Polarising filters.

[Dno]

I'm just starting to look at some filters, and this is the first one that I think I'll try out.. For wildlife/airshows, I presume this is suitable?

Am I right in saying it basically boosts contrast in the sky, and the colour saturation in the scene in general?.

I understand it also cuts the reflections out from water etc due to the reflected light being at a different angle to the initial light, but I'm not sure why this helps the sky etc..

Also, I've different sized glass, so I presume I should get the size to fit the largest lens, and then an adapter to fit the others?

How about which one to go for? Hoya?

[Pheonix]

It'll make the sky a deeper blue normally (provided you've rotated it correctly), but you need to remember it can also make the sky an uneven shade of blue, depending on the conditions. Your other assumptions are indeed correct.

[Woz]

Don't you need to make sure you get the right sort nowadays?
It used to be that there were 2 types, and you had to get the circular for an autofocus camera.

[Dno]

There seems to be linear, and circular, but for DSLR's it's the circular yeah?

Not that I know what the difference is.

[pkr]

Worth noting is that they don't work very well with wide angles. A rule of thumb is not to use with lenses of a f/l less than around 25mm.

This is why -

http://homepage.ntlworld.com/pkroberts/nikon/DSC_0078-800.JPG

Note the very uneven sky. It has applied lots of polarisation just to the left of centre but because the light is different at the extremes, the effect falls away from the centre. So careful with your 12-24!

I have a non 'Pro' Hoya and a B&W Kaesemann. The B&W is superb, both optically and mechanically ( the rings are made of brass not aluminium on the Kaesemann variant ). Just so you're aware, B&W Kaesemann filters are often found in slim form which do not have a front filter thread so your lens cap doesn't work with them.

The problem with step down rings is using your lens hoods. In fact, the use of hoods becomes tricky anyway owing to access to the filter to rotate it.

[pkr]

There seems to be linear, and circular, but for DSLR's it's the circular yeah?

Not that I know what the difference is.


Linear doesn't work very well with autofocus. Circular is good.

[Dno]

Worth noting is that they don't work very well with wide angles. A rule of thumb is not to use with lenses of a f/l less than around 25mm.

This is why -

Note the very uneven sky. It has applied lots of polarisation just to the left of centre but because the light is different at the extremes, the effect falls away from the centre. So careful with your 12-24!

I have a non 'Pro' Hoya and a B&W Kaesemann. The B&W is superb, both optically and mechanically ( the rings are made of brass not aluminium on the Kaesemann variant ). Just so you're aware, B&W Kaesemann filters are often found in slim form which do not have a front filter thread so your lens cap doesn't work with them.

The problem with step down rings is using your lens hoods. In fact, the use of hoods becomes tricky anyway owing to access to the filter to rotate it.

Ta. The B&W look pretty pricey.

Is ~£25 for an imported 77mm sound about right?.. I'm clueless on prices atm. Also, where can you get the adapters for smaller threads?

Not got the 12-24 yet btw, that's in the 'wanted' section... Will seriously consider it for my Nepal trip later in the year though..

[pkr]

I think my Kaesemann 67mm was about £45 from HK.

Step down rings on eBay (http://www.thedvdforums.com/jump2.php?url=http://rover.ebay.com/rover/1/711-1751-2978-71/1?AID=5463217&PID=582776&mpre=http%3A//search.ebay.co.uk/search/search.dll%3Fcgiurl%3Dhttp%253A%252F%252Fcgi.ebay.co.uk%252Fws%252F%26fkr%3D1%26from%3DR8%26satitle%3Dstep+down+filter%26category0%3D)

Or try SRB film in Luton. They're good for esoteric stuff but I'm not certain they can equal eBay and the like for the more mundane. http://www.srb-griturn.com/

What was the £25 for? Hoya? Like B&W, Hoya have different grades. The 'Pro' is supposed to be good, the others, not so.

[FishBoy]

I understand it also cuts the reflections out from water etc due to the reflected light being at a different angle to the initial light, but I'm not sure why this helps the sky etc..

How about which one to go for? Hoya?

...because light in the sky is not polarised in one direction, it's scattered all over the place by particles in the atmosphere, water vapour, clouds etc. - so by using a polariser you cut out the extraneous scattered particles and are only letting light through in one "plane" basically, hence the darkening effect.

Yeah, Hoya are the ones to go for, I would say.

[Highlander]

Onestop are very competitive on Hoya filters.

