50D: an important setting (1 Viewer)

Please excuse me starting a new thread on this if this is the wrong thing to do, but I thought this important regarding the 50D and that it deserved a thread of its own....

On a recent thread, mjobling said:

"Out of the box settings [on the 50D] have a major flaw. A feature called "Auto Lighting Optimizer" is enabled by default, which leads RAW images to look noisy even at 100 ISO, when viewed in DPP. Once this is disabled and the images which had it enabled have the effect removed in DPP, the there is no noise at low ISO and noise handling via DPP at higher ISOs is superb.
I'm wondering if this Auto Lighting Optimizer setting combined with poor RAW handling algorithms from Adobe are causing the lukewarm reception for this camera, as many owners may be oblivious to the problem."

As one who has 'upgraded' from a 40D to a 50D and had not noticed this setting, this is most interesting. Could it explain why I have a general impression that my photos are noisier with the 50D than they were with the 40D? But I am not using DPP. I am processing my photos (always RAWS) in Photoshop CS3 and much prefer to keep doing so if I possibly can. Now, if taking RAW, should this setting always be turned off if processing RAWS in Photoshop CS3 rather than DPP? Does Photoshop recognise and include this setting when it opens files? My initial tests suggest yes, perhaps I should turn this setting off, at least regarding noise, but I am not sure. Does the setting have other positive effects on the image? Any advice much appreciated.

I can only go from what I have read but on the DPreview forums it is generally held that turning off ALO will show a marked improvement noise wise. Again it is generally held that Canons' own RAW converter in DPP is superior to Adobes, especially noise wise. ALO is supposed to help the image retain detail in, I think, the highlights in contrasty situations. In effect extend the dynamic range in these situations. No doubt I will be corrected if I am wrong!

Hirundapus said:

Please excuse me starting a new thread on this if this is the wrong thing to do, but I thought this important regarding the 50D and that it deserved a thread of its own....

On a recent thread, mjobling said:

"Out of the box settings [on the 50D] have a major flaw. A feature called "Auto Lighting Optimizer" is enabled by default, which leads RAW images to look noisy even at 100 ISO, when viewed in DPP. Once this is disabled and the images which had it enabled have the effect removed in DPP, the there is no noise at low ISO and noise handling via DPP at higher ISOs is superb.
I'm wondering if this Auto Lighting Optimizer setting combined with poor RAW handling algorithms from Adobe are causing the lukewarm reception for this camera, as many owners may be oblivious to the problem."

As one who has 'upgraded' from a 40D to a 50D and had not noticed this setting, this is most interesting. Could it explain why I have a general impression that my photos are noisier with the 50D than they were with the 40D? But I am not using DPP. I am processing my photos (always RAWS) in Photoshop CS3 and much prefer to keep doing so if I possibly can. Now, if taking RAW, should this setting always be turned off if processing RAWS in Photoshop CS3 rather than DPP? Does Photoshop recognise and include this setting when it opens files? My initial tests suggest yes, perhaps I should turn this setting off, at least regarding noise, but I am not sure. Does the setting have other positive effects on the image? Any advice much appreciated.

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Thanks for the info. Will try it out.
EW

ALO may cause shots to be somewhat underexposed to preserve the highlights, therefore the higher noise levels...

Can you explain to me how I disable ALO in camera please?

torpid dormouse said:

Can you explain to me how I disable ALO in camera please?

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Go to the camera's menu, then it's Custom Function II image. Unless anyone knows better (quite likely as I'm no expert), it's best turned off if taking Raws.

Apparently it is on Page 177 of the manual.

macshark said:

ALO may cause shots to be somewhat underexposed to preserve the highlights, therefore the higher noise levels...

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I think you'll find that HTP (Highlight Tone Priority) is the setting that underexposes to protect highlights, while ALO (Auto Lighting Optimiser) is designed to lift shadow detail. Each may have its merits when shooting straight to JPEG but has no place for people shooting raw. Ditto the noise reduction settings. I only shoot raw and I turn off all these little "enhancements". They are more likely to harm IQ than enhance it (for raw shooters) and may even cause the camera to slow down its shooting speed/capacity.

Here's a quote from Canon on ALO....

