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02-10-2008, 07:59 AM   #1
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Pentax Lens series question

OK... this has probably been asked before and I did try to do a search, but my search argument is not working. I've also browsed the Lens Database, which is good for details of each lens, but what I cannot find is "what is the difference between the SERIES of the Pentax lenses?"

I imagine 'M' is completely manual, and I am guessing that 'DA' and 'D FA' are the newer lenses for digital cameras, but what are the differences between 'A', 'F', 'FA', & 'FA J'?

I've found a "PENTAX smc P-FA 50mm F1.4" which if I read the database correctly, is an excellent all-purpose lens that is fast enough for me to take pictures of dimly lit conference rooms (I go to sci-fi conventions and the 'star guest panels' are not well lit except for the stage they are sitting on). Anyway, the cost for this lens new is $184 but I also find the same lens in an F series for a little over $200 (albeit different vendor). I would imagine FA trumps F, correct?


02-10-2008, 09:44 AM   #2
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K lenses are fully manual. M lenses are fully manual, except they are more compact than K lenses. A lense are like M lenses, except some of them have poorer build quality, support all of the shooting modes on the latest cameras, and have constant metering. The F lenses have all the features of the A lenses, have plastic bodies, and support autofocusing. The FA lenses have all the same features as the F lenses with poorer build on certain lenses and transmit more information to the bodie. The DA lenses have an imaging circle that only covers the digital sensor, not full frame. The FOV is still subject to the crop factor. These lenses are marketed as digital-only because at certain focal lengths there can be pronounced vignetting when used on film cameras. The D FA lenses are like the DA lenses, but support both film and digital. Optics haven't changed significantly across A, F, and FA lenses.
02-10-2008, 11:16 AM   #3
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K & M: Manual focus, mechanical aperture coupling
A: Manual focus, mechanical & electronic aperture coupling
F & FA: Autofocus, mechanical & electronic aperture coupling
FA-J & DA: Autofocus, electronic aperture coupling only (no aperture ring)

Additionally, most DA lenses only work on a DSLR.

Last edited by Finn; 02-10-2008 at 08:16 PM.
02-10-2008, 12:39 PM   #4
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I just want to clarify few points on Finn's short and precise description. Mechanical aperture coupling means you control the aperture only on the lens, while electronic you can control it on the camera body. Mechanical aperture would not record the aperture information into the file.

As for the difference between FA-J, D-FA, FA:

FA: full format lens with both mech. and elec. aperture coupling

D-FA: same as above with aditional optimization for digital format (probably additional coating to reduce internal flare)

FA-J: low cost, consumer version that has elec. aperture coupling only.

The DA version is designed specifically for digital so if you use it on a FF camera, vignetting will be a problem.

02-10-2008, 01:19 PM   #5
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I've found this link pretty useful: Pentax Lenses Explained
02-10-2008, 07:37 PM   #6
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02-10-2008, 09:56 PM   #7
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Thanks all! Good info! Links bookmarked even!


p.s. just a thought... it would be nice if the Lens Database here in this forum had brief descriptions after the series name. A great resource, regardless.
02-10-2008, 10:33 PM   #8
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QuoteOriginally posted by DigiNoob Quote
Thanks all! Good info! Links bookmarked even!


p.s. just a thought... it would be nice if the Lens Database here in this forum had brief descriptions after the series name. A great resource, regardless.
Well explained by all of you that responded. If this information could be implemented into the lens database it would be most helpful for those that need a better understanding.


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