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08-14-2009, 07:15 PM   #31
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And a particular issue with the wide focus target is that it pushes the ruled scale way to the far edge (although I suppose you could shoot it from farther away). The problem with the scale being so far to the side is that if the design of the lens is such that the focus plane is not perfectly flat, you'll see the focus zone moved forward (or backwards if that's how the lens is designed, but that should be pretty bare). I'll bet a number of people have erroneously concluded they have an FF problem for this reason alone - focus is correct in the middle, but further forward on the edges.

08-15-2009, 12:57 AM   #32
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QuoteOriginally posted by fulcrumx29 Quote
Hi All,

Now I really feel frustrated about my K-7... I just cannot get as sharp image from K-7 ...

Tony
May I ask if your eye piece diopter is set correctly so you are certain you are getting an in-focus image on the focusing screen?

I found if the diopter setting is incorrect the resulting focus screen image can appear incorrect. The natural tendency is to quick shift (or manually adjust) the image into focus, thereby producing an OOF or soft-focus photo.

Do you wear glasses, or contacts? You may find that your prescription needs updating. If you do not wear glasses, you might need them.

Cheers...
08-15-2009, 07:37 AM   #33
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Can I ask how do these test charts have any relation to real world photography?

I can see it being relevant if you are shooting macro photography but even then manual focus is the way to fine tune such photography.

As one poster pointed out that the test chart used here doesn't even cover the entire frame which undoubtedly would cause problems of it's own.
08-15-2009, 08:08 AM   #34
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QuoteOriginally posted by Rico Quote
Can I ask how do these test charts have any relation to real world photography?.........................
Good question. In my experience, they don't. I have used the charts several times and I always end up making some fine-tune adjustments after shooting actual pictures at different distances.


Last edited by Parallax; 08-15-2009 at 09:51 AM.
08-15-2009, 12:15 PM   #35
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Well, I believe the chart since I saw real world difference. For example, the focus error will be magnified when shooting distantly. At I observe from the chart, my FA50/1.4 FF on apertures larger than 2.8 and RF otherwise. When I shoot a tree about 200 m to me, f2.8 can get way sharper image than f2. Maybe you will argue the DOF thing but I really believe you should get sharp image with f2 if focus is right. And I can see a tree leaf nearer is clear on the f2 shot which means a front focus in real life.

Here are the pictures:
Attached Images
   
08-15-2009, 12:50 PM   #36
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You are aware that the AF boxes in your viewfinder are actually much smaller that the AF sensor... If you used center AF in shot #2, the palm is within the sensor range and would naturally be the one in focus.

too late for grammar and spellcheck, but did it anyways...

Last edited by Shashinki; 08-15-2009 at 02:38 PM.
08-15-2009, 01:43 PM   #37
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Its probably already been mentioned, but make sure your SR is off when using a tripod. I've actually had SR kick in on longer exposures with my K10 and fuzz what should be a perfectly sharp image.
08-15-2009, 02:11 PM   #38
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QuoteOriginally posted by fulcrumx29 Quote
Here are the pictures:
These pictures demonstrate nicely that if you focus on a tree that has a plant in front of it, you get a sharp tree and a fuzzy plant in front, and if you focus on the plant in front, you get a sharp plant and a fuzzy tree. I don't see what any of this has to do with apertures or FF/BF - the camera very clearly choose a completely different place to focus here betwene one picture and the other, and that's the difference between these pictures. I don't see any camera or lens problem here - the scene is far too convoluted to be able to force the camera to focus where you wanted. This is user error, plain and simple.

08-15-2009, 02:29 PM   #39
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QuoteOriginally posted by Marc Sabatella Quote
These pictures demonstrate nicely that if you focus on a tree that has a plant in front of it, you get a sharp tree and a fuzzy plant in front, and if you focus on the plant in front, you get a sharp plant and a fuzzy tree. I don't see what any of this has to do with apertures or FF/BF - the camera very clearly choose a completely different place to focus here betwene one picture and the other, and that's the difference between these pictures. I don't see any camera or lens problem here - the scene is far too convoluted to be able to force the camera to focus where you wanted. This is user error, plain and simple.

Agree with you Marc on this.





