50D. An Important Setting.

CT

CT

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IanC_UK drew my attention to this thread over on The Bird Forum.

http://www.birdforum.net/showthread.php?p=1407014

It's well worth a read, but apparently a setting on the 50D - Auto Lighting Optimiser is enabled by default on new cameras and causes undue noise when used shooting RAW files. I've checked mine which is set at the lowest 'Standard' setting but I've now disabled it.

Highlight Tone Priority I've noticed, also causes a noise increase as it under-exposes to protect highlights and thus increases noise. i can imagine that with both ALO and HTP enabled it's highly likely to have an adverse effect on noise. Both settings it seems are intended for use when shooting jpegs - not RAW files. They're both now switched off on my 50D, so I'll see if there's a difference.
 
Hi C,

thanks for that I will give it a go, still mucking around with various settings here, with a little success I might add, so things beginning to look a little better. Been switching between Jpeg, RAW and sRaw1, still think for higher ISO's that sRAW1 is better if cropping, I now have C1 and C2 set to allow a quick switch between RAW at 400 ISO and sRAW1 at 800 ISO.

There is no doubt though as you say the pulling power of this camera is superb, I am now able to use shots at around 7 or 8m that would have been binned with the 1D Mark II and even the 30D.

No chance to try the new settings out now as the sun has just gone in :(

Let you know how I get on later in the week.

Mike.
 
The Highlight Tone Priority, seems to have been "discredited" when shooting RAW when it became available on the ID series of cameras. It seems Canon have a concern about blown highlights on jpeg file ( my reading of the situation). Underexposure does certainly put the noise up on those cameras with higher pixel count ( hence smaller photosites, and higher amplification) I tend to add about 2/3 stop as standard to stop this happening.
 
CT said:
IanC_UK drew my attention to this thread over on The Bird Forum.

http://www.birdforum.net/showthread.php?p=1407014

It's well worth a read, but apparently a setting on the 50D - Auto Lighting Optimiser is enabled by default on new cameras and causes undue noise when used shooting RAW files. I've checked mine which is set at the lowest 'Standard' setting but I've now disabled it.

Highlight Tone Priority I've noticed, also causes a noise increase as it under-exposes to protect highlights and thus increases noise. i can imagine that with both ALO and HTP enabled it's highly likely to have an adverse effect on noise. Both settings it seems are intended for use when shooting jpegs - not RAW files. They're both now switched off on my 50D, so I'll see if there's a difference.
Click to expand...

Just a little extra info that may help when assessing the results of any tests.
ALO has mixed blessings. On bright days when shooting at lower Iso settings then it's likely to add a little noise that would be avoidable and give no benefit. If the light is flatter and there's less contrast in the scene then ALO will probably give a more pleasing result and may be worth having to "Ninja out" the resulting noise

HTP is only applied to pixels recording 18% grey or brighter. Any shadows or mid-tones on the darker side will remain unaffected. In essence, it's clipping the dynamic range at the right side (histogram).

The ALO issue was touched on in a thread back in October but few people had the 50D at the time.
Also worth noting that setting up a 5D2 will require the same decisions but the personal "when to" and "when not to" threshholds are likely to be higher due to the lower pixel density and improved photosites.

Bob
 
Good info Bob. That Canon Manual you keep by the side of the bed comes in handy. :D

Just took this quick shot of GTomo posing in the kitchen - 3200 ISO 1/500th at f1.2 with the 85mm 1.2 Seems pretty damned good to me. No NR run on it at all.

3282824370_48e8bfd857_o.jpg
 
sorry i havent contributed before now, had a mates daughters first birthday to go to. I have been fairly unhappy with some of the results i have had with the 50D since i got it, and been discussing it with CT on and off since, i have noticed noise where i shouldnt have any and its been annoying me. Thats why when i saw the thread i thought i would let CT know and see what his thoughts were on it. I havent had chance to try now i have switched it all off, but hopefully it will help to make me have some more confidence in the camera !

By the way CT that shot doesnt look bad at all for ISO3200 !
 
Well I hope you get it sorted Ian - to my mind you have the best of both worlds with the 1DMK3 and the 50D - till they roll the two camera into one. ;)
 
CT said:
Good info Bob. That Canon Manual you keep by the side of the bed comes in handy. :D
Click to expand...
The details (not opinions) were drawn from Canon's design white paper for the 50D and 5D2....should I be worried that you have knowledge of what I leave at the side of my bed?


CT said:
Just took this quick shot of GTomo posing in the kitchen - 3200 ISO 1/500th at f1.2 with the 85mm 1.2 Seems pretty damned good to me.
Click to expand...
Just done a little sharpening on it...er, is that a 50/1.4 I can see reflected in his glasses? :whistle:
 
Canon Bob said:
The details (not opinions) were drawn from Canon's design white paper for the 50D and 5D2....should I be worried that you have knowledge of what I leave at the side of my bed?
Click to expand...

LOL Don't worry Bob I wont tell 'em about the Canon badge on your pyjamas. :D


Just done a little sharpening on it...er, is that a 50/1.4 I can see reflected in his glasses? :whistle:
Click to expand...

