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XT, ISO 3200-6400 and Noise Ninja

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DodgeV83

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I just learned about pushing the Iso to 3200 and 6400 by underexposing to -1 ev or -2 ev and pushing up the exposure in RAW or Photoshop (this is how the 20D gets ISO 3200). I have found the results to be quite usable at 3200! If your ever at a sporting event and just NEED that extra shutterspeed, this is a good technique.

Here are some demo shots. All taken in RAW, converted in RSE 2005 and saved to 16-bit TIFF, auto-profiled in Noise Ninja with default settings.

Larger versions available here
http://www.smugmug.com/gallery/1263427

Iso 1600
Shutter 1/8



ISO 3200
Shutter 1/15



ISO 6400
Shutter 1/30



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ISO 1600
Shutter 1/50



ISO 3200
Shutter 1/100



ISO 6400
Shutter 1/200



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ISO 1600 100% crop



ISO 3200 100% crop



ISO 6400100% crop

 
The ISO 6400 shots still look underexposed... did you neglect to push them two stops in post?

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-CW
 
Look great, thanks for sharing!

In some situations I wished the XT had ISO3200. But you are right, the 20D doesn't do anything other than boosting an underexposed image! Should have thought about this myself. :)

Regards,
Andreas

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Please take a look at my galleries at http://nordic.smugmug.com
 
Chez Wimpy said:
The ISO 6400 shots still look underexposed... did you neglect to
push them two stops in post?

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-CW
Click to expand...
Nope I didn't forget, thats just how they look when I do +2 EC in RSE. They look closer when I do +3, but I don't think that'd be ISO 6400 so I didn't post that.
 
the 300D makes very usable 3200ISO denoted by an H on the ISO meter with undutchables firmware hack especially when processesed with neatimage pro noise software... another very good and fast noise cleaner.
 
So where is a hack for the 350D so I don't have to do this in software everytime? :(
 
That's very interesting...

Do you know if it is the way the camera works at the other isos?

Is a Iso 200 shot like an undexposed Iso 100 shot (EV-1) with EV+1 during post-processing (in the camera)? (explaining the increased noise)

Or is it only true for iso 3200 and up?

A Leblond
 
I'm no expert, but the way I understand it is when you increase the ISO you in effect amplify the signal which introduces noise. I don't believe it is the same as what you are doing here. If you were to do what you suggest I doubt you would have any detail in the image.
 
I don't quite understand this. Increasing ISO lets in more light, so if you keep a constant shutter speed/aperture then increasing the ISO will result in lighter shots. If I apply positive exposure compensation my shots are lighter, so surely this is the equivalent of a higher ISO?

As an example, I shoot ice hockey so need fast shutter speeds but don't want increased noise. I use ISO 800 with +2 EC. Isn't the +2 giving me the equivalent of 2 extra stops of light, ie the equivalent of ISO 3200 (just without the increased noise)?
 
Julianne Bonner said:
I don't quite understand this. Increasing ISO lets in more light,
Click to expand...
No, it is my understanding the ISO in digitial, boosts the sensor voltage allowing more sensitivity at the expense of crosstalk of photosensors thus noise but yielding more information from whatever aperature and shutter settings. ISO does not really let in more light, your aperature lets in more light, which is why small f lenses (or fast, not that f stands for fast) are so darn expensive.
Julianne Bonner said:
As an example, I shoot ice hockey so need fast shutter speeds but
don't want increased noise. I use ISO 800 with +2 EC. Isn't the
+2 giving me the equivalent of 2 extra stops of light, ie the
equivalent of ISO 3200 (just without the increased noise)?
Click to expand...
I have tried this and yes it works to a certain extent that shadow detail and contrast is sometimes lost like blown detail in an overexposed image, but it does work. I am not sure how that equates to actual ISO speed.
 
This is what I routinely do for me Canon G6. In low light situations, I shoot RAW exclusively, the crank up the exposure setting afterwards. It does introduct quite a bit of noise, but for web galleries and small prints, it's not too objectionable.

Once I get my own XT, I plan on doing the same thing if circumstances require it - at least to begin with.

So perhaps it's safe to say that it's possible to get this "free" increase in ISO sensitivity with any camera that's RAW capable.

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---------
Terence
http://www.pbase.com/auriga_m38
 
Underexposing and then post proccessing in RSE or ACR or anything for that matter will yeild acceptable results but it is not the same as increasing the ISO on your sensor...

Try the situation like someone suggested. Take picture at ISO 100 but underexpose by three or more stops then post process.

Do you have any detail at all?? By all accounts the piicture probably looks likes it was taken with a cell phone at a dark nightclub?? No??
 
Auriga said:
This is what I routinely do for me Canon G6. In low light
situations, I shoot RAW exclusively, the crank up the exposure
setting afterwards. It does introduct quite a bit of noise, but for
Click to expand...
I suspect you will have to do a lot of less of this with your new 350D or even 300D since both have significantly lower noise at much higher ISO's than your G6. You should be very pleased with this.
 
I regularly expose at ISO 100 and need to push the shadow areas up 1 or 2 stops. this should be equive to ISO 200-400 but it produces up to ISO 1600 noise, even using Adobe Lightroom. It also shows bad forms of noise like banding patterns and so forth. Bassically, lighting is very important, more important than anything that can be done in PP. Unfortunately I can't shoot at ISO 400 because that would blow the highlights, its just a strange world of sensitivities with digital.

And Pushing/Pulling ISO's is MUCH different than true sensitiveity changes. A true ISO change aplifies the sensitivity of each sensors signal. Pushing an underexposed image simply allows the computer to guess based on algorythms with that image WOULD look like. If you know photography, you know in any case its better from real information to be recorded rather than digital guesses. Noise is always lower using the actual ISO.

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Cliche statements don't strike my fancy.
 
..is a form of noise reductions. And your 100% crops were of an ambiguous part of the image that can't really be used for any evaluation.
 
I get much less noise shooting ISO 800 and +1 or +2 EC than I do shooting at ISO 1600. I need to boost exposures in post-processing very little using this method and I seem to get a full range of tones (I check my histogram on the LCD, especially when shooting at a different rink). For my situation, the results from under-exposing (-EC) in-camera are way worse.

...and I'm shooting with a 2.8 lens!
 
Hi DodgeV83,
how are you taking these shots?
Is it shutter priority to force the shutter speed, or full manual?
I think I need to experiment ;-)

As I understood it setting of the ISO worked as follows;

The information off the sensor is digitised within a certain voltage range. In order to get best dynamic range the gain of the amplifiers on the sensor can be increased boost a small signal to make more use of the voltage range, but at the expense of noise.

Once the amplifiers are cranked right up the only thing that is left is to do the trick in PP, but this adds more noise.
 
For sportts shots, I totally disagree with the premise. I will say that in a dire pinch you can get a decent snapshot with this approach. But every single SPORTS shot I've seen (not a guy sitting at a table) that tries to push 2 stops in raw conversion looks pretty bad. The resulting noise damages too much detail. Noise ninja can remove noise, but it can't add back detail. And, add to that the simple fact that many sports shots require cropping, the results just aren't good.

If you want good sports shots at high ISO you need exposure right on. At most you can push exposure by a stop. Again, try your method shooting indoor sports not posed shots and see how many keepers you get.

At lower ISOs, it is certainly possible. I don't mean to offend, it's just my opinion that for sports this doesn't yield acceptable results on more than a snapshot basis.
 
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