Something I don't understand about Cokin filters


WobblyGoblin

Link Posted 14/03/2010 - 10:20
Hello All

I'm currently pricing up a Cokin filter system. Considering I don't have much consistency in filter thread size but do have some large diameter lenses it is a much more cost effective way of getting a comprehensive filter set. For the price of 2 decent polarisers for a 72mm and a 77mm I could get an entire filter setup! It's also attractive that I can buy it in stages and for the cost of an £11 adapter they can be used with any lens.

What I don't get is the lens hood issue. I understand a lot of the reasons for using a lens hood (preventing flare, increasing contrast etc). I don't understand how you achieve these with the cokin filters attached. Is it just a case of "you don't" or is there something I'm missing?

If so I presume the conclusion is that the best quality is probably obtained from circulars filters with a lens hood.

Cheers
You will only prise my 43Ltd from my cold, dead hands...

johnriley

Link Posted 14/03/2010 - 10:25
The best quality is obtained by using a lens hood with no filters at all. The dedicated lens hood for a lens usually is the most efficient.

The Cokin filters are not the best quality and may well still be uncoated. There is a Cokin lens hood and it's a horrible unwieldy affair IMHO.

Circular multicoated glass filters are the best if you need to use filters.
Best regards, John

nass

Link Posted 14/03/2010 - 11:17
Agree with John. I've done the Cokin filter system and although it's fine for first filter explorations, I'm personally now in the process of replacing it with dedicated filters.

One set of very large filters with step downs for your smaller lens filter diameters are a reasonable compromise cost-wise.
... just another middle-aged guy with a hobby. I have an extreme macro learning site at extreme-macro.co.uk - Pentax-centric, your feedback and comments would be appreciated!

Pentaxophile

Link Posted 14/03/2010 - 11:30
I'd pick up a couple of round polarising filters for your most used lenses, and you can always get stepping rings to adapt them for other lenses if need be.

Anything Hoya is probably acceptable. I'm not sure if you need the new slim-fit, HD-ready, "it's got electrolytes" versions. I use an old second hand Hoya basic linear pol - it's fine! Perhaps there would be a bit more flare compared to the new so-called pro versions, if I shot into the sun, but I can live with that. If you bought 2nd hand and you aren't happy with the results, you can resell without being left out of pocket.

Even with a screw in pol, you might sometimes have to take the lens hood off though! Some lens hoods make it tricky to turn the filter.

I would only invest in a square filter system if you want to use grads. I find them a bit unwieldy and over-conspicuous in use, but acceptable shooting landscapes.
[link=https://500px.com/will_brealey/[/link]
Last Edited by Pentaxophile on 14/03/2010 - 11:34

WobblyGoblin

Link Posted 14/03/2010 - 11:42
Aha! But doesn't that give the same problems? You still can't use your lens hood that way. Are the Cokin filters not particularly good quality then?

Maybe it would be false economy to buy into the system. Perhaps I should be saving for polarisers for my walkabout and landscape lens (once I get it...) and then some NDand ND grad filters for both.

Hmmm.
You will only prise my 43Ltd from my cold, dead hands...

gartmore

Link Posted 14/03/2010 - 12:32
You may have noticed a little square part that pops off on the bottom of your Pentax hoods, with it removed you can rotate your polarising filter, that is its purpose.

Shooting into the sun isn't an issue with polarisers since they would have no effect whatsoever, they work when the light source is at an angle to the lens axis. With wide angle lenses you will need a Hoya Pro low profile filter or similar to avoid vignetting.

You do need a 'square' filter system with grads.
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

Pentaxophile

Link Posted 14/03/2010 - 12:40
You can't use a lens hood with filter holders, but a lot of people do use them and I think with a little care there is little effect on iq.

People use them because there is no way of reproducing the defect without making multiple exposures and pp-ing. Screw in grads don't give you enough control. PP is the only real alternative. It's probably worth exploring before you invest in a filter system, unless you are averse to photoshop.

Amateur photographer did a grad filter test last year. From memory many of them induced a slight colour cast. Kood seemed slightly better than cokin, of the budget options.
[link=https://500px.com/will_brealey/[/link]

nass

Link Posted 14/03/2010 - 12:47
Fyi, stacked cokin ND filters are a particular problem for Pentax cameras - Pentax lets in more IR than most systems. By the time you've stacked several, your image becomes magenta. Cokin filters in their own (ie just 1), seem fine.
... just another middle-aged guy with a hobby. I have an extreme macro learning site at extreme-macro.co.uk - Pentax-centric, your feedback and comments would be appreciated!

paulgee20

Link Posted 14/03/2010 - 13:38
I made the mistake initially of buying 'cheap' CPF's for the Sigma lenses I have. Fatal mistake and money thrown away.
If your going to buy filters buy the best quality. Save up and wait!

