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01-13-2007, 08:42 PM   #1
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Focus Calibrations for Pentax DSLRs and Lenses

Here is the most lengthy techical article I've ever written in my Blog!

RiceHigh's Pentax Blog: Focus Calibrations for (Pentax) (D)SLR Bodies and Lenses

.. for anyone who is interested or even suffered from those daily reported Front Focusing or Back Focusing issues!

Enjoy and I hope that you folks will find this to be useful!

01-14-2007, 10:21 AM   #2
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I wish that RicheHigh would stop spamming this board. Apparently he was banned from the "other" site for good cause.

I think that RH's expectations are not reasonable. IMHO Pentax does NOT make a professional DSLR. Some would argue that the k10d is a pro camera, but the professional photographers that I know spend thousands of dollars for a body from C/N. The Canon EOS 5D body costs about $3000, and the Nikon D2x body about $4,000. Pentax makes GREAT cameras for hobbyists, the prosumer market, and for light commercial use, the cameras the do have their limitations. Personally, I am very happy with my k100d and the lens selection available.

I think the problems are not with Pentax, but with RiceHigh. BTW Rice, do you use your cameras to take photographs? In case you forgot, that is what they were designed for.

Last edited by superfuzzy; 01-14-2007 at 10:28 AM.
01-14-2007, 10:26 AM   #3
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daily reports? i'm here everyday, and it's like once in a blue moon someone posts up a focus problem.

and i thought they were isolated incidents...

man...seriously...enough w/ the technical stuff, and just take photos...
01-14-2007, 10:38 AM   #4
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The degree of 'professionalism' doesn't depend upon nor is it contained in the equipment. It is also not indicated by how much the 'pro' spends versus any other photographer--it IS in how much he or she earns from photography----i.e. money flow entirely opposite to what you suggest.

01-14-2007, 10:46 AM   #5
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It is mainly because of the potential for focussing inaccuracy that I have until now avoided auto focus SLRs (accepting AF in P&S cameras). This extract (by Izumi Taniguchi) from the Pentax Web site a reasonable (in my view) and pragmatic response to criticism about auto-focus inaccuracies...

Take advantage of the quick-shift focus function for final, minute adjustments

Remember that, no matter how advanced your camera’s AF system is, your eye is always the most reliable tool in focusing. It takes a great deal of time and trouble to do everything from the start with manual focus, but an effective combination of autofocusing and manual focusing can offer tremendous benefits.

Such benefits are all yours, if you own a PENTAX digital SLR camera and a PENTAX interchangeable lens equipped with the quick-shift focus mechanism. Incorporated in all PENTAX digital SLRs, the innovative, user-friendly quick-shift focus function makes manual focus adjustments simple and effortless: While keeping the shutter release button at the half-depressed position, rotate the focus ring of your lens to make final, minute adjustments manually from the initial autofocus position. Thanks to the bright, clear viewfinder featured in all PENTAX digital SLRs, this PENTAX-original function is an effective and efficient aid for your focusing operations.

When you have difficulty in making such minute adjustments by the eye, there is a simple, effective technique to assure sharp, crisp focus on your subject. After reaching the manual-focus stage, manually shift the focus ring little by little, and take an image after each shift. You will end up with several images with slightly different in-focus points, so choose the most accurately focused image later. Called “focus bracketing,” this technique is commonly used by professional photographers.

Last edited by Simon; 01-14-2007 at 10:47 AM. Reason: Hedging in the first sentance
01-14-2007, 11:00 AM   #6
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QuoteOriginally posted by jfdavis58 Quote
The degree of 'professionalism' doesn't depend upon nor is it contained in the equipment. It is also not indicated by how much the 'pro' spends versus any other photographer--it IS in how much he or she earns from photography----i.e. money flow entirely opposite to what you suggest.
I was stating a first hand *observation*. The pro photographers that I know spend big bucks on their cameras, because the amount of money they earn justifies it.
I'm talking about pros that shoot covers of national magazines and do serious commercial work. You just don't see Pentax DSLRs used by those folks -- not yet anyway. I'm not talking about people that earn a living shooting weddings or whatever. Of course some world class photographers do use Pentax DSLR, but I doubt there are many amateurs that use C/N pro cameras.

All the best!
01-14-2007, 11:06 AM   #7
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QuoteOriginally posted by Simon Quote
When you have difficulty in making such minute adjustments by the eye, there is a simple, effective technique to assure sharp, crisp focus on your subject. After reaching the manual-focus stage, manually shift the focus ring little by little, and take an image after each shift. You will end up with several images with slightly different in-focus points, so choose the most accurately focused image later. Called “focus bracketing,” this technique is commonly used by professional photographers.
Thanks -- VERY good advice. Much more effective than choosing the focus points on the k100d menu.
01-14-2007, 12:09 PM   #8
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Beware small sample sizes.

And the fact that much of that equipment you see is not owned by the photog-but rather the publication or the studio----in several popular and highly visible 'venue's' equipment you see is not actually owned at all by shooter or magazine, but 'traded-out' for publicity purposes.

