DA25mm 645 lens Internal Filter options?

Thomasbrowphoto · 01-21-2015, 07:45 PM

Hey guys and girls, just wondering if any of you have insights into using a Internal ND filter on the 25mm lens. If anyone could give me a link to where I can find some that would be great.

Thanks, Tom

Adam · 01-21-2015, 10:01 PM - **1 Like**

Any 40.5mm screw-in filter will work, such as this one:

Tiffen 40.5mm Neutral Density 0.9 Filter 405ND9 B&H Photo Video

Remember that every 0.3 neutral density equals 1 f stop.

Ryan Tischer · 01-22-2015, 08:55 AM

I believe I have the same filter that Adam posted. Works fine. Takes a little time to change as you need to be more careful so as to not drop the filter holder or let anything get into the lens. Usually I just lay a lens cloth over the lens opening while I swap filters.

jwoodland · 01-22-2015, 10:32 AM

Too bad there doesn't seem to be anyplace to order additional filter holders to make it quick and easy to change them out - Pentax/Richo has been no help, nor B&H, or anyone here when I asked about this several months ago. I tried to get a filter made by Sing-Ray, but they required me to send them one of the filter holders, which I could never buy anywhere. If someone here has a source to purchase one of these filter holders, please let me know. Thanks!

mikeSF · 01-23-2015, 03:14 PM

in addition to the clear 40.5mm and C-PL that came with the lens, I also use a B+W F-PRO 10-stop ND

**Ed Hurst** · 01-25-2015, 01:53 AM - **2 Likes**

I would also love to know a way to get hold of further examples of the filter holder. It would be much better to have the most frequently used filters ready loaded in those holders than fiddling around with large, clumsy hands in the half light as wonderful conditions change quickly...

Thomasbrowphoto · 03-31-2015, 09:58 PM - **1 Like**

Originally posted by mikeSF

in addition to the clear 40.5mm and C-PL that came with the lens, I also use a B+W F-PRO 10-stop ND

Hey mike Im wondering what kind of long exposure time you can get from the above mentioned lens filter. Would it be good for architecture/ long exposure clouds?

Thanks mate.

mikeSF · 03-31-2015, 10:26 PM

Originally posted by Thomasbrowphoto

Hey mike Im wondering what kind of long exposure time you can get from the above mentioned lens filter. Would it be good for architecture/ long exposure clouds?

Thanks mate.

its great for that.

angerdan · 02-17-2021, 11:31 AM - **1 Like**

Originally posted by jwoodland

Too bad there doesn't seem to be anyplace to order additional filter holders to make it quick and easy to change them out - Pentax/Richo has been no help, nor B&H, or anyone here when I asked about this several months ago.

If someone here has a source to purchase one of these filter holders, please let me know. Thanks!

Hey Tim!
Sorry i'd took that long, it seems i've been distracted.
Ricoh offers the Pentax Filter Holder for DA560mm (article number 35656), which seems identical to the holder for the 645 DA 25mm:
Buy Filter Holder for DA 560mm lens, for £90.37! | Ricoh Imaging UK

**kaseki** · 02-18-2021, 05:38 PM

Originally posted by angerdan

Hey Tim!
Sorry i'd took that long, it seems i've been distracted.
Ricoh offers the Pentax Filter Holder for DA560mm (article number 35656), which seems identical to the holder for the 645 DA 25mm:
Buy Filter Holder for DA 560mm lens, for £90.37! | Ricoh Imaging UK

That filter holder must be a state secret outside of Europe. I couldn't find it as an available part in any USA Ricoh-Imaging literature. B&H doesn't list it. The image of the filter holder (see below) appears with Amazon's web page for the lens, but no separate purchase information is listed. And Ricoh Imaging UK doesn't sell into the USA, at least via their web site link above.

Except for the color, in the orientation seen in the attached image the 645 DFA 25mm filter holder appears identical as @angerdan noted.

Flipped over, one finds that the externally exposed knurl for circular polarizer rotation has a small (~7mm) metal gear on its shaft. This mates to a second metal intermediate idler gear (~8mm), which drives a fine tooth (~47mm) plastic ring gear on the outside of the filter adapter ring.

References I found by @angerdan: Pentax Normal 40.5mm Filter (for rear filter holder of DA 560mm and 645 DA 25mm) - Page 2 - PentaxForums.com

And a note: Previously reported testing by me of the 25mm confirmed my suspicion based on optics behavior in general, there must be glass in the filter, for example a CP filter or a clear filter or an ND filter. Otherwise, the optical prescription deteriorates.

**Ed Hurst** · 02-18-2021, 06:17 PM

If this does indeed turn out to be compatible with the 645 25mm DA/DFA, I would be VERY interested in knowing about it. THANKS SO MUCH for this... Please keep us all informed!

**kaseki** · 02-18-2021, 06:30 PM

Originally posted by Ed Hurst

If this does indeed turn out to be compatible with the 645 25mm DA/DFA, I would be VERY interested in knowing about it. THANKS SO MUCH for this... Please keep us all informed!

