Real world implications of ISO ratings


TPF Noob!
Jun 24, 2013
Reaction score
Nashville, TN
Can others edit my Photos
Photos OK to edit
According to DxOMark low light ratings the Nikon D7100 is good to ISO 1256 and the D600 is good to ISO 2980.

What are the real world implications of 2980 vs 1256?

In a previous thread I asked about a camera setup for HS marching band night performances and ended up buying a Nikon D5200 with the 18-55 kit lens and a Nikon 180mm F2.8 lens. I did not realize at the time that the D5200 would not autofocus the 180mm lens. My wife has decided she needs her own camera and is perfectly happy to keep the D5200 for herself and let me buy another camera for me.

My choice at this point is either a new D7100 or a refurbished D600. If I go with the D7100 I would be buying the D7100 with 18-105 kit lens. The D600 would be body only and I would have to get a cheap every day lens to go with it (like this) with the idea of getting better lenses for it as money permits. So is the ISO 2980 worth getting the D600 for?

1256 and 2980?
The refurbished Nikon D600 was just dropped to the $1,400 price range TODAY, direct from the Nikon USA on-line store. The difference between ISO 1256 and 2980 is one full f/stop, and a bit more. Meaning one full shutter speed value faster, or one full f/stop smaller, for the D600 as opposed to the D7100. That's the by-the-numbers difference. The other difference is that the D600 will easily adapt to so many older Nikon lenses...a 35mm will "be" a thirty-five millimeter lens, specifically, a semi-wide angle lens with wonderful characteristics; a 50mm lens will be a "fifty". When it comes right down to it, FX format makes the Nikon lens lineup what it was always designed to be. Nikon has fewer than two dozen DX-format lenses; they have made HUNDREDS of different lenses that were designed for full-size 24x36mm capture.

DX was always a compromise driven by sensor costs, and NIkon's lens design offerings have always lagged in DX.
Honestly, I own and love my D7100 but I would shoot for the Refurbished D600 instead...especially with them in the $1400 range.
About +1EV. In practice in low light, not a whole lot IMO - some will most certainly disagree, and with valid points.

But as others have pointed out, this is far from the only advantage.
The DXO Mark Sports low-light ISO rating means:

DxOMark - Use Case Scores
Sports & action photography: Low-Light ISO
Unlike the two previous scenarios in which light is either generous (studio) or stability is assured (landscape), photojournalists and action photographers often struggle with low available light and high motion. Achieving usable image quality is often difficult when pushing ISO.

When shooting a moving scene such as a sports event, action photographers’ primary objective is to freeze the motion, giving priority to short exposure time. To compensate for the lack of exposure, they have to increase the ISO setting, which means the SNR will decrease. How far can they go while keeping decent quality? Our low-light ISO metric will tell them.

The SNR indicates how much noise is present in an image compared to the actual information (signal). The higher the SNR value, the better the image looks, because details aren't drowned by noise. SNR strength is given in dB, which is a logarithmic scale: an increase of 6 dB corresponds to doubling the SNR, which equates to half the noise for the same signal.

An SNR value of 30dB means excellent image quality. Thus low-light ISO is the highest ISO setting for a camera that allows it to achieve an SNR of 30dB while keeping a good dynamic range of 9 EVs and a color depth of 18bits.

A difference in low-light ISO of 25% represents 1/3 EV and is only slightly noticeable.

As cameras improve, low-light ISO will continuously increase, making this scale open.
^^^ Not quite 2 stops...

1256 + one stop would be 2512. It would be something like a 1 1/3 or 1 1/2 stop increase.
^^^ Not quite 2 stops...

1256 + one stop would be 2512. It would be something like a 1 1/3 or 1 1/2 stop increase.

yeah. I realized that and changed it. thanks for pointing out my mistake.
FWIW, the exact difference is +1.246EV

log base 2 (2980) - log base 2 (1256)
I would absolutly go with the D600.
Get a used 24-85m VR lens which is the D600 kit lens.
I own it and its very close to the 18-105mm VR performance, good lens.
This lens used goes for around 350$.
I got mine mint on kijiji for 325$.
I was going to buy the D600 until i saw how tight the auto focus points were in the center of the frame, ok for portrait or lanscape photgraphy, but not so much for sport or other fast moving objects.

The D600 also gives up a stop of shutter speed having a max shutter speed of 1/4000.
The D7100 max shutter speed is 1/8000.

Most reactions