HDR question


Status
Not open for further replies.

foxxkat

New Member
Jun 5, 2007
252
0
0
36
#1
i've read some guides on HDR and most of them mentioned bracketing..

confused, must use bracketing? or can i use the same raw file to create 2 files with different exposure and then do HDR? :dunno:
 

lastboltnut

Senior Member
Mar 23, 2006
4,528
0
0
Where the wind blows...
#2
There were some discussion on this single raw file HDR before.....if you search, you can find.

But if you read the definition of HDR, it should be at least 16bit/colour channel to capture the real dynamic range of a scene. Therefore, if your sensor is only 10 or 12 bit/channel, then the amount of data collected in the RAW file is never enough to qualify as a HDR. So, with a single RAW, I personally think you can get the same effect by adjusting the Highlight/Shadow of the RAW file....dun need to do a fake "HDR".

i've read some guides on HDR and most of them mentioned bracketing..

confused, must use bracketing? or can i use the same raw file to create 2 files with different exposure and then do HDR? :dunno:
 

koayst

New Member
Dec 29, 2006
95
0
0
#3
There were some discussion on this single raw file HDR before.....if you search, you can find.

But if you read the definition of HDR, it should be at least 16bit/colour channel to capture the real dynamic range of a scene. Therefore, if your sensor is only 10 or 12 bit/channel, then the amount of data collected in the RAW file is never enough to qualify as a HDR. So, with a single RAW, I personally think you can get the same effect by adjusting the Highlight/Shadow of the RAW file....dun need to do a fake "HDR".
Hmmm ... which DSLR has 16bit/colour channel? FujiFilm S5 Pro? What else?
 

night86mare

Deregistered
Aug 25, 2006
25,541
0
0
www.pbase.com
#4
i've read some guides on HDR and most of them mentioned bracketing..

confused, must use bracketing? or can i use the same raw file to create 2 files with different exposure and then do HDR? :dunno:
You shoot in JPG with different exposure, then combine all. Not necessary to have 7 like I usually do, but definitely more than 3.

But you can use a single RAW file to create HDR, Photomatix (the best HDR program imho) does it automatically for you, but RESULTS are not as good as those using a number of JPGs, more noise, etc.
 

g-khoo

Senior Member
Mar 4, 2007
2,027
0
0
Under your Blanket
www.wix.com
#5
i've read some guides on HDR and most of them mentioned bracketing..

confused, must use bracketing? or can i use the same raw file to create 2 files with different exposure and then do HDR? :dunno:
Yeap you can.

If you shoot in raw, just open the raw editor and export the picture as JPEG 3 times:

a. underexposed by 1 stop, decrease the brightness/exposure value by 1
b. correctly exposed.
c. overexposed by 1 stop, increase the brightness/exposure value by 1

When you launch the HDR programme it will tell you that it cannot detect diff expo levels and will ask you to manually key in the exposure levels for each photo

Put -1, 0 and + respectively. After generating, click tone mapping and adjust accordingly.

It should work.

There are instances whereby you can only shoot one picture and if you want to HDR it, then RAW is your only option.

Example, during my friend's commissiong parade, i took this RAW image and HDR'ed it. JPEG would not have been as effective due to the ghosting effect it will cause if i take 3 JPEGs and the men are moving around.



For normal landscapes, taking bracketing would be better as it is more accurate.



An impt thing to note when taking HDR is the noise levels it tends to create when the highlights are strong. To reduce this effect use a GND filter or noise reduction software.

Hope this clarifies.
 

foxxkat

New Member
Jun 5, 2007
252
0
0
36
#6
thanks for the pointers g-khoo.. that's very nice pics u got there.

i dont understand why for landscape, it's better to use bracketing? do u mean to use tripod? coz if without tripod i'm almost certain my hands will move a bit. then how to fit the diferrent images?
 

g-khoo

Senior Member
Mar 4, 2007
2,027
0
0
Under your Blanket
www.wix.com
#7
Thx for the compliments.

Bracketing means to shoot a picture in 3 diff exposure levels. Your DSLR should have an AEB (Auto exposure bracketing) mode. Select that mode, and shoot from a remote, or use cable release.

And use you need to use a tripod.

2 reasons why:

1. All 3 picts need be framed in the same manner, cannot move or else it affect your HDR PP.
2. Prevent blurring during long expo times.
 

lastboltnut

Senior Member
Mar 23, 2006
4,528
0
0
Where the wind blows...
#9
Hi g-khoo, did you try to use shadow/highlight and masking with layer if necessary to get the same "HDR" you get with one RAW?

