Two Filter Questions

[Crtm]

Hi I recently purchased a B+W cilcular POL MRC Filter and a I am having great difficulty in figuring out once it's attached to the lens at what position the filter is sitting. Is there a way of telling or can I mark the filter while it is off so when it is put back on to the lens I know where to turn it to.

Second question has anyone purchased filters from SRB photographic I was wanting to purchase a variable ND filter and these were very reasonably priced.
I would be interested in your thoughts before I go and buy one.

Carol

 

[dinners]

Does your CPL not have an indicator line marked on the turning ring ?

I know you don't always want the filter rotated to the same position but it does at least enable you to know roughly what angle it's at.

I can't comment on SRB but I think the The Light Craft Mk II variable filter is supposed to be good. I'm sure Hoppy had good things to say about it.

 

[G.K.Jnr.]

Hi, As Phil said there is usually some sort of mark etc on the rim of the filter to indicate the angle. As for SRB Photographic, I've never had any problems with any of their equipment. Hope this helps.

 

[Crtm]

Hi Guys thanks for your replies I have other filters which are marked but this one has nothing no intents no lines I even looked at it through a magnifying glass but to no avail.

Thanks for the positive remark re the SRB Photographic filter I think I will purchase one.

Carol

 

[kendo1]

Mark it with a pen.

Simples.

 

[Crtm]

Yes I was going to mark with a pen, I just wanted to make sure there was no other way of working it out.

Thanks

Carol

 

[HoppyUK]

Does your CPL not have an indicator line marked on the turning ring ?

I know you don't always want the filter rotated to the same position but it does at least enable you to know roughly what angle it's at.

I can't comment on SRB but I think the The Light Craft Mk II variable filter is supposed to be good. I'm sure Hoppy had good things to say about it.

No, Hoppy doesn't have anything good to say about any vari-ND filter - even the very expensive ones. Use them with a wide-angle and they all create a dark cross over the image at higher densities. Quick google threw up this example http://www.dgrin.com/showthread.php?t=215207 which is typical, and the cheaper ones create flare and impact sharpness on longer lenses. I sent mine straight back, though the LCW fixed density ND500MC filter is good.

Carol, I think the reason some polarisers don't have an index mark is because the glass itself can sometimes rotate in the mount. Anyway, while an index mark will usually get your close, for optimum results you should adjust by eye through the viewfinder.

 

[hollis_f]

No, Hoppy doesn't have anything good to say about any vari-ND filter - even the very expensive ones.

Me too. As well as the nasty X-factor there's the problem with setting exposure.

With a proper ND you can easily calculate how to change the exposure. With a 6-stopper, for example, you change the shutter speed by a factor of 64. So an exposure of 1/250s changes to 1/4s. Easy peasy.

But, with a VND you don't know if a particular position is 5, 6 or 7 stops - so you can't calculate the required exposure settings. You have to take a test shot, change settings, repeat.

 

[dinners]

No, Hoppy doesn't have anything good to say about any vari-ND filter

I could have sworn it was you that had good things to say about one particular model - albeit a while back

My mistake, did a search and found this. It was the lightCraft ND500MC filter thre that you said was excellent - within a variable filter topic.

Yes. Completely useless IMHO. With anything approaching a wide angle lens, you get a dark cross pattern from corner to corner at higher levels of ND. All cross-polarisers do it, it's a technique used to vary the lights in video/movies, which doesn't work for our application. I sent mine straight back, and I'm not the only one.

On the other hand, the LightCraft ND500MC is excellent

 

[HoppyUK]

 

[Crtm]

Thanks Hoppy and Dinners for your replies.

The problem is Hoppy when I add the filter to the lens I am not seeing any change no matter what way I rotate it, perhaps its just me! I will try again and study the picture through the viewfinder, I am not in the habit of using live view would this make the difference?

Carol

 

[dinners]

A CPL can be quite subtle if the light is diffused. You certainly won't see a difference in the way you would an ND Grad for example.

With a sunny sky or strong direction of light or glare - you should be able to just hold it in your hand and see the effect as you rotate it.

Try taking a short video whilst you turn it.

 

[Canon Bob]

The problem is Hoppy when I add the filter to the lens I am not seeing any change no matter what way I rotate it, perhaps its just me!

Even if you don't see an obvious change, Carol, keep an eye on the shutter speed display....it generally becomes slower at the point of maximum polarisation (if you're in AV mode).

Bob

 

[HoppyUK]

Thanks Hoppy and Dinners for your replies.

The problem is Hoppy when I add the filter to the lens I am not seeing any change no matter what way I rotate it, perhaps its just me! I will try again and study the picture through the viewfinder harder, I am not in the habit of using live view would this make the difference?

Carol

A polarising filter needs polarised light to work, eg blue sky (not facing the sun) or reflections off a dark shiny car. In which case, the effect should be obvious.

It's not unknown for filters to be assembled back-to-front at manufacture, in which case a circular polariser will do absolutely zip. Try just looking through it off the camera, from each side in turn. Your PC screen is a good test, assuming it's a flat LCD type - rotate the filter and it will turn black.

Edit: with the PC screen test, when the screen goes black, the correct position for the index mark is exactly at the top of the filter - or exactly at the bottom (same difference).