ISO & Noise Level

[ddt0725]

Someone please educate me!


I went out shooting for a short while tonight and with the sun setting earlier and earlier, I really had to push the ISO. When I got home, I pretty much deleted every one of them. Could someone please tell me why ISO of 3200, 4000, 5000, 6400 is even an available option on the 7D? I can understand the wide range availble for shutter speed & f/stops but high ISO? Could someone give me a good scenerio where a shot would be worthy of this? I don't have PS but I can't believe there is a post-processing application that would be able to decrease the noise level & maintain a decent sharpness to still get a quality print level, except for maybe at 3200. Since I am a post-processing flunky, I most definitely could be wrong but I just can't imagine good prints @ ISO 6400, at least not from my 7d. Is ISO 6400 usable on a FF camera? Should I be getting more tolerable high ISO settings out of my 7D than I am possibly??


Denise

[bouwy]

Hi Denise


I too often wonder myself why we have such ISO's available on the 7D. I do realize that at times there are reasons for using fast glass and high ISO to take that magic shot due t light conditions. Even with the 5D /2 anything over 2000 is pretty average. I have spoken to some experts friends, but even they could not shine a good light on it. Pardon the pun.


Look forward to the expert opinions. []


Wally

[Daniel Browning]

Could someone please tell me why ISO of 3200, 4000, 5000, 6400 is even an available option on the 7D?

Because everyone has different shooting conditions, processing software, display resolution, and taste.


For shooting conditions, the color temperature of the light has a significant affect. In "bad" light, the could be a very big imbalance between the color channels. For example, red and green might be OK, but blue could be two stops darker. That means evenyou might have the camera set to ISO 3200, the blue channel is *effectively* ISO 12,800. So unless you get rid of that blue channel noise somehow (such as by converting to black and white without using much blue), the result will be as noisy as if you had set it to 12,800 in "good" light.


Processing software makes a big difference as well. For example, Lightroom 2 made a terrible mess of noisy images -- all blotchy and clumpy. LR3 is much better. The style of the post processing makes a huge difference too. High contrast, low-saturation, low-dynamic range image development shows noise a lot less than low-contrast high dynamic range images.


Display resolution is another vital factor. Every time you divide resolution by four you can increase ISO 1 stop and still have the "same" noise level. For example, if you felt that ISO 1600 was the highest you could go and still print a full-resolution 18 MP 18x12 beauty, then you would find that printing a 4.5MP 9x6" would give you the same noise visibility at ISO 3200. And 1 MP 3x4.5" print would again be the same at ISO 6400. And a 200x200 facebook image would look fine at ISO 12,800.


Taste is the big and obvious factor. Some people dislike noise more than others. (Personally, I actually *add* noise to my images.)

[ddt0725]

Thank you, Daniel! That is exactly how I needed explained to me!! I figured there had to be some reasoning behind it or it wouldn

[Sheiky]

I for one dislike ISO and I guess what I found out is probably what Daniel is saying. I don't like to get higher than ISO1600 on my 5D. But mainly because I view my images big and like to have the full benefit of all the megapixels. However lately at a wedding I also shot ISO1600 and for some reason, the shots with extra light from a flash look well....pretty amazing for ISO1600 shots.


I have seen this before and I don't know what's up, but the lightsource definitely plays a big role in ISO-noise as far as I''m concerned.


The noise application that I have is called noise-ninja. A lot of people and companies use it, but it does make your images softer. At least I think my poster prints look better without it. For some reason with printing you also get rid of some of the noise.


Don't ask me how though [A] Probably the smooth transitions between the different colors of ink or somethink.


But honestly, I also don't get why they put ISO12800 and even 25600 on my 5D other than marketing purposes. ISO6400 is actually very nice with video. But the same story here again, noise depends a lot on lighting conditions.


Jan

[Kayaker72]

Could someone give me a good scenerio where a shot would be worthy of this?

Snowstorm? [:P] (someone had to say it....ok, maybe not [])


Seriously, I agree. The part that drives me nuts isn't that we have the option to shoot at high ISOs, options are fine with me, but that Auto ISO goes all the way to 3200 on my 7D and that is clearly too noisy. My understanding is that some cameras have the ability for the user to set the Auto ISO range, butthe 7Ddoesn't seem to have that feature. As a result I've stopped using Auto ISO. It was giving me too many noisy pictures when I could get the picture with changes to the exposure settings, not ISO increases.

[neuroanatomist]

My understanding is that some cameras have the ability for the user to set the Auto ISO range, butthe 7Ddoesn't seem to have that feature.

True. The T2i and the 60D allow you to specify a maximum ISO for the Auto mode. In fact, the PowerShot S95 also has that feature. It's something that Canon could easily incorporate in a firmware update, but they've got a poor history of adding features via firmware.


Personally, I'm not a fan of ISO 3200 on my 7D, so for me that's a problem with Auto ISO. That's one area where the 5DII will perform better - like the 7D, the 5DII's Auto ISO is 100-3200, but ISO 3200 is cleaner on the 5DII. On the flip side, in M mode on the 5DII, Auto ISO is locked at 400, whereas on the 7D the Auto ISO is functional in M mode which is very convenient sometimes.

[barba]

ISO is the new megapixel in camera marketing. Just don

[neuroanatomist]

There are times where it could be argued that getting a shot, any shot, is better than nothing I suppose.

Yep. The S95 actually has a 'low-light' mode where the ISO ranges from 320 to 12800 - it does so with 2x2 pixel binning meaning you get a 2.5 megapixel image from the 10 megapixel sensor. ISO 12800 on a 4x crop sensor sounds horrible, but in practice it's not as bad as it sounds, because binning increases the signal-to-noise ratio. If Canon were to implement that with a larger sensor, the results would be interesting...

[clemmb]

I don't have PS
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What are you using for post processing?


Mark