Seek help on IR process flow

[Montmelo]

I've read the steps on IR photography but have been repeatedly unsuccessful with IR photography on my Nikon D80 and would appreciate some feedback from the gurus.

This is what i've done :
I've tried performing the Custom White Balance (CWB) by pointing the lens on a bright patch of grass on a very hot sunny day. Lens (18-200VR) is fully extended and with the Hoya R72 IR filter on. Set it to manual mode, f/8 with 8 seconds exposure. But the CWB keeps saying "No Good" no matter how i try it. Any thoughts?

So i tried another method. I took a shot of the grass patch just like taking a normal shot (i.e. not in the present CWB mode). IR filter is on. Zoomed to the max 200mm. Manual Mode. f/8 and 8 seconds exposure. And took a normal short. With the D80, there was an option for CWB to use an existing picture from the menus. So i chose the one that i just took. Is this correct?

In any case, I then took a shot with this CWB. zoom at 28mm. f/8. 8 sec exposure. I get this jpeg file.8 and 8 seconds exposure



Then i loaded it into PhotoShop, did an auto contrast, went to channel mixer to swap the colors between Red & Blue.
This is what I get.



Its no where near the images seen in the forum, even if i tried to adjust the hue/saturation.
Have i missed something out in the workflow?

I've tried taking some shots with f/5.6 or with 15seconds shutter speed but it more or less ended up quite similar

[TrailsofLife]

Hi,

When your CWB is wrong, your image will be wrong. So no point telling you story about post process.

When I use my D70, I normally use P mode to do CWB. When it fail to Customise WB, I normally point it at the sky or some white wall to do WB.

You may want to try that.

[ark19]

D80 should be similar to D70, pls follow the steps listed here:
http://forums.clubsnap.org/showpost....03&postcount=4

[Montmelo]

Originally Posted by Max 2.8 Hi, When I use my D70, I normally use P mode to do CWB. When it fail to Customise WB, I normally point it at the sky or some white wall to do WB.

Is the purpose of CWB is actually to find the white point? Wouldn't poining to a green patch of grass versus pointing to a white wall be very different?

I did try to point to the sky. The result was similar the 1st pic i posted but perhaps a little brighter.

Also, what are your typical zoom, shutterspeed & expsoure readings when using "P" mode? Its just for my reference.

In any case, i'll be trying your inputs out tomorrow.

[TrailsofLife]

when you put on the R72, any bright areas will appear red to the camera, so doesn;t matter.

Just a stupid question, After you did your CWB, Did you shoot with your WB set to CWB or you shot with your WB still set to Auto WB?

[u2nofear]

look like D80 same problem as olympus, i using olympus E-500...inside got some filter to block liao...any IR expert already test on D80? pls feedback to us D80 capability on IR....

[teerex]

Originally Posted by Montmelo Is the purpose of CWB is actually to find the white point? Wouldn't poining to a green patch of grass versus pointing to a white wall be very different? I did try to point to the sky. The result was similar the 1st pic i posted but perhaps a little brighter. Also, what are your typical zoom, shutterspeed & expsoure readings when using "P" mode? Its just for my reference. In any case, i'll be trying your inputs out tomorrow.

I may be wrong, but I think the D80 sensor is different from the D70 and D50. Thus you may have to use a different method of setting the CWB.

I suggest you try deadpixel's method of setting CWB for the D200. It may work, post your results to let us know. THE THREAD IS HERE.

Follow his method of setting as stated in the paragraph just above the picture he posted.

[Montmelo]

For sure it was set to the custom white balance mode because if its set to auto, i get a very reddish picture instead.

What should an original picture with correct CWB look like?

[TrailsofLife]

Originally Posted by Montmelo For sure it was set to the custom white balance mode because if its set to auto, i get a very reddish picture instead. What should an original picture with correct CWB look like?

Reason I asked is because your pix shows shooting with Auto WB. Thats what you get(red pix like your 1st pix).

Normally an IR pix should look like this:


After channel switch, it should look like this:


Not the best example, its cloudy today

[Dennis]

D80 may be similar to D200, use the correct exposure time (i.e. may be quite long like >5 sec) and you may be able to set your WB properly.

