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05-10-2011, 01:25 PM   #1
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K 30/2.8 vs. A 28/2 bokeh side-by-side

Hi all --

Looking for a perfect lens around 30mm I find myself owning two pretty rare ones: K 30/2.8 and A 28/2. Both lens are regarded for color reproduction and 3D effect. K 30/2.8 is so called "poor man's 31mm ltd". I do not have time and desire to do a lot of testing, but had a chance to shoot with both lens in the same conditions over weekend. Note, this is not a resolution test and nothing scientific.

Everything handhold, K5 in-camera JPEG. Nevertheless, I hope somebody will find it interesting.

1. K 30/2.8 f2.8, A 28/2 f2.8, A 28/2 f2.



2. K 30/2.8 f2.8, A 28/2 f2.8, A 28/2 f2.

Unfortunately, sun goes from the clouds on the A-lens shots here, so color is different. You can guess from the previous one, however, that color reproduction is the same when light conditions are similar.



3. K 30/2.8 f2.8, A 28/2 f2, A 28/2 f2.8 -- I messed up A-photos. f2 goes first.



4. Just bokeh, midfocus.

K 30/2.8 f2.8, A 28/2 f2. I missed A 28/2.8 f2.8 picture somehow.



5. Picked absolutely different animal for comparison. Guess what it was:



Last edited by kaipa; 05-10-2011 at 02:40 PM.
05-10-2011, 01:56 PM   #2
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Nice shoots.
I don't have the A28f2, but the bokeh of K30 is just beautiful.
Bokeh of A28f2 @f2 is a bit harsh - very similar to the K35f2.
Thanks for sharing.
05-10-2011, 02:13 PM   #3
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Thanks for the comparison. I agree about the A28/2 rendering at F2, the bokeh is a little bit busy (but doesn't always mean unusable). However, there doesn't seem to be a whole lot of difference in bokeh when they are both at F2.8. I would even give the nod to the A28 because there are no longer halos at F2.8 on the A28 while the K30 still has some slight halos towards the edge of the frame.

Anyways, I have the A28/2 as well, and love it as a walkaround/normal lens on DSLR...although can produce some nasty purple fringe at F2 if you aren't careful...I usually shoot F2.8 or higher, occasionally F2 if I need the speed or want some drama in my bokeh. Not as good IQ as the 31Ltd, but much smaller, slightly wider FOV, and better manual focus feel. So I keep both .
05-10-2011, 03:34 PM   #4
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I think the A series lens is more usable at f/2 than the K though that situation gets reversed when you accidentally stopped down the K 28 f/2 - which actually puts in a decent performance. I don't find the octagonal bokeh distracting...it's just different from what you get from a rounded aperture. none of the lenses tested really can compete with the FA31 - the only lens under 100mm that can directly compete for bokeh against the FA31 is the Pentax A/K 50mm f/1.2 lenses.


Last edited by Digitalis; 05-10-2011 at 03:39 PM.
05-10-2011, 04:53 PM   #5
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QuoteOriginally posted by kaipa Quote
5. Picked absolutely different animal for comparison. Guess what it was:
Thanks for an interesting comparison, Kaipa. Was #5 taken with your Porst 55?


Tim

Last edited by .a.t.; 07-17-2011 at 11:38 AM. Reason: oversight
05-10-2011, 09:04 PM   #6
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I would believe the image rendering would had been different if this was the K version. K and A version are completely different lenses. I think it is clearly stated that the successors to the K version are sharper at wider openings but less pop-ish. something like the Super-Tak 50 compared to the S-M-C and SMC version.
05-11-2011, 01:00 AM   #7
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Thanks, guys.

Looking at these pictures I find A and K almost identical at f2.8, but A is easier to focus, it is f2, and it is A. I do not see why K 30 is regarded so much.

Here is another example. ISO 6400, 1/30-1/45 handheld. Background is LP sleeves, right after the turntable. K30/2.8 f2.8, A28/2 f2.8.



QuoteOriginally posted by all thumbs Quote
Thanks for an interesting comparison, Kaipa. Was #5 taken with your Porst 55?
Since there are no other versions, let me answer. No, it was Voigtlander 90/3.5. Porst has less vivid colors and bokeh is also different.
05-11-2011, 03:54 AM   #8
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no from what I have seen from my own Pentax 30mm f/2.8 it doesn't hold a candle to the FA31.

05-11-2011, 04:15 AM   #9
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It does seem that K series in general has very nice OOF rendering, thanks for the comparison
05-11-2011, 07:18 AM   #10
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what would have made this comparison really interesting would be a comparison to the K 28mm f/2 which is a lens design developed by the collaboration of zeiss and pentax the A series 28mm f/2 lens is purely a pentax design.
05-11-2011, 09:15 AM   #11
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QuoteOriginally posted by kaipa Quote
Looking at these pictures I find A and K almost identical at f2.8, but A is easier to focus, it is f2, and it is A. I do not see why K 30 is regarded so much.
"A" version also seems to have significantly more saturated colours.
05-11-2011, 01:03 PM   #12
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QuoteOriginally posted by rparmar Quote
"A" version also seems to have significantly more saturated colours.
As I mentioned, light conditions change. If you look at first photo in the original post or at the photo of the headshell -- the saturation is the same.
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