Tim Hoover

Wrong again. The image information contained in either file is a set of RGB values at each pixel. How that information maps to the original scene is what varies. This mapping is degraded (i.e. there is an information loss relative to the original scene) in JPEG files due to the processing and file compression that is performed. Oh, and of course there is also an information loss, relative to the original scene, in the RAW file, it's just less.

OK - that's it for me. No more posts on this thread. You're welcome.

R.G. Loc: Scotland

I would have to see how recoverable the shadows were in #1 before I came to any meaningful conclusions. The pushing and pulling of PP can hide all sorts of things. HDR processing (lift shadows, lower highlights etc) will typically result in a loss of contrast, while adding contrast does the opposite (push more detail into the shadows and highlights).



Shouldn't the comparison have been between raw files?

Anyway, both of the comparison shots have noise, and it would have been less noisy if proper exposure had been achieved by capturing more light at base ISO.

Definitely a thought-provoking thread . I'm going to make sure that my next camera is ISO-invariant.

RRS Loc: Not sure

The sensor sensitivity is set in stone when made or produced. The setting (changing) of the ISO is an electrical amplification that you can look at like a volume control on a radio, turn it up so you can hear or turn up (ISO on camera) so that the computer will produce an image corresponding to the shutter and aperture settings that you have made.

PGHphoto Loc: Pittsburgh, PA

At the cost of time spent in PP, you can certainly get an ok shot. I am not sure how similar or dissimilar the camera signal amplification is to the algorithm used by a Lightroom or other PP software so if one is more effective or yields higher IQ, then that is the one which should be employed. (I unscientifically would expect that the camera version of amplification would be better paired to the sensor and yield better results but thats just a feeling.) With your specific example, the use of high ISO to get your correct out of camera exposure lends itself to less sharpness due to noise confusing the detail between light and dark. So the image quality assessment compares something that is not optimal as a standard of comparison.

I think I understand your premise to be that PP can be fairly effective at correcting for sensor sensitivity (ISO) but to suggest that one would probably be able to pick an ISO and use it there for every situation does not take into consideration the optimal result that could be attained and doesn't address that different camera sensors have different DR capabilities.

I appreciate your post and think it did bring the mechanics and impacts of DSLR ISO out, but maybe I am reacting more to the suggestion that ISO can be adequately addressed in PP and we need not be concerned with ISO in-camera unless it is outside of the +-3 EV range you identified. Just saying there is more than EV which needs to be evaluated to support the suggestion you made.

twillsol Loc: St. Louis, MO

Yes, that is so. But the OP said that there is no difference in shooting at ISO 200 or 1600 when shooting RAW. There is a big difference as the magnification is done at the time the RAW file is generated. So the two raw files would be different and they are.

selmslie Loc: Fernandina Beach, FL, USA

She did not say that and neither has anyone else.

Her statement was that, "...taking a shot with ISO 1600 or 200 makes no difference if you are shooting raw." That does not mean that both raw files are the same. It just means that the final results may be indistinguishable.

twillsol Loc: St. Louis, MO

If you go back to her original post, the end of the second sentence says. "So taking a shot with ISO 1600 or 200 makes no difference if you are shooting raw."

Am I misinterpreting this statement?

CatMarley Loc: North Carolina

Yes one file has no additional electrical noise caused by electronic amplification. That is the file which was taken at the sensor's base output (in the Fuji = 200) The other file contains additional noise data introduced by the analog amplification. (the file which was taken with an ISO higher than the base.) What I said is there may be no difference in the visual quality of the ultimate jpegs or tiffs produced, one from a raw with analog amp, and one from a raw where the amp was applied digitally during conversion.

twillsol Loc: St. Louis, MO

then I misunderstood you. Thanks for clearing that up.

I must admit, this is a very interesting post and I have enjoyed reading all the responses.

RRS Loc: Not sure

Right on, I agree.

CatMarley Loc: North Carolina

Not if you take the words out of context. The context of the post was the quality of THE FINISHED PRODUCT i,e, what you will see on your big screen or your print. The steps one takes to arrive there are obviously different. The raw files are different, the initial jpegs automatically made by the camera are different, but the final jpegs, after all the messing about, may be indistinguishable, and therefore the route taken (ie shooting at 1600 or 200 and everything in between that and the finished product) makes no difference. Does that make it clear? Or have I tumbled down the rabbit hole into camerageek land, and become completely unintelligible to the folks up topside?

2mdman

Interesting. I usually now try to shoot under-exposed (i.e. lower ISO) to avoid highlight blowout and recover what is needed in post-processing. That goes against the "shoot to the right" philosophy that I used to use. I just worked on a picture that I took years ago that was extremely underexposed. It was amazing to see the detail I could get after adjusting it in Photoshop. With overexposed, you're blown out and can't recover any detail.

CatMarley Loc: North Carolina

Yes! I always did that with slide film - slight underexposure gave much better results in a projector, which was the way we viewed most of those slides. Negative color film was the opposite. I did a bit of color printing. You had to be pretty much spot on with your negative to make a nice print. With digital you have almost unlimited ability to lift detail out of darkness. It is almost magical!

rafael izakov

Is it right that you used Manual (M) setting?
By my knowledge if using M setting you instal any combination such ISO, F and S or T (shutter speed) and camera itself used it.
ISO 1600 and 200 mean different 8(eight) times, so exposure will be overexposure or underexposure.
You stated the different 3VE.
This I am completely don`t understand.

DaveC1 Loc: South East US