

[Ken Kovak]

Ian,

I agree with the comments above, that you can open up the exposure some more. There are a couple of locations where the brights may start to blow out, maybe the reflection on the beak and the left leg.

If you convert this RAW file in Adobe Camera Raw you can move the exposure up somewhat ahd use the "recovery" slider to get back those pixels that may be jammed up against the right side of the histogram.

I've just finished reading Jeff Schewe's book on ACR and he says that it is actually possible to recover detail from the highlights that are "blinking" on a camera histogram using Recovery, if they are not blown too far. I have tested this and itis true.

Otherwise, nice capture with getting him to be looking right at you.

Take Care,
Ken

[Ian McHenry]

Thanks Ian for posting this neat picture and enquiry re histogram is so useful for us still fairly new to digital.
Axel : I take it by "open up more" you mean add further plus EV compensation to say e.g.plus 2/3.
As you say when out in the field there is frequently very little time to change settings especially with birds in flight pix so I usually just set (on JPEG) to either mins 1/3 or minus 1/2 but this is unlikely to bring out detail in black birds.
Ian McHenry

[Robert Amoruso]

Ken mentioned using Recovery to get back blown highlights. What is happening there is that many times only one channel, like Red, is blown and the other two (Green and Blue). In those cases you can get detail back.

In the early morning and late afternoon, red channel can get blown when pushing the envelope (i.e., Exposing Right) as the sun is red channel dominate at that time. Ken is right that Recovery in ACR is a good way to get back slightly blown highlights.

[Grace Scalzo]

Robert- Your second paragraph, is that why often in delicious am or pm light, it's so easy to overexpose? Esp on a white subject.

[Gus Hallgren]

Thanks Folks, Living in very bright sunny skies nearly every day surrounded by white adobe buildings at 3000' in Southern Arizona i very often getting overblown whites and light colors. After reading the tips I'm paying more attention to the histogram on my camera. When the right side of the histogram is butting the right side, I'll notice highlights blinking. By adjusting the - EV, this morning to 0-70 it moved the graph over about 3/16" from the right side & checking the highligts there is nothing blinking. So, I leave my camera set on Highligts, and every photo I take I can check for highlights right then. Appreciate all the tips.
Gus
BTW: Wish I could see live view in the bright sun.

[Robert Amoruso]

Robert- Your second paragraph, is that why often in delicious am or pm light, it's so easy to overexpose? Esp on a white subject.

You got it Grace. I find that my Red Channel will overexpose first. The red light is predominate. If you are using only the luminance histogram in the camera, it can read no exposure but an RGB histogram display can show that the red channel is spiking on the right. It is a fine line we walk.

I tell my workshop participants, the histogram is your best friend. You camera's review mode should be set to bring up the image AND the histogram.

[Ian Colley]

Thanks everyone, appreciate all the advice.