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08-16-2009, 12:56 AM   #40
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I am geeting similiar results as for Fulcrumx29. Whether RAW or JPEG they are blurred and overexposed. Tests taken of plants in the backyard but all of the scene is OOF. If it is as Marc says then in my case it is at F8 which should not matter. I have 3 lenses and the 2 seeming to have the problem are both Sigma. The Pentax 55-300 seems okay..
08-16-2009, 01:40 AM   #41
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oh man.

Anyone else crushed by the underwhelming quality of K7 and willing to throw the thing out of the window, please send it to me, I`ll pay the postage!

I *think* I could put it to the good use.

Thanks,
Ilya.
08-16-2009, 03:21 AM   #42
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QuoteOriginally posted by fulcrumx29 Quote
Well, I believe the chart since I saw real world difference. For example, the focus error will be magnified when shooting distantly. At I observe from the chart, my FA50/1.4 FF on apertures larger than 2.8 and RF otherwise. When I shoot a tree about 200 m to me, f2.8 can get way sharper image than f2. Maybe you will argue the DOF thing but I really believe you should get sharp image with f2 if focus is right. And I can see a tree leaf nearer is clear on the f2 shot which means a front focus in real life.

Here are the pictures:
This is exactly the observation I made earlier, where you have a busy focus field, and the AF will focus on whatever it locks on.

Nothing to do with FF or BF. In fact, you should be happy the focus showing here is pretty sharp - on the object the AF locked in on.

The FA50 f/1.4 is a very sharp lens, if you learn to work with its quirks.

Sorry, all I can say is learn to work with your gear, instead of assuming it is busted.

Of course, sometimes the camera or lens really is faulty, but this one doesn't look like it.
08-16-2009, 07:58 AM   #43
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QuoteOriginally posted by Peterm Quote
I am geeting similiar results as for Fulcrumx29. Whether RAW or JPEG they are blurred and overexposed. Tests taken of plants in the backyard but all of the scene is OOF. If it is as Marc says then in my case it is at F8 which should not matter. I have 3 lenses and the 2 seeming to have the problem are both Sigma. The Pentax 55-300 seems okay..
Subject blurring and (especially) over-exposure aren't necessarily focus related at all.

In your case something else is going on aside from any focus issues, I suspect. What lenses? What camera? Maybe your Sigma lenses are not KAF2 mount and aren't talking to your camera at all, and you haven't properly setup shake reduction for them either perhaps.

Posting example pictures, with EXIF intact preferably, would once again help people try and figure out what may be going wrong here.
08-16-2009, 09:44 AM   #44
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wait, you mean a "gear problem" posted on the interwebs might actually be due to user error or not understanding the equipment?!?!?

Crazy talk!
08-16-2009, 10:07 AM   #45
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QuoteOriginally posted by fulcrumx29 Quote
Well, I believe the chart since I saw real world difference. For example, the focus error will be magnified when shooting distantly. At I observe from the chart, my FA50/1.4 FF on apertures larger than 2.8 and RF otherwise. When I shoot a tree about 200 m to me, f2.8 can get way sharper image than f2. Maybe you will argue the DOF thing but I really believe you should get sharp image with f2 if focus is right. And I can see a tree leaf nearer is clear on the f2 shot which means a front focus in real life.

Here are the pictures:
Did you use AF for these shots ?
First shot is focused on the tree. Second shot is focused on the green plants in front.
The FA 50/1.4 is not the sharpest wide open. If you want tack sharp wide open, get the 31 lmt.


QuoteOriginally posted by rawr Quote
As others will no doubt suggest, perhaps you could ask your Pentax service centre to 'tune up' your K7 and the two lenses that are having problems as a package.

That's the only way you will solve the issue once and for all, due to the issues with lens and body tolerance variation that this article discusses:

LensRentals.com - "This lens is soft" and other myths

The same issue crops up with all autofocus systems and cameras quite often. I notice from lurking around the dpreview nikon forums the same thing crops up frequently, and it seems Nikon do tune up body and lens as a package under warranty if the customer has FF/BF issues. Maybe Pentax will do so too.

'Softness' as an issue is harder to talk about because it needs to be defined better. Some example soft JPGs would be useful to see in order to understand your issue better. It could be caused by many many things - poor focus, poor lens optics, camera movement, motion blur, JPG settings, etc etc.
thanks for the link

Last edited by Jonson PL; 08-16-2009 at 10:58 AM.
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