HDR - Sample and a question - DPChallenge Forums

02/16/2007 11:19:30 PM · #1

Here is a new try.

Original

HDR

The hdr was composed of 3 shots bracketed at -1, 0, +1

The question has to do with this:

Three shots taken in raw were converted to this hdr. However, when looking at a raw in photoshop, it automatacally adjusts an underexposed image to a "normally" exposed image. For example, when viewing my underexposed raw...Photoshop raw view adjusted the exposure to 0 instead of leaving it -1. The same was true for the overexposed shot.

Before using Photomatix, I adjusted each shot manually to -1, 0, +1 and then clicked "done".

I then imported to photomatix and did the hdr and tonemapped.

My question is this ....is in necessary for me to manually adjust the raw to match what my camera settings were or will Photomatix do this on its own?

Thanks

Sony 24-70mm F4 Vario-Tessar T* FE OSS

02/17/2007 08:55:05 AM · #2

Bump for morning HDR people !

Bear_Music

Samsung Galaxy S24 Ultra

02/17/2007 10:20:37 AM · #3

I have read this several times and i really don't understand the question. But for what it's worth, the original doesn't look like it NEEDS any HDRI work. It's not a shot that appears to have an out-of-the-gamut tonal range.

R.

Neil

Fujifilm X-T30

Sony 24-70mm F4 Vario-Tessar T* FE OSS

02/17/2007 10:40:17 AM · #4

I'm not sure how you adjust a raw file except in sidecar (e.g., XMP) files, and as far as I know those aren't used by Photomatrix anyway.

Photomatrix can read the raw files and the built in metadata. Just try it and you can confirm.

Bear_Music

Samsung Galaxy S24 Ultra

02/17/2007 10:47:19 AM · #5

Further discussion: basically, HDRI is designed (or "intended) for use when the dynamic range of the scene exceeds the sensor's ability to capture it all in one pass. So, more or less by definition, the "purpose" of HDRI is to produce and image with detail in both its darkest and its brightest parts.

That's not to say you can't use the tool/technique for other purposes; whatever floats your boat, go for it. But in this particular instance you showed us an original with muddy tonalities and blocked-up dark areas. You showed us a putative HDRI version which really doesn't address either of those "flaws" in the original, except that the blues are brighter. So I'm not sure what you're doing here, but it isn't HDRI even if you used HDR tools to accomplish it.

For purpose of comparison, I have taken the original and skewed it to level the back edge of the lake/pond to a more natural line, then I have simply used Photoshop's shadow/highlight tool to recover shadow detail:

In this version I have worked off the "recovered" version above, added a sky gradient, done just a little hue/sat to brighten it up, adjusted levels for a little pop, and just for the hell of it threw in a touch of glow.

It's not a very inspiring image to work with, so that's as far as I would want to take it; these are just "studies", if you will, to show you a couple paths you can go down. The important thing is that this image doesn't NEED any HDRI to work; although I used shadow/highlight, you can get pretty much the same recovery from curves.

R.

Greetmir

Nikon D60

Sigma 18-200mm f/3.5-6.3 DC OS for Nikon

02/17/2007 10:55:47 AM · #6

erm ... what Robert said ...

There is no HUGE difference in brightness over the totality of the original photo here that begs for HDR technique.

nicklevy

Canon EOS-350D Rebel XT

Tamron SP AF 28-75mm f/2.8 XR Di for Canon

02/17/2007 11:05:52 AM · #7

Originally posted by kenskid:

Here is a new try.

Original

HDR

The hdr was composed of 3 shots bracketed at -1, 0, +1

The question has to do with this:

Three shots taken in raw were converted to this hdr. However, when looking at a raw in photoshop, it automatacally adjusts an underexposed image to a "normally" exposed image. For example, when viewing my underexposed raw...Photoshop raw view adjusted the exposure to 0 instead of leaving it -1. The same was true for the overexposed shot.

Before using Photomatix, I adjusted each shot manually to -1, 0, +1 and then clicked "done".

I then imported to photomatix and did the hdr and tonemapped.

My question is this ....is in necessary for me to manually adjust the raw to match what my camera settings were or will Photomatix do this on its own?

