Filters

[Penguin_101_1]

I was reading the article on filters in this months Shutterbug and saw that filters don't do anything on digitals unless they are in raw because of AWB. Is this true for everything? I guess stars would works since I have used them on it before and it worked. :? What do you think??

BTW: That is a great article. :)

[Penguin_101_1]

Anyone???? :cry:

[Don Schaeffer]

I used a yellow filter in the monochrome mode with my A70. It darkened the sky very effectively. I now use circular polarizer to darken the sky and reduce glare on glass. It workd very well. I have used a diffraction filter with interesting effect. I even mounted a sunglass lens to darken bright sunlit images. Whoever said that is wrong.

--Don

[paulj48]

don't do anything on digitals unless they are in raw because of AWB

Can you not just switch into maual mode?

As with any camera though when using certain filters (graduated filters for example) you need to take a meter reading before you place the filter over the lens, lock the exposure settings, then fit the filter, then take the picture.

[Don Schaeffer]

I use my filters BEHIND the lens, since I am using a large wide angle auxillary lens as a normal lens. My cameras is in manual mode and I usually underexpose by one stop.

[stopbath]

The author was likely refering to colour correction filters such as warming, cooling, and florescent lighting filters. These are basically covered by AWB or by the specific white balance settings. If you add a filter that deviates from daylight spectrum, then yes AWB will try to correct the image back to daylight spectrum. But if you correct TO the daylight spectrum, AWB has no choice but to fine tune the image, or leave well enough alone...

Filters such as polarizers, neutral density, soft focus and star filters that do not change colors can not be nullified by AWB.

Filters that block entire chunks of spectrum such as IR, Red, Yellow, Green and Blue filters (black and white filters) might be *modified* by applying White Balance settings, but they can't be negated... (if you block all blue and greens with a Red filter, how is AWB going to put that data back in? It can't... but it may alter it a bit..)

So the author is right, but also wrong.

[Don Schaeffer]

An you turn off the auto white balance. I made a manual white balance that corrected for my polaroid filter.

--Don

[docker]

I don't understand what happens with AWB and polarizing filter. Could someone please explain this interaction. I understand each concept generally.

Thanks

[stopbath]

A polarizer should be neutral colour. It may intesify colour by cancelling out reflections, but the colour spectrum before and after the filter should be identical. Perhaps there may be a side effect colour shift in a batch of filters, but generally, they should not shift the colours.

A pair of sunglasses which remove polarized light may very well indeed pollute the colour spectrum (likely a green or brown tone) and would thus need correcting (if it the change was not too severe...)

[Don Schaeffer]

My polaroid filter had a definite green cast. It had to be corrected fromthe begining. Initially, I used post processing software until I discovered how to do the manual color balance.

[matrad]

I use nd filter and pola without problem on my A70 in p mode or AV-TV-M....


read
http://www.cliffshade.com/dpfwiw/index.htm

[Drbeagle]

What brand of filters do you recommend for a canon A70? Thanks

[Penguin_101_1]

I have always used Cokin.

[stopbath]

What brand of filters do you recommend for a canon A70? Thanks
It depends on your requirements...

You need to balance out your expectations of cost and expectations of quality, and needs.

Optical glass, is more expensive, but the superb quality is there.
Green (window) glass, is moderately priced, but less quality...
Plastic is cheaper, and with again less quality, but you have a lot more options to play with.

The top notch optical glass filters would not be suited on the A70, but if you're likely going into an SLR, you might consider them (as you won't need to replace them when you get great lenses on your SLR...)
If you want to play and experiment, then plastic may be best suited.
If you just want a filter, but don't to pay an arm and a leg, then green glass may work out fine...