Blown Highlights on S2!

[Ron Green]

This is really just a conversation starter about film vs. digital when shooting bright white. Although it’s somewhat rare, the biggest problem with all digital images (video or still) is blown highlights as shown in this example. Underexposing doesn’t really work either. Remember when people couldn’t wear white shirts when they appeared on television under bright lights? Well, they still can’t wear white feathers in bright sunshine. Slide film would have easily handled the dynamic range in this scene, digital failed. How are you dealing with this problem?

[Seachicken]

Interesting post, but is it really true? According to the figures at least, it shouldn't be a problem.

Firstly, I assume you are shooting in RAW. If not, there's your answer!

RAW images on the S2 have a dynamic range of 8.9 stops (or 7.5 stops) depending on whether you believe this "scientific test report" (http://www.uschold.com/pdf/Report%20SLR%20Public%2009.02%20N.pdf) or Thom Hogan (http://www.bythom.com/s2d100.htm). Color slide film is reputed (http://www.photonaturalist.com/gallery/print_info4.html) to have a dynamic range of 5 stops, and color negative film around 7 stops.

.. so I reckon with RAW mode you should be in business with the underexposure trick to fix this... or at least as much business as you would get with slide film.

Andy.

[Tom V]

For the most contrasty subjects, I use RAW files converted with RAW File Converter EX, either in 24bit or 48bit mode.

I haven't had much problems with contrast at all to tell you the truth. The most difficulty I've had was with a shot I was not expecting it on: A bunch of pastel flowers. The deep green shadows and the near-white, delicately textured flower petals presented quite a range. I was not able to position a light above the shot in order to penetrate down to the stems because of shiny plastic objects also in the shot.

I posted the shot and a discription about it in another forum here.
http://www.s2pro.com/forums/showthread.php?s=&threadid=83

I am sure that you lose range using .jpg compression - there is no way the compression scheme will retain the few fine details in the highlights. The more compression, the more detail you lose.

I am getting more range out of the digital camera than I would with slide film.

[Wichita Wayne]

B&W film has a tne range that seems much greater than color film or digital sensors. Kodachrome is based on filtered B&W layers so it also has a tone range that approaches B&W film. This is one of the things that makes a good B&W print look so wonderful. The tone range is much closer to our eyes than color film or digital sensors.

Wayne

[Seachicken]

http://www.andrewfinch.com/dynamicrange.jpg

All these images from one raw file... seems there's a fair bit of latitude there.

[SSonnentag]

Seachicken, I am impressed! I haven't played with raw files all that much, but I am now seeing the true advantage to shooting in this mode. Looks like I may be in the market for a larger hard drive. ;)

Shawn

[jknights]

Shawn,

You really must try the RAFs.
It gives you sooooo.....much more.

A SeaChicken has shown the felexibility is much greater in his post.

However the Fuji S2 produces really big RAFs = 12,8MB (6.1MP CDD) compared with my Nikon D1x NEFs at 7.2MB (5.7MP CCD)

I'm not sure why there is so big a difference in file size. I guess it is just the algorithm used in camera.

I'm waiting for the 1GB CF cards (80 shots/3 rolls of film :D ) to come down in price or else for Pretec to release their 2GB card as that will be really great.

[jknights]

Wayne,
Agree with you B&W has a greater logical dynamic range.
10 stops in the Zone System. That is dependent on processing and exposure being absolutely correct.

Tests with my D1x indicate that I get an 8 stop dynamic range.
I must re-do the test with the Fuji S2.


Correct exposure is the key in digital and film.
However in digital the rule is never over-expose or try and keep the highlight from 'over-blowing'.

In film it is the reverse.

[Tom V]

When I shoot transparency film, I "expose" for the highlights. I am careful about getting the proper exposure so the highlights do not blow out.

When I shoot b&w or color negative film, I "expose" for the shadows. I am mindful about getting enough detail in the shadows I care about, and the highlights will take care of themselves, due to negative films' typically wider exposure latitude.

When I shoot digital, I "expose" according to the histogram, but think about it as if I was shooting transparency film. I watch the right side to make sure I am not blowing out highlight detail (I don't worry too much about blowing out specular highlights). I usually shoot RGB TIF files, but I dread waiting for the image to "PLAY" in order to check the histogram. I find it easier and faster to shoot a JPG just to check the exposure on the histogram. If the exposure is OK, I switch back to RGB TIF, if the exposure is too contrasty (histogram levels overflowing left and right), I adjust my lighting and/or switch to RAW.

I find it too risky to use the Preview with Histogram Mode. I often forget to save the image after looking at the histogram.

[Seachicken]

As for me, I only shoot RAW.

All that extra information is worth the extra fuss to me. Sure they are not as convenient as JPGs... but the extra 'digital darkroom' work involved is nothing compared to what the real darkroom equivalent used to be...

RAW gives you a chance to adjust exposure, contrast and color balance after the fact. without doing damage to the image quality. Also (and this is just a suspicion), I believe that RAW files have less tendency to have moire problems (others seem to believe this too), and possibly other artifacts introduced by in-camera image processing algorithms that have to use shortcuts because the user wants that image on the CF card NOW!

Tom, I wonder why you favor TIFF over RAW? I haven't used TIFF but as far as I understand it, a TIFF file is an 16-bit image file containing a lossless rendition of the RAW image, but filtered through the cameras color balance, tone, and sharpening algorithms. Kind of similar to RAW but HUGE and presumably slower to work with.

The camera's tone, color balance and sharpening settings are embedded in the RAW file, and then applied as the default by the RAW file conversion program (which has your PC's horsepower at its disposal - so has the option to employ better algorithms). It kind of reminds me of levels of undo in photoshop.. with a RAW file, you can undo all the back to the start.

I guess with a TIFF file you can open it directly in an image editor. I'm surprised that dynamic range is lost with the TIFFs. They are 16-bit, so could in theory hold it all.

What I don't like about RAW files though is their size. 6MPixels x 12bits = 9MB
+ an embedded jpg image = 9.5MB .. that's the size of the D100 RAW file.

Fuji use 16bits to store 12bits of info, leaving 4bits unused! .. so 3MB of the 12.5MB raw file is just waste .. and CF cards are expensive! Perhaps this makes the files faster to process in camera.

Anyway, that's my tuppence ha'penny worth. Actually, looks a bit long.. more like thruppence worth!

Andy.