Filter recommendation/help

[ellisn]

I have decided to buy a Sigma 10-20 as I think it might be a nice range to have in Venice. But of course this is going to mean new filters as my Cokin P will not be big enough. Now having purchased a few lenses recently I can't afford to get a full range of filters, the 1680z and 70300g can share so they are covered with what I have but I want to get a grad filter for the 1020 but can only afford one so what one do you think would be the best to start with ND2, ND4 or ND8?

I'm thinking ND4 as it is in the middle but wanted to check. Guess I will have to get a 72mm c/pl as well... more money. Will have to sell some of the redundant 55mm filters I have laying around.

Thanks in advance for any help

Neil

[ellisn]

I'm wondering if my P filters will be OK if hand held in front of the lens... could save a few pennies. May hold back on purchase until the lens turns up.

[David Kilpatrick]

I thought the Sigma was a 77mm thread - can't remember now, but if it is 72mm, then a good solution is to buy a 62-72mm step up ring and acquire a filter holder for 72mm, then you can use the filters on all your lenses. I often hand-hold Cokin size P filters which are 82mm wide.

I've just tried the Cokin P adaptor on my 17-35mm on Alpha 900, which gives a good idea of how it might work on a 10-20mm on APS-C. The filter holder appears in the pic at any length shorter than 24mm, equal to around 15-16mm, but you could use a grad filter at this setting. The same goes for the circular filters like the polariser. If you cut the front two slots off the Cokin holder (mine has three slots) you might get away with zooming to 13mm or so and using a single grad, you would have to buy a spare filter holder to saw the front off.

I have here a Cromatek 100 wide-angle holder. The filters are 100mm wide, and the holder is very simple, but I don't have a 72 or 77mm ring to test it with. It still seems a bit deep at the edges for a 10-20mm at its shortest length.

David

[ellisn]

Thanks David

Yes your right 77mm not 72, good job I held back on purchase.

From your experiments.. thank you for the trouble.. it looks like hand holding will be the best option anyway. I would use a screw in c/pl rather than square, low profile on the wide lens.

This has thrown up a lot of questions regarding lenses and filters, how do you use them with lens hoods? do you remove the hood (especially on the 70300g) turn the c/pl then replace it? Use square grad filters with no hood? Not use any filters but use exposure bracketing and photoshop? Is there a book on this as I think my brainn is going to explode.

[harveyzone]

Thanks David

Yes your right 77mm not 72, good job I held back on purchase.

From your experiments.. thank you for the trouble.. it looks like hand holding will be the best option anyway. I would use a screw in c/pl rather than square, low profile on the wide lens.

This has thrown up a lot of questions regarding lenses and filters, how do you use them with lens hoods? do you remove the hood (especially on the 70300g) turn the c/pl then replace it? Use square grad filters with no hood? Not use any filters but use exposure bracketing and photoshop? Is there a book on this as I think my brainn is going to explode.

I have both Sigma 10-20mm and Cokin P filters, but I can't remember using them together, certainly not at the wider end of the zoom. I will have a look tonight if I can find them and see how it behaves.

You cannot use the lens hoods with the filter holder. You can get a square cokin hood that will fit into the folded outside the filters. I usually use my hand or a convenient nearby object (branch, sign post, passer-by etc)

[ellisn]

Thanks Tom, do you use a c/pl on the 10-20

[Greg Beetham]

My Cokin literature is out of date now, I had a look at the site and they now have (as well as the original A and P holders) Z-Pro and X-Pro (extra large holders) for filters suitable for use as wide as 15mm on 35mm format, that's going to be seriously big...and expensive no doubt, and also a new shoe mount system for attaching to the thread on the base of the camera (might be usefull for non extendable type lenses).
Greg
http://www.cokin.com/ico15-A.html

[harveyzone]

Thanks Tom, do you use a c/pl on the 10-20

I haven't to date, but here are the results of a few tests. (nothing scientific. P mode, and rattled off a few shots with filters on. No PP etc)...

From approx 14mm it is not a problem. Wider and you start getting the corners compromised.

At 10mm you can see the holder (this has no filters mounted). If the holder is mounted horizontally then it cannot be seen, but this is not useful for many filters...

the same at 15mm...

and 10mm with a polariser inserted (mount turned horizontally so that the edges do not show)...

[harveyzone]

...continued...

Here is the result of a ND grad ( positioned diagonally at 10mm) with light coming from behind and reflected in the corners. Potentially easy to shield if you are aware, but could cause problems.....

The same shot at 15mm...

I have also just realised that this was mounted on an existing UV filter (a Hoya pro1 slimline) so results may be marginally better without.

Hope this helps.
Tom

[ellisn]

Thanks Tom, very good of you to go to the trouble. Looks like hand held is the way to go or spend a fortune on larger holder and filters. I'm guessing a screw in type c/pl will show as well as the one I had on my kit 1870 lens did when wide so will be worse on the 1020. Although that was a hama job and very deep standing out 8mm from the front of the lens. The Marumi only stands out 5mm. I will have to research c/pl depths.

Thanks again

Neil

[ellisn]

This looks just like the same effect as cutting down a normal holder: http://www.cokin.com/ico6-WIDE-ANGLE-HOLDER.html, the sigma has a wide angle of 102.4 so this should be OK. I may just go for the z-pro holder though but will wait until I get the lens to see how it works with the P or hand holding. The hoya c/pl pro 1 seems the best bet as it is only 3mm deep.

[ellisn]

After taking a few pictures of my ceiling with the Sigma 10-20 and the Cokin Z-pro filter holder I have found that to keep the holder out of view at the wide end, 10mm, I have to reduce the holder to 2 slots. That is better than I thought as I was expecting to only have one slot available. 2 slots should be plenty for me. I did reverse the bolts so they protruded from the back just to make sure and the adapter ring is mounted in reverse so it sits in the side away from the lens. This does mean you have to screw the adapter ring to the lens with the holder attached.



If it was the z-pro c/pl (which looking at the cost it never will be) filter the spacer could be moved to the back and the adapter ring mounted normally but like this the little prongs stop the insertion of a normal square filter.

So anyone searching for this answer here it is.

Neil

[ellisn]

One other discovery I hadn't thought of, and not wanting to sound like a Cokin Z-Pro salesman as the same will be true for Lee filters this size etc.

On the 62mm thread size lenses the grad filters should be able to be used as stop down filters by moving them down in the holder as they are 150mm long. So even though more expensive than the P filters you do get 2 filters for the price of 1. Yet to test this theory though and no use if you want a ND4 grad at the same time as an ND4 stop down but with 3 different strength grads you can certainly cope with a lot of situations.

[David Kilpatrick]

Thanks for some useful thoughts and photo of the eventual rig-up. This may help others wanting to use filters on digital. I know it's popular to do it all in Photoshop, but the very best results will still be obtained by using filters. Of course, I never do

David