ME Super - What Polarising Filter?

Hello All!
Probably everybody already knows but could someone tell me whether I can use a linear polarising filter with my ME Super or would I need one of the circular ones.
Also should I choose a Cokin type filter or a Hoya screw on type?
Thanks!

Linear is fine.

Buying a Cokin will enable you to use the filter on lenses with different filter sizes. If you have, or plan to get, several lenses with different filter sizes, this would be the more economical path to take. Buy the P type, which can be used on larger lenses.

As above lin = cheaper too.

jayson

Hi

Linear polarisers tend to mess up Autofocus modules (which have an internal linear polariser, so I'm told), the ME Super doesn't have Autofocus so linear will be fine.

If you're ever planning on getting an Autofocus camera it might be worth investing in a circular polariser though.

Reinforcing George's point, the Cokin P system is a good bet as you can share a set of filters over all your lenses, rather than having to buy the same filters in different thread sizes. You could instead get adapters to enable you to screw larger filters onto smaller threads (in effect replicating the idea of the Cokin system but with large screw filters), but such large screw-in filters are very pricey. The Cokin P system lets you use wider angle lenses, as the smaller system can result in vignetting (darkening of edges) as the smaller filter does not extend far enough. I bought a pre-packaged set of filters from Cokin, I got the holder, circular polariser, Tabacco grad and some nasty starburst, all for less than the price of the seperate circular polariser. No idea why it was so cheap, perhaps to get people to invest in the system. Anyway, keep an eye out for kits as they can work out very good value.


Matt

I think it's a pity to have a Super-Multi-Coated Pentax lens and then add an uncoated piece of optical grade plastic on the front. As a consequence, I only use Multi-coated glass filters, always a lens hood, and if at all possible even the filters are either Pentax, B&W or Heliopan.

Hi John

Unfortunately Pentax etc. don't make the 'system 'filters, hence a few might be needed of each if you have an extensive lens collection, although I agree that they are top notch - I have a Hoya circualr polariser and this is also surprisingly good. If you can afford to get such filters as those made by Pentax or B&W then they are very good quality, but at a price (I have one B&W flter and it is very good indeed, but I was lucky to get it on a used lens I bought!)

Lee filters are perhaps the best of the system type, and are also unfortunately quite expensive. I use the cheaper Cokin and they work fine, which is probably as I use them very judiciously and make sure that there are no problems with flare (flare reduction being perhaps the main benefit of the SMC coating, although there are others re. colour aberration etc.). Unfortunately Cokin do not intrinsically allow the use of a lens hood, although I have seen some bespoke cutting and gluing of holders to achieve this. I tend to just use my hand to keep direct sunshine off of the front element and filter assembly.

The general point John makes is valid, there seems to be little point investing in precision lens glass only to stick a cheap filter in front. However, remember that all filters really do (or, more correctly, all they SHOULD do) is to reduce the amount of a certain wavelength of light (unless it's close-up, and a polariser works according to 'light angle' rather than wavelength). In this respect the actual 'optical quality' of the filter glass isn't as important as it doesn't have to bend light* in a controlled manner as lens glass does. However, filters do introduce significantly more chance of flare and of vignetting, and any extra glass is of course going to reduce transmission. I highlighted that filters shouldn't have any influence on light path but, this being the real world, in practise they do. Higher quality filters should have less influence (I say 'should' as I've no real experience or means of comparison for this). The better quality filters also tend to have better 'filter qualities', by which I mean that grads have finer gradients, the colour corrections are much more accurate in terms of wavelength control, and pretty much all of them have better transmission than cheaper filters.

You're quite right to focus upon flare as problem with the Cokin system, I have had it before and have also suffered quite bad vignetting with stacked filters - it's amazing how quickly a few ruined slides makes you learn!

As long as you're aware you might have problems when using filters, and do something to counteract these problems, then you should be OK.

Matt

* I appreciate light isn't 'bent' as such, please consider this description as shorthand!

I think Matt has given a very extensive and extremely good summary - excellent stuff.

In the days of the Spotmatic Pentax made a "Ghostless" filter, only as a UV I think, and this has a curved construction of the same angle as the front element of the 50mm lens. The idea was to reduce any deviation in the light path and eliminate ghosting. An interesting idea, but I don't think it ever caught on.