Using the DA* 300 on a K-1

BrianR · 11-27-2017, 06:47 AM - **1 Like**

Originally posted by UncleVanya

Is the crop mode on the K-1 1.6? if not why is Ricoh using Canon math to give their bad information? Shouldn't it be 450mm equivalent not 460mm? And yes I get that it is a bit of an illusion.

According to Ricoh the K-3's sensor size is 23.5mm x 15.6mm. "Full frame" is 36mm x 24mm and "crop factor" is the ratio of the diagonals, so 1.5339203377.....

1.5 is 'close enough' for most purposes. Other Aps-c models may have slightly different dimensions.

Their text is crappy as already noted, but improves slightly on the pages for later zoom lenses (the 70-200mm and 150-450mm) where they at least acknowledge the possibility of 35mm film camera use in the field of view summary. The text is long overdue for an update as it's riddled with confusing slop and doesn't seem to acknowledge the K1. Example- HD PENTAX-D FA 150-450mmF4.5-5.6ED DC AW / Telephoto Lenses / K-mount Lenses / Lenses / Products | RICOH IMAGING. Where are those interns when you need them?

**UncleVanya** · 11-27-2017, 08:04 AM

Ahh 1.53 x 300 = 459... Got it

**bkpix** · 11-28-2017, 10:02 PM

I believe Pentax crop factor is 1.53.

1.53 x 300mm = 459mm

Close enough.

**UncleVanya** · 11-29-2017, 07:23 AM

Originally posted by bkpix

I believe Pentax crop factor is 1.53.

1.53 x 300mm = 459mm

Close enough.

It varies slightly by sensor from what I recall. Some I thought are close to 1.52.

BrianR · 11-29-2017, 07:53 AM

Originally posted by UncleVanya

It varies slightly by sensor from what I recall. Some I thought are close to 1.52.

Yup, the k5iis is listed as 23.7 x 15.7mm, which gives a crop closer to 1.52.

If we totally abuse the accuracy of Ricoh's reported sensor sizes, crop factor from the k5iis down to the smaller k3 is 1.00786864129...

I really like my DFA100 on my k5iis. I'd upgrade to a k3 but there's no DFA99.2192790837 to take its place

**UncleVanya** · 11-29-2017, 08:43 AM

Originally posted by BrianR

Yup, the k5iis is listed as 23.7 x 15.7mm, which gives a crop closer to 1.52.

If we totally abuse the accuracy of Ricoh's reported sensor sizes, crop factor from the k5iis down to the smaller k3 is 1.00786864129...

I really like my DFA100 on my k5iis. I'd upgrade to a k3 but there's no DFA99.2192790837 to take its place

I'm crying laughing at the idea of a D FA 99.2192790837 being floated at a Ricoh marketing meeting.

wanderer2 · 12-02-2017, 05:30 PM - **2 Likes**

The DA* 300mm arrived yesterday and the FOV is indeed 300mm on the K-1 (equivalent if that needs to be added) as everyone said it would be. As best I can tell from the first half dozen or so shots of the Teton Range from my home it's IQ is indeed terrific. I'm looking for sharpness that will support the occasional very large print and it appears this lens has that . I much appreciate all of your opinions, uniformly positive, on this lens - it sure looks like a keeper.

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11-27-2017, 06:47 AM - 1 Like	#16
BrianR Veteran Member Join Date: Dec 2010 Location: Ontario Photos: Gallery Posts: 3,332	Originally posted by UncleVanya Is the crop mode on the K-1 1.6? if not why is Ricoh using Canon math to give their bad information? Shouldn't it be 450mm equivalent not 460mm? And yes I get that it is a bit of an illusion. According to Ricoh the K-3's sensor size is 23.5mm x 15.6mm. "Full frame" is 36mm x 24mm and "crop factor" is the ratio of the diagonals, so 1.5339203377..... 1.5 is 'close enough' for most purposes. Other Aps-c models may have slightly different dimensions. Their text is crappy as already noted, but improves slightly on the pages for later zoom lenses (the 70-200mm and 150-450mm) where they at least acknowledge the possibility of 35mm film camera use in the field of view summary. The text is long overdue for an update as it's riddled with confusing slop and doesn't seem to acknowledge the K1. Example- HD PENTAX-D FA 150-450mmF4.5-5.6ED DC AW / Telephoto Lenses / K-mount Lenses / Lenses / Products \| RICOH IMAGING. Where are those interns when you need them?

11-27-2017, 08:04 AM	#17
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,400	Ahh 1.53 x 300 = 459... Got it

11-28-2017, 10:02 PM	#18
bkpix Site Supporter Join Date: Feb 2010 Location: Creswell, Oregon Photos: Albums Posts: 568	I believe Pentax crop factor is 1.53. 1.53 x 300mm = 459mm Close enough.

11-29-2017, 07:23 AM	#19
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,400	Originally posted by bkpix I believe Pentax crop factor is 1.53. 1.53 x 300mm = 459mm Close enough. It varies slightly by sensor from what I recall. Some I thought are close to 1.52.

11-29-2017, 07:53 AM	#20
BrianR Veteran Member Join Date: Dec 2010 Location: Ontario Photos: Gallery Posts: 3,332	Originally posted by UncleVanya It varies slightly by sensor from what I recall. Some I thought are close to 1.52. Yup, the k5iis is listed as 23.7 x 15.7mm, which gives a crop closer to 1.52. If we totally abuse the accuracy of Ricoh's reported sensor sizes, crop factor from the k5iis down to the smaller k3 is 1.00786864129... I really like my DFA100 on my k5iis. I'd upgrade to a k3 but there's no DFA99.2192790837 to take its place

11-29-2017, 08:43 AM	#21
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,400	Originally posted by BrianR Yup, the k5iis is listed as 23.7 x 15.7mm, which gives a crop closer to 1.52. If we totally abuse the accuracy of Ricoh's reported sensor sizes, crop factor from the k5iis down to the smaller k3 is 1.00786864129... I really like my DFA100 on my k5iis. I'd upgrade to a k3 but there's no DFA99.2192790837 to take its place I'm crying laughing at the idea of a D FA 99.2192790837 being floated at a Ricoh marketing meeting.

12-02-2017, 05:30 PM - 2 Likes	#22
wanderer2 Veteran Member Join Date: Jul 2016 Posts: 301 Original Poster	The DA* 300mm arrived yesterday and the FOV is indeed 300mm on the K-1 (equivalent if that needs to be added) as everyone said it would be. As best I can tell from the first half dozen or so shots of the Teton Range from my home it's IQ is indeed terrific. I'm looking for sharpness that will support the occasional very large print and it appears this lens has that . I much appreciate all of your opinions, uniformly positive, on this lens - it sure looks like a keeper.