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06-04-2014, 06:17 AM   #16
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John, thanks. I wear usually glasses for approximately that distance. I can post another test shot soon.

I appreciate all the suggestions from everyone. I should to mention again that I have the problem with all five lenses, although somewhat differently with each, which suggests it could be the way I take photos. I've used the MF lens for diagnosis because AF isn't especially useful for close-up. If I got a good one on eBay, the Pentax-M 100mm f4 should be my best lens.

06-04-2014, 06:35 AM   #17
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Being on a tripod is the most important point that some of you have made. When i took those three shots (Above) The camera was stabilized on a tripod. In my opinion you should ALWAYS and I mean ALWAYS use a tripod for macro shots. It doesn't matter how steady you hand hold a shot, it will most certainly come out blurry if you do not stabilize. I know in some certain situations, you have no choice, but if you dont have a tripod, you may as well not shoot with a manual lens. I had made that mistake many many times in the past, and wondered why the images came out just a LITTLE bit off focus like Ellen is explaining. And like Lowell explained, one millimeter back or forward, and your image is blurred.

---------- Post added 06-04-14 at 06:39 AM ----------

QuoteOriginally posted by Just1MoreDave Quote
I notice there are already suggestions on focus points, which is what I was thinking, right up until I saw the lens. The only active point with any manual focus lens is the center. It's useful to remember for AF lenses but not for this lens.

Handholding might be part of the problem. Sometimes you might unintentionally rock or tilt the camera when you shoot. It might not be noticeable at regular distances, but close up magnifies these errors.

I like to use lines of text to see if the sensor and viewfinder are seeing the same thing. A flat paper with text on it is a good subject. Set up the camera on a tripod so it's pointed at a 45 degree angle to the paper. Ideally only one line of text is in focus. I have to tape the paper to the floor, because inevitably I get it almost right and the paper moves. Anyway, you can manually focus on one line, then take a shot with the lens wide open and see if you got the same line in focus in the shot. You can also use live view, focus peaking, etc. Everything should agree. (The reason for text is that I always remember what line I want in focus, but I forget numbers on a ruler or marks on a test chart.)

I agree with you Dave. I just wanted to reiterate what I was saying. Yes, focus points do matter, even in manual mode, which is the only mode I use for Macro shots. I manually turn the focus until I get focus lock, which is what I meant. Even though you have the camera in manual mode, and the lens is only looking in the center, the focus lock will still use those 11 focus points, and will be confused. So in turn, what I am saying is, use the center focus point, and focus lock, and you should be ok.
06-04-2014, 10:27 AM   #18
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QuoteOriginally posted by JohnX Quote

With regard to wearing glasses, you need to consider that when you focus on the image shown on the focus screen the eye-piece optics are designed so that the screen itself is at an effective distance of around 1 metre, so you should wear glasses with a prescription to suit reading a book or computer screen in order to focus well on the screen image.
I am not sure that glasses are the issue or not. Assuming the eyepiece diopter is set, so that the user can distinguish between out of focus or not, glasses or the lack of them should not impact correct focus itself, because your eyes are not focusing on the image, but the projection of the image on the focusing screen

One of the things I wondered about and this might only be coincidence is that of the first sample images presented, the lower left of he screen was also the consistently the closest part of the subject, maybe it is just chance, or are we really talking here about simply front focus due to the need to shim the focusing screen?

The reason I ask this is for all lenses to be sharper / more focused in the bottom left quadrant of the frame could imply that the sensor is not parallel with the lens mount.
06-04-2014, 10:50 AM   #19
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QuoteOriginally posted by Lowell Goudge Quote
...One of the things I wondered about and this might only be coincidence is that of the first sample images presented, the lower left of he screen was also the consistently the closest part of the subject, maybe it is just chance, or are we really talking here about simply front focus due to the need to shim the focusing screen?

The reason I ask this is for all lenses to be sharper / more focused in the bottom left quadrant of the frame could imply that the sensor is not parallel with the lens mount.
I have many more examples of this pattern, and I think it's usually the part that is closer to the camera. Because of what the subjects are, this is usually the lower part, often to the left. (I've been trying out all the lenses on a particular plant not shown here.) I had an instance of the upper part being in sharper focus, and it was also the closer part of the subject.

Thank you!


Edited to add two images - cropped example and zoomed in. In an absolute sense and compared to the closer rock above and to the right, I don't think the spider is in focus.

