Filters (Circ-Pol + ND)

[burnsy]

Originally Posted by flamingice

Nope, it'll just be a bit of a pain, because you'll have to readjust it after every shot.

Originally Posted by MXM

And it's not something you can fix by getting another filter. All polarizers are direction-dependent, as you can probably tell from this tutorial

thankyou guys. i guess i can handle that. it'll be good to use when going to the ALMS race this weekend at Mid-Ohio. use the CPL for taking shots of the cars stationary, then the uv and maybe the CPL for on track shots.

[napoleondyna]

I just bought a hoya 52 MM CPL on ebay literally 2 hours ago. Am i really going to have to adjust it for every shot? That kinda sucks and yes my lens turns when focusing (damn nikon). Dont get me wrong nikon is great it just kinda sucks that i have to re-adjust. Also, if you dont have it rotated correctly will it just look normal? If its close will you get some effect?

[MXM]

Yes, you will get *some* effect, just maybe not the one you want.
Look at the example photos in first post. By rotating you gradually adjust from one photo to the other.

If you want to get rid of reflections on a car, by rotating you're basicly chosing a plane in which light will be polarized and reflections removed. So in horisontal position side windows will be transparent, and in vertical windshield. Roughly anyway.

I'm not sure how nikon's 18-55 rotates, maybe just by holding CPL's adjustment ring you can keep it in one position while focusing? Not too tight, so you don't damage the focusing mechanism or something

[mautzel]

Originally Posted by BerserkerCatSplat

That's his problem, pretty much guaranteed. The 75-300 is f/5.6 at the long end, and sticking a CP on the end further restricts the light getting to the AF system.

But that shouldn's cause such serious effects at 300mm if I'm not mistaken:

That's the best I was able to focus with the filter in both manual way and AF:


That's the same pic with the filter removed:


Both pictures taken at 11.15am in full sunlight.

[MXM]

That's really bad. Are you able to focus normally on wide?

[mautzel]

The smaller the focal lenghth is, the better I'm able to focus properly with the filter put on, but I feel that there's still a noticeable difference.

Same pics at 70mm:
with filter:


without filter

[Shadowness]

That's bizzare! Like I said before, CPLs should have no effect on focusing. I use one on my 100-300mm and it has no effect on auto focus.
What brand is your filter?, I can only think that it's, sorry to say, a bit naff!

[MXM]

Funny, I think I can see more details on wide-photo with CPL than on tele-photo with CPL.

[Paddy]

I had a simliar problem before, around this time last year ...


'When I use a Circular Polarizer on my 70-200 2.8 the pictures become wildly unusable and very much so out of focus. When the polarizer is removed the pictures become clear again. I've included two examples. The filter is a Tama Pro C-POL


With Circ Pol


Without Circ Pol


Moral of the story, don't skim on essential products. Ordered a new Hoya one last night (I know, a year later )

[mautzel]

I guess that's the solution for me as well - my filter's a no name filter that I got "surprisingly" cheap off ebay. So everybody thinking about getting one of these - let the pictures above be a warning to you!

[MXM]

Ok, something I want to add here... I got a Hoya HMC CPL a week ago, and it blocks ALOT of light. How much f-stops are you supposed to lose? I just tried 2 shots in shutter priority with same exposure, and without filter I get f/4.5 and with filter f/8 (varies depending on the polarization plane). But 4-6 steps always. Is it supposed to be that bad?

Edit: I've seen mentioned on internet that 1.4 to 3 f-stops are lost. But are my camera's steps equal to f-stops?

[Paddy]

1.5 to 2 stops usually ...

If your going from f4 to f8, thats around right ....

[.cmd]

Sorry for what is most likely a very stupid question, but what difference does the size (55mm, 67mm, etc.) of a CPL make? Does it change what size lens they can be used on?

[Shadowness]

Originally Posted by .cmd

Sorry for what is most likely a very stupid question, but what difference does the size (55mm, 67mm, etc.) of a CPL make? Does it change what size lens they can be used on?

The different sizes are purely for lens with different thread sizes. So my 100-300mm Sigma lens has a 82mm thread size, and my 12-24mm Nikon has 77mm. So you could buy a seperate size filter for each lens OR alternatively, you could buy the 82mm filter and a 82mm to 77mm step down ring, which would allow you to use the 82mm filter on the 77mm thread (so you would have 1 filter for both lenses).
I would advise that you only use a larger filter on a smaller lens thread, and NOT a small filter on a larger thread, as you would see the filter in the shot.

Apart from that, the size would make no difference, each filter size should perform equally.

[zenkidori]

What's the best place online to get filters and such?

what I'm looking at right now is this:
http://www.amazon.com/Canon-LAH-DC20...879800-8870365
plus this:
http://www.amazon.com/Tiffen-58mm-Ph...879800-8870365

[IceBone]

I bought a Cokin c-pol 55mm for about 32 euro and i have no problems focusing, pics just tend to turn out a bit blurry at lower light, because exposure time needs to be longer.

the only thing is that the "band" of reflection removal is quite narrow

here in your pic the entire glare on whe windscreen is removed:



but with mine it would be just a part of it. Is it because it's more expensive and better or am i doing something wrong?

[Shadowness]

Icebone: It may just be because you havent set it up quite right, and it might need a tiny bit more rotation to get the whole windscreen clear.
When you say its a bit blurry, what shutter speeds are you using?

Practice setting up the filter on stationary cars, as you will have more time to 'play about' as opposed to a moving car.

Posting an example pic may help

[IceBone]

looking... wait for edit

EDIT:



and about the blurriness, i shoot on Apperture priority, so the exposure sometimes falls quite a bit bellow 60, because the filter lets less light through.

[STi Nut]

Hey guys,

I am in the market for a CPL filter for my Nikon 18-135mm lens, i believe that it needs a 67mm Filter but being new to this whole thing i don't know what to look out for, such as brands.... i don't want to go into the store in the city since every time i go in there they are dicks and try and sell me either the most expensive thing or what ever they want to get rid of..... so i need your help guys

Thanks,

[Paddy]

As you can see, don't go cheap ! If you stick with Hoya you'll be fine !