Does the command appear to be working on any other pictures?
Walnut,
Look at your histogram before and after Auto Levels and you may see that some pixels have been changed. I’ve experienced no visual change after using Auto Levels but the histogram shows a slight change. I guess it’s Photoshop’s way of saying, ‘do the adjustment yourself!’
Thanks for the reply Mark and Raymond.
Raymond-It looks like it affects some pictures, but there are alot where the change isn’t noticeable.
Which now goes to Mark-The Histogram does show change, nothing we want, major let down.
I have a question for both of you now. What can we do to make a better picture to respond more to Auto Levels? Should we place a pure white object in the picture to shoot along side our picture focus? Would this make a better Auto Level adjustment?
Thanks for the responses!
Why not just try using regular levels instead? You’ll almost always get better results.
Or sometimes you may not need levels. Generally the pics from my s400 need a levels adjustment while most of the images from my A1 only need autocontrast because the camera has a live histogram so I can correct as I shoot.
Thanks Barbara for the reply.
We are pushing towards that, and learning every step. In the future we will be doing what you suggested.
Many of the experts (authors) seem to think auto color is the only one of the auto adjustments that gives good results. You might try Barbara’s suggestion and use a levels adjustment layer for better results.
—
Have A Nice Day, 🙂
James Hutchinson
http://www.pbase.com/myeyesview http://www.myeyesviewstudio.com/ wrote in message
Have a dark and warm picture taken on a digital olympus E10 camera
with settings the same. Auto Levels doesn’t change a pixel on the photo. Any reason why? This is PE2. Thanks
Many of the experts (authors) seem to think auto color is the only one of the auto adjustments that gives good results
You know, James, I’ve seen that over and over again and I have to say that for me it usually gives perfectly horrible results. Guess you have to have a pretty good photo to start with, maybe.
With my old camera none of the auto adjustments gave good results consistently, with the new one auto color seems to work the majority of the times I try it, which is seldom.
—
Have A Nice Day, 🙂
James Hutchinson
http://www.pbase.com/myeyesview http://www.myeyesviewstudio.com/ wrote in message
You know, James, I’ve seen that over and over again and I have to say
that for me it usually gives perfectly horrible results. Guess you have to have a pretty good photo to start with, maybe.
Only Auto I use is Auto Contrast – works in about 75% of my images because I underexpose 1/3 stop routinely.
Thanks for all the support from everyone. My expectations were low to start this thread and all of you helped out to my surprise. Thanks!
Walnut and the others.
I am quite surprised that autolevels does not respond.
The few times I do not get a response is when I have used auto and the image is spot on on averages.
Walnut did you make these images with the camera settings on auto?
I am asking this purely out of curiosity.
Robert
The camera was set on P for Program which after reading the book almost sounds like auto to me. There was some Exposure Adjustment settings we can apply on the camera, so it’s a little less than auto but not full manual.
Hope that answers your question.
Walnut,
Thank you for your reply.
Your answer seems to confirm my expectations that when you set your camera to auto, the settings for auto contrast, colour and levels are in fact used.
Afterwards, once the picture is taken and you want to enhance the image with the help of auto enhancement of contrast, colour and levels these do not respond as there is no deviation of the already fixed auto settings. I hope I made sense. 🙂
Robert
Hello Robert. Wouldn’t this only hold true if the auto setting of a particular camera precisely matched the auto settings in Elements.
—
Have A Nice Day, 🙂
James Hutchinson
http://www.pbase.com/myeyesview http://www.myeyesviewstudio.com/ wrote in message
Walnut,
Thank you for your reply.
Your answer seems to confirm my expectations that when you set your
camera to auto, the settings for auto contrast, colour and levels are in fact used.
Afterwards, once the picture is taken and you want to enhance the
image with the help of auto enhancement of contrast, colour and levels these do not respond as there is no deviation of the already fixed auto settings. I hope I made sense. 🙂
Robert
Robert,
Thanks for your insight. That does make alot of sense now.
And I’m wondering on jhjl1’s statement.
Does this all boil down to just a bad picture(s).
Any way to improve that deviation to have that image respond better in Elements?
Thanks all.
Walnut,
James has a valid point although I am not sure how valid it is.
I believe there must be some sort of correlation between auto settings of a(ny) camera and Elements. Would this not be the case each image enhanced with auto settings would respond differently to the auto settings of Elements.
However this is not the case is it? I mean if I use auto enhance the image jumps to an average quality that is perceived by everyone as good quality. Wheras if James uses auto enhance with his camera the quality also jumps to the same good quality. Ergo, there must be some sort of benchmark setting in both.
May be some one else can help us a bit further in this?
Robert
PS: walnut you did not make a bad picture. I believe you made one that is very close to what is perceived as "auto" and thus is a good picture. 🙂
May be you can make an image which is seriously underexposed. Then click for instance auto contrast or levels and see if there is any change. That should confirm whether your Elements works properly.
It seems to me that maybe Elements is using possibly the same formulas and algorithms that possibly would be set on the camera itself, hence the minor adjustment in the Histogram.
And really would this be any different? There are alot of variables out there, but most of which can be defined, not enough light, or too much, would be handled say on the camera as the same in Elements.
