[jpzk]

I want to use my DA 15 Ltd with a screw in ND filter (possibly a GND if available).
This would also work for my FA 43 Ltd ... same filter size @ 49mm.

I've seen a reference to this: https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/111248-using-f...m-limited.html

but it doesn't quite answer all of my questions:

1. Are high quality screw in GND and/or ND filters available ? The lens is of high quality and I wouldn't want to waste its qualities with a chepo filter.
2. I suppose I will need a step up ring (or more than one) before mounting the filter ? I have an idea to use a cheap 49mm filter, break the glass off and use that as a step up ring before installing the filter ... is that a better choice or should I just get the step up rings - I've read they are cheap ? Can't remember where I read that though.
3. Am I going to get a lot of vigneting due to the distance from the filter to the lens' front element?

I am presently using the Cokin system with my DA*16-50 .... works great but I want to give it a go with the Limited's listed above, so a different "system" is required.


Anyone wants to jump in and offer solutions?

Cheers.

JP

[thebigcat]

Many 49mm filters will fit directly on the lens without interfering with the hood. My advice is go to a store and try them.

[Anvh]

You can consider doing digitally if the key of the ND is to get longer exposures.
For GND, you can stack exposures and i see you shoot with the K5 that has 13EV of exposure range in RAW so if you underexpose your photo a bit not to clip the highlights you can often up the darker parts to normal level without much problem if you are shooting low ISO.

I know it feels a bit like cheating but it works.

[jpzk]

You can consider doing digitally if the key of the ND is to get longer exposures.
For GND, you can stack exposures and i see you shoot with the K5 that has 13EV of exposure range in RAW so if you underexpose your photo a bit not to clip the highlights you can often up the darker parts to normal level without much problem if you are shooting low ISO.

I know it feels a bit like cheating but it works.

Thanks Anvh.

Well, I have "sort of" tried this technique a couple of times and while it does allow to use a longer exposure time, I believe I had some trouble with the highlights/shadows -- nothing dramatic but still some.

As for stacking the images ... I am all for that and I know how to do it but if what I am looking for is to have long exposure time.
I don't quite get how stacking a bunch of images and wanting to have, for example, the effect of near-cloud-like moving water ... ?
Care to tell me how to do this?

Example: daylight, bright; moving water: I want to have this "sliky" effect, so I am going to need a "very" long exposure time.
If I am already using ISO 80 , stop down @ f11-16 ... with NO filter(s): I am quite sure the shutter time will still be too short, no ?

I have used the Cokin system with my DA*16-50, and it works great, but I find the whole gear sometimes a little too "busy" (akward/cumbersome).

JP

[jpzk]

Many 49mm filters will fit directly on the lens without interfering with the hood. My advice is go to a store and try them.

Thanks BigCat .

Problem here: no store carrying those sort of circular/screw in ND/GND filters around here!

I live in a small Canikon town where two stores sell cameras/lenses ... not much else .... forget about accessories.
Oh well, they do have UV filters but that is not what I need.

Cheers.

[jpzk]

Found these:

Filters (Faders, ND, ...):

Polaroid 49mm Neutral Density Fader Filter PLFILFDND49 B&H Photo
Heliopan 49mm Neutral Density (ND) 3.0 Filter 704989 B&H Photo
B+W 49mm #106 Solid Neutral Density (ND) 1.8-64x BW106CS49 B&H

I thought that "variable" screw on filters would be a good idea ? Maybe not?

and, step up rings:
49mm step up ring

Edited: I could not find a straight 49mm to 49mm "extension" ring nowhere though.

I REALLY want to be able to use a low sutter speed in day time. (much like I am doing with the Cokin system at the present time, with a different lens).

JP

[abacus07]

I'm not really understanding why you need the extension ring to use 49mm screw in filters. I think there are reports of one or two specific filters (possibly the fader filter by the looks of it) that interfered with the hood but it seems rare. You will get vignetting if you do this. It will turn your DA15 into a DA15.5 after you crop it out.

I use these frequently with my DA15. The outer two filters are just there as a sandwich to keep them clean and scratchless.

[Andrew Faires]

If you use a 49mm polarizer thats thin, such as the xs pro from b+w, you can add a solid nd filter or attach a 49mm cokin p holder to it. It will vignette wide open, but stopped down, the problem will vanish. Otherwise, make a spacer like I posted in the other thread and you can do all cokin filters.