Let the EOS 450D brighten your day by turning muddy, underexposed shots into bright, beautiful images. When shooting, the camera analyzes your photos to determine proper exposure and contrast. If a shot is too dark, Auto Lighting Optimizer applies just the right amount of brightness and contrast to save the day. This intelligent feature can correct underexposed images, shot in AE mode or with a flash, as well as images exhibiting low contrast due to mist or haze. There is also a new face detection feature that brightens faces in backlit scenes — ideal for obtaining crisp, nicely exposed portraits and group photos when shooting into the sun. Auto Lighting Optimizer can be turned off when not needed in Creative Zone mode.

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Here are what I understand to be comparable RAW histograms with HTP on and off. The version with HTP on clearly shows a lower exposure and is the very antithesis of good practice, when shooting raw, to expose to the right.

http://forums.dpreview.com/forums/read.asp?forum=1019&message=24943011

Here's an explanation of how HTP works. It's not my description but it mirrors exactly my own understanding of how HTP works, and why it is such a stupid setting for raw shooters....

http://forums.dpreview.com/forums/read.asp?forum=1019&message=30841171

Hirundapus said:

Please excuse me starting a new thread on this if this is the wrong thing to do, but I thought this important regarding the 50D and that it deserved a thread of its own....

On a recent thread, mjobling said:

"Out of the box settings [on the 50D] have a major flaw. A feature called "Auto Lighting Optimizer" is enabled by default, which leads RAW images to look noisy even at 100 ISO, when viewed in DPP. Once this is disabled and the images which had it enabled have the effect removed in DPP, the there is no noise at low ISO and noise handling via DPP at higher ISOs is superb.
I'm wondering if this Auto Lighting Optimizer setting combined with poor RAW handling algorithms from Adobe are causing the lukewarm reception for this camera, as many owners may be oblivious to the problem."

As one who has 'upgraded' from a 40D to a 50D and had not noticed this setting, this is most interesting. Could it explain why I have a general impression that my photos are noisier with the 50D than they were with the 40D? But I am not using DPP. I am processing my photos (always RAWS) in Photoshop CS3 and much prefer to keep doing so if I possibly can. Now, if taking RAW, should this setting always be turned off if processing RAWS in Photoshop CS3 rather than DPP? Does Photoshop recognise and include this setting when it opens files? My initial tests suggest yes, perhaps I should turn this setting off, at least regarding noise, but I am not sure. Does the setting have other positive effects on the image? Any advice much appreciated.

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Only just got my 50d, its a bit unclear when you are looking at the these settings C.Fn I to IV, as a
quick look through and everything is set to 00000000 But you need to disable them.
I have now disabled C.Fn II 4 ALO and C.Fn II 2 High ISO

Not taken many pics yet as no sunshine and need to get out where the birds are

I just shot a couple of images with the 50d + 400mm f5.6 jpg, the goldfinch was shot
through the double-glazed conservatory and the fieldfare goldfinches outside...

I have alot to learn with this 50d

EDIT I know why these are rubbush now I took them at ISO 1250 8000 sec

Nice one Terry. The EDIT message tells all.

Great thread! My 50D ALO setting was set to the minimum 'Standard' setting, but I've now disabled it.

Tim, when you say it is good practice to expose to the right, do you mean you try to overexpose your photos (without clipping) and then fix them in pp? I always find that my pics need to be brightened up a little in pp. To be honest I never look at histograms as I really have not understood what the histogram SHOULD look like, this is after being involved in photography for nearly 2 years. I still shoot JPG by the way.

Excellent dp links, tdodd, thank you very much indeed. These people seem to know what they're talking about and have explained it to me. My ALO setting is now firmly off!
Incidentally, at first I thought the default ALO setting of 'Standard' was lower than 'Low', but in fact it is between 'Low' and 'High', so even more important to turn off if you are shooting raw. Also, I'm now converting my 50D files (always raws) in DPP rather than ACR and I'm much happier. The noise has gone! Cheers.

I am no expert you all know that, but I have always needed to to add a touch of
brightness to my raw files, thats when I have been using 450d, and the few shots
I have done with the 50d also. I need to also learn more about the histogram/RGB and what it means but i suppose it all comes with practice and patient

Oh, and while on the subject, should the Picture Style be set to 'Neutral' or to 'Faithful' when shooting raws?

My understanding is that the RAW file is as taken by the camera without it being affected by such settings. You can then do what you want with it. Correct me if I am wrong please.

stu78 said:

Tim, when you say it is good practice to expose to the right, do you mean you try to overexpose your photos (without clipping) and then fix them in pp? I always find that my pics need to be brightened up a little in pp. To be honest I never look at histograms as I really have not understood what the histogram SHOULD look like, this is after being involved in photography for nearly 2 years. I still shoot JPG by the way.

