K10D - underexposed images

Dear Iceblinker

Few points -

1 - I perfectly understood the article, the last sentence of which is - " “Exposing to the right” is an advanced technique that many experienced photographers are still getting used to, so don’t worry if you find it confusing." -

These are not my words, but the author's. I don't think the article is contraddictory, because it clearly states that it all applies to a RAW image, rather than a jpeg one.

2- This is not my personal opinion, its the opinion of an expert, that writes for a digital photography magazine. I therefore take it as TRUE (unless diproven by a higher authority in the field...) - it not really a theory - there is actually physical evidence for the calculations metionned.

3- I think that the article proves one essential point that differs from your's and hefty's;

A digital image which is UNCOMPRESSED like a RAW file, will have more levels on the right side of the histogram, and therefore, it will retain EXPONENTIALLY more information than the dark side of the histogram. There isn't more detail in the shadows, there is more detail in the highlights. (Obviously what you say about "clipping" is true - see point 4)

4 - The article is not meant to be for an "uninformed" public; It talks about a particular condition when a photographer uses manual settings on his camera (or Av/Tv) and shoots in RAW - which is already somewhat advanced. This OBVIOUSLY doesn't apply to any photographer who is not concerned with absolute quality of image, unlike a professional.

Regarding the "clipping" advice; this technique will apply in cases where - whilst exposing a shot - the photographer will have a choice of various settings, and the ability of not buring the highlights. Say you are a landscape photographer and you have a window of various apertures that can more or less correctly expose the photo, and you decide (according to ETTR) to go the overexposed side of the exposure to maintain more detail. This does not apply to a walkabout technique, nor an un-experienced photographer.

5 - on a more personal level: I did not inted to offend what you or any other member of the forum that has said about this topic. I tend to read every single topic that comes about, and very rarely make a comment unless I actually know exactly what we are talking about. I like this forum because it is very professional, and usually the advice given comes from very experienced photographers- and not people that don't know what they are talking about.
THis is why I did not give my personal opinion on the matter (I am learning - not teaching) but only took a good half hour to rewrite an interesting article that would provide a professional opinion on the matter - opinion which (in part) differs from what was said previously.

I hope you haven't been offended by my posts, I was only trying to provide serious information to the other readers!

CHeers,

Nathan

I deal with this issue regularly.

In another thread, I posted a photo of my grey card.
I made that by taking a solid black peice of mattboard, a solid peice of white mattboard, a kodak greycard, and a strip of (my favorite photo paper, printed on MY printer) black to grey to white (16 tones) paper.

taking a tightly cropped photo of that card:

Your in-camera meter if it gets a perfect exposure (seldom does):
is to get three spikes, on the histogram, one for the blacks, one for the greys, one for the whites.
black at the left edge, grey just left of center, white at the right edge, with no clipping......

exposing to the right:
is to adjust your exposure to get the blacks just a bit more to the right of the edge, your greys a bit over to the right of center WITHOUT pushing the whites past the edge on the right of your histogram.

This really helps to get midtones, and shadows without noise or colorcasts in your final image after processing the RAW file.

Nathan, the only offence I take is the suggestion that the advice in the article contradicts the advice given in this thread. I do not see that it does.

There being more "levels" towards the right of the histogram is academic if you HAVE to underexpose in order to preserve the highlights (when that is what you want to do). In this case, you HAVE to extract and push some vital info from the left.

I'm also concerned that you are putting too much faith in one person's expertise. You need to read more opinions and combine them (and combine them with your experience) to draw your own conclusions and to get the whole picture.

Great,
So no offence taken there, it is only a matter of understanding what one or another opinion states!

Please don't worry about my ignorance, I tend to read a lot, and when a topic is of my interest I never rely on one single opinion, and tend to read as much as I can - whilst also experimenting in practice....

THese are some links on the topic - they are all very interesting!

http://www.adobe.com/digitalimag/pdfs/linear_gamma.pdf
https://www.luminous-landscape.com/tutorials/expose-right.shtml
http://www.luminous-landscape.com/forum/lofiversion/index.php/t9510.html

Happy (not-too-much-overexposed) shooting to everybody!!!

Nathan

Indeed, and that's not easy with such a complex subject as this.

Cheers.

Great idea, Don. I missed your other post. I'm ceratinly going to try this.

Ken

Well I've just tried a very simple test and it is interesting but very inconclusive as I had very limited material (ie lean out of window shoot trees plus grey sky) and I don't think that's a fair test.

That said EV+2 adjusted in Silky reports no blown highlights while standard exposure did and the image looked OK when I fiddled about with brightness etc. I don't think I hav ereally taken this in yet.

I read this thread with some considerable doubts but now I'm wondering and thinking which can only be a good thing. I can see more trials coming on in more interesting light.

As an aside how do I adjust gamma in PS or Bridge please?

Mike

Yesterday I finally saw the 'blown highlights' warning - the corresponding parts of the image (sky at sundown) flashing red.

I also understood one more thing: if there is a big difference in exposure values for different parts of the image (sky at sundown at 1/640s and dark trees at 1/50s both with f/2. then the exposure must be corrected so the sky is not white. But this leads to the trees becoming very dark. I don't remember having similar problems with slides... do they have higher dynamic range that k10's sensor (fuji sensia 100)?

You'll find that film (slide and print) generally has a larger dynamic range than any digital sensor currently on the market, however, digital technology is still comparatively new so don't be suprised if this situation is reversed in the near future. We may not be there yet, but I bet there's a scientist somewhere working on it as I speak...

The dynamic range is about the same... however, film does not fully saturate as you approach the highlights. In contrast, the CCD being basically linear in response, will hit the blown highlights and stop there.

That's why there's so much talk of slightly underexposing when on digital. You can quickly correct the scene, and even simulate film response curves (as Silkypix does). But once you get the blinking red highlights on the LCD preview - there's absolutely no information there at all.

You will find, though, that "pushing" a digital shot into the "correct" exposure - raking detail out of the shadows - is a far, far cleaner thing than on film. Likewise, high ISO on digital is much cleaner than film (e.g. Fuji ISO1600)!

Just a case of slightly re-learning the bounds... that's all
Matt

Yes, I tried to play with the exposure correction and it seems that I'll have to use it much more often than with the slides. Basically pushing it to longer exposure than the multi segment metering is suggesting - but not too far to get the highlights saturated (in most cases) nor to have no dark areas. Of course there are exceptions when one wants to have either dark or bright areas saturated.
Anyway, considerably more time will be necessary for image processing...