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07-27-2012, 04:17 PM   #1
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Stopped down focusing ?

Hi Guys,
I just read a review of the K-01 in a local mag. Quite positive but he really was down on the focus, AF and MF.
I emailed him asking if he did find the peaking useful.
He replied
" : the Manual focusing and focus-peaking.
The issue is that when you view the LCD, the camera only lets you view with a narrow aperture, even if you have a wide aperture set. The narrow aperture means that everything looks in focus.
But when you press the shutter, the camera takes the photo with the preset wider aperture, which means the focus point could end up anywhere. Focus-peaking doesn't change that, as it is based on the contrast of the picture at the narrow aperture setting. The Pentax isn't the only camera to do this. The Fujifilm X series including my fave, the X100 does it as well. The Leica X1 used to, but they fixed it in a firmware update.


Not having the camera, I wonder if anyone would like to comment on his view ?
Thanks
Pete
ps sorry I had this post in another thread but it was a bit OT for it and got no reply.

07-27-2012, 04:32 PM   #2
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I think this is just a technical view; I mean, he did not answer to your question about the peacking focus, he just explain you how does the LV focus work.
If you want know if you can see in the LCD the final picture (with the DOF you set), maybe is better to wait someone with this camera (I don't have).
About the title (stopping down), instead, I think that you can use this procedure, but it's not linked with the image in the LCD. As he said, until you "fire", you will see the subject at the same aperture, it's not important what you set.
07-27-2012, 05:18 PM - 1 Like   #3
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Interesting comment from the reviewer, but not my experience at all. In fact I just went to test all this with my K-01 and that is definitely not how I see it working. It seems to be just the opposite. I have just fired off some snaps and compared the LCD view in manual focus, and auto focus at f2.8 and f13 . What I see is that the LCD view on the back of the camera used to compose the photo looks like it is using a wide aperture, ie not everything is in focus but just what the camera is AF locked on , or just what the focus peaking has highlighted in manual focus. This is true whether you have the aperture set for f2.8 or f13 and in manual or auto focus. However the final photo is true to the aperture setting - meaning at f13 even though the LCD looks like the AF point is focused and the background is blurred, everything is in focus in the final photo. Also, if the the photo is taken at f2.8 the outcome will show the "AF- locked" or "MF- focus peaked highlighted" area to be in focus, but everything else nicely out of focus. I find that focus peaking only highlights a plane of focus and "everything" is definitely not in focus. This plane of focus is highlighted in white and you can see it sweep through the LCD as you are rotating the focus ring to find the desired focus point. Therefore, it seems that when using the K-01 the LCD is always defaulting to a wide aperture type of view where there will be out of focus areas, even if the aperture is set to a narrow aperture like f8 or higher, but the photo will be true to the aperture set by the photographer in spite of the LCD. Also, focus peaking does work well in MF to highlight the desired focus point for selective focus and out of focus areas where that type of photo is desired, and definitely, everything is not in focus. Keep in mind that all this was done on AV mode, evaluative metering,40 mm XS in my dark living room tonight as a test, since I was quite surprised by this review. No opportunity to test outside in bright light to see if the camera is doing the same thing. Finally, the focus point does not end up just anywhere as suggested, but rather on the exact point of AF or MF.

Phew!! Sorry for the long winded post and hope it is not too confusing!! It would be nice to hear from some other users on this one. I'm surprised by the lack of effect of the lens aperture on the LCD screen.

Last edited by fotogaffer; 07-27-2012 at 05:45 PM.
07-28-2012, 01:18 AM   #4
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Cheers gabro822, Thanks fotogaffer, I thought he was observing the opposite to expected function...
Pity, as his review was very fair but crashed on his low focus rating
Pete


Last edited by Transit; 07-28-2012 at 01:44 AM.
07-28-2012, 03:15 AM   #5
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Hm, the K-01 is basically constantly in live view, and it does change apertures depending on light (to use lowest sensitivity). In my experience it is usually fairly wide or near to the setting you have. The focus peaking doesn't necessarily show the accurate DoF of the final image with A lenses. With a preset lens (where the camera has no control over aperture), you can change the aperture on the lens and the screen will get darker or brighter (for a second, until the camera adjusts sensitivity) and the DoF will also change. So, the reviewer may be right in that the DoF is not accurate, but in my experience the camera doesn't use a narrow aperture often. Don't know what light conditions the reviewer was using it in, though. Maybe he was trying wide open shots in very bright sunlight? The camera basically has to close the aperture in that setting though, so the sensor doesn't get damaged, because in live view it can't use a fast shutter to compensate since it has to do constant video.
But yes, generally contrast detection AF isn't as great as phase detect. The K-01 isn't an AF machine gun, it does need some time with certain lenses. But if you take the couple of seconds to focus, the peaking does help and it produces good images.
07-30-2012, 03:26 PM   #6
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Thanks Na Horuk.
Sounds like I should give him the benefit of the doubt

now, about his comments that all the jpegs were oversaturated...
What is it about camera reviewers that that paint a jpeg as a set in stone thing?
Are they purposely trying to dumb down the audience ?
Pete
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