Sunday, June 12, 2011

D700 versus D7000 – A low light ISO ladder in very balanced light …

My previous article shot the D700 against the D7000 in some pretty awful light. The results showed that the D700 retained a lead of perhaps one stop, but that the D7000 was very competitive. Sports shooters in gyms might find it acceptable with the right glass. Not quite as good as the D700, but more than serviceable.

So now we should be wondering if that prowess is going to carry over to the more balanced light of gyms with windows or perhaps outdoors in shade or in the evening. Admittedly, temperature does cool off, but that’s probably better than the crazy warmth of the last ISO ladder.

In the last test, I almost crippled the D700 by shooting the same lens on both from the same position. This time, I shot the D700 with the Nuikon 85mm 1.8D and the D7000 with the 50mm 1.8D from the same position. This puts the field of view (FOV) very close and takes care of the equalization that hurt the D700 last time.

But the equalization in pixel dimensions still has to happen. So, presuming that we are shooting for sports posters, and since we are in pretty good light (low, but somewhat well balanced) I upsize the D700 to match the D7000 pixel dimensions. It’s not that far to go from about 4200px to about 5000px, about 20% or so … and that’s hardly anything to a camera like the D700.

Methodology this time was AF on each image, self timer from tripod … the usual. Distance was the same, which equalized FOV well enough. Both lenses were set at f/5.6 which maximized sharpness and simulates a kit lens wide open to make this more interesting for the majority of readers.

Since that is is 5590 pixels across, you really want to click through and make sure you tell your browser to display it full size (if you see a cursor with a plus, click again.)

Some observations:

  • It appears that the D7000 with 50mm has a slight back focus issue (about one crayon diameter.) But the wool is in focus and so is the coin. So ignore this.
  • Looking at background noise on the left side of the wool, you can see about 1.5 to 2 stops of difference. The D700 is an older generation sensor, which shows more in bad light than in good. Here, the huge photo sites can really stretch their legs and deliver a bit of a spanking to the baby brother.
  • Mid-tone noise (look at the crayons) is pronounced on the D7000 by 1600 ISO. Still well within acceptable limits for enlargements, but obvious at 100%. Again, the D700 shows similar noise at about 6400 ISO. Note, though, that Nikon has made the noise even finer than with the D300 and D700, which was one reason that they were such a revelation in low light. So the D7000 noise is very easy to deal with.
  • Bottom left corner of the wool – the frizzy part retains excellent detail to 1600 ISO on the D7000. It starts to lose definition quite dramatically at 3200 and is really soft by 6400. The D700 retains that detail right up to 12800, which is close to 3 stops of difference. Clearly, the D7000 cannot really replace the D700 as an evening sports camera outdoors.
  • Tiny details on the crayons (e.g. the first fully visible crayon on the left) are essentially suppressed by noise at 1600 ISO. So they are really good up to 800. On the D700, they are still somewhat visible at 6400 ISO. Again a three stop difference.
  • Saturation is excellent throughout for both cameras.

I think it is pretty obvious that the larger photo sites are able to assert themselves in well balanced light, despite the disadvantage of being an older generation of sensor. This should not be a surprise to anyone, but I’ll bet that it will be. Especially for those who think that they have an FX-lite in the D7000. Well, they don’t.

So what does this all mean? It means that you will start losing definition in hair and skin texture as ISO is forced to rise. If you shoot the D700, you will be able to retain these details up to three stops higher, and that’s a pretty big advantage.

But in a more practical sense, the D7000 is pretty good at 3200 ISO if you know how to process noise. If you have the D7000, then you really need to think about maximizing the speed of the lenses you shoot. Forget the 70-300VR and grab a used 80-200 2.8, the push-pull variety often goes for 500 bucks. And that is two stops faster than these tests used. That is a huge shutter speed advantage in the field. Or try the 85mm 1.8D, which is razor sharp as early as f/2 … that’s a three stop advantage.

And if you do this with the D700, then you will be getting some wicked imagery with super high shutter speeds.

Anyway, good luck. I hope you enjoyed this pair of articles. I always like to be surprised and the bad light prowess of the D7000 is a great thing. Even in this ISO ladder, the images are not half bad at extreme ISOs.

As I demonstrated in the last article, a little processing can go a long way. So here are two images at 25,600 ISO. Yes, you read that right. Even the D7000 can shoot there and the results can be usable after processing. No kidding …



The D700 was a bit easier to process, but both worked out very well. For snapshots for the web, this extreme ISO can actually be used, even on DX. Wow …

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