Understanding Noise

[cjcampbellphoto]

Hi Canon Community,

I'm an amateur photographer looking to improve my skills and I'm struggling in low light situations.  I recently took some photos of my friends using a Canon 7D (the oldest model) and an EF 100-400mm f4.5-5.6L IS USM with the settings of:
ISO250 at 100mm f/4.5 and 1/125 sec.  The picture shows up with a TON of grain and I'm confused. The ISO isn't that high at all.  I bumped up the exposure by +2 in Lightroom just to show how much grain is in the photo:

Any tips or understanding would be greatly appreciated! The photo was shot in RAW and edited in RAW.

-CJ

[BurnUnit]

I can't tell from your sample image where you're seeing a problem with noise, but I suspect that it may be in the darker, shadow areas. But I'm also wondering if you're confusing "grain" with "noise".

Are you viewing the images at 100% on your monitor, or at a higher rate of magnification? Above 100% you'll start to see grain and a loss of sharpness that will be unavoidable. And neither should be apparent in a standard size print.

The main thing I notice is that the image is generally under exposed. For the lighting conditions I think I'm seeing I'd start out with at least ISO800 if you are shooting without a tripod. I'd guess that a 7D could handle this without major noise issues, especially if you slightly over-expose your shots.

You may have seen the suggestion to "ETTR" to help control noise in the shadows of your image. This stands for "Expose To The Right". In other words, you want to move the bulk of the image information slightly to the right side of the histogram.

[kvbarkley]

Why are we rehashing this again?

[BurnUnit]

Apparently I missed this the first time around . . . I guess I need to start coming to the rehearsals.

[kvbarkley]

I don’t know what is wrong with the board. There seem to be several repeated threads.

[RobertTheFat]

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@kvbarkley wrote:
I don’t know what is wrong with the board. There seem to be several repeated threads.

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It isn't the board. The two introductory posts are in different subgroups, and the text is not identical. It appears that for whatever reason, the OP started the thread up again here.

[Waddizzle]

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@RobertTheFat wrote:

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@kvbarkley wrote:
I don’t know what is wrong with the board. There seem to be several repeated threads.

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It isn't the board. The two introductory posts are in different subgroups, and the text is not identical. It appears that for whatever reason, the OP started the thread up again here.

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Bob is correct.  This is a duplicate post.  Notice the date on the "original" post in this thread.  This post should have either been merged or deleted.