CPL Filter Question

[Geoff79]

Hey guys,

At the moment I am using a Hoya 72mm CPL filter. So far I haven't minded it, but I used it a lot in Tonga and I noticed that a lot of the shots taken in broad daylight had a pretty solid yellow/brown/red tinge to it. I printed everything out and looked at it last night and it was really quite evident. So much so that today I colour adjusted a heap of the photos in Faststone, -10 for the Red and +10 for the Blue... just to get it looking close to "normal." I really don't want to have to do this everytime I take a photo in the middle of the day, so my question is this:

Is this just because Hoya is a cheap model CPL filter? Or is this an effect commonly found with the use of any CPL filter?

If it's just because of the cheap filter, what sort of price, and brand should I be looking at to get a more neutral colour result?

To be a little more specific, the Tonga shots were being given a yellow/brown tinge to the clouds... which really didn't work for me.

Thanks for any help at all!

[Lance B]

I take it you were using auto white balance on your camera? If you shoot RAW, you should be able to easily correct it in a RAW processor. If jpeg, then that is a little more difficult.

A polariser should not introduce that sort of colour balance to the image and even if it did, it should be almost corrected by the auto white balance.

Having extensively used polarisers, I have never obtained that sort of extreme colour shift, except when I have accidently moved it from auto to a pre set white balance.

I use B&W Kasemann polarisers and have used Hoya Pro 1. If you do not get satisfactory answers to your troubles, I am more than happy to meet up with you somewhere and see if we can nut it out.

[JM Tran]

as Lance said, there should not be such a shift in the colours if using a CPL.

is your monitor calibrated? Could you post up some photos for us to see and see if we can help?

[Speedway]

As said previously there should not have been that extreme shift I have a cheap hoya 58mm and a very cheap $35 77mm and have not had that sort of shift with either. Both produce good results with the latter only useful between 18-20mm on my 10-20mm sigma giving severe light to dark blue shifts in the skys at under 18mm, this is due to the extreme wide angle giving so much variation with the angle to the sun.
Keith.

[jjphoto]

Hey guys,

At the moment I am using a Hoya 72mm CPL filter. So far I haven't minded it, but I used it a lot in Tonga and I noticed that a lot of the shots taken in broad daylight had a pretty solid yellow/brown/red tinge to it. I printed everything out and looked at it last night and it was really quite evident. So much so that today I colour adjusted a heap of the photos in Faststone, -10 for the Red and +10 for the Blue... just to get it looking close to "normal." ...

Polarising filters will change the colour temp of an image as they alter the way polarised light is filtered through them. Of course the surfaces of objects themselves can be more or less blue depending on how it reflects polarised light and how this light is filtered. If you should RAW, which I think most people should, then it's very easy to correct for whatever colour balance works best for you.

For example:

B+W Polarizing filter adjusted to have minimal polarizing effect.


B+W Polarizing filter adjusted to have maximum polarizing effect.

...Is this just because Hoya is a cheap model CPL filter? Or is this an effect commonly found with the use of any CPL filter?

If it's just because of the cheap filter, what sort of price, and brand should I be looking at to get a more neutral colour result?...

I think it's completely wrong to imply that Hoya filters are cheap therefore bad or inferior. That's just wrong.

A while ago I compared a cheap Hoya and an expensive B+W polarising filter to see what differences there are, if any. Interestingly the cheap Hoya filter seemed to perform slightly better than the more expensive B+W.





No filter, reference image. All 100% centre crops from Leica APO-Telyt-R 3.4/180 at F5.6.


Hoya polarizing filter. Sharpness (not resolution) is almost better than the reference image due to higher contrast.


B+W polarizing filter. Sharpness is slightly lower than that of the Hoya Polarising filter.


I've used the above 2 filters interchangeably for years and never noticed a 'real-world' difference in image quality between them, hence the above comparisons to see if there really are any.

There's a lot of info about the tests that I've left out here, for brevity, but if you want more info then go to http://photocornucopia.com/1018.html.

JJ

[arthurking83]

I have a few CPL's myself too, mostly cheapo, and one super pro thingy, and they all mess up AWB to varying degrees and in different circumstances.

Even if you subsequently set a WB value on the raw file in PP, you may still notice some slight variations in hue or tint(red/green shift).

FWIW, my main CPLs are my two 77mm's, and the cheapie version usually produces a slight greenish tint, whereas the Super Pro1 leans more to the red.

