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mychillybin team

Posts 590
The mychillybin team are noticing quite varied levels of noise in low ISO images coming from Canon EOS 7D cameras from different owners. The web has lots of discussion about 7D's in this respect, which is somewhat time consuming to study.

Are there any mychillybin Canon EOS 7D users who have studied this and got to the bottom of this variability, or who are just consistently pleased with the image quality they are getting - and would like to share on the forum their typical camera settings and post processing steps being used?

Cheers for now
the Chillys

Canon_S.I.

Posts 273
I'm not a technical person but i've heard the 7D was the first canon camera to have 18mp pushed onto the the 1.6x crop body censor which could bugger image quality whereas most crop bodies sensors have 10.1 mp spread,good luck to you 7D owners in finding out the problem,but i'd say it's a manufacturers problem trying to make fast bucks and trying to keep ahead of the competition ect.

mychillybin team

Posts 590
Thanks - have read about this too. There must be more to it as well as in some cases the images we get from 7D's are superb, and other cases definitely not so.
the Chillys.
edited by mychillybin team on 1/08/2011

Canon_S.I.

Posts 273
I also found this snippet @ digital photography review which may help.


I work at a Canon dealer... we just got a batch of 7D's in. My first customer picked one up, took it home and came back to exchange it reporting focusing problems. Sure enough, on two bodies we tested, in Single AF Point or Spot AF Point mode, the AF fails on about one out of four shots, sometimes more. We tested this extensively with a variety of lenses and it happened with every lens, even from a tripod with a fixed subject.
However a later serial number of camera (after 101000) did not exhibit this problem nearly to the same extent (though it still happened, it was barely noticeable).

mychillybin team

Posts 590
That seemed to be an early problem but we have not seen any evidence of focus issues - just, in some cases, excessive 'noise/grain or texture' in the background, even with low ISO value images.

the Chillys

kathleen

Posts 221
Just a couple comments on the noise and grain if your having trouble with any camera actually. Check your screen on the back shows you exactly the exposure your end photo comes out as (the image you see in photoshop/computer).
Some people brighten the screen view on the camera for easier viewing, but the actual image is taken darker but you don't notice that on the back screen until you get it back onto your computer, which then means in your levels you have to lighten the image.
For cameras that have a problem with noise, try to take your images on the light end of the histogram and then darken in photoshop back to normal. More noise will show on a dark image that you try to lighten and less noise will show on a image taken brighter (BUT DON'T OVER DO IT AND BLOW OUT THE HIGHLIGHTS) and then darken it.

This is where you need to make sure what you see in your screen on camera is what you are getting in the final image. You can then use your exposure compensation on the camera to lighten the image but not blow it out.

ISO's is another thing you have to work out what you can go to with cameras that show noise. It might say 1200 ISO on the camera but you might be lucky to get 400 ISO with not much noise.

Hope this helps. Been there.

eyeball

Posts 31
programs like Noise Ninja and Neat Image (which I use) are great for reducing noise

mychillybin team

Posts 590
Thanks Kathleen and Eyeball for your helpful comments too. Much appreciated, as Kathleen is your earlier post about adjusting exposure and lighting histograms.

Almost every day the Chillys notice that almost all the really great images arriving have not only great composition but also very well positioned lighting histograms.

One of the good things with digital photography is being able to look at the histogram at time of shoot and then (usually) being able to modify exposure settings and shoot again if necessary to 'optimise the histogram'.

We have asked Canon about the particular 7D images in question as well, sent in some cropped samples, and expect an answer which we will share in due course.

the Chillys
cheers for now
edited by mychillybin team on 3/08/2011

Pixelated

Posts 106
I'll be interested to hear results from Canon on this.

Pixelated

Posts 106
I made my comment of interest because I have a new 7D.

I have also made a point of testing the camera and find that the exposure and noise levels correlation is very different to my old camera body.

My findings indicate that although viewing through the viewfinder you think you have set the correct exposure (under all meter settings) it seems in fact to be slightly under exposed. This wouldn't be so bad except that there is more noise in the darker end of the spectrum than the lighter, and subsequent exposure correction in post processing will reveal this.