Paul
K5's (2)both gripped, K10d gripped, Pentax 28-90 f3.5, Sigma 18-250mm, Sigma 150-500mm. Sigma 105mm f/2.8 EX DG Macro, Sigma 10-20 f.4-5.6.EX DC, Hoya 135 f2.8, Take on 28mm f2.8 Pentax AF360 flash, 2 fill in slaves. 30 metre remote release, Rt angle viewfinder, Giotto NOT 3261B Tripod with Manfrotto 808Rd4 ball head, Manfroto 4861RC2 monopoly, shoulder stock, various filters etc, Panasonic SET HBS HD Video cam, Tamrac Explorer 8x backpack and a sore back.....
-------------------------------------------------------
Photography is an index for measuring futility and pride.......

Paul

:wink
http://s743.photobucket.com/home/pg20_photos/index http://www.flickr.com/photos/pg20

Anvh

Link Posted 14/03/2010 - 15:48
nass wrote:
Fyi, stacked cokin ND filters are a particular problem for Pentax cameras - Pentax lets in more IR than most systems. By the time you've stacked several, your image becomes magenta. Cokin filters in their own (ie just 1), seem fine.

The P and A series indeed have that problem but the Z-pro and the X-pro have it far less but they are more expensive though.

Like Ken says, you need to use the square system for GND (graduated natural density) filters because it's hand you can turn the filter at different angles and move the transition up and down.
For the rest it's better to get screw-in filters.
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
Last Edited by Anvh on 14/03/2010 - 15:50

techno-terminator

Link Posted 14/03/2010 - 15:55
What filters are you using Stefan ?
let the education continue

proud owner of a couple of cameras and a few bits and bobs

Anvh

Link Posted 14/03/2010 - 16:36
6 at the moment.
1 - B&W MRC CPL 49mm (for the DA40 & DFA100)
1 - B&W Kasemann MRC CPL 67mm (for the DA*50-135, is on it 99% of the time)

Then for the Cokin Z-pro holder.
1 - GND soft 2
1 - GND soft 4
1 - GND soft 8
1 - Infrared 89B

When I'm outdoors the CPL is almost standard fitted for me, indoors I only take it off when I need more light.

I also actually wonder what the other users have.
Do you've any filters Technoidiot?
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
Last Edited by Anvh on 14/03/2010 - 16:39

techno-terminator

Link Posted 14/03/2010 - 17:59
Just 3 at present A skylight , a circular polarising and a Fluorescent. All I need at present . I have the skylight on both lenses [ yes - have 2 of them ]

But then I'm very much a newcomer to all this .
let the education continue

proud owner of a couple of cameras and a few bits and bobs

WobblyGoblin

Link Posted 14/03/2010 - 18:47
Sounds like sticking to the circular filters is the plan for most applications and then a square set for some graduated NDs.

Can probably get away with:

Walkabout lens:
- polariser
- an ND or two

Landscape lens:
- polariser

Tele and macro:
- nothing

Cokin/square filters:
- ND grads to fit the walkabout and landscape lenses

I probably wouldn't know what to do with any other filters anyway. I've already found out that an infrared filter is useless with the GX20. I get better pics from the old Kodak superzoom I took apart and removed the ir pass filter from.

Thanks for the advice and comments everyone. Always useful stuff to consider when I ask questions on here.

Cheers
You will only prise my 43Ltd from my cold, dead hands...

Anvh

Link Posted 14/03/2010 - 19:14
WobblyGoblin wrote:
I probably wouldn't know what to do with any other filters anyway. I've already found out that an infrared filter is useless with the GX20. I get better pics from the old Kodak superzoom I took apart and removed the ir pass filter from.

They say that about the K10D to.


The problem is there is a IR filter infront of the sensor like you said so it takes a bit longer but it can be done.
Model: PENTAX K10D
Shutter Speed: 1 second
Aperture: F/5.6
Focal Length: 18 mm
ISO Speed: 400

Used a monopod for this shot, not bad right

As for the ND, I at least would get them for the square filter because they are quite a lot cheaper or get a VARI-ND (basicly two pol filters) as a screw-in.
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
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