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03-05-2012, 04:04 PM   #16
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QuoteOriginally posted by Andrew Faires Quote
With the xs-pro cpl, you can add an nd filter of 49mm or add a cokin 49mm adapter ring and use any p-series ssized filter. The xs-pro is very slim but it gives you enough clearance of the hood. I personally use the b+w 6 stop nd on the cpl a lot and if I need to use grads, I add the cokin holder to the cpl and use a singh ray 2 or 3 stop gnd with a 3 stop nd (if required).
I also have the DA15. By attaching the cokin p holder directly to the 49mm xspro cpl do u get any vignetting?

Edit: sorry. Saw your other post re the cokin filter. Questions answered.

03-06-2012, 05:05 AM   #17
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Hi guys, from BHP's site, I can see that there are many versions of the 49mm B+W CPL filters. Are B+W CPL filters good? I mean better than Hoya's HD range?

I am led to believe that Hoya's HD range is the best in terms of CPL. Hoya HD Polarizers. I think the Hoya ones loses the least amount of light vs the other CPL (which typically loses 2 stops)?

The Hoya HD CPL only comes in 52mm version.

What are your opinions?
03-06-2012, 05:55 AM   #18
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Personally, I'm quite pleased with the b+w xs pro cpl. How it stacks up against the hoya, I don't know, but the xs pro is only 4 mm thick and stll allows for adding filters on top of it. It's also multi-coated. I suspect there's not a lot of difference between the two optically.
03-06-2012, 02:45 PM   #19
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QuoteOriginally posted by ladybug Quote
What are your opinions?
All the B+W filters are good, or at least all the ones I've tried which are various CPL's and ND's. You can't go wrong with B+W IMHO.

03-06-2012, 03:52 PM   #20
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I think the op is saying that the b+w loses 2 stops of light whereas the Hoya HD loses 1 1/6 stop only. That could be significant in the field.
03-06-2012, 04:10 PM   #21
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QuoteOriginally posted by Andrew Faires Quote
Personally, I've gone with the b+w xs-pro mount cpl. Costs more money, but it won't vignette and you can use a second filter on top of it with only a small part of the corners vignetting.

The other thing you can do is take a beater filter, pop the glass, remove the retaining ring and sand the filter ring down to 2.5mm to 3mm (iirc). This should allow you to attach the step-up ring and will only vignette in the most extreme of the corners up up to f/5.6. I did a thread on this a year or two ago, so if you check the threads I've started, you should find it pretty quickly. Just do yourself a favour and be careful of the edges after you sand....they are sharp.


ETA: https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/90610-those-da...d-filters.html

Seems I don't start that many threads
Andrew:

I use Cokin filters with different lenses but never could find a way to use them on my DA 15 Ltd, so this information comes in handy.
I've browsed the (link) thread you had started on using the 49mm filter (with the glass knocked out):

You said you'd post some pics of the setup "before" and "after".


For those who, like me, can only go with visual help, can you get some of those pics?
I am confused with the part where you sanded down the filter ring and using a step-up ring.

JP
03-06-2012, 04:37 PM   #22
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QuoteOriginally posted by raider Quote
I think the op is saying that the b+w loses 2 stops of light whereas the Hoya HD loses 1 1/6 stop only. That could be significant in the field.
I thought B+W loses 1 1/2
03-06-2012, 04:43 PM   #23
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QuoteOriginally posted by jpzk Quote
Andrew:

I use Cokin filters with different lenses but never could find a way to use them on my DA 15 Ltd, so this information comes in handy.
I've browsed the (link) thread you had started on using the 49mm filter (with the glass knocked out):

You said you'd post some pics of the setup "before" and "after".


For those who, like me, can only go with visual help, can you get some of those pics?
I am confused with the part where you sanded down the filter ring and using a step-up ring.

JP
Because there was no interest at the time, I didn't persue the matter any further. Because it was 2 years ago, the pics are gone.

However, it just so happens My original ring (with the sanding job) bit the biscuit and I need to go through the steps again....likely this weekend. I'll re-photograph the steps and some samples of vignetting with the final result and post on Saturday or Sunday.