[teerex]

Dennis may be right, the sensor of the D80 is different from that of the D70 or D50.

Deadpixel has been successful in setting the CWB for the D200, you may like to try the same method for your D80.

THE THREAD IS HERE

[Montmelo]

In fact, i've tried dead pixel's method (of setting to long exposure on a sunny patch of grass at 12 noon) but didn't manage to get a "good" status on CWB. Tried it on several occassions at several places

I plan to try jc1's method during lunch time today and will post the results

[vortex]

did u mount on tripod or not?

[Dennis]

What is your exposure time ?, IIRC the auto exposure will not work, you may need to set it to manual and try for long exposure untill you get almost correct exposure than the WB will work.

Originally Posted by Montmelo In fact, i've tried dead pixel's method (of setting to long exposure on a sunny patch of grass at 12 noon) but didn't manage to get a "good" status on CWB. Tried it on several occassions at several places I plan to try jc1's method during lunch time today and will post the results

[deadpixel]

Originally Posted by vortex did u mount on tripod or not?

No need lah, CWB images do not even have to be clear...

Cheers,
Matt

[deadpixel]

Originally Posted by Montmelo In fact, i've tried dead pixel's method (of setting to long exposure on a sunny patch of grass at 12 noon) but didn't manage to get a "good" status on CWB. Tried it on several occassions at several places I plan to try jc1's method during lunch time today and will post the results

This is a quote taken from Bjørn Rørslett's review on the D200:

"Each generation of Nikon D-series cameras has had its IR sensitivity decreased; or put the other way, the efficiency of the filter pack has increased."

Looks like it's true for the D80 as well.

First thing to know is that you do not have to use small apertures for CWB. Your photos do not need to be sharp for the camera to calculate the correct white balance. All it needs is a more or less uniform patch of colors.

Considering that an 8 second exposure came out so much under on your D80, you might wish to try doing this:

• Set you lens to 70mm (you don't need to push it to 200)
• Set your camera to manual focus AND 'M' mode. Make sure it is 'M', not 'A', not 'S', not 'P'
• Set your aperture to the largest possible, likely to be f/4 or f/4.5 at 70mm
• Set your shutter speed to 10 seconds
• Activate the CWB measuring, point at a sunlit patch of grass and shoot

If it does not show 'Good', increase the shutter speed to 13", then 15" then 20".

If all of this fails, then you'll have to try JC1's method.

I'll see if I can 'borrow' a D80 from a friend to do some test.

Cheers,
Matt

[Yippy]

Able to Preset WB for D80 at f2.8, 30s. But, result not so acceptable. Anyway, will try it out again.


[IMG][/IMG]

[TrailsofLife]

Originally Posted by Yippy Able to Preset WB for D80 at f2.8, 30s. But, result not so acceptable. Anyway, will try it out again. [IMG][/IMG]

I think your pix is fine. Just need slight tweeking of colours to your preference.

From the look of it, D80 have a tougher hot mirror! 30secs at f2.8!

[Dennis]

If want a faster speed maybe can set your iso higher as well.

Originally Posted by deadpixel This is a quote taken from Bjørn Rørslett's review on the D200: "Each generation of Nikon D-series cameras has had its IR sensitivity decreased; or put the other way, the efficiency of the filter pack has increased." Looks like it's true for the D80 as well. First thing to know is that you do not have to use small apertures for CWB. Your photos do not need to be sharp for the camera to calculate the correct white balance. All it needs is a more or less uniform patch of colors. Considering that an 8 second exposure came out so much under on your D80, you might wish to try doing this: Set you lens to 70mm (you don't need to push it to 200) Set your camera to manual focus AND 'M' mode. Make sure it is 'M', not 'A', not 'S', not 'P' Set your aperture to the largest possible, likely to be f/4 or f/4.5 at 70mm Set your shutter speed to 10 seconds Activate the CWB measuring, point at a sunlit patch of grass and shoot If it does not show 'Good', increase the shutter speed to 13", then 15" then 20". If all of this fails, then you'll have to try JC1's method. I'll see if I can 'borrow' a D80 from a friend to do some test. Cheers, Matt

[ark19]

Wah like that better stockup on D70S....