[jpzk]

I'm not really understanding why you need the extension ring to use 49mm screw in filters. That was intended to give more length to the set up so it would clear the hood. I think there are reports of one or two specific filters (possibly the fader filter by the looks of it) that interfered with the hood but it seems rare. You will get vignetting if you do this. It will turn your DA15 into a DA15.5 after you crop it out.

I use these frequently with my DA15. The outer two filters are just there as a sandwich to keep them clean and scratchless.

Thanks for the reply.

So you're saying that screwing those filters directly to the lens thread will do the trick without much vignetting, if any ?
Those Hoya filters ... what would you say about the quality IQ-wise ?
And, what is the coresponding number of stops with those ... i.e.: the ND X8 and the ND X400 ?

[jpzk]

If you use a 49mm polarizer thats thin, such as the xs pro from b+w, you can add a solid nd filter or attach a 49mm cokin p holder to it. It will vignette wide open, but stopped down, the problem will vanish. Otherwise, make a spacer like I posted in the other thread and you can do all cokin filters.

Thanks Andrew.

I must have an old 49mm circular polarizing filter somewhere ... gotta find it and see how it fits, then I'll be able to see how a ND filter of the same size will fit.
Abacus, (post above) mentions that there is no need for a spacer if the filter fits directly on the lens' thread ... !?

JP

[Nuff]

Is this the kind of photos you are talking about?

15mm limited, f11, iso 80, 10s + 49mm B&W #110 ND filter



I don't really see the point of ND filter on camera like K5 if you shoot raw. If you had issues with highlights and shadows, spending extra time experimenting, learning and asking questions could work wonders. I'm still learning how to post process correctly and everyday I'm learning something new.

Right now I'm of the opinion that few ND filters and PL should be enough.

[abacus07]

Thanks for the reply.

So you're saying that screwing those filters directly to the lens thread will do the trick without much vignetting, if any ?
Those Hoya filters ... what would you say about the quality IQ-wise ?
And, what is the coresponding number of stops with those ... i.e.: the ND X8 and the ND X400 ?

1 filter = no vignetting
2 filters = vignetting that requires a slight crop

there might be better filters (slightly) but Hoya is a respected brand and I doubt i could tell the difference between them. I only buy MC filters.

The numbers are exponential if you understand your math. It is kind of tiresome how every manufacturer wants to number them differently.

2 stop = 2^2 = ND4
3 stop = 2^3 = ND8
ND400 is advertised as 9 stop but I've found it to be closer to 8. Not surprisingly 2^8=256 and 2^9=512.

[Anvh]

As for stacking the images ... I am all for that and I know how to do it but if what I am looking for is to have long exposure time.
I don't quite get how stacking a bunch of images and wanting to have, for example, the effect of near-cloud-like moving water ... ?
Care to tell me how to do this?

Example: daylight, bright; moving water: I want to have this "sliky" effect, so I am going to need a "very" long exposure time.
If I am already using ISO 80 , stop down @ f11-16 ... with NO filter(s): I am quite sure the shutter time will still be too short, no ?

Yes the shutter time will be short but if you've 10 photos of 3 seconds then together you theoretically have captured 30 second off information.
The trick is to combine them.
I'm no expert at this and never actually done it.

I wonder if to use the transparency slider and if you've 10 photos you set that to 10% so it ends up with 100% or to use "lighten" layer option.
This can be done in gimp and photoshop.

Do you maybe still have those photos?


with photoshop CS extended, you have stacking mode and i just read to use “mean” or “median”.

[twitch]

The DA15 is great with B+W 10 stop or Hoya ND 9 stop screw in filters. I use my DA15 with a 10 stop a lot, you can get photos that are not possible to emulate in PP with shorter exposures. B+W also make a 0.6 GND filter, although it is restrictive due to the nature of a screw in filter and not being able to adjust for where the horizon is in the composition, it is always across the middle.

[fs999]

I have the B+W ND1000 49mm which is great. For CPL, the best is the Hoya Pro1 Digital but 52mm is the smallest, so I am using a 49 to 77mm step-up on a 49mm neutral filter and I don't have vigneting.

with CPL


with ND1000 30" F16 80 ISO