Hell no - it's the 85mm 1.2. :love:
 
IanC_UK said:
sorry i havent contributed before now, had a mates daughters first birthday to go to.
Click to expand...

I didnt know you still did the clown job on the side Ian, You must be getting really good at doing balloon animals now..:D

I will try this on my 50, hopefully i will notice a difference..though to be fair i mainly shoot in jpeg...
 
CT said:
Hell no - it's the 85mm 1.2. :love:
Click to expand...

Ooow, I was bad today....lent my 85L to someone to try on his 5D for half an hour :naughty:...then put it back in my bag and drove off :LOL:

Bob
 
Canon Bob said:
Ooow, I was bad today....lent my 85L to someone to try on his 5D for half an hour :naughty:...then put it back in my bag and drove off :LOL:

Bob
Click to expand...
LOL. I must be honest, I'd be a bit nervous handing mine over, the way that back element protrudes! :eek:
 
OK - I've hung back on the test shots with ALO and Highlight Priority turned off until I could take some shots where I'm familiar with what they normally look like. I thought I'd turned ALO off for the shot above of GTomo, but I hadn't! :shrug:

These are 700mm and 1600 ISO with no NR at all.

3289686155_4a3140d87a_o.jpg


3289686299_5851ea3b17_o.jpg


I'd expect more noise than this normally in the dark parts of the image at that location, so I think I can safely confirm that with ALO turned off you should see a marked mprovement in noise if you shoot RAW.
 
Blimey ! it makes a huge difference, the bokeh looks a bit odd, specially int he first one, is that down to JPG compression (ie can you see it in the RAW) ?

Its all switched off on mine now just need to get out and try it :)
 
I can't see it's odd mate. Just the distance to the bg I think. Looks much the same in RAW
 
Hi,

look good to me (y)

Mike.
 
LOL. Same in the RAW version anyway.

It's a bit overgrown back there - snakes and all sorts! ;)
 
Well it's odd that ALO is enabled by default, and I can't see any reference in the manual to it's adverse effect on RAW images, unless I'm missing something. :shrug:
 
So disabling HTP on the 40D will help too then I presume?
 
Definitely Janice. I've noticed an increase in noise using HTTP on the 40D . Sometimes though it's a trade off innit in contrasty light between not blowing the highlights and a bit more noise. It all seems a bit giomicky though overall, I tend tol leave it off in favour of keeping ISO expansion at your disposal.
 
Janice said:
So disabling HTP on the 40D will help too then I presume?
Click to expand...

CT said:
Definitely Janice. I've noticed an increase in noise using HTTP on the 40D . Sometimes though it's a trade off innit in contrasty light between not blowing the highlights and a bit more noise. It all seems a bit giomicky though overall, I tend tol leave it off in favour of keeping ISO expansion at your disposal.
Click to expand...

This one's confusing me a little. Canon say that HTP is only applied to pixels recording 18% grey (well, they say gray) or lighter. This is not the usual areas where noise would would become problematical, at least in the first instance. I can envisage a situation where exposure is pushed to the right and darker areas may then fall into the 0-18% bracket but not as a general thing. Maybe it's possible that the EV shouldn't be increased if HTP is on? I guess it depends whether it is the photosite's output or the processed data that is used to determine the brightness level.

Worth a test to see what happens CT...whilst you've got your lab coat and safety specs on, that is.

Bob
 
Well I've just deliberately shot against dark backgrounds today Bob, knowing that that's where the damned noise shows the most,so I'm happy that I'll see an improvement, and I don't have your enquiring mind for the real techy bits. :D
 
800 ISO.

As you can see this is quite a substantial crop and no sign of noise despite sharpening after reducing the image size, which will amplify any noise present.

3291905427_d73f731758_o.jpg


An even bigger crop, again sharpened after reducing. I'd definitely have been running NR on the bg with a crop this large before disabling ALO, but I really wouldn't bother on this image.

3292724650_371fbe4acf_o.jpg


On this showing I think I'll be inclined to use 800 ISO by default even in good light, for bird shots anyway, in favour of keeping the shutter speed up or being able to stop down a bit.

The 50D has had a mixed reception from reviewers on the noise issue, largely I think because Canon have claimed a one stop improvement in ISO over the 40D (an excellent noise performer) despite the huge pixel increase, and with ALO enabled it certainly isn't so. With ALO switched off then I'd say Canon's claim is easily justified, it's just a shame they've gone and shot themselves in the foot (again) with lack of info about the ALO setting.
 
right then, time for a few tests myself - i hate you all as this now bugging me but at the same time my thanks :notworthy:
 
Thanks for bringing this thread back up again - I meant to change the settings last time, but forgot, forgot which setting sthey were and did nothing!! Camera out and all changed. ALO and HTP disabled!!
 
Just been sent to this link in another thread, thanks!!

Maybe this should be a sticky?

Dave.
 
if CT doesnt mind id like to copy this thread to tutorials and guides?
 
eeverson said:
BTW...

Has anyone changed the "High ISO speed Noise reduction" setting?
Click to expand...

I haven't changed mine -it's still on the 'Standard' setting. I'm not seeing any obvious NR side effects, so I'm guessing it's doing more good than harm, although I have thought about trying with it OFF.
 
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