When you convert your RAW, just "exposose" it to the mid range for a start.

Yeap you can.

If you shoot in raw, just open the raw editor and export the picture as JPEG 3 times:

a. underexposed by 1 stop, decrease the brightness/exposure value by 1
b. correctly exposed.
c. overexposed by 1 stop, increase the brightness/exposure value by 1

When you launch the HDR programme it will tell you that it cannot detect diff expo levels and will ask you to manually key in the exposure levels for each photo

Put -1, 0 and + respectively. After generating, click tone mapping and adjust accordingly.

It should work.

There are instances whereby you can only shoot one picture and if you want to HDR it, then RAW is your only option.

Example, during my friend's commissiong parade, i took this RAW image and HDR'ed it. JPEG would not have been as effective due to the ghosting effect it will cause if i take 3 JPEGs and the men are moving around.



For normal landscapes, taking bracketing would be better as it is more accurate.



An impt thing to note when taking HDR is the noise levels it tends to create when the highlights are strong. To reduce this effect use a GND filter or noise reduction software.

Hope this clarifies.
 

g-khoo

Senior Member
Mar 4, 2007
2,027
0
0
Under your Blanket
www.wix.com
#11
Hi g-khoo, did you try to use shadow/highlight and masking with layer if necessary to get the same "HDR" you get with one RAW?

When you convert your RAW, just "exposose" it to the mid range for a start.
Nope i didnt. I just manually adjusted the exposure levels when editing the RAW files and then export them as JPEG.

After that i just use photomatrix.

I suppose you could also do it in photoshop, duplicate the layer -> stack -> overlay -> adjust shadow/highlight -> mask/unmask.

But photoshop more troublesome la... Although it gives u more control.

Nice HDR u got there bigboy_cad
 

night86mare

Deregistered
Aug 25, 2006
25,541
0
0
www.pbase.com
#12
Nope i didnt. I just manually adjusted the exposure levels when editing the RAW files and then export them as JPEG.

After that i just use photomatrix.
:bigeyes::bigeyes:

Bonk.

Did you know that you can just open your RAW file in Photomatix, and it'd do all that and more for you? =D
 

lastboltnut

Senior Member
Mar 23, 2006
4,528
0
0
Where the wind blows...
#13
Hey night86mare, do you know where I can buy photomatix (not online, dun like to do online transaction) from store in CD/DVD form? Thanks.

:bigeyes::bigeyes:

Bonk.

Did you know that you can just open your RAW file in Photomatix, and it'd do all that and more for you? =D
 

lastboltnut

Senior Member
Mar 23, 2006
4,528
0
0
Where the wind blows...
#14
Oic, yah, tricking the software with diff exposure JPGs from a single RAW file is a fast way to juice out the 10-12 bit data from a single shot lah. May be I should try it to save time next time.:)

Nope i didnt. I just manually adjusted the exposure levels when editing the RAW files and then export them as JPEG.

After that i just use photomatrix.

I suppose you could also do it in photoshop, duplicate the layer -> stack -> overlay -> adjust shadow/highlight -> mask/unmask.

But photoshop more troublesome la... Although it gives u more control.

Nice HDR u got there bigboy_cad
 

foxxkat

New Member
Jun 5, 2007
252
0
0
36
#18
i've tried experimenting with photomatix and creating 3to5 different exposure files from One raw..

but the results is no where near g-khoo's nor bigboy's piece of work :sweat:

is there more to it than just photomatix? it's really simple to use. but results look so different heheh.
 

calebk

Senior Member
Jul 25, 2006
10,596
0
0
Clementi
#19
i've tried experimenting with photomatix and creating 3to5 different exposure files from One raw..

but the results is no where near g-khoo's nor bigboy's piece of work :sweat:

is there more to it than just photomatix? it's really simple to use. but results look so different heheh.
Are your exposures far apart enough in terms of dynamic range?
 

foxxkat

New Member
Jun 5, 2007
252
0
0
36
#20
Are your exposures far apart enough in terms of dynamic range?
i've tried 3 exposures and 6 exposures at about 1stop apart.

the end result is some parts of pic is toooo bright. i wonder if anything else needs to be done after photomatix hav produced the hdr pic. like do i need to drop exposure?

just have another thought.. hdr works better in evening/darker shots?
coz i've tried day shots only.
 

Status
Not open for further replies.