Question regarding the new forthcoming Pentax DFA 100mm f/2.8 WR macro lens

mikesbike · 11-13-2022, 11:06 PM

This new lens has been designed and is apparently in production, and will soon be available. It is shown along with description and specs on the B&H website. I did not think I would be interested, since I've long had the current Pentax DFA 100mm f/2.8 WR macro and have been quite satisfied with it. However, upon taking a better look, I noticed in addition to an upgrade in optics, the new one also features nice, quiet, and most likely improved DC AF. For me this might be a deal-maker. But, I also noticed quite a difference in one particular spec- the minimum focus distance, which for the new one is at 5.1 " where apparently it will deliver its maximum 1x magnification, while the old one is at nearly 12". Would this not mean you would get that maximum 1x magnification with the lens farther from the subject with the old lens, and have to get closer with the new one?

Adam · 11-14-2022, 12:26 AM

Perhaps B&H has some typos, as the two lenses have a very similar minimum focusing distance and the new one certainly doesn't have DC autofocus

I think the main improvement (beyond the WR -> AW upgrade) is the reduction in aberrations.

Not a Number · 11-14-2022, 12:32 AM

Where do you get 5.1 inches? The Ricoh web page says the minimum focus distance is 0.303 meters or 11.93 inches for both lenses. The B&H page is probably in error.

https://us.ricoh-imaging.com/product/smc-pentax-d-fa-macro-100mm-f2-8-wr/
https://us.ricoh-imaging.com/product/hd-pentax-d-fa-macro-100mmf2-8-ed-aw/

mikesbike · 11-14-2022, 02:13 AM

Unfortunately, I can no longer bring up the US Ricoh website. My fine, expensive Mac Pro II laptop, bought new about 5 years ago, responds with "This connection is not private" and stating it might be an imposter.

Strange, that B&H would present such misinformation. They are usually reliable. I wonder where their incorrect info came from- maybe mixed it up with that of another brand?

Thanks to both of you for clearing this up. I'm sure others will be or have been misled upon visiting B&H regarding this lens.

**Rondec** · 11-14-2022, 03:40 AM

It's basically the same lens with respect to size and auto focus. The only difference is less fringing, if that bothers you with the older lens.

**Astropaps** · 11-14-2022, 07:20 AM

Ricoh says 13 centimeters which comes to 5.1”.

Fogel70 · 11-14-2022, 08:14 AM

It is 13cm from front of the lens, but minimum focus distance is 30.3 cm (from senor).

Although it is probably not the best translation.

Quote:

This macro lens captures life-size images at a distance of 13 centimeters from the front end to the subject.

The description from Ricoh Imaging JP is better IMO.

Quote:

A working distance of 13 centimeters (at life-size magnification)...

https://news.ricoh-imaging.co.jp/rim_info2/2022/20221020_037611.html

Last edited by Fogel70; 11-14-2022 at 09:05 AM.

**Ron Boggs** · 11-14-2022, 10:08 AM

The confusion is due to the difference in minimum working distance--which is the distance to the front of the lens at 1:1 VS minimum focus distance at 1:1 which is measured to the sensor thus adding the length of the extended lens and the space from the mount to the sensor. Both Ricoh and B&H are correct...

Not a Number · 11-14-2022, 01:44 PM

Ah, right, I forgot about sensor to subject vs front element to subject distances.

Paul the Sunman · 11-14-2022, 02:01 PM

Originally posted by Not a Number

Ah, right, I forgot about sensor to subject vs front element to subject distances.

It's when the former is less than the latter that you have a design flaw.

mikesbike · 11-14-2022, 02:44 PM

In practical use it would seem the figure for the front of the lens distance would be more informative. But then B&H gives the other figure for the old lens, which then provides a misleading comparison.

As to the DC AF, this is listed as one of its features in the product description, with a paragraph headed in big letters DC AUTOFOCUS MOTOR which then includes the type of focus system called FREE.

pschlute · 11-14-2022, 02:50 PM

Originally posted by Paul the Sunman

It's when the former is less than the latter that you have a design flaw.

......

Fogel70 · 11-14-2022, 10:16 PM

Originally posted by Ron Boggs

The confusion is due to the difference in minimum working distance--which is the distance to the front of the lens at 1:1 VS minimum focus distance at 1:1 which is measured to the sensor thus adding the length of the extended lens and the space from the mount to the sensor. Both Ricoh and B&H are correct...

B&H are wrong as they specify minimum focus distance as 5.1". They apparently have mixed up minimum working distance with minimum focus distance. They also use the term "minimum focus working distance" in the description which seems to be a mix of both.

11-13-2022, 11:06 PM	#1
mikesbike Pentaxian Join Date: Dec 2016 Location: Southeastern Michigan Posts: 4,186	Question regarding the new forthcoming Pentax DFA 100mm f/2.8 WR macro lens This new lens has been designed and is apparently in production, and will soon be available. It is shown along with description and specs on the B&H website. I did not think I would be interested, since I've long had the current Pentax DFA 100mm f/2.8 WR macro and have been quite satisfied with it. However, upon taking a better look, I noticed in addition to an upgrade in optics, the new one also features nice, quiet, and most likely improved DC AF. For me this might be a deal-maker. But, I also noticed quite a difference in one particular spec- the minimum focus distance, which for the new one is at 5.1 " where apparently it will deliver its maximum 1x magnification, while the old one is at nearly 12". Would this not mean you would get that maximum 1x magnification with the lens farther from the subject with the old lens, and have to get closer with the new one?

