MW

Many cameras now will correct chromatic aberration, distortion and vigneting. Example D7100. However, I had a conversation the other day where I said I thought these corrections were only applied to jpeg files whereas the other party claimed they were applied to the RAW file as well.

Anyone here have an authoritative resolution to the disagreement?

daveboy9582

No expert, but I am going with you.

Rongnongno Loc: FL

raw prevents all form of camera processing regardless of setting.

Capture48 Loc: Arizona

First don't ever do this in camera. Getting rid of noise in camera does not work very well, and the algorithm will prevent you from doing it in PP later. I assume the same is true for Vignetting & CA.

DavidPine Loc: Fredericksburg, TX

Raw really means "only sensor data". There is no editing within the camera. The camera interpolates data to show you a Jpeg image. If you shoot Jpeg and edit within the camera you can really screw the pooch. Best results will come from shooting raw and editing in post photographic processing.

SonyA580 Loc: FL in the winter & MN in the summer

Wikipedia says that Nikon automatically does some noise suppression to all RAW files. But, the Nikon D7100 manual says that RAW files are sent directly to the storage device. Either way, doesn't look like the photographer has any input.

MW

Sounds like my understanding was correct for once. Thanks for the info.

malco555 Loc: Kenilworth UK

At last! The light came on! No need to apologize Ron! :-D :-D :-D

Rongnongno Loc: FL

Symphony for an horse ass.
This one is even better. 10 hours of the same thing, something we are all familiar with when it comes from 'teachers' en 'mensa' claimers.

:lol: :lol: :lol: :lol:

rook2c4 Loc: Philadelphia, PA USA

Interesting question. The RAW editor that I primarily use includes various manual controls for correcting chromatic aberration, distortion and vignetting. Because of this, I have always assumed that cameras do not apply any of these processing corrections on their RAW file output, only on the jpegs. Or perhaps just as a default setting that one can override/alter in the RAW editor.

amehta Loc: Boston

There is high ISO noise suppression and long exposure noise reduction. I believe the long exposure one is done before the raw data is saved, but the high ISO one is only applied to jpegs.

amehta Loc: Boston

If you use the camera manufacturer's software, these changes can often be applied to the raw file exactly as the camera would.

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

No corrections can be applied to the raw file.

Apaflo Loc: Anchorage, Alaska

Why would you surmise that no "editing" (lets call it processing instead) is done to the sensor data?

The real distinction between a RAW file and anything else with that the raw sensor data has color encoded with a Bayer Color Filter Array. That's it. It can be processed in any other way (noise reduction, chroma aberration reduction, vignetting reduction, and even color or tone mapping too may not be common, but are possible with raw data) and still be just as RAW as RAW can be!

The processing that makes the data no longer "raw sensor data" is demosiacing, which produces an RGB color encoded image. There is great significance to that process because while raw sensor data can be used to produce a nearly infinite number of different images, an RGB image is just that: it defines one specific image. And the process cannot be reversed, so a RAW file cannot be generated from a JPG (simply because the JPG image doesn't have the data for the other bazillion potential images the original raw sensor data could correctly produce).

Nikon cameras typically process raw sensor data in two ways that can be controlled with camera configuration. One is "Long exposure noise reduction", the other is "High ISO noise reduction".

The first, Long Exposure NR, can simply be turned on or off. It operates only when the shutter speed is 1 second or longer. When enabled the camera makes two exposures, one with the shutter open and another for the same length of time but with the shutter closed. The second exposure is subtracted from the first, thus eliminating hot pixels caused by the heat generated with a long "on" time for the sensor.

The second, High ISO NR, can be configured for High. Normal, Low and "Off". The "Off" selection is interesting, because it does not turn it off! It reduces the NR to something less that the Low setting, and it is only applied at and above a specific ISO (the D4 is ISO 3200 and the D800 is ISO 1600, for two examples).

Those are the raw processing modes that a user can control, and that we know about. We have no idea what else Nikon, or any other company, actually does to the raw sensor data before it is saved. It is very likely that output from each ADC is also adjusted too, and that it is factory calibrated individually for each camera!

Apaflo Loc: Anchorage, Alaska

Except for the corrections that are.

Noise reduction is one example. But it is also very likely that each camera manufacturer processes raw sensor data in other ways, but since it isn't user configurable we just aren't told about what it is.