high dynamic range picture problem

[nikolo5]

Hello everyone !

 

Recently I got the Photomatix software for high dynamic range (HDR) pictures

making but first results are dissapointing.

As you can see from the second attached picture which is a HDR picture the

software adds some uncontrollable bright spot on the right, since maybe that

part of sky was bright on the initial picture, which is attached also (first one).

For those who are familiar with Photomatix the Tone Mapping was used in this

case to produce the picture 2. Three initial jpg files at -1,0, and +1 EV made

from a raw file were used to get the HDR file.

 

Did I miss something? Maybe I can control the appearance of such a bright spots

somehow?

If somebody have a similar experience please reply to this post.. It will be

appreciated!

Thank you!

N.B.<div></div>

[nikolo5]

Sorry I could not upload the second pictue at once. Here it is (a HDR one)<div></div>

[ronald_moravec1]

I would just clone them out and move on. The spots are probable a reflectio in the lens and the program does not know if they are good or bad.

[nikolo5]

I think it not a reflection from lens, because on the other pictures it appears as well. It is kind of bright spot or line typically between the clouds which are white and the buildings or threes which are dark. So the software make the white clouds darker than the blue parts of the sky resulting in the bright spots which are always close to the dark objects (say trees..).

How to fix it ?

N.B.

[jacopo_brembati]

The sky is too dark, and radiance recovery or tonemaping failed. <br>

I don't know if the problem is in your settings or in the product.<br>

I think you have to get somthing like this<br>

 

 

<a href="http://imageshack.us"><img src="http://img137.imageshack.us/img137/7666/00mw5z39113884newcn6.jpg" border="0" alt="Image Hosted by ImageShack.us"/></a><br/>

 

Jacopo<br>

[steve_dunn2]

<p>You said you made three JPEGs at -1, 0, and +1 <em>from a RAW file</em>, singular. You didn't say <em>from RAW files</em>, plural. So the implication is that you took one shot, made three JPEGs from it, and then merged them using your HDR program.</p>

 

<p>That's the origin of the problem. The scene's dynamic range is likely too high for a single shot to capture. Look at that area of the sky in your -1 JPEG; is it also blown out? I'd expect it is. And so it's unreasonable to expect that it won't be blown out in your final picture. HDR software can't extract detail that simply isn't in the files you feed it. You could get a very similar result from your single shot without HDR software by careful use of RAW converter settings followed by some manipulation in Photoshop.</p>

 

<p>To fix this particular image, there are some things you can do. Select that section (and either work on the selection directly, or make it a new layer and work on the layer; either way, we want to affect that area without affecting nearby things like the trees) and manipulate it manually. Dodge it, or clone onto it from a nearby area that isn't burnt out, or use Levels (which I've used a bunch of times to manufacture blue sky out of a burnt-out area).</p>

 

<p>To do HDR properly, you have to take multiple shots, with different exposures, with your camera. For instance, if you take a bracketed sequence at ±2, you will likely get detail in every part of the scene in at least one of the frames. You'll want to use a tripod to ensure the composition doesn't change, and you might have some issues if some of the things in the scene (kids, trees blowing in the wind, etc.) move between one frame and the next.</p>

[cjmalcolm]

Yes it's likely your -1EV exposure still had the sky blown out, as Steve said you will likely do

better by bracketing at +/- 2EV.

 

Always check your histograms before completing your shots to make sure there is absolutely

no clipping, sometimes it's prudent to to get another exposure at say +/- 4EV or more if

need be.

 

Also it's better practice not to use JPEG's, rather your original RAW files or refined TIFF copies

to load into Photomatix or Photoshop.

[nikolo5]

As I thought when was creating that pic it is always should be like this: if you do not need a really strong effect then it is enough to make a small (exposure) variation. On that picture I didnt really need +-2 and +-4 EV.

 

Often I need just to increase the DR a bit, say by +-1 EV, or even by +-0.5 is enough.

I thought also that the general principle, when the bigger the effect the bigger the side effects (e.g. brightness deviations or whatever) should work. Now you are telling me the opposite.

 

Well Im maybe first of all dissapointed by the fact that i got a lot of side effects changing the bracketing just only by +-1EV.

 

Thats a point.

[nikolo5]

To Steve Dunn:

 

1. Thank you for nice advises, the reason probably because of 3 jpg from 1 raw.. but really boring to take a tripod. And I dont really trust that alignment option in the software. In case of raw, however, the points on three shots are just digitally same, whereas in case of tripod they are just approximately same and blur by few pixels is welcomed.

 

2. Photoshop - maybe, but for now I prefer something smaller and more dedicated. If Photomatix will finally fail -- then....

[cjmalcolm]

By using one image, you are essentially creating a quasi-HDR. It's important to understand

that the reason why multiple exposures are taken (bracketing +/- 2EV is standard) is to

attain more detail in the shadows & highlights that would otherwise be impossible to

retrieve from one image.

 

In your case, the original JPEG image has no pixel information in that white area of the sky,

and no digital exposure adjustments will fix the problem. If you had bracketed shots for

that scene you would have had pixels to play with.

 

Your best bet is to open your original RAW image straight into Photomatix, it will create a

Quasi 32 bit HDR automatically (no need to fake multiple exposures). Then go to Tone

Map and you may find with any luck that it has rescued the sky.

 

Good luck

[howard_owen]

"but really boring to take a tripod"

 

Really boring to carry all those silly lenses around too. Why not trade in your dSLR for a point and shoot... if you haven't already.

 

If you want to attain excellence, it will require time and effort on your part. If you aren't willing to use proper technique, you'll never be satisfied with your results.

 

Maybe you should just buy a nice book with some HDR photos and call it a day.

[nikolo5]

To Howard Owen:

 

"If you want to attain excellence, it will require time and effort on your part"

 

I know this.. then why people now dont use old Daggers with photoplates which are with tripod by default and which provide a nice HDR ? Why they use mostly DSLRs ? Dont tell me please that DSLR is for housewifes..

[nikolo5]

To Steve Dunn:

 

Steve, thank you for the extended explanation. It seems it works just fine with +- 2EV with JPEG.

I got some nice results recently... (see picture)

 

The only problem it works just at non mooving objects.

 

N.<div></div>