SMC Pentax-A 50mm 1:1.7


Link Posted 15/02/2012 - 23:44
Hi all,

Can anyone tell me if an 'SMC Pentax-A 50mm 1:1.7' lens (dating back to the older style manual cameras)would be compatible with a Pentax K-x DSLR camera? If yes, would it be any good for macro photography?



Link Posted 16/02/2012 - 00:09
Hi Becky, the simple answers to your questions are 'Yes' and 'Yes'!

Pentax have kept the same lens mount for many years so all of the old K-mount lenses will work, including the one you have mentioned. As a bonus, this is an 'automatic' lens so will work on your K-x in 'Av' mode where the camera automatically sets the lens aperture.

With regard to Macro, you will need to buy a set of Extension Tubes (v. cheap on ebay or Amazon); these fit between the lens and camera and enable you to focus much more closely, hance you get a bigger image and true macro performance. You will lose the automatic function of the lens aperture if you use the tubes, but this is not a massive issue. When using the tubes, be sure your K-x is set to allow a manual lens to be used, this is item no 22 in the 'Customer Functions' menu and is the very last setting on your K-x menu. Set it to number '2' and always leave it on this setting. Your camera will then work with all the old lenses, whether or not they are 'automatic'. Just use your camera set to 'manual' mode on the top dial.

Hope this helps.

Some cameras, some lenses, some bits 'n' bobs


Link Posted 16/02/2012 - 00:22
Hi David

WOW, thankyou so much for your quick response. That's put my mind at rest and I will now confidently make the buy I was hesitating over

If I ever need to know anything else I now know where to come for advice, thankyou sooo much, your help is much appreciated




Link Posted 16/02/2012 - 00:24
No problem Becky, it is a pleasure to assist. I'm sure you will find others are also very helpful on here.

Best wishes,

Some cameras, some lenses, some bits 'n' bobs


Link Posted 16/02/2012 - 19:14

Here is a link to my Flickr SMC A 50mm f1.7 set. The recent shots (2009 onwards , just check the tags for info) are taken with the lens attached to my Pentax K-M DSLR, the older edition of the K-X but with less pixels!
For close up work I have a +3 Cokin lens to slide into its holder - but I do not seem to have any images in the set. Older images are from our 35mm Pentaxes.
All the best,
Last Edited by SteveA on 16/02/2012 - 19:15
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