GLKTN Loc: TN

Newbie question. My Nikon d750 has ISO Lo0.3, Lo0.7 and Lo1.0 below ISO 100. What are the gradations below ISO 100? When would they be used? Same at the other end of ISO. Above ISO 12800, there is Hi .3, Hi .7, Hi 1 and Hi 2? Thanks.

BobHartung Loc: Bettendorf, IA

As I understand it Lo1.0 would be the ISO one full stop below ISO 100. The opposite holds for the Hi numbers. You can look up the ISO equivalents for yourself.

CO

One of the uses would be to slow down the shutter speed for photographing waterfalls to get the smoothed out effect.

RWR Loc: La Mesa, CA

Below ISO 100, they are ISO 80, 64 and 50, respectively, in 1/3 stops.

lamiaceae Loc: San Luis Obispo County, CA

I've tried to figure that out, why Nikon has to be mysterious and not just use ISO values though out. My Pentax cameras are pretty direct about what they mean. Though if the actual values are what they are implying, that is a fantastically wide range for the D750!

SKAN Loc: Chennai INDIA

In lieu of a ND filter.. To allow slowing down of shutter speed.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

The ISO extension of 80, 64 and 50 is to allow lower shutter speeds for more blur (water), or wider aperture for shallower depth of field. Because it requires the altering of the camera's response, shifting the dynamic range one stop from normal, which can result in overexposed highlights. If you shoot jpegs and crank up the contrast, you don't want to use anything lower than native ISO.

cthahn

Read your manual.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

It is all in the manual. The manual is your friend, read it. Then, get back to us. Understand Grasshopper.

steveg48

These are 'extra' isos beyond the hardware capability of the camera. They are accomplished by software processing in the camera and artificially extend the dynamic range. You are either sacrificing highlights or increasing noise when these settings are used.

GLKTN Loc: TN

Billnikon, thanks Captain obvious, uhm I did. The great advice on UHH is much more informagive and detailed.

GLKTN Loc: TN

Informative.

pithydoug Loc: Catskill Mountains, NY

Anything below 100 is the software playing with the picture - it not all goodness and has some faults.

camerapapi Loc: Miami, Fl.

Just keep in mind that the best images usually come when the camera is set to base ISO.

amfoto1 Loc: San Jose, Calif. USA

0.3 = 1/3 stop and 0.7 = 2/3 stop, while 1.0 is a full stop and 2.0 is two full stops. Keep in mind that each full stop higher represents a doubling of sensitivity, while each full stop lower represents a halving of the sensor's sensitivity to light.

Your D750 appears to have a "native" ISO range of 100 to 12800.

That range is "expandable", in 1/3 stop increments:

Low 0.3 = ISO 80
L 0.7 = ISO 64
L 1.0 = ISO 50

Standard range: 100 to 12800 in 1/3 stop increments.

High 0.3 = ISO 16000
H 0.7 = ISO 20000
H 1.0 = ISO 25600
H 2.0 = ISO 51200

So, why not just say the camera has an ISO range from 50 to 51200?

Well, as I understand it (very simplistically), ISO expansion is not "real". It's interpolated from the native range by the camera's software or firmware. ISOs both above and below the standard range tend to have decreased dynamic range. ISO above the standard range also tend to have a significant increase in image noise, as well as a lot of loss of resolution. So most camera manufacturers do similar to what Nikon does... treating ISOs outside the native range as expansions that the user needs to enable to use... or can keep disabled to avoid. (Canon cameras typically just provide full stop increments: L = ISO 50, H1 = 1 full stop, H2 = 2 full stops, H3 = 3 full stops.)