Would a different body help me with noise reduction?

Question

I've been spending time shooting people ballroom dancing under subdued lighting (without a flash or other lighting controlled by me). The kit I have been using for doing this is my Nikon D7500, paired with the Nikkor AF-S 18-140mm VR DX lens, and I have been shooting handheld (as these people move around all over the place, and I have to track them, and compose my images on the fly)

This is a section of a typical exposure that I would make:

The settings for this particular image were:

• ISO 6400
• Shutter 1/125
• Aperture f/5.6
• Focal length 130 mm (for 195 mm full frame equivalent)

The sample represents 1024x1024 out of an RAW size of 5568x3712 (and yes, I know it is slightly out if focus). Also bumped the exposure a bit when when converting from RAW to this sample, as the RAW was still fairly dark.

As can be seen the image is very noisy.

As I want to keep shooting with this style and subject, I'm looking at where best to direct my efforts to capture similar image with substantially less noise. I've already invested in ON1 NoNoise AI 2023 to help with post processing (and while it does a fantastic job of noise reduction, it can't perform miracles).

The first thing I can think of is that I should have reduced the aperture to 3.5, which should have allowed an ISO of either 2000 or 2500 (based on my D7500). I think that would be the best option with the kit I have. However, in hindsight I still want to bump the shutter speed to something like 1/250, which means that I'll be back to an ISO around 4000 or 5000 to get an equivalent exposure.

A different lens could get me down to f/2.8, which would let me get away with an ISO in the 3000's, but I suspect that my current body would still have significant amounts of noise in the images.

Thus I think my questions boil down to:

• Would a different Nikon body exponentially reduce the noise in my images, and if so, would it be another crop sensor body, or a full frame body?

• Would going mirrorless help at all?

• Am I fundamentally damned by physics, and no technological solution exists to my problem?

Answer 1

With most relatively modern Nikon DSLR's the primary factor in image noise is light/image area... more light is less noise. The ISO is not causing noise; it is only making the noise more visible (image brightness). Similarly MP/pixel size is not causing noise; it is only making it more visible (at 1:1 zoom).

With digital "light" and "exposure" is aperture and SS; but it is also sensor size. I.e. the same image, at the same brightness, but at a larger physical size (sensor area), IS more light.

• A FF sensor will gain you ~ 1stop advantage.
• A FF BSI sensor will gain you a little more, maybe ~1.5 stops.
• A 135/2DC will gain you 3 stops.
• A 70-200/2.8 on FF BSI will gain you about 3.5 stops.

If you have to crop for composition you are discarding light; the same as using a crop sensor vs FF.

Answer 2

Other than the one stop or so you gain when going from an APS-C sensor to a FF sensor, the difference between different camera models is fairly incremental. From one generation to the next of the same model series is rarely one-third stop better. Competing models in the same price range with the same sensor size are similarly usually very close to one another in terms of low light performance.

Faster lenses are where you can significantly increase the amount of light entering the camera without sacrificing motion blur caused by longer exposure times. There's a four stop difference between shooting at f/2 with a FF camera and f/5.6 with an APS-C camera or f/4 with a Micro Four-Thirds camera. That's SIXTEEN times more light, which is the same thing as sixteen times more Signal when computing the signal-to-noise ratio, or SNR (S/N). Even going from f/4 with an APS-C camera to f/2 with a FF camera is eight times more light passing into the camera for the same exposure duration.

Sensors haven't improved 3-4 stops in the past 20 years.

I've been shooting with full frame bodies for well over a decade now. Most of the time f/2.8 zooms can do the job. But when the light gets dim enough it's time to pull out the f/1.8 and f/2 primes. Of course it takes a bit more skill to manage the much shallower depth-of-field at f/2 than at f/4.

Answer 3

My 2 cents.

You can try shooting a flash to the ceiling, of course, this depends if the ceiling's light color. If it is high, maybe more than 5m the light will be less, but it will look more natural.

If you are a known photographer in the ball room, maybe you can put some other remote-triggered flashes across the room.

One lens that Is interesting is the Sigma 1.8 50-100 mm. The range is not that great but you will retain some zoom capability.

And a third option is that you get good denoiser software. Neat Image and Topaz have a good reputation. Probably some for Lightroom or DxO.

This is Neat Image right out of the box.