Attached Images
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PENTAX K-50  Photo 
View Picture EXIF
PENTAX K-50  Photo 

Last edited by EllenJ; 06-04-2014 at 10:58 AM. Reason: added images
06-04-2014, 10:55 AM - 1 Like   #20
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It might be that the camera mount is slightly bent or the sensor misaligned. Or the AF module.
It would be great if you could test with another camera. Then you could quickly identify if its user error, lens problem, or camera problem.
If you still have warranty, you might want to get the camera exchanged (not "repaired"). That would also fix the problem or indicate the problem is not with the camera

Edit: Also, I hope you tried using centre point and the focus adjust function, as well as turning on/off the SR. If you shoot with "auto AF point selection" maybe the camera just chose that point. You can download a free focus chart and see how that works out (there are threads about focus adjustment and where to find free focus charts that you can print out yourself). Still, a consistent error like that would indicate a slight misalignment somewhere

---------- Post added 4th Jun 2014 at 20:03 ----------

Oh and btw, what about focus peaking? Try using live view and enable Focus Peaking. The DoF should be relatively parallel to the camera (even though it might be curved and so on). Is the DoF visibly diagonal? You can test this by mounting a fast prime and setting it to closest focus and placing the camera on a table (parallel to the surface), then moving the focus a little

Last edited by Na Horuk; 06-04-2014 at 11:04 AM.
06-06-2014, 06:29 PM   #21
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Micro-adjustment for AF lenses has no impact whatsoever when using MF lenses because -you- are setting the focus.

Also, when using MF lenses, don't rely on the focus confirmation signals. Why? Because being human, you can easily overshoot the proper focus point before the camera gives you the beep. Don't trust the indicators, trust your eyes. (That is assuming of course you have your diopter set correctly.) Be aware too that all lenses get soft wide open (with some obviously worse than others). When focusing a MF lens it is best to open the aperture wide open and then close it down a stop, and then focus. That helps keep you from getting frustrated trying to focus a lens that no matter what you do is always going to make things look a tad blurry when it is wide open.

Last edited by zekewhipper; 06-06-2014 at 06:35 PM.
06-07-2014, 08:23 AM   #22
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The same thing happens to me quite often. I also shoot handheld and usually use my tak 50/f4 macro. You asked what you are doing wrong, and to that I say you are doing nothing wrong. My DoF calculator tells me that if you are shooting with your 100 mm at f4 at a subject 10 inches away that your DoF is 0.025 inches! That doesn't leave much room for error. The slightest movement from you or the subject being shot will be enough to cause you to miss focus. I definitely miss more shots on focus than I capture, which leads me to take several pictures of each subject with the hope that one or two of them will be in focus. Handheld macro/close up shots are definitely a challenge. To me, the challenge is the reward...when you do catch the image that you're after it's like hitting a home run.
06-10-2014, 11:57 AM   #23
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Thanks for all the great information.

I discovered that I hadn't reset the diopter adjustment on the viewfinder some of the times when I changed eyeglasses, but even after checking that, it still seems to be focusing on the parts that are closer than my target area. By focusing slightly behind where I want, I'm getting some acceptable shots, at least that's how it seems. I haven't had time to do systematic testing yet.

Just for the fun, I'm posting a recent chive photo that I like, and a spider I like as a subject (even though the lighting and position wasn't ideal). I'm still trying to see if I can get sharp shots with the M 100mm f4 handheld, even if it isn't always exactly where I wanted to focus.

Attached Images
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PENTAX K-50  Photo 
View Picture EXIF
PENTAX K-50  Photo 
06-10-2014, 12:23 PM - 1 Like   #24
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QuoteOriginally posted by Just1MoreDave Quote
Handholding might be part of the problem. Sometimes you might unintentionally rock or tilt the camera when you shoot. It might not be noticeable at regular distances, but close up magnifies these errors.
I believe you stated the entire problem. At close distances, manual focusing is a must, especially handheld. You can get in the ballpark with autofocus, but even your breathing will move the plane of focus after the camera has locked. You need to learn the technique of rocking your body ever so slightly in and out of focus, while the camera is focus locked or in manual, and then pressing the shutter at just the correct instant. The only other option is to use a tripod. But, all this fuss about focus points and calibration is not going to help one bit when we're talking about handheld close focusing.

Last edited by OregonJim; 06-10-2014 at 12:30 PM.
06-10-2014, 12:42 PM   #25
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It seems odd to me that in hundreds of shots, the same part of the photo is in or out of focus -- usually the part closer to me (almost always the lower part) is clear when I'm trying focus elsewhere. Is that consistent with what's described in the post above? Also, I think I have the same problem with a tripod, but I haven't yet tested that extensively. I did some tests with a stable set-up, but I had the viewfinder diopter adjustment wrong and plan to do it again.

I appreciate all the comments, but I want to make sure people know what's going on here. This isn't about random or general focusing problem with handheld MF.
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