Lower ISO setting quandary

[invisible]

I used to keep my camera's ISO setting at L 1.0 by default, until I read something along the lines of Nikon's low ISO settings (L 1.0, 0.7 and 0.3) not being "native" to the sensor (or something like that). From that moment on my default setting has been 200.

What I really want is the cleanest image possible. To that end, should I stick with ISO 200 and only use the L settings when I need a longer exposure? Or shooting at L 1.0 is as clean as ISO 200?

 

[Majeed Badizadegan]

Buy a Canon

 

[invisible]

Buy a Canon

But if I buy a Canon, would I be checking the Nikon forum? (You know, like you )

 

[Overread]

The cleanest ISO you'll get will come from the cameras Native ISO. This is not always the lowest ISO that the camera can do, although most do have it as the typical lowest selectable ISO without enabling special low ISO values.

For Nikon it varies a little - some cameras its native ISO 100 and others native ISO 200 (I think 200 might be more common for Nikon). It should be fairly easy to google the native ISO of your specific camera or it should be on the cameras specifications sheet on the Nikon website.

For Canon its generally ISO 100


But in short, provided there is enough light for a good exposure* the native ISO should give the cleanest possible shot.


* Note best possible exposures for Digital cameras want to be based upon the expose to the right theory which refers to the histogram and bunching as much data as possible on the right hand side of the bar without actually hitting the right hand side (ie without overexposing to the point of recording no data). This is, of course, an ideal world theory, but the general principle is that the more light data you have the less noise you will have in the shot.

 

[Majeed Badizadegan]

But if I buy a Canon, would I be checking the Nikon forum? (You know, like you )

I just go to the "home" page. I rarely check what subforum it's in. That way, lucky souls in all subforums can occasionally be graced with a comment

 

[480sparky]

........It should be fairly easy to google the native ISO of your specific camera .....

I've tried that. All I get is "100-1600".

or it should be on the cameras specifications sheet on the Nikon website. .......

I've never seen Nikon publish any single 'native' ISO. All they say is what is available to the camera:
ISO 100 - 6400
Lo-1 (ISO 50)
Hi-1 (ISO 12,800)
Hi-2 (ISO 25,600)

 

[Derrel]

"Lo" might very well be costing you some dynamic range!!! Your camera body's lowest ISO value that is NOT in the "Lo" range is considered its native or baseline ISO value. What basically happens is as the ISO values go upward, overall dynamic range capability, and color depth, will tend to decrease. This relationship can be seen in the DxO Mark graphs. Some of the newer sensors, made by both Sony, and by Nikon, have exceptionally good performance, in which the DR and the color depth do not drop off precipitously, as was the case with sensors, "A few generations back". From all I have seen, the "Lo" settings compromise overall dynamic range a bit--usually around one full stop of loss. Buuuut--that might not be a big deal all of the time.

I'm not sure which specific camera you have, but it might pay to cruise on over to the DxO Mark site and look carefully at their graphs and see what you are losing or gaining.

I dunno...ISO 200 is a nice baseline value...it's high enough to provide decent shutter speed and or f/stop...but at times, the "cleanest" image can often be a blurred-but-super-clean image, and so I frequently find myself doubling or tripling from my camera's "best" ISO (which is 100) to go to ISO 200 or 250 or 320, or even 400... Of course, an experienced shooter like yourself understands this.

 

[KmH]

Of the 11 DSLR's Nikon currently offers, only 2 have a native base ISO of 200, both use the same image sensor and are in the later stages of their product cycle - the D90 and the D300s.

The other 9 Nikon's currently offered all have a base native ISO of 100.
Native ISO is accomplished using amplifiers on the image sensor chip before the pixel voltages are run through the Analog-to-Digital (A/D) converter.

Lo and Hi ISO values are accomplished using software after the pixel voltages have been converted to digital values.

Analog voltages have a very much broader range of possible values, than the 12-bit or 14 bit output of the A/D converter. The limited range of possible values coming out of the A/D converter is where the non-native ISO losses in overall image quality occur. The non-native ISO losses in overall image quality are essentially 'rounding error'. http://en.wikipedia.org/wiki/Rounding_error

 

[invisible]

Thanks everybody for the feedback.

 

[BrianV]

Lo and Hi ISO values are accomplished using software after the pixel voltages have been converted to digital values.

Analog voltages have a very much broader range of possible values, than the 12-bit or 14 bit output of the A/D converter. The limited range of possible values coming out of the A/D converter is where the non-native ISO losses in overall image quality occur. The non-native ISO losses in overall image quality are essentially 'rounding error'. Round-off error - Wikipedia, the free encyclopedia

Typically, you have programmable gain settings on the analog (pre)amplifiers before getting into the digital side of things. As noted before, the analog signal often has more detail than the converted digital image. A programmable gain basically boosts the analog signal before converting to digital. Analog gain settings are typically 1x through to 8x. So, if the native ISO is "100" with the analog gain set to 1x, you should be able to get to 800 with an analog gain setting of 8x.