question about the SMC Pentax-DA* 300mm F4 ED [IF] SDM

retired2007 · 08-19-2019, 11:50 AM

just want to make sure i understand, the
SMC Pentax-DA* 300mm F4 ED [IF] SDM used on a crop sensercamera will be equal to 450mm and with the 1.4 con verter would equal 630?

would this also be the same on the k-1?

thanks

**pepperberry farm** · 08-19-2019, 12:03 PM

no - on a crop sensor camera, you'll have same field of view as a 450mm lens or 630mm with the TC...

it will always be a 300mm lens, no matter what camera you put it on...

**c.a.m** · 08-19-2019, 01:43 PM - **1 Like**

Originally posted by retired2007

question about the SMC Pentax-DA* 300mm F4 ED [IF] SDM

As @pepperberry farm; says, the DA* 300mm lens has a focal length of 300mm, which doesn't change regardless on which format camera it is mounted.

On an APS-C 'crop sensor' camera, the lens provides a horizontal angle of view of 4.6 degrees. On a full-frame camera (i.e., K-1), the same lens would give a wider angle of view of 6.9 degrees -- you would see more of the scene. Note that the angle of view varies in the same ratio as the 'crop factor' -- 1.5 times in this case.

To get the same angle of view as a DA*300 on a crop camera, you would use a 450mm lens on a full-frame camera.

- Craig

pschlute · 08-19-2019, 04:48 PM

Originally posted by retired2007

SMC Pentax-DA* 300mm F4 ED [IF] SDM used on a crop sensercamera will be equal to 450mm and with the 1.4 con verter would equal 630?

A 300mm lens is 300mm whatever format you use it on.

You asked if the lens "would be equal" ? If you mean "does a 300mm lens on a crop body have the same field of view as a 450mm lens on a FF body , then yes it will.

If you mean "does a 300mm lens give greater magnification on a crop body , the answer is no.

**mikesbike** · 08-19-2019, 07:19 PM

Originally posted by retired2007

just want to make sure i understand, the
SMC Pentax-DA* 300mm F4 ED [IF] SDM used on a crop sensercamera will be equal to 450mm and with the 1.4 con verter would equal 630?

would this also be the same on the k-1?

thanks

The simple, practical answer to the first part of your question, as to the image size you would get in your frame- yes, when compared to a Full Frame sensor body.

Which makes the second part of your question- no. The K-1 is a FF sensor body.

08-19-2019, 11:50 AM	#1
retired2007 Veteran Member Join Date: Aug 2011 Location: new Albany IN Posts: 861	*question about the SMC Pentax-DA 300mm F4 ED [IF] SDM just want to make sure i understand, the SMC Pentax-DA* 300mm F4 ED [IF] SDM used on a crop sensercamera will be equal to 450mm and with the 1.4 con verter would equal 630? would this also be the same on the k-1? thanks**

08-19-2019, 01:43 PM - 1 Like	#3
c.a.m Site Supporter Join Date: Jan 2013 Location: Ottawa, Canada Photos: Gallery \| Albums Posts: 4,189	Originally posted by retired2007 question about the SMC Pentax-DA* 300mm F4 ED [IF] SDM As @pepperberry farm; says, the DA* 300mm lens has a focal length of 300mm, which doesn't change regardless on which format camera it is mounted. On an APS-C 'crop sensor' camera, the lens provides a horizontal angle of view of 4.6 degrees. On a full-frame camera (i.e., K-1), the same lens would give a wider angle of view of 6.9 degrees -- you would see more of the scene. Note that the angle of view varies in the same ratio as the 'crop factor' -- 1.5 times in this case. To get the same angle of view as a DA300 on a crop* camera, you would use a 450mm lens on a full-frame camera. - Craig Last edited by c.a.m; 08-19-2019 at 01:50 PM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
question about Pentax-DA* 300mm F4 ED [IF] SDM	oh_9000	Pentax SLR Lens Discussion	56	05-01-2019 05:57 AM
SMC Pentax-DA 55-300mm F4-5.8 ED vs SMC Pentax-DA* 300mm F4 ED [IF] SDM	Budster48	Pentax SLR Lens Discussion	12	06-30-2013 11:00 AM
Sigma 120-400mm f4.5-5.6 DG Vs Pentax 300mm F4 SMC DA ED IF SDM	rayhf1485	Pentax SLR Lens Discussion	9	04-07-2011 12:32 PM

08-19-2019, 12:03 PM	#2
pepperberry farm amateur dirt farmer Join Date: Dec 2014 Location: probably out in a field somewhere... Photos: Gallery \| Albums Posts: 41,661	no - on a crop sensor camera, you'll have same field of view as a 450mm lens or 630mm with the TC... it will always be a 300mm lens, no matter what camera you put it on...

08-19-2019, 04:48 PM	#4
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,198	Originally posted by retired2007 SMC Pentax-DA* 300mm F4 ED [IF] SDM used on a crop sensercamera will be equal to 450mm and with the 1.4 con verter would equal 630? A 300mm lens is 300mm whatever format you use it on. You asked if the lens "would be equal" ? If you mean "does a 300mm lens on a crop body have the same field of view as a 450mm lens on a FF body , then yes it will. If you mean "does a 300mm lens give greater magnification on a crop body , the answer is no.

08-19-2019, 07:19 PM	#5
mikesbike Site Supporter Join Date: Dec 2016 Location: Southeastern Michigan Posts: 4,549	Originally posted by retired2007 just want to make sure i understand, the *SMC Pentax-DA 300mm F4 ED [IF] SDM used on a crop sensercamera will be equal to 450mm and with the 1.4 con verter would equal 630? would this also be the same on the k-1? thanks** The simple, practical answer to the first part of your question, as to the image size you would get in your frame- yes, when compared to a Full Frame sensor body. Which makes the second part of your question- no. The K-1 is a FF sensor body.