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09-21-2014, 06:39 AM   #1
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Newb question: using A 50mm F1.7 on Pentax K-5 II

Just got my k5-ii and already diving into manual focus, if i can pry it out of my 21 year old sons hands. But with next to no knowledge about dslr photograpy or the functions of a camera, i have a question. I have been looking at the Pentax A 50 mm f1.7, would i need a special adapter for that lens or does it fit the body of a k5-ii just like the da lenses?

And where do you find the "A" setting on the camera at??

Sorry for the ignorance

09-21-2014, 06:43 AM   #2
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It will work fine with no adapter. Anything ever made for Pentax pretty much works with no adapter.

You MAY have to go in and change one setting in the menu on your camera to use full on manual lenses, but no you do not need an adapter.

"A" setting lenses means the camera body will adjust the aperture from the camera body by turning the little wheels next to your pointer finger or thumb. You simply don't have to take the camera and look down and twist the aperture ring to get a different aperture. You can do it more on the fly with "A" series lenses on.
09-21-2014, 06:44 AM   #3
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No adapter is necessary for that lens, and as long as you keep the aperture ring at the base of the lens set to A (that's where the "A" setting is ), it will support full exposure automation as well as in-camera aperture control just like any other modern lens. You do not need to change anything in the menu.

The A 50mm F1.7 is a quite popular lens by the way as it delivers great image quality at an affordable price.

Even though the lens has an aperture ring, you should always use the scrollwheel on the back of the camera to set the aperture and leave the aperture ring at the "A" position. If you were to move the aperture ring away from A, the exposure capabilities of the lens would be crippled and you would need to resort to stop-down metering as with older M and K series lenses.

Hope this helps!

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09-21-2014, 07:08 AM - 1 Like   #4
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QuoteOriginally posted by alamo5000 Quote
It will work fine with no adapter. Anything ever made for Pentax pretty much works with no adapter.
Just for some clarity, the Pentax Forum lens database includes M42 screw-mount lenses such as the various Takumar lenses. These do require an adapter, and your best bet is to only use the Pentax-made adapter. Other off-brands can be a pain to use . . . in my case literally as I sliced my finger with a knife trying to take one off my camera when I first switched to Pentax and its branded adapter was on backorder. The is an excellent guide by Adam on using M-42 lenses.

09-21-2014, 07:27 AM   #5
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Pentax K-Mount Lenses Explained: The differences between various Pentax lens series
09-21-2014, 09:23 AM   #6
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The A is on the lens's aperture ring. Putting the ring in the A position means the camera body controls the aperture, not the aperture ring itself. Pentax lenses often make it green, with a little corner symbol next to it on the right and a button on the left.

Older Pentax lenses with K-mounts will have aperture rings like this. The oldest ones won't have the A. Those work but with limitations. Newer lenses, mostly the DA series with a handful of exceptions, won't have an aperture ring. They are built so only the camera body can set the aperture.
09-21-2014, 10:17 AM   #7
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Also note the button left of the A - you cannot get past 22 unless you push the button first! That locks the A in place. Looking on the screens or viewfinder, you will see the aperture value now - if you see F-- instead then it is not on the A setting any more!
09-21-2014, 12:04 PM   #8
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Thank you all for your responses and thank you dave for the picture in the explanation. That truly helped.


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