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Forum: Pentax SLR Lens Discussion
03-17-2017, 07:58 AM
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Hi again Mac
Thanks very much for a very comprehensive and helpful reply on the original query. It's a good welcome for me to the forum.
I'll follow up based on this useful advice.
Michael
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Forum: Pentax SLR Lens Discussion
03-16-2017, 08:32 AM
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Hi Mac
Thanks for your reply.
The lens I am using is: tamron af aspherical xr ld 28-300mm 3.5-6.3 macro. (If you copy and paste into google you'll see my lens)
So, this is a lens that ranges in focal length from 28mm to 300mm, and as it is adjusted towards the 300mm zoom position the aperture closes down (from initially being 3.5, at 28mm, to 6.3, at 300mm).
I have half stops on my Pentax. Between 5.6 and 8 is 6.7, so I assume the 6.3 is a one third stop? So a 2x teleconverter would push the aperture to just smaller than f11?
In regards to light, usually I am shooting this type of shot in daylight with reasonably and/or with high speed film so light is probably okay.
The issue I hadn't considered was the effect on clarity / contrast. Thanks for pointing this out. I was initially wondering if such teleconverter betters existed. It seems they do but that the next consideration would be which is best in reproducing clarity / contrast.
Please let me know what you think from the lens I am using.
Thanks, Mike.
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Forum: Pentax SLR Lens Discussion
03-16-2017, 02:45 AM
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Hi
If anyone can help here it's appreciated.
I have a Pentax pz-20 film camera. The lens mount is type KAF 2. I'm wondering if it's possible to buy a teleconverter (such as a 2x magnification) that would allow me to effectively double the focal length of my lens.
If such a teleconverter exists, it would be the cheaper option rather than buying a new lens with double the focal length.
Thanks
Mike
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