As already said, if you shoot in raw, this isnt' an issue other than the need to watch for it and balance it back to taste.

[Geoff79]

Thanks for the replies, guys. Especially the live tutorial offer, Lance.

To answer a few of the questions:

I was indeed using AWB. I've learned SOOO much since joining up to this forum, but I'm yet to tackle WB in any detail yet.

I officially gave up on RAW about a month prior to Tonga. I gave it a red hot go for a long time this year but in the end I don't have the PP skills or knowledge, the hard drive (inc. externals) space or time to really do anything worthwhile with RAW. For the basic PP I do, it works so much better and easier for me, plus I skip a whole a heap of conversion effort and time.

I am honestly not sure if my monitor/s are callibrated? I would guess no?

Just want to note, I wasn't saying Hoya were inferior or bad... it was a legitimate question, just wondering if because it was so cheap, if that meant it was of lesser quality than others? Sounds like that's not it at all... which means I can save my coins.

Thanks for the demos too, JJ. Very interesting.

I want to also add this. So I changed all my images this afternoon, adding blue and taking away red. Anyway, so I printed them out this afternoon and turns out they looked dreadful. Better on screen, no doubt, but not in print. Yuck. lol.

Anyway, here's some demos as per request. I don't know if I'm looking too much into them, but to me the colouring doesn't look correct to me. I should add, I've done slight highlight/shadow adjustments (very slight) and adjusted sharpness... that's about it. No colour adjustments.

IMG_0652.JPG

IMG_0639.JPG

IMG_0605.JPG

Wow. Just did a preview post and this brings me to another thread I was going to start. Who uses Faststone, and for those who do, does the image displayed in Faststone have little or no resemblance to the same image posted on the net??? I have worked on these images in Faststone and printed them and as I said, I had issues with the colour... but they do not look that dull and lifeless as they do in this post. Same thing happened with the Tonga images I posted the other day which were received as well as herpes.

Anyway, hope it's a start anyway...

[arthurking83]

...... Who uses Faststone, and for those who do, does the image displayed in Faststone have little or no resemblance to the same image posted on the net??? I have worked on these images in Faststone and printed them and as I said, I had issues with the colour... but they do not look that dull and lifeless as they do in this post. Same thing happened with the Tonga images I posted the other day which were received as well as herpes.

...

Dull? Lifeless???

WOW, I'd hate to see how they look on your PC then.

All three images are vibrant and have good contrast. Any more saturation and they'd be oversaturated.

I also use FSViewer, (and constantly keep it up to date to boot!) and also use it as my portable viewing program(on a USB stick).

One thing with FSViewer is that if you view a raw file, it may be rendered according to how the embedded jpg file is set(ie. camera settings, WB, color mode, etc) and by default it previews the raw file from the embedded jpg file. (faster to view multiple raw files, especially as file sizes become large).
There is an option to use the actual raw file data, but in doing this, you are at the mercy of Fastsone's raw file algorithm, and (my personal taste!!) is not the best raw file generating software I've come across.

I tend to use it more so for two things.
Quick raw file viewer only(especially on my Tablet, but not limited too that device) and for those times when I cant' get a jpg file under a pre determined file size and pixel size AND quality level.
I've found that if I have issues with downsampling an image from raw file to jpg, and want a small file size as well(eg, 200kb) this is one of the better software to do this.

from the three images you've posted, the first two seem to lean very slightly towards a green tint, whereas the last one seem to be more magenta by comparison .. but this is only ever so slight in that it's not worth worrying about at all.
Images look fine.

One other small(actually major) gripe I have with FSViewer is that the histogram doesn't show the RGB histogram with each channel overlaid over each other and only as individual graphs.
For a slightly better indication(for yourself), try to find another program as well that allows you to see an overlay of the RGB histogram.
(and even tho I've listed a few flaws in FSViewer, it's still one of my favourite imaging programs! )
This is not imperative, but is still important.

I'd say you may have screen calibration issues as well, but as they are all set in RGB, they should still look the same on the net as they do on your PC.

Another thing to note with your dumping of the raw file format. Even though you don't have the time or PC space, as as you use a Canon, I'd be inclinded to go back to raw and try out Canon's free raw converter program and work with raw files again.
First thing to do when you work on the raw file, is to set WB manually via the Canon software, leaving the camera to AWB.
As a quick test, you could try this under different lighting conditions, especially those infernal compact fluoro lights and see how it pans out. No filters no special lenses, nothing. just take a few snaps of whatever under CFL conditions and see how it works.
Something you could try as well is to separate the jpg image from the raw file, in that you could do a straight raw -> jpg conversion before you play with the WB value in the Canon software.
Try to balance the colour balance on the jpg file with whatever software you think is good enough to do so, and then use the WB setting tool in the Canon software on the raw file.