If I could get one I could tell you how it turns out. At this writing it seems to be vaporware in the USA.

Note: previous message had various edits over time that might have been missed.

**Ed Hurst** · 02-18-2021, 06:56 PM

Can it not be bought from the UK site? A pain - but possible...?

**kaseki** · 02-18-2021, 07:21 PM

Originally posted by Ed Hurst

Can it not be bought from the UK site? A pain - but possible...?

Perhaps they might answer the telephone if the UK lock-down hasn't chased them out of the office. Perhaps of the myriad dialects in the UK not conforming to std. rcvd. English, I will understand what I hear. An email might also work; didn't look at that. Spelling is close enough.

I noticed for EU shipping by UPS that they listed 30 pounds sterling. Seems pretty high for a couple of ounces. I also don't know what the shipping conditions are UK to USA. Japan has to use DHL for camera stuff at present. It was very easy previously. The Japan Post had a deal with the USPS and one could declare and mail a package that quickly got to its destination. DHL has to deal more deeply with Customs, so there can be delays. Also, one's telephone number seems to not get passed along in the process, so when no package arrives, one has to call and find it, and maybe pay a Customs inspection fee.

Correction: the website is an English version with UK denominated currency, but the actual business location is in France. I'll try their contact system.

Tilt! That form only allows messages from listed EU countries. I'll think further about "pain" vs. reward.

**Ed Hurst** · 02-18-2021, 07:40 PM

They certainly will be speaking/writing in English rather than American, that much is true for sure

Can't comment on the shipping/payment issues these days. Although I am British, I live in Oz and when I was last home, it was in a pre-Covid, pre-brexit world, so things may have become harder and less logical.

01-21-2015, 07:45 PM	#1
Thomasbrowphoto Veteran Member Join Date: May 2014 Location: NSW, Australia Posts: 335	DA25mm 645 lens Internal Filter options? Hey guys and girls, just wondering if any of you have insights into using a Internal ND filter on the 25mm lens. If anyone could give me a link to where I can find some that would be great. Thanks, Tom

01-21-2015, 10:01 PM - 1 Like	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Any 40.5mm screw-in filter will work, such as this one: Tiffen 40.5mm Neutral Density 0.9 Filter 405ND9 B&H Photo Video Remember that every 0.3 neutral density equals 1 f stop. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

02-18-2021, 05:38 PM	#10
kaseki Loyal Site Supporter Join Date: Dec 2017 Photos: Gallery \| Albums Posts: 1,138	Originally posted by angerdan Hey Tim! Sorry i'd took that long, it seems i've been distracted. Ricoh offers the Pentax Filter Holder for DA560mm (article number 35656), which seems identical to the holder for the 645 DA 25mm: Buy Filter Holder for DA 560mm lens, for £90.37! \| Ricoh Imaging UK That filter holder must be a state secret outside of Europe. I couldn't find it as an available part in any USA Ricoh-Imaging literature. B&H doesn't list it. The image of the filter holder (see below) appears with Amazon's web page for the lens, but no separate purchase information is listed. And Ricoh Imaging UK doesn't sell into the USA, at least via their web site link above. Except for the color, in the orientation seen in the attached image the 645 DFA 25mm filter holder appears identical as @angerdan noted. Flipped over, one finds that the externally exposed knurl for circular polarizer rotation has a small (~7mm) metal gear on its shaft. This mates to a second metal intermediate idler gear (~8mm), which drives a fine tooth (~47mm) plastic ring gear on the outside of the filter adapter ring. References I found by @angerdan: Pentax Normal 40.5mm Filter (for rear filter holder of DA 560mm and 645 DA 25mm) - Page 2 - PentaxForums.com And a note: Previously reported testing by me of the 25mm confirmed my suspicion based on optics behavior in general, there must be glass in the filter, for example a CP filter or a clear filter or an ND filter. Otherwise, the optical prescription deteriorates. Attached Images Last edited by kaseki; 02-18-2021 at 06:28 PM.

02-18-2021, 07:21 PM	#14
kaseki Loyal Site Supporter Join Date: Dec 2017 Photos: Gallery \| Albums Posts: 1,138	Originally posted by Ed Hurst Can it not be bought from the UK site? A pain - but possible...? Perhaps they might answer the telephone if the UK lock-down hasn't chased them out of the office. Perhaps of the myriad dialects in the UK not conforming to std. rcvd. English, I will understand what I hear. An email might also work; didn't look at that. Spelling is close enough. I noticed for EU shipping by UPS that they listed 30 pounds sterling. Seems pretty high for a couple of ounces. I also don't know what the shipping conditions are UK to USA. Japan has to use DHL for camera stuff at present. It was very easy previously. The Japan Post had a deal with the USPS and one could declare and mail a package that quickly got to its destination. DHL has to deal more deeply with Customs, so there can be delays. Also, one's telephone number seems to not get passed along in the process, so when no package arrives, one has to call and find it, and maybe pay a Customs inspection fee. Correction: the website is an English version with UK denominated currency, but the actual business location is in France. I'll try their contact system. Tilt! That form only allows messages from listed EU countries. I'll think further about "pain" vs. reward. Last edited by kaseki; 02-18-2021 at 07:30 PM.

