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Finally, a D300 Near UniWB JPEG

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lorange said:
I´m not sure myself how it works but found this thread using search.

http://forums.dpreview.com/forums/read.asp?forum=1021&message=22208265
Click to expand...
Sounds to me it is important only if you use the color histograms a lot to adjust exposure. The color histogram reflects the distribution of each channel after the white balance is applied. The "UniWB" white balance setting will make the white balance a non-operation, that is, the pixel values are not adjusted by the white balance. I guess your preview will look off-color, but the net result is that the histograms will correspond much more closely to the distribution of color values in the raw data.

Very interesting, but I have to admit that I'm still too much of an amateur to pay a lot of attention to the histogram. For me the "blinkies" are good enough. There are a lot of other aspects of my technique I'll have to work on first :-).

Eric
--
http://www.lumenssolutions.com/photography/
 
Thanks will give it a go thanks!

Cheers,

Ray
 
UniWB provides a WB setting that allows the camera's color histograms to reflect far more accurately the exposure of each color channel. These histogram readings, therefore, allow one to assess exposure more correctly.

You would use it when shooting RAW (not JPEG) and would reestablish the correct WB for the shot during PP. The images taken with UniWB do indeed have a very greenish tint as displayed on the camera's LCD, but, of course, the RAW files themselves are not affected by the WB setting -- but the histograms are.

While this WB can be used at any time, its main value is when the scene is particularly lively in one or more color channels and one needs more accurate information to know the proper exposure to prevent clipping in those channels.

The purpose of the file to be downloaded at

http://www.pochtar.com/Nikon_D300_NearUniWB.zip

is to provide a JPEG file that allows D300 owners to establish the UniWB as a manual preset in a very convenient manner. The process for effecting this is explained on page 142 of the D300 manual. Essentially, you copy the downloaded image DSC0001 to the image folder on your CF memory card. This folder is located inside the DCIM folder and is named xxxND300, where the x's can vary. Restore the memory card to the camera and follow the instruction on page 142. You can copy the WB information from this JPEG into any of the four manual preset d1, d2, d3, or d4, and then use the chosen preset when you want to employ UniWB.

Note: if you already have a file named DSC0001 on your camera's CF card, you should change the name of the downloaded file to some DSCxxxx that does not conflict.

--
gollywop

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Thanks again for the NearUniWB file it works great and here is a shot from today with it. The WB looked excellent and I had much less spiking of highlights. I look forward to using it more. I processed the RAW in NX and used my whibal card as a grey reference.



--
Ray
 
Super catch, Ray; really nice.

We had decent weather today for the first time since I got the Near UniWB going, so I was out today knocking about with it as well. I just got through assessing the results, and I must say, I am impressed. I could push exposure in some instances further than I normally would have and still kept within bounds. But it is going to take some getting used to.

How far were you from this bird? I see you used flash and a 420mm lens. Interesting settings with a -1 EC and A priority. What leads you to these settings? They sure worked for you here.

--
gollywop

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I'm using a better beamer flash extender on the SB800 and it adds about 2 stops they say. I haven't got it dialed in yet and more often then not its hit and miss.

The GBH was not that close guessing about 30-40 meters or so. I don't think the flash did much, but I'm not sure. I just checked the image and I had added exposure compenstation of +0.17 in PP, as I felt the sky was running close to 140.

--
Ray
 
Great picture btw.

I've loaded this WB to the camera. But when i took picture (outdoor and indoor) it looks greenish. Now what should I do to get perfect WB as you've got?
Humanoid said:
Thanks again for the NearUniWB file it works great and here is a shot
from today with it. The WB looked excellent and I had much less
spiking of highlights. I look forward to using it more. I processed
the RAW in NX and used my whibal card as a grey reference.



--
Ray
Click to expand...
--
Thanks
Jemini Joseph

http://www.wildbirdimages.com

 
Are you shooting JPEG or RAW? If the former, forget it; it's not really for your workflow. If the latter, adjust WB in your RAW converter. See prior post "A Brief Explanation".

--
gollywop

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So if we have to adjust WB in the converter what's the advantage of having this WB? I use Capture NX for conversion. Do we have to use auto WB in NX to get the use of this? I guess I'm not getting the point....
gollywop said:
Are you shooting JPEG or RAW? If the former, forget it; it's not
really for your workflow. If the latter, adjust WB in your RAW
converter. See prior post "A Brief Explanation".

--
gollywop

-----------

Click to expand...
--
Thanks
Jemini Joseph

http://www.wildbirdimages.com

 
jeminijoseph said:
So if we have to adjust WB in the converter what's the advantage of
having this WB? I use Capture NX for conversion. Do we have to use
auto WB in NX to get the use of this? I guess I'm not getting the
point....
Click to expand...
jeminijoseph said:
--
Thanks
Jemini Joseph
Click to expand...
It will look green just make sure you exposure is good for maximum DR expose to the right (ETTR). Now that you a properly exposed image you need a grey reference to bring it to the correct color. I shoot a whibal or grey card or something close to neutral grey in the same light and save that when processing and apply it to other images with similar light. This is easly done in NX. The point is with UNIWB your exposure will be accurate with maximized DR and proper WB. You still need a grey reference.

Also, the camera should be setup with a linear curve, but I found good results with Standard Picture control with minimal settings.

Best of Luck!
--
Ray
 
I copied it to my camrera and will be playing around with it to get to know it.
 
jeminijosepth: This is explained above in this thread in the post labeled "A Brief Explanation." This WB helps set proper exposure, but basically assumes you are shooting RAW. You would then correct for WB in PP using a gray card or some such device. I should suspect that the WB adjustment that would be needed for JPEG would be problematic.

I guess in principle, when shooting JPEG, you could use UniWB to determine the proper exposure then switch to an appropriate WB before actually taking the shot. But this is going to be very awkward for everyday use -- maybe for special occasions when you have plenty of time to set up the shot and ETTR is very important.

So, basically, if you are shooting JPEG, whether or not with RAW, this is not likely to be of much use.

--
gollywop

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