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Have a look at this article about Expose To The Right (ETTR) technique....

http://www.luminous-landscape.com/tutorials/expose-right.shtml

There's also this brief thread, which mentions the simplicity of achieving an ETTR exposure and ties in with one of my techniques for setting a manual exposure at +3 stops from spot metering off the brightest part of the sky/scene for which detail is required. The article itself says +2 but I suspect that is a limit of the old camera and the limit of the EC range at +2 stops. With manual exposure, or a 1D camera, you are freed from that +2 stop limitation.

http://www.dl-c.com/discus/messages/2/3622.html

Hirundapus said:

Oh, and while on the subject, should the Picture Style be set to 'Neutral' or to 'Faithful' when shooting raws?

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miketoll said:

My understanding is that the RAW file is as taken by the camera without it being affected by such settings. You can then do what you want with it. Correct me if I am wrong please.

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The picture style does not affect the raw data, other than to set a flag that DPP or Zoombrowser can recognise and apply when rendering/converting the image. That's also true of most other settings, including sharpening, contrast, saturation, noise reduction and white balance.

However, those settings do affect the thumbnail preview image that is displayed within the camera and from which the in camera histogram is generated. Thus the preview image histogram generated by the Standard picture style will look different from the equivalent histogram if you switch to Neutral or Landscapefor example. It is generally regarded as best practice to shoot with Neutral picture style and to minimise any settings for contrast/sharpening/saturation in order to get the closest histogram as possible to the raw capture.

The big fly in the ointment here is the white balance setting. White balance does more than anything to skew the RGB values of individual pixels as it can generate very large swings of colour and that in turn must have a substantial effect on the brightness levels of those respective colour channels and the resulting RGB histogram. For example, let's say you are shooting indoors with only tungsten light as your illumination. The fact is that the light in the room will be very heavy at the red/yellow end of the spectrum and very lacking at the blue end. In terms of the raw capture it is quite likely that you could overload the sensor in the red channel and possibly green, but almost impossible to blow the blue channel unless you are a real klutz with your exposure.

But now consider what effect the WB setting has. If you use the tungsten setting, or set an accurate manual WB, or even use auto, the camera will adjust the red channel to reduce its dominance and give a huge boost to the blue channel. The JPEG histogram you see within the camera will look very different from the true raw histogram. You could be fooled into thinking that your reds are safe when in fact they are blown and red things seem to be very lacking in detail because they were blown during the raw capture. However, the WB adjustment will pull back the red channel and it may appear not to be blown the problem is that your reds might be a flat, featureless 240, 240, 240, 240 across the board rather than the blown but equally lacking in detail 255, 255, 255, 255 etc..

In order to overcome this limitation there is a special setting of white balance called Uni-WB, which is a custom WB to try to neutralise the effect of any WB adjustments and to create a JPEG preview file that represents the actual raw saturation levels. Although the preview image itself will look terrible - strong green cast - the resulting histogram within the camera will be a close reflection of the actual saturation levels of the sensor.

If you Google for uni-wb you will, I'm sure, learn more....

http://www.google.co.uk/search?sourceid=navclient&hl=en-GB&ie=UTF-8&rls=GGLJ,GGLJ:2009-02,GGLJ:en-GB&q=uni%2dwb

I gave it a try because I am a bit of a purist in these things and did want to squeeze every last drop of performance from me and my camera, but it was a brief love affair and I have stopped using it. Nowadays I mostly just leave the camera on Daylight WB, Neutral picture style, all picture style settings at default values and all gimmicks (HTP, ALO, NR) turned off.

If you want to give Uni-WB a try the quick way is to shoot a black frame - 100 ISO, f/32, 1/8000 in a dark room or with the lens cap on and then force the camera to use that image for a custom white balance. The camera may protest but should allow you to use it if you insist. You can try some test images and use some free software called Rawnalyze to check out the true RGB histogram of the raw file. Then compare that histogram with that within the camera nd see how closely aligned they are.

Here's the Rawnalyze software - http://www.cryptobola.com/PhotoBola/Rawnalyze.htm

Sorry to slightly change the subject, I have just got a 50D, in C1 and C2 HOW DO I CHANGE From "P" to "AV" I must be stupid I just can't seem to do it.
All other advice has been followed, thanks.