11-14-2022, 12:26 AM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,124	Perhaps B&H has some typos, as the two lenses have a very similar minimum focusing distance and the new one certainly doesn't have DC autofocus I think the main improvement (beyond the WR -> AW upgrade) is the reduction in aberrations. 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, 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:

11-14-2022, 02:44 PM	#11
mikesbike Pentaxian Join Date: Dec 2016 Location: Southeastern Michigan Posts: 4,186 Original Poster	In practical use it would seem the figure for the front of the lens distance would be more informative. But then B&H gives the other figure for the old lens, which then provides a misleading comparison. As to the DC AF, this is listed as one of its features in the product description, with a paragraph headed in big letters DC AUTOFOCUS MOTOR which then includes the type of focus system called FREE. Last edited by mikesbike; 11-14-2022 at 02:55 PM.

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11-14-2022, 12:32 AM	#3
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 9,623	Where do you get 5.1 inches? The Ricoh web page says the minimum focus distance is 0.303 meters or 11.93 inches for both lenses. The B&H page is probably in error. https://us.ricoh-imaging.com/product/smc-pentax-d-fa-macro-100mm-f2-8-wr/ https://us.ricoh-imaging.com/product/hd-pentax-d-fa-macro-100mmf2-8-ed-aw/

11-14-2022, 02:13 AM	#4
mikesbike Pentaxian Join Date: Dec 2016 Location: Southeastern Michigan Posts: 4,186 Original Poster	Unfortunately, I can no longer bring up the US Ricoh website. My fine, expensive Mac Pro II laptop, bought new about 5 years ago, responds with "This connection is not private" and stating it might be an imposter. Strange, that B&H would present such misinformation. They are usually reliable. I wonder where their incorrect info came from- maybe mixed it up with that of another brand? Thanks to both of you for clearing this up. I'm sure others will be or have been misled upon visiting B&H regarding this lens.

11-14-2022, 03:40 AM	#5
Rondec Loyal Site Supporter Join Date: Mar 2009 Location: Gladys, Virginia Photos: Gallery Posts: 25,889	It's basically the same lens with respect to size and auto focus. The only difference is less fringing, if that bothers you with the older lens.

11-14-2022, 07:20 AM	#6
Astropaps Loyal Site Supporter Join Date: Mar 2017 Posts: 97	Ricoh says 13 centimeters which comes to 5.1”.

11-14-2022, 08:14 AM	#7
Fogel70 Pentaxian Join Date: Sep 2009 Location: Stockholm, Sweden Photos: Albums Posts: 2,861	It is 13cm from front of the lens, but minimum focus distance is 30.3 cm (from senor). Although it is probably not the best translation. Quote: This macro lens captures life-size images at a distance of 13 centimeters from the front end to the subject. The description from Ricoh Imaging JP is better IMO. Quote: A working distance of 13 centimeters (at life-size magnification)... https://news.ricoh-imaging.co.jp/rim_info2/2022/20221020_037611.html Last edited by Fogel70; 11-14-2022 at 09:05 AM.

11-14-2022, 10:08 AM	#8
Ron Boggs Site Supporter Join Date: Feb 2008 Location: MT Photos: Gallery Posts: 1,328	The confusion is due to the difference in minimum working distance--which is the distance to the front of the lens at 1:1 VS minimum focus distance at 1:1 which is measured to the sensor thus adding the length of the extended lens and the space from the mount to the sensor. Both Ricoh and B&H are correct...

11-14-2022, 01:44 PM	#9
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 9,623	Ah, right, I forgot about sensor to subject vs front element to subject distances.

11-14-2022, 02:01 PM	#10
Paul the Sunman Pentaxian Join Date: Aug 2011 Location: Melbourne Photos: Gallery Posts: 4,353	Originally posted by Not a Number Ah, right, I forgot about sensor to subject vs front element to subject distances. It's when the former is less than the latter that you have a design flaw.

11-14-2022, 02:50 PM	#12
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 6,289	Originally posted by Paul the Sunman It's when the former is less than the latter that you have a design flaw. ......

11-14-2022, 10:16 PM	#13
Fogel70 Pentaxian Join Date: Sep 2009 Location: Stockholm, Sweden Photos: Albums Posts: 2,861	Originally posted by Ron Boggs The confusion is due to the difference in minimum working distance--which is the distance to the front of the lens at 1:1 VS minimum focus distance at 1:1 which is measured to the sensor thus adding the length of the extended lens and the space from the mount to the sensor. Both Ricoh and B&H are correct... B&H are wrong as they specify minimum focus distance as 5.1". They apparently have mixed up minimum working distance with minimum focus distance. They also use the term "minimum focus working distance" in the description which seems to be a mix of both.

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