To clarify though, there's no step up ring. Once the 49mm filter ring is sanded down, you screw the cokin 49mm adapter ring to the front of the filter ring. With the retaining ring and glass removed, the cokin 49mm adapter screws in quite deeply into the sacrificial filter ring.

Another thing I've learned is that if you can, use a brass filter ring if possible. The original I used was aluminum and when I had to separate it from the cokin adapter ring, it involved pliers, some cussing and the need for a new blank filter to attach to the cokin adapter ring.

03-06-2012, 04:59 PM   #24
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QuoteOriginally posted by twitch Quote
I thought B+W loses 1 1/2
Yes u are right. I checked bhp website and it states that the CPL loses 1.5 stops. So not a bad choice then.
03-08-2012, 12:45 PM   #25
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A couple of days early, but I was bored last night:

Using the Cokin P-series system with the DA 15mm f/4.0 Limited Lens:

Step 1: Find a sacrificial 49mm filter which you no longer use (don't like or one that you just want to destroy for the fun of it)
Make sure of the following:
a) The retaining ring holding the glass of the filter in place is at the front of the filter and not in the rear
b) Brass filters would work best. While you can use aluminum, aluminum filter rings can bind to the Cokin 49mm adapter ring.
c) Tiffen filters are fine to use, but because they use a thick filter ring of 7mm or so, you will end up doing a LOT of sanding. A thinner ring would help things go quicker.


Step 2: Pop the glass out
Because the retaining ring holding the glass in place is quite tight, you'll likely need to break the glass to get it out.
As a tip, take an old rag or a tea-towel to wrap around the filter prior to breaking it. You may also want to put card-board directly above/below the filter to prevent glass dust from contaminating the rag.
Another tip: Unlike what I did, turn the filter up-side-down. This will prevent the device being used to break the glass from sliding to the side and will likely require less force to actually break the glass.

The 'Glass Extraction Kit':



Step 3: Clear the glass and remove the retaining ring
Carefully (over a small box) remove the glass. This will leave a gap between the retaining ring and the filter ring.
Use gloves for this!
With the glass gone, the retaining ring unscrews quite easily.

No purpose, other than to celebrate destruction:


Glass cleared:


Retaining Ring being removed:


And gone:



Step 4: Sand the filter ring
On a flat surface, turn the filter up-side-down and start sanding the filter ring down to size. It may help if you attach the filter to the lens first so you have a rough idea of how much material needs to be removed, then remove the filter ring from the lens (I know you assumed this, but I figured I'd be safe and state it) and start sanding it down.
I used 100 Grit Sandpaper for this and even still, it took a lot of sanding....(see Step 1 c - or, as I like to refer to it: do as I say, not as I do)
After sanding for what seems like ages, wipe the filter down and attach it to the lens. See how much further you have to go.
**Caution**
The inside edge of the filter takes on quite a sharp edge.
Don't say I didn't warn you

Sizing:


Sandpaper on a flat surface: NOTE: you will get dust on the surface, so make sure it's not your new dining-room table. Wipe the surface down when you're done....your spouse won't thank you, but he/she won't kill you for leaving fine metal dust laying around


When you're done, the filter ring should sit just a hair lower than the top edge of the lens-hood:

**I'm almost embarassed by the abuse my 15mm has been put through, and it's showing, but it's been/being used rather ruthlessly**

Step 5: Thoroughly wipe down/rinse/dry the filter ring. Attach the Cokin 49mm adapter ring to the filter and and you're good to go.

Cokin adapter ring attached to the filter ring after sanding is done. NOTE how deep the adapter ring threads into the filter. Also, don't over-tighten as you don't want to bind the adapter and the filter ring:



I've been through this process twice now and I haven't had any problems attaching anything. The sanding doesn't seem to clog the inside threads of the filter ring...only sharpens the inside edge.

Here's two photographs taken with the filter ring/49mm adapter ring attached to the 15mm. These shots are taken wide open (f/4.0). The first shot is with the lens at infinity focus (excuse my shadow in the middle of the frame). The second shot is with the lens at the closest focus distance. The vignetting is there but it's soft and workable in post processing. I believe (but may be wrong) this is mostly the natural fall-off (hope that's the right term) of the lens wide open.



Last edited by Andrew Faires; 03-08-2012 at 01:18 PM.
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