"The pro photographers that I know spend big bucks on their cameras, because the amount of money they earn justifies it" Hogwash; the 'pros' I know are EXTREMELY frugal-they buy and keep what works. That may be N or C but there is no correlation between income, equipment and talent/professionalism per se.

You're buying into a myth and helping to spread it when voicing your 'observations'.

01-14-2007, 01:03 PM   #9
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QuoteOriginally posted by superfuzzy Quote
I wish that RicheHigh would stop spamming this board. Apparently he was banned from the "other" site for good cause.
Would you be so hostile also in case when your Pentax camera consistently backfocus? There are quite a lot of cameras which front/back focuses. There is no need to make a photos of focus charts. When your camera has back/front focus issue you see it in your pictures. Take 100 pictures, focus on person eyes and only a few in a focus. In all other you can see that focus is somewhere like 0,3-0,5 metres behind. What would you say then?

I bet you would be very happy with RiceHigh post then. It really gives links to posts which help to understand and fix problem.
01-14-2007, 03:35 PM   #10
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QuoteOriginally posted by superfuzzy Quote
I wish that RicheHigh would stop spamming this board. Apparently he was banned from the "other" site for good cause. -snip-
I can see RiceHigh have posted about ten posts for the last two weeks. Sometimes he has refered to his site, sometimes he has given some plain advices just as many of us do.

There is no need get upset, in my opinion.

RH got banned from DPR due to brand bashing. As I never was able to have a rewarding communication with RH (regarding some of his measure methods) I just ended up ignoring most of his posts. At the same time we agreed about the DS exposure metering and other things. I really think we should have some space for him here. I'm still not intended to get into any discussion with RH as I guess it will fail again, but I see no reason to ask him to stop posting about his findings. Btw, I have seen pictures taken by RH and there was nothing wrong with them.

regards,
01-14-2007, 03:54 PM   #11
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QuoteOriginally posted by Edvinas Quote
Would you be so hostile also in case when your Pentax camera consistently backfocus?
Hmm, if my camera had focusing issues--verifiable, objective, repeatable (by ANYONE) focusing issues--I'd send it back. I would know it had a problem, and would get a new one; no muss, no fanfare, no gratitude to a questionable internet source, just a new body.

One of these days, I'd really love to get my hands on the dud, because I'd take it apart. Unfortunately, these duds seem to be in short supply (gee...how can that be? Is it likely that there just aren't that many? Is it just easier for the manufacturer to replace a camera for a hysterical owner rather than convincing them the the problem is user error?), and its unlikely that I'll ever get to do it.
01-14-2007, 04:09 PM   #12
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QuoteOriginally posted by bdavis Quote
Hmm, if my camera had focusing issues--verifiable, objective, repeatable (by ANYONE) focusing issues--I'd send it back. I would know it had a problem, and would get a new one; no muss, no fanfare, no gratitude to a questionable internet source, just a new body.
Good for you in USA. In some other places you would have really hard time trying to prove that your camera is front/back focussing. And not necessary succesfully.

Also what about when you bought used camera with front/back focusing problem? No warranty then.
01-14-2007, 05:42 PM   #13
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RiceHigh rides again...

...like you, I think RiceHigh is mainly harmless. The broken English is a severe impediment to communications and much of his material is beyond the grasp of the non-technically-inclined.


BUT...


His findings here are without basis. No actual measurements just a lot of inferences to the quasi-scientific testing of others. and I suspect that pseudo scientific is a more appropriate description of those test.

There is a complete lack of sound scientific analysis, or credentialing to verify his status to make such tests or inferences.

AND FINALLY...

His suggested 'repair' solve a minuscule problem at one point of the entire operating envelop of the camera BUT SACRIFICES all other points AND voids the users warrantee.

This is at least ill-advised; perhaps it rises to the level of carelessly reckless that could be considered actionable in some countries--I don't know.

Following his advise would require a level of ineptitude that puts a users at about the moronic level--imbecile at least.
01-14-2007, 05:58 PM   #14
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QuoteOriginally posted by Edvinas Quote
Good for you in USA. In some other places you would have really hard time trying to prove that your camera is front/back focusing. And not necessary successfully.

Also what about when you bought used camera with front/back focusing problem? No warranty then.
Huh? Yes, I am an American. I don't see how my geographic location would make it easier/difficult to prove that the camera is faulty. (As you said, it would show up in the pictures!) It also doesn't make it possible for me to snap my fingers and magically make a new body appear. I'd have to work with my source/dealer/service center just like everyone else. As I said before, my verifiable, objective, repeatable issues would be seen by whomever I took the camera to.

Second, if you buy a garbage camera used, then you were either duped by the person who sold it to you (unfortunate, but a learning experience), and/or stupid for not checking it before you put down the dough.

Last edited by bdavis; 01-14-2007 at 06:13 PM.
01-14-2007, 06:11 PM   #15
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QuoteOriginally posted by RiceHigh Quote
Here is the most lengthy techical article I've ever written in my Blog!

RiceHigh's Pentax Blog: Focus Calibrations for (Pentax) (D)SLR Bodies and Lenses

.. for anyone who is interested or even suffered from those daily reported Front Focusing or Back Focusing issues!

Enjoy and I hope that you folks will find this to be useful!
Thanks RH. Looks like some interesting reading.
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