Thanks

The answer is you don't adjust at all. The exposure value in ACR is exposure compensation so if you set it at anything other than 0 you compensate for what you did in camera. don't let ACR in auto mode because he will detect the underexposed and overexposed images and try to correct them. If you shot three images with EV of -1, 0 and +1 in order to make a HDR out of it the intention IS to have an underexposed and an overexposed image as well as a correctly exposed one. Then you convert them "as is" removing every auto function ACR might have and you set the curve to flat. Now you let photmatix to is magic.

02/17/2007 01:45:33 PM · #8

Thanks...yours is the answer I was looking for...

When I open my 3 raw files they are "auto" checked which makes them all look about the same even though they were -1 0 +1

...so if i'm hearing you right, I should uncheck the auto function in the raw before taking it to Photomatix?

Thanks

[/quote]

The answer is you don't adjust at all. The exposure value in ACR is exposure compensation so if you set it at anything other than 0 you compensate for what you did in camera. don't let ACR in auto mode because he will detect the underexposed and overexposed images and try to correct them. If you shot three images with EV of -1, 0 and +1 in order to make a HDR out of it the intention IS to have an underexposed and an overexposed image as well as a correctly exposed one. Then you convert them "as is" removing every auto function ACR might have and you set the curve to flat. Now you let photmatix to is magic. [/quote]

Neil

Fujifilm X-T30

02/17/2007 02:39:23 PM · #9

My point (before) is that you shouldn't be going through ACR first! Take the raw files directly into Photomatrix.

02/17/2007 04:21:17 PM · #10

Ahhhhhh is that what all those xmp files are in my folder !!!

Ok...another question...

Bear_music has some shots in his portfolio that says he took one raw file and processed it 5 times at different exposures. Is this done by going to the raw file...changing what you need and then saving as tiff or other format...and then doing the process again on the raw file and name it #2 or such...etc etc...for 5 different saves?

After that, is Bear going to "generate" in Photomatix and loading those files?

If so...Is that process the same or close to having taken 5 separate shots?

Bear???

Originally posted by nshapiro:

My point (before) is that you shouldn't be going through ACR first! Take the raw files directly into Photomatrix.

Message edited by author 2007-02-17 16:22:40.

Neil

Fujifilm X-T30

Canon RF 24-105mm f/4.0L IS USM

02/17/2007 04:51:36 PM · #11

I've had some personal comm with the tech folks at Photomatrix.

They swear up and down that there's no benefit to doing that. The best way in that case is simply to bring in the one file into PM. Here's their exact response to my question about that:

Deriving "fake" exposures from a single file by changing the settings called
"Exposure Adjustment" in RAW converters never creates exposures as a camera
would have taken when set to another exposure value unfortunately. It just
clips differently the dynamic range already captured by your RAW file. So, it
is better to directly take the dynamic range captured by the camera sensors,
converting the RAW data into HDR as Photomatix currently does. Doing it in a
convoluted way by first clipping the tonal range in a multiple manner can only
add processing time and result in loss of information.

You will find more on this at
//www.hdrsoft.com/resources/dri.html#raw

hajeka

Canon EOS R5

02/17/2007 04:56:08 PM · #12

While discussing HDR, is it really usefull outside? Trying to adjust an image from one shot, ok, but with multiple exposure shots, aren't you lose too much sharpness, since there always seems to be some movement (wind, clouds, animals, etc.)?

02/17/2007 06:35:16 PM · #13

In answer to the "sharpness" question, I think you are referring to things moving in your frame. If you look at most of the HDR images at flikr.com you will rarely see a "flying bird" or "running dog"...it just doesn't work unless your camera can bracket and shoot 20 frames/sec !

HDR seems to work best on non-windy days for landscapes. I've seen some great HDR shots of buildings also.

Kenskid

Originally posted by hajeka:

Canon RF 24-105mm f/4.0L IS USM

02/17/2007 06:36:23 PM · #14

That is interesting b/c many people swear by it but I've read all over internet that it is not useful using "one" raw.

I'll keep reading.

Originally posted by nshapiro:

Message edited by author 2007-02-17 18:54:16.

hajeka

Canon EOS R5

02/17/2007 06:54:45 PM · #15

Originally posted by kenskid:

I'm referring more to branches, grass and clouds. Can't remember a day without wind and to be honest: I don't see it (the day without any wind) on most of the HDR images, shooted outside.