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06-06-2011, 12:49 PM   #1
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[langtitle=it]Kx e DA 35 mm 2.4 confusione???[/langtitle]

Chiedo chiarimenti agli esperti del forum.
Utilizzando la Kx e il DA 35 mm 2.4 in alcuni casi mi produce delle foto diverse da ciò che mi aspettavo per chiarire meglio ho allegato due scatti. Il primo scatto è fatto con apertura f3.5 il secondo scatto con apertura f8 in entrambi gli scatti il polline al centro del fiore è nitido i petali vicino sono sfocati mentre quelli più esterni sono più nitidi. Vorrei capire dove sbaglio, io mi aspettavo che il centro del fiore fosse nitido e le parti più esterne sfocate.

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06-06-2011, 01:57 PM   #2
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Well I wouldn't classify myself as an expert but what focus mode are you set on (no exif data on those images)?
For this sort of thing you really want a fix point focus and maybe even tweak manually.
The 35 f2.4 is capable of a lot shallower depth of field than kit lens and so where you focus at wide aperture is much more critical.
06-06-2011, 02:24 PM   #3
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Come faccio ad allegare i dati exif?
06-06-2011, 02:28 PM   #4
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Where you point your camera is of crucial importance when trying to autofocus.
Cameras can also be confused with subjects that have elements at different distances from the lens in the same line of sight, which is what I suspect has happened here with your flower.
The middle of the frame has the stamen with many parts to it at different depths all in the same small area. The camera chose to focus on the very outer element of the stamen, which is clearly in focus in your image. There is nothing wrong with your camera or the lens.

06-06-2011, 02:28 PM   #5
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You have to make sure that the camera focuses in the central point. I suggest you visit the manual--read about focus and focusing points. The camera might have focused on the petals because it was set up to do so.
06-06-2011, 02:32 PM   #6
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QuoteOriginally posted by causey Quote
You have to make sure that the camera focuses in the central point. I suggest you visit the manual--read about focus and focusing points. The camera might have focused on the petals because it was set up to do so.
La fotocamera ha scatto con af punto solo centrale puntando il fuoco al centro del fiore.
06-06-2011, 02:45 PM   #7
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Read my post above.
The camera has to 'guess' which part of the center of the flower you wanted to focus on.
06-06-2011, 02:49 PM   #8
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QuoteOriginally posted by Ash Quote
Read my post above.
The camera has to 'guess' which part of the center of the flower you wanted to focus on.
Quindi mi consigli di rifare lo scatto con fuoco in manuale o avrei sempre lo stesso problema ?

06-06-2011, 04:16 PM   #9
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Assuming you were using the center "point" - which is not a point but a fairly broad area - I'd say in the first shot, the camera focus on the *tips* of the stamens around the center of the flower, and in the second, on the base of them. Plus, the first image appears to have been shot a much larger aperture (f/3.5?). When DOF is that shallow, it makes a big difference, which is why macro photography is virtually always done using manual focus.
06-07-2011, 10:42 AM   #10
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QuoteOriginally posted by Marc Sabatella Quote
Assuming you were using the center "point" - which is not a point but a fairly broad area - I'd say in the first shot, the camera focus on the *tips* of the stamens around the center of the flower, and in the second, on the base of them. Plus, the first image appears to have been shot a much larger aperture (f/3.5?). When DOF is that shallow, it makes a big difference, which is why macro photography is virtually always done using manual focus.
Credimi l'apertura era f 3.5. Alla fine ho scperto che il problema era il piano focale, il centro del fiore si trova sullo stesso piano focale dei petali più esterni ecco il perchè della nitidezza dei petali estremi.
Ciao e grazie a tutti.
06-07-2011, 12:19 PM   #11
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You are saying the aperture f/3.5 for both shots? That seems pretty hard to believe; DOF looks *much* larger in the second. You might want to check the Exif.
06-07-2011, 01:08 PM   #12
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From the original post, #1 was f/3.5 and #2 was f/8
06-07-2011, 10:22 PM   #13
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It was kind of hard to decipher the post, but you're probably right. In which case, I don't understand what the question really is. #2 has a smaller aperture and thus more DOF, and that's why more petals are in focus. Is there something surprising about that?
06-08-2011, 01:28 AM   #14
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QuoteOriginally posted by Marc Sabatella Quote
It was kind of hard to decipher the post, but you're probably right. In which case, I don't understand what the question really is. #2 has a smaller aperture and thus more DOF, and that's why more petals are in focus. Is there something surprising about that?
No nessuna sorpresa.
Quello che mi aspettavo era un centro fiore nitido e tutti il resto sfocato, questa è stata la mia sorpresa.
Credo che il problema sia stato l'angolazione di scatto e il piano focale diverso concordate ?.
Forse mi sono espresso male nella mia richiesta ma parlo pochissimo inglese e mi sono affidato al traduttore automatico.
Ho inserito la 1a foto con i dati exif.
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06-08-2011, 08:41 AM   #15
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Thanks for the clarification; much better the second time!

I'd say your best bet is to manually focus using the DOF preview to get the whole center in focus. You'll be focusing somewhere between the tips and the base of the stamen. And you might need a larger aperture than f/3.5 to get the whole center in focus; the DOF preview will also help show you this.
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