raw - whitebalance adjustment -grainy result

Hello my fellow photographers.

I'm experimenting at shooting raw with my dslr, no flash, no filters. Intention is to adjust the whitebalance (afterwards)

I'm quite pleased with the results, but when adjusting the levels, after i adjusted the white balance, the pictures are getting quite 'grainy'. In my opinion this is because i don't use a red filter, and adjusting the levels (especially the red channel) degrades teh picture too much.

I ordered Alex's magic filters, and i hope it will be better, but the shop didn't recieved them yet. It's hard to wait though

What are your thoughts about this?

example picture:

example (sorry for the link, this site doesn't seem to accept my pictures on site)

tx guys

Hi,

I'm wondering what program you are using to process your images. I'm also curious as to when you are seeing the "grain" show up. The 55K jpeg file you posted you tells me you might be having problems when you down res the image. Just guessing. I recently ordered the Magic filter from Ryan at Reef photo and recieved them in three days so they are out there. Can you tell us more about your software and workflow?

Steve

What noise reduction settings are you using in your RAW converter?

Most cameras do not apply any noise reduction to RAW (unlike JPEG), so it may just be that you need to up the filtering in the converter.

ok, some more info

I open my raw images with bridge, so adobe raw converter 5.2 opens. I adjust the whitebalance using the eyedropper, and adjust exposure if necessary. i didn't touch noise reduction settings, they are on: luminance 0, color 25.

Workflow continues to photoshop cs4. Adjusting levels, sliding the gliders in the histogram to the curves. It is in this process the graining starts to come. That's why i hope it will be better with redfilters, because there will be already more 'red data' in the image.

jejochen,

yes I know exactly what you are talking about. this is expected behaivor. it's not noise, you seeing the lack of data in your red spectrum.

you should resist the urge to slide the red slider

there is very little red in your photo, unless you shoot in 8ft of water or less. using the magic filter will help with this, if you shoot in shallow sunny conditions.

In general I find that I don't need to use the sliders in CS4, I do all of my adjustments in the adobe raw converter.

Scott

Yes, that's what it is. If there isn't a good balance of red light then the red channel essentially gets amplified - and so does the red channel noise.

Cheers

James

Yes, that's what it is. If there isn't a good balance of red light then the red channel essentially gets amplified - and so does the red channel noise.

Sorry to be pedantic, but a filter can't amplify anything. What happens is that the green/blue end of the spectrum is cut so it's at a similar level as the red. You then expose the image more. (Edit: Sorry I mis-read, you never said it did)

I just wanted to point out there's a downside to using filters, and that's either a longer exposure time, a shorter DOF (due to a wider aperture), or more noise from a higher ISO (in which case, was it worth it?).

An alternative might be (I haven't tried this), amplify the red channel in Photoshop to correct the white balance, but then run a (heavy) noise reduction on just the red channel. You'll then keep the detail in the Blue and Green channels. Most of the detail is in the green channel anyway.

An alternative might be (I haven't tried this), amplify the red channel in Photoshop to correct the white balance, but then run a (heavy) noise reduction on just the red channel. You'll then keep the detail in the Blue and Green channels. Most of the detail is in the green channel anyway.

That might be a good approach for an image that's already been shot but it's not a good plan to go out shooting flawed shots to begin with. Cranking up the gain on an underexposed red channel and filtering just that channel may be better than nothing but it will posterize the image and lead to color variation in fine details. Keep in mind also that badly color-balanced images aren't just a problem with reds.

I just wanted to point out there's a downside to using filters, and that's either a longer exposure time, a shorter DOF (due to a wider aperture), or more noise from a higher ISO (in which case, was it worth it?).

In many cases it is worth it. Most of the time there is enough light to continue shooting at base ISO without compromise. Other times, a 1 stop increase in ISO might be justified but your camera may be able to do that with surprisingly little penalty. The strongest of the filters we use is about two stops I believe. I have no personal experience with magic filters though. I shoot with filters constantly at base ISO. They actually help with sunballs.