TriX Loc: Raleigh, NC

Rich and Ron,

I’m not trying to be a spoiler here. We’re having a technical discussion here over the advantages/disadvantages of a technique, and if that is “pushing my luck”, then so be it. If you propose a particular technique, then I think you’d be open to an unfettered technical discussion. I haven’t insulted anyone, just questioned the premise behind it, and if you find that disagreeable, you can ignore me on future posts if you wish, but that’s hardly in keeping with a free and open forum.

This particular technique isn’t useful to me and many other shooters because I/we don’t have an ISO invariant System, but I am quite interested in the technical aspects, and since I don’t “have a dog in this hunt”, I’m perfectly willing to adopt your position if you demonstrate an advantage. My point is under what circumstances does it actually IMPROVE the shot over just setting the ISO appropriately? From Gene’s postings and from every thing I’ve read (referenced earlier in the thread), the advantages accrue mostly in low light or night scenes (the referenced article specifically mentions this) and offers the the following benefits: 1) it allows you to accidentally underexpose and save the image in post (2) it allows you to selectively edit the photo and potentially increase the DR in specific sections by masking, curves, etc. What neither you or Gene or the author of the article Gene referenced earlier in the thread have demonstrated (yet) is that it actually IMPROVES an image taken under normal circumstances.

Again, the premise is that ISO and DR (and noise) are inversely related, (and this is shown in any ISO vs DR graph), so shooting at a lower ISO results in lower noise. The point that is missed is that raising in post accomplishes has exactly the same effect as raising the ISO - when you multiply the signal, you multiply the noise as well, and if you do this in SW, then multiplying the individual pixel values or gamma has exactly the same effect on both whether you do it in-camera or after the fact. Further, if the particular camera uses an amplifier between the sensor and the A/D, then not using the ISO amplifier decreases the signal to the A/D and actually diminishes the DR since the maximum DR of an A/D is realized when the signal just reaches the most significant bit (MSB) - anything less just “wastes” the DR of the A/D.

This will be my last comment since it seems to be redundant, but my challange still goes: post an unaltered shot underexposed by 5 stops (or whatever) at base ISO, the same “correctly” exposed shot, and the underexposed shot changed ONLY by increasing the overall gamma - no masks, curves, etc., with EXIF information and demonstrate an improvement, not merely that you can “save” an underexposed shot. If you demonstrate an IMPROVEMENT, I will gladly reconsider my position. Ron, I thank you for an interesting technical discussion and hope my critical comments haven’t been unwelcome.

Cheers,
Chris

blackest Loc: Ireland

Pull down the highlights and raise the shadows , probably :)

The usual problem is blowing highlights but having them recorded at lower values makes for detail to be recorded that might otherwise have been lost. If all you do is bit shift and increase the gain on the recorded image there probably is little difference if you do it or the camera does it. But you can be selective.

The film way would be to use a graduated filter to pull down the highlights but that would pull everything in the upper region down. Now you can just adjust the brightness of the brighter pixels. You can be selective. Potentially the result will be better.

Maybe a 1 shot hdr if you like, of course you could blend 3 shots if the subject is stationary, if not well perhaps this will work.

Rongnongno Loc: FL

No, you got me wrong. I just do not understand when other folks state that their experience are similar to mine you still try to put it down. Personally i just try it myself when I am not in agreement and I see other folks agree. Part of the mechanism that makes me progress in all fields.

It is not about 'saving a shot' but about using a new technology. My camera is a measly D500. I posted a few images already (playing with a D500*) with print screens that illustrates what it can do. Apparently the D850 does the same thing, better. I do not have this camera so I can only wait for someone to post the same thing you ask. Not to verify, I know it works, but to see how good it really is. I even made a call for that to no avail.

I am not willing to purchase a D850 just for a damned test. I am planning the purchase one in about six months (after most users give a less than enthusiastic feedback and the real appreciation takes hold).

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* I even offered the .NEF for download but no one took the offer so...

TriX Loc: Raleigh, NC

Thanks Ron (I swear I won’t post again...). Nothing “measly”about a D500 - one of the top 1 or 2 crop cameras in existence - wish I had one (and a D850 as well).

Cheers,
Chris

Fotoartist Loc: Detroit, Michigan

You're right, that's it. Ensures against blowing highlights. Which is a more serious error than underexposing the shadows.

blackest Loc: Ireland

I hope so :) I was reading tete a tete portraits by henri cartier-bresson and some of his portraits half of someones face might be black in shadow. Maybe it was a bad copy but he seemed to get away with having fairly high black levels, so it's at least tolerable :)

Rich1939 Loc: Pike County Penna.

"As an old dog with not so steady hands anymore, just knowing that if the situation calls for it I can use faster shutter speeds with out raising the iso(noise) makes me a happy man. It also means smaller apertures are back in play"

since you don't use raw files it won't help you as adjusting jpgs in post is limited.

dsmeltz Loc: Philadelphia

[quote=rehess]<snip>(2) More and more we are seeing sharpness, what I call "needle sharpness" because it seems almost like an addiction, as a basic requirement images are measured against. Combined with (1) above, photographers have to go to higher ISO values so they can go to higher shutter speeds.<snip>/quote]

I think you hit the nail on the head with this one.

Advances in technology have raised the bar on what is accepted as a "good" shot.

Fotoartist Loc: Detroit, Michigan

Needle sharpness is in. Selective sharpness is out. Just a fad?

Rongnongno Loc: FL

Make a thread out of this.