For step down rings, I'm sure they're around a fiver from Jessops (http://www.thedvdforums.com/jump2.php?url=http://clkuk.tradedoubler.com/click?p(17211)a(60823)g(106115))

[snoopstah]

Linear doesn't work very well with autofocus. Circular is good.
And auto-exposure, apparently. Although I use a linear polariser on my Sigma 10-20mm, cos I'm a cheapskate, and haven't noticed any problems with either AF or AE.

For anyone interested, a circular polariser is basically a linear polariser with a quarter-wave plate mounted directly behind it. The linear polariser chucks away any light that isn't polarised on the correct axis, and the quarter-wave plate takes that polarised light and jumbles it up so it's unpolarised again. Result: all the effects of a linear polariser, but without sending polarised light through the lens and into the camera.

This is also why a circular polariser only appears to work in one direction (hold it up to an LCD monitor with the screw-thread facing you and rotate, and it works, hold it up with the screw-thread facing away from you and rotate, and it doesn't)

[Dno]

I think my Kaesemann 67mm was about £45 from HK.

Step down rings on eBay (http://www.thedvdforums.com/jump2.php?url=http://rover.ebay.com/rover/1/711-1751-2978-71/1?AID=5463217&PID=582776&mpre=http%3A//search.ebay.co.uk/search/search.dll%3Fcgiurl%3Dhttp%253A%252F%252Fcgi.ebay.co.uk%252Fws%252F%26fkr%3D1%26from%3DR8%26satitle%3Dstep+down+filter%26category0%3D)

Or try SRB film in Luton. They're good for esoteric stuff but I'm not certain they can equal eBay and the like for the more mundane. http://www.srb-griturn.com/

What was the £25 for? Hoya? Like B&W, Hoya have different grades. The 'Pro' is supposed to be good, the others, not so.

Thanks, for the links.

Not sure which version it is tbh:
77mm Hoya Polariser (http://www.thedvdforums.com/jump2.php?url=http://www.onestop-digital.com/catalog/product_info.php?cPath=39_41&products_id=133)

[Fozzybear]

Interesting stuff here - pkr's shot is very useful, I have been wondering about buying a wiiide zoom and thought about how I'd use a polariser but if that's the result I'll not worry about one for it (if I get one!). I had a 24mm lens on my 35mm kit and had a little of this problem, but it wasn't 'too' bad. Mind you, at the time I was in the 'black sky' phase of polariser use! :D

[pkr]

Thanks, for the links.

Not sure which version it is tbh:
77mm Hoya Polariser (http://www.thedvdforums.com/jump2.php?url=http://www.onestop-digital.com/catalog/product_info.php?cPath=39_41&products_id=133)

It's certainly not the 'Pro' version. It is one of the lesser Hoya types, but I'm not sure which one. Hoya is a bit confusing as their ranges are packaged by colour ( blue, purple, green ? ) but what each one means is a mystery to me.

A quick query in the
OneStop Digital (http://www.thedvdforums.com/jump2.php?url=http://www.onestop-digital.com/) thread should answer your question.

[Highlander]

It's the purple one. It's where I bought mine, and that was what was sent to me.

[pkr]

Interesting stuff here - pkr's shot is very useful, I have been wondering about buying a wiiide zoom and thought about how I'd use a polariser but if that's the result I'll not worry about one for it (if I get one!). I had a 24mm lens on my 35mm kit and had a little of this problem, but it wasn't 'too' bad. Mind you, at the time I was in the 'black sky' phase of polariser use! :D

It does depend on which way you're facing. In that shot, the sun was to my left ( West ) and I was looking North ( standing on the Nany-Y-Moch dam wall western end ) so it was across the sun's light path. If I'd been looking East, the result may have been a bit better.

[spearce8]

Do you really need a filter?

Anyone on here don't use them?

For those who do, is it a protection thing more than anything else?

[Fozzybear]

You don't 'need' filters, I used to use them on film SLRs but when I changed to digital I photographed without them for years. It's only recently that I've started trying them again, just polariser and grey grads though - I'm not going to use a sunset filter like I did for a little while when I started out in photography!

[Dno]

I've not really tried much lanscape stuff yet, but with digitals smaller dynamic range, then surely gradient filters are even more important than with film?

[Fozzybear]

They are more important - that's the main thing I got my grads for. Until now I hadn't had a huge need for them though, even with grey skies I managed pretty well without them. It's easier if you have them though!

[RobDickinson]

Do you really need a filter?

You dont need filters to do something you can do in photoshop, warmify etc but theres a few that cant be done.

Circular polariser is needed because it removes reflections etc which cannot be done later.

Gradiated & ND filters too.

But to the OP , remember CP need adjusting all the time and remove 1-2 stops of light so for airshows I wouldnt bother.