It would be interesting, to see if that is what’s happening. And if so then sometimes, bad pictures will just stay bad without manual help.
thanks again for all the posts. This has been exciting.
Walnut,
you beat me to it.
Let’s hope we are right.
Robert
It is my understanding that Elements uses certain algorithms to make the adjustments. One camera in auto mode may be closer to these defaults than another camera. Actually in full Photoshop you can make adjustments that effect the defaults of some of the auto corrections. I would think if your not seeing a change when using the auto corrections it is because a particular image is very close to what Elements uses a default.
—
Have A Nice Day, 🙂
James Hutchinson
http://www.pbase.com/myeyesview http://www.myeyesviewstudio.com/ wrote in message
Walnut,
James has a valid point although I am not sure how valid it is.
I believe there must be some sort of correlation between auto settings
of a(ny) camera and Elements. Would this not be the case each image enhanced with auto settings would respond differently to the auto settings of Elements.
However this is not the case is it? I mean if I use auto enhance the
image jumps to an average quality that is perceived by everyone as good quality. Wheras if James uses auto enhance with his camera the quality also jumps to the same good quality. Ergo, there must be some sort of benchmark setting in both.
May be some one else can help us a bit further in this?
Robert
PS: walnut you did not make a bad picture. I believe you made one that
is very close to what is perceived as "auto" and thus is a good picture. 🙂
May be you can make an image which is seriously underexposed. Then
click for instance auto contrast or levels and see if there is any change. That should confirm whether your Elements works properly.
About auto colour and auto levels: I use these features quite often and mostly it works for me.
Usually I create a layer, apply auto levels and by means of the slider I check what seems to be the right amount to me. I follow the same procedure with auto colour. Usually auto colour doesnot work; especially when skin tones are involved. People mostly turn blue.
This procedure allows me by using the erasertool at a low percentage (<10%)to apply various amounts of contrast and colours to different parts of the image.
Leen
My guess at the relation between camera Auto settings and the auto levels command: (long technical post of dubious value follows….I’m guessing here, but I think what I say is OK – feel free to disagree!)
The auto settings in the camera are attempting to give the best possible exposure for some theoretical "average’ scene – the algorithms that calculate the right exposure will vary – some exposure modes just use a centre weighted average of the light coming in and some are more complex and look at the patterns of bright and dark areas, compare them to a database and make an educated guess about the type of subject. If the scene corresponds to the camera’s guess work and the range of contrast is the five or so stops that a digicam can cope with then you will get a perfectly exposed shot – the histogram will not be blocked at either end ie there will not be blown out highlights or stopped out shadows and the peak of the histogram will be centred on the median level of brightness in the scene.
So if you take this image into Elements and hit auto levels or auto contrast, what will happen? Well both these commands involve setting the black point to the darkest point in the image and the white point to the lightest highlight to give the maximum range of contrast. So if the range of contrast of the scene corresponds to the range of contrast that the camera can cope, with nothing happens – the darkest and lightest points in the image are already at the far ends of the histogram. On the other hand if the scene is lower in contrast than the camera can deal with the darkest and lightest ponts will be further into the histogram and the auto levels command will improve the contrast as it will stretch the image’s histogram out so it fills the full range available.
Images which fool the camera exposure metering will also be affected by auto levels. Camera metering systems have tradionally assumed the average level of a scene brightness matches up to that of a standard photo grey card (18% grey I think it is called) If the scene doesn’t match up to this average level then the camera can be fooled – it will tend to underexpose a scene that is brighter than average and overexpose a scene that is darker than average. As a result the histograms will tend to be pulled in the wrong direction leaving a gap at one end or other of the histogram. Auto Levels may fix this to some extent. (however running auto levels on a correctly exposed high key scene where you want a gap at the bottom end of the histogram as you don’t want it to look dark, will tend to make things look worse)
Susan S.
Leen, thank you for that one and Susan I believe you are right in what you are saying.
Robert
Susan, as far as I know you are right. Many amateur cameras have algoritmes that do choose and set the white and blackpoint. That leaves very little to do for "auto contrast". The majority of people don’t bother about tweaking their images in Photoshop or other software. They just only want prints, just like in the days before digital (BD).
Prosumer and pro cameras however don’t process the images to this extend as their owners often prefer to add a personal touch.
About the Kodak 18% grey card: this is the standard for light meters, but don’t use it as neutral grey for checking the colours in the image. This neutral grey isn’t neutral when it comes to colour.
Leen
Just an FYI since no one else has mentioned it and Susan did bring up Auto Levels and Auto Contrast…
As Susan mentioned, both commands set the black point and white point and spread the pixels proportionally along the histogram. The difference is that Auto Levels adjusts the R, G, B channels independently, one at a time, and thus can possibly correct a color shift or introduce one. Auto Contrast adjusts the composite RGB image all at once (and not the individual R, G, B channels separately) and will not introduce a color shift.
By the way, all that’s needed for auto levels to not make a change is for each of the R, G, B channels to already have pixels at both ends of the histogram (no change in black or white point means no adjustment).
Bob
Bob, Thanks for that explanation. I was working on an image this morning and saw exactly what you describe, now I know why.
Dick