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01-22-2015, 08:55 AM	#3
Ryan Tischer Veteran Member Join Date: Feb 2012 Location: Duluth, Minnesota Photos: Albums Posts: 458	I believe I have the same filter that Adam posted. Works fine. Takes a little time to change as you need to be more careful so as to not drop the filter holder or let anything get into the lens. Usually I just lay a lens cloth over the lens opening while I swap filters.

01-22-2015, 10:32 AM	#4
jwoodland Forum Member Join Date: Dec 2011 Location: Arkansas Posts: 96	Too bad there doesn't seem to be anyplace to order additional filter holders to make it quick and easy to change them out - Pentax/Richo has been no help, nor B&H, or anyone here when I asked about this several months ago. I tried to get a filter made by Sing-Ray, but they required me to send them one of the filter holders, which I could never buy anywhere. If someone here has a source to purchase one of these filter holders, please let me know. Thanks!

01-23-2015, 03:14 PM	#5
mikeSF Pentaxian Join Date: Jan 2009 Location: East Bay Area, CA Photos: Gallery Posts: 6,622	in addition to the clear 40.5mm and C-PL that came with the lens, I also use a B+W F-PRO 10-stop ND

01-25-2015, 01:53 AM - 2 Likes	#6
Ed Hurst Site Supporter Join Date: May 2010 Location: Sydney Posts: 1,657	I would also love to know a way to get hold of further examples of the filter holder. It would be much better to have the most frequently used filters ready loaded in those holders than fiddling around with large, clumsy hands in the half light as wonderful conditions change quickly...

03-31-2015, 09:58 PM - 1 Like	#7
Thomasbrowphoto Veteran Member Join Date: May 2014 Location: NSW, Australia Posts: 335 Original Poster	Originally posted by mikeSF in addition to the clear 40.5mm and C-PL that came with the lens, I also use a B+W F-PRO 10-stop ND Hey mike Im wondering what kind of long exposure time you can get from the above mentioned lens filter. Would it be good for architecture/ long exposure clouds? Thanks mate.

03-31-2015, 10:26 PM	#8
mikeSF Pentaxian Join Date: Jan 2009 Location: East Bay Area, CA Photos: Gallery Posts: 6,622	Originally posted by Thomasbrowphoto Hey mike Im wondering what kind of long exposure time you can get from the above mentioned lens filter. Would it be good for architecture/ long exposure clouds? Thanks mate. its great for that.

02-17-2021, 11:31 AM - 1 Like	#9
angerdan Pentaxian Join Date: Feb 2015 Photos: Gallery \| Albums Posts: 2,642	Originally posted by jwoodland Too bad there doesn't seem to be anyplace to order additional filter holders to make it quick and easy to change them out - Pentax/Richo has been no help, nor B&H, or anyone here when I asked about this several months ago. If someone here has a source to purchase one of these filter holders, please let me know. Thanks! Hey Tim! Sorry i'd took that long, it seems i've been distracted. Ricoh offers the Pentax Filter Holder for DA560mm (article number 35656), which seems identical to the holder for the 645 DA 25mm: Buy Filter Holder for DA 560mm lens, for £90.37! \| Ricoh Imaging UK

02-18-2021, 06:17 PM	#11
Ed Hurst Site Supporter Join Date: May 2010 Location: Sydney Posts: 1,657	If this does indeed turn out to be compatible with the 645 25mm DA/DFA, I would be VERY interested in knowing about it. THANKS SO MUCH for this... Please keep us all informed!

02-18-2021, 06:30 PM	#12
kaseki Loyal Site Supporter Join Date: Dec 2017 Photos: Gallery \| Albums Posts: 1,138	Originally posted by Ed Hurst If this does indeed turn out to be compatible with the 645 25mm DA/DFA, I would be VERY interested in knowing about it. THANKS SO MUCH for this... Please keep us all informed! If I could get one I could tell you how it turns out. At this writing it seems to be vaporware in the USA. Note: previous message had various edits over time that might have been missed.

02-18-2021, 06:56 PM	#13
Ed Hurst Site Supporter Join Date: May 2010 Location: Sydney Posts: 1,657	Can it not be bought from the UK site? A pain - but possible...?

02-18-2021, 07:40 PM	#15
Ed Hurst Site Supporter Join Date: May 2010 Location: Sydney Posts: 1,657	They certainly will be speaking/writing in English rather than American, that much is true for sure Can't comment on the shipping/payment issues these days. Although I am British, I live in Oz and when I was last home, it was in a pre-Covid, pre-brexit world, so things may have become harder and less logical.