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Old Aug 19, 2006, 12:36 AM   #1
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Although I still own my Nikon D70s, I am a Pentax convert. I have a question that I would appreciate your opinion(s) on:

I can buy a NIB FA 50 macro or a NIB 50 D-FA macro for my Pentax istDL and K100D. Putting aside the argument about going with a 50mm or a 100mm, in this case I can get the FA50 for $ 200. from a national retailer vs $ 355. after rebate from Adorama.

All things considered,what features of the newer D-FA wouldjustify spending the extra money? Thanks for your help - I really appreciate it!
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Old Aug 19, 2006, 3:34 AM   #2
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Hi bobbysox,

Please take this answer FWIW, as I don't own either.

From what I've read, the FA is a bit larger in size and heavier (13.5 oz as opposed to the D FA's 9 oz). The FA also has a focus ring clamp that unfortunately supposedly doesn't work that effectively, but it's there and was removed on the D FA -- don't ask what it does exactly 'cause I don't really know). The FA takes a 52mm filter while the D FA takes a 49mm.

Optically, I believe they are the same, or close to the same with at least one main difference -- the D FA is "digitally optimized" in that it supposedly has a different coating on the rear element that takes into account the added reflectivity of the sensor as opposed to film. The only effect this might have is the occasional (very -- only noticed in a very small percentage of frames taken) and apparently unpredictable appearance of a strange flare spot in the middle of the frame either in bright sunlight or with flash. I'm not sure if I remember any reports of this flare with this particular lens, so this might be a false alarm. Reports of this have been few and far between, and basically unrepeatable, so AFAIK nobody has been able to pin it down to a specific cause, other than the absence of the extra coating (seems to have only happened on non "digitally optimized" lenses (from varying mfgs), and only on a few frames so it's not really a terrible problem).

If weight isn't a problem, then price might be the deciding factor. If weight or time critical perfection in production is a factor, then it might be worth the extra to get the D FA. I know that you can't really go terribly wrong with either. I believe all the Pentax 1:1 f2.8 macros are pretty much in the "pick of the litter" class, even across mfg lines.

I'm a hobbyist, so I'd probably opt for the FA. I think that $200 is a great price for a brand new one, and it's not a really heavy lens (but I did personally choose the D FA 100/2.8, mostly for the weight savings, and since the price new with the rebate was not much more than what used FAs were going for at the time).

Others with direct experience might give different advice, so please take this for what it might be worth. . .

and congrats on your show of fine taste in that you're a Pentax convert :-) . . .just kidding!


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Old Aug 19, 2006, 5:41 AM   #3
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The Pentax FA 100mm f2.8 is one of the best macros around - its well worth the extra pennies, absolutely fantastic lens

I am buying this myself
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Old Aug 20, 2006, 6:37 PM   #4
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The clamp on my used FA 100 works great. It is there to keep the lens from drifting if it is pointed down and is intended for use in MF. The manual recommends that it be disengaged when using AF.

I can't fully compare with every Pentax lens ever made but it is the sharpest lens I own. I also have the A50/1.7, FA 35/2, A28/2.8, M135/3.5, M200/4 along with some nice zooms.

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Old Aug 21, 2006, 8:16 AM   #5
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I second that (together with that of Rob22315) about FA100mm2.8.

Its use is more than for macro use. Its use for non-macro use is just as sharp or overly sharp as it can be.

At time I have to soften the image too. Here is one (non-macro shots) that I got while hunting for macro chance.


I do not have the DFA version for comparison.

I want to add the pros and cons list (see the above). FA100mm is full frame. One day (expected to be within 5 if not 10 yrs), full frame may come back.


errno_gmm wrote:
The Pentax FA 100mm f2.8 is one of the best macros around - its well worth the extra pennies, absolutely fantastic lens

I am buying this myself
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Old Aug 21, 2006, 11:47 PM   #6
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I've got an F 100 2.8 macro. It's an amazing macro lens. On film cameras, it would make an amazing portrait lens but for one difficulty - it picks up every little detail. Still, when taking macros on the D, it is always my lens of choice. Well worth the weight and price

This is a truly sharp lens.

Larry in Dallas
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