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06-22-2009, 01:03 AM   #1
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Interesting shots that show the CA side of the FA 77mm vs. DA 70mm

I have read the debate about this issue as well as which is better...I dunno but Over on Lumo's blog site he ran an interesting test using the new K-7 on their focus target wall chart really shows the issue when you view the originals:


FA 77mm on K-7


DA 70mm on K-7

Not a big deal but just though it was an interesting side discovery add fuel to the debate...I know this much...I like the shots I see from BOTH. And since I already order the 77mm...it's the best. Though I had to settle for freaking silver...I wish it was sealed...the spay paint would come out in minutes!!

EDIT: To save confusion...I whiffed this one big-time...I have no clue what in the heck i was thinking and seriously got something confused while hunting K-7 reviews last night....sigh...I added more later...but there is NOT issue in the above shots other than some artifact/fringing in the first shot but that is not the same as CA, even I know better...all I can say is I feel too stupid to live...

here is the blog article: http://falklumo.blogspot.com/2009/06/comparative-resolution-study-k-7-vs.html


Last edited by brecklundin; 06-22-2009 at 01:19 PM.
06-22-2009, 01:11 AM   #2
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Not surprisingly. I had some shots on film with quite severe PF too even at f4. Can't blame the sensor huh?
06-22-2009, 01:25 AM   #3
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did not know some might have been pointing to the sensor for the issue. Nope...and also maybe. Remember that body is a preproduction body with a different sensor than will be in the RTM spec version. I would hope he runs all the same tests post production to see what real changes happened.

I am still looking forward to the thing...I do love the images it takes. Then again I also love the 70mm...sigh, so many lenses...but one simply must sample as many as possible.
06-22-2009, 08:48 AM   #4
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Which post was that? The only ones I found has him comparing the K20 to the K-7, using only the DA 70 (no 77)?

(exif was missing from the linked photos too, so couldn't check that way)

06-22-2009, 09:00 AM   #5
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Am I missing something here? It may be my work monitor, but I don't see significant CA in either shot. I do see moire and jpeg artifact since the photo is not full resolution.

Steve
06-22-2009, 10:18 AM   #6
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YAUT (Yet Another Useless Test).
I have yet to see any signs of CA or PF in either of my 77s or my 70. A picture of a test target is the equivalent of taking a shot of tree branches against a blown out sky. It's a good way to see if you can make the equipment screw up, it's not a good way to see how the equipment will work in real world situations (unless your real world revolves around pictures of test targets or tree branches with no aesthetic appeal).
Also, unless the K-7 used is a production body, as opposed to a pre-production one, the test has no relevance to what to expect from a production camera, since there is no way of knowing if it has a K-7 sensor or a K20 sensor mounted.
06-22-2009, 10:26 AM   #7
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Yeah, I'm not seeing it either.
06-22-2009, 10:29 AM   #8
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According to photozone.de, FA 77's lateral chromatic aberration is near 0, purple fringing is there, but "This happens only in extreme contrast situations when the bright portion is at or beyond the contrast latitude capabilities of the sensor."

Another reason for fringes can be that the image is very slightly out of focus (longitudinal chromatic aberration).

06-22-2009, 11:00 AM   #9
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I still don't see what you guys are talking about. All I see is moire and jpeg artifact from downsizing the image. Color fringing from moire is not the same as CA.

Is there a 100% crop of the full resolution image showing the "CA" out there?

In case anyone is interested, here is the graph from photozone.de for the 77/1.8 for lateral CA:



and here is the graph for the 70/2.4:



Both are very low and in actual images one would be hard put to see CA from either lens.

Steve

Last edited by stevebrot; 06-22-2009 at 11:05 AM.
06-22-2009, 11:36 AM   #10
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Hey "guys",

I have no idea what I was seeing last night because you are all right! I do not see any CA at all...plus it is NOT and this is the real embarrassing part, the shots were taken with the DA 70mm to boot!! I suppose it was just reading too much at 2AM?

The only thing I see, and it is in the first shot, is some artifact/purple fringing and that is all. And I would have sworn the EXIF was there too. Maybe I had looked at a different page and got them bassawkards but, was not searching for tests of the 77mm and remember it was just one of those accidental "discoveries".

Really sorry if my "brain cloud" stirred up a hornets nest...d'oh!! Call it an error of enthusiasm rather than a mistake of complacency?

FYI, I had already order an FA 77mm because I just love the shots people get with it. Of course I have no actual camera yet...now I will go sit in my corner and be quite while waiting patiently for the K-7 release. hehehehe....

Oh, here is the blog about the test he was actually doing:
Falk Lumo: Comparative resolution study K-7 vs. K20D

sign...I truly feel stooooopid....hehehehe...
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