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08-19-2019, 11:50 AM   #1
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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, 12:03 PM   #2
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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, 01:43 PM - 1 Like   #3
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QuoteOriginally posted by retired2007 Quote
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

Last edited by c.a.m; 08-19-2019 at 01:50 PM.
08-19-2019, 04:48 PM   #4
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QuoteOriginally posted by retired2007 Quote
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
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QuoteOriginally posted by retired2007 Quote
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.
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