Although noise reduction in software is quite far advanced and will help a lot there is a downside to it as it often needs some edge sharpening done with it as well, and we all know this is time consuming. Plus, if shooting in jpg to begin with, you are compounding the issue as you've let the camera process the file noise and all and apply its compression algorithms to form the jpg. Which, we all know means less data to work with if the need to post process arises. My preference is to shoot in RAW which allows better use of minor post processing and then I can output to jpg in any size I wish for whatever purpose and know that it will be the best quality possible. It is more difficult to save a jpg in to subsequent sized jpgs as each time this is done it degrades the file.

But back to exposure and noise. I am fast realising that with this camera it is most important to 'shoot to the right'. That is I may do what seems like over-exposing slightly when setting up the shot in order to get as much data as possible on the bright side. It means reading the histogram and getting the data pushing the right side without actually creating a very steep cliff there (which means you've gone too far and blown the data out of the highlights altogether). Bearing in mind that the camera renders a jpg preview on the lcd on the back of the camera and it bases the histogram also on the jpg data. So, although at times it may appear you have overexposed, when viewing the RAW file it often is a correct exposure as shooting in RAW does give you a stop or two of leeway.

If however you feel the exposure, although not blown out, is just too bright, it is very easy in post to notch back the exposure slider to a more correct exposure. You will find then that you will have little or no noise, whereas you increase noise levels when adjusting from a darker image to make it brighter.

Most of what I've mentioned is common knowledge amongst photographers anyway, but I've explained it more for any of our photographers who are newer to the craft, and also to point out my finding with the 7D as opposed to my previous camera. My thoughts are that it's the smaller sensor and high megapixel ratio that makes this more sensitive. I have also used different ISO settings in trialling this, and have found that even with a higher ISO setting it's important to 'shoot to the right'.

It's not insurmountable and I know for myself that it's a matter of getting used to a slightly different technique.

Forgive me for the length of this post. But I do hope it may help someone...

Cheers

Pixelated

Posts 106
http://www.luminous-landscape.com/tutorials/optimizing_exposure.shtml

I've included a link here to an article I've just found, while not actually about the 7D, it nevertheless talks about exposure and noise. Very interesting reading.

Pixelated

Posts 106
More experimentation means I've discovered the following:

7Ds Custom Function II-2 High ISO speed noise reduction -
I've tested this function now and the manual says that noise reduction is applied to all ISO speeds, but particularly effective at high ISO. At low ISO speeds the noise in the shadow areas is further reduced.

0: Standard 1:Low 2: Strong 3: Disable

With the camera on the default Standard, then setting it to Strong, I found a slight reduction in shadow area noise in low ISO. It is better in high ISOs but I am particularly interested in the low ISO as this is the issue of this thread.

Still, I didn't see enough reduction in noise to help, and can find no other camera function settings that are applicable.

I am looking at my workflow and as I shoot RAW there are a lot more options to deal with this issue than shooting in jpg. I realise not everyone shoots RAW, but I suggest those that shoot jpg might like to reconsider or perhaps conduct their own investigation into this problem, though be aware that camera 'baked' jpgs are more difficult to deal with in post as each save to jpg degrades the image.

I use Lightroom but I think Aperture and other software will have similar functions. On importing there is a default setting in the sharpness and noise panel - the colour noise slider is set to 25 by default, and the sharpness slider to 25 by default. This is input sharpening and nothing whatsoever to do with output sharpening (ie to jpg, print, or whatever).

The Luminance slider's default is 0. And it seems it's Luminance noise we are dealing with here. Currently I'm finding that a default setting of 10 here seems adequate in taking care of noise in the shadow areas without degradation or additional sharpening and provided the exposure was fine initially as I talked about in my post on this. With slightly under-exposed shots this setting needs to be higher. Of course the higher this slider the more you have to bump up the Details slider too. It always comes down to getting it right as much as possible in camera.

Am I making sense here Chillies?
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