I've never used Canon's software, but if it's anything like Nikon equivalent, you may have a grey point tool(dropper/sampler) that helps to get a very good WB/colour/tint balance with a single click.
All you need to do is find an area of even RGB distribution and click on that and your WB is easily set. Things that have even RGB channel distribution are anything that is supposed to be rendered grey or white(that is easy to for the human eye to visualise).

if the WB value shot in the jpg file is pretty close to what your taste prefers, then even shooting jpg and colour balancing out is not too hard a task.
But if the WB value is way off(as it sometimes can be under variable light conditions) then colour balancing a jpg is difficult if not impossible, whereas in a raw file, it's always possible .. no matter how far off you are in the raw file.

[Lance B]

Your images look fine on my calibrated screen. There might be a very, very slight warmth to them, but it is ever so slight that not many would even notice it and I actually like it as I use brown polarised sunglasses and like the warmer look it gives, so to me these look fine. They are vibrant and colourful and contrasty.

I think you may have a monitor issue judging by what you say about when you adjust your photos to look fine on screen but when they are printed they look awful. This says to me that your monitor is out of whack as these photos posted look fine.

Here is a good test of polarisers for those that are interested:

http://www.lenstip.com/115.1-article...ters_test.html

And the overall results:

http://www.lenstip.com/115.4-article...d_summary.html

[Geoff79]

Thanks Arthur and Lance.

One of my brothers says how I seem to pretty much hate every photo I've taken a week or so after I've taken it, so maybe he has a point and I am too harsh on them.

Don't get me wrong - I do like the snaps. In fact, they look great in the album. But specifically I was hoping for a little more individual clarity in the water, rather than picking up all the browns of the rock and sand. But then, I hear you say, why'd you use the CPL filter? Haha. Hard to get the right balance, but yeah, maybe I'm just being harsh. I'm also wondering if the clouds/weather played a big part. I remember these moments well, where I would be literally standing there with my frame set, waiting for the sun to shine through the clouds for 2 seconds so I could take my photo. I wonder if the result would have been more to my liking on a less overcast day.

End result, maybe I won't give up on the CPL filter just yet.

As for the monitor callibration, sounds like it may be a real issue for me. Something to look in to, as I actually am not quite sure what it all means as we speak, to be totally honest.

As for the RAW stuff, I did try a lot. Including the Canon software. In the end, the main gripe I had with it that I was losing so much clarity in sharpness in converting from RAW to JPEG and adjusting the sharpness each time. Alternatively, sharpening a straight JPEG image has proved to be infinitely better, I've found. Because I'm not really confident enough to adjust colours too much, I found that all the processing I was doing with the RAW image is probably already being done better by just taking a JPEG image right away. I admit I still have MILES to go in learning about PP, but for me now the PP of a JPEG image just seems like the far better option for me personally, with my "skill set."

I actually now solely use Faststone for all my editing. I find it so efficient, and everything I was doing in Photoshop (with my basic knowledge of it) I can do in Faststone. I have no doubt that one day I will bite the bullet and buy Photoshop (rather than continually using that trial version) when I learn more about PP, but for now I really like Faststone. The only thing I really miss in Photoshop was the vibrance option.

[Lance B]

Using a polarising filter can be very helpful and I use one extensively, but try to avoid it on super wide angle lenses, like less than 24mm of FF and 16mm on APS C, as it can introduce quite a range of blue across the sky, polarisers work best at 90 degrees to the sun, so at one side of the photo furthest from the sun it can give a dark blue sky and at the othe side closer to the sun it can be quite light. This is the effect you get when using a polariser with super wide angle lens, in this case 16mm on a FF camera, and due to the fact it is such a wide angle lens, the polarising effect can be seen across the sky:





Polarisers do more than just bring out the clouds and make the sky a nice blue on a sunny day. They are very useful for bright days by reducing the bright spots on foliage and other reflective surfaces and therefore your shots of bush and trees etc show the leaves better. Polarisers are fantastic for removing reflections from water, where you want to see the beautiful greens and blues etc of the water come through:



Used judiciously, a polariser is a very important tool to help improve your photos, so don't give up on them.