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06-05-2011, 12:03 PM   #1
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Problems auto focus assist in manual

Hello to all!
Friend of mine, who had no photographic experience at all, where pressuring me to get back in to photography, to have a body to hang out with - him and his Canon 350, I guess. And, since digital came to somewhat more mature age I decided to give it a shot. First I picked up Fuji S700 and plaid with it for a year. Friend teased me a lot, pushing me to splurge on full frame but I went for Pentax k100D body, that came along refurbished by factory, supposedly, at Best Buy. Also, decided to order with it, one AF lens at very least as well. After some researching I chose its stock 18-55mm DAII brand new (based on Q/P ratio) lens, hoping to get use of old manuals later as well. Just try to imagine frustration of an old white-birded guy getting a hold of a "new" "body" a few weeks later and awaiting for weeks more for its lens to come! That was a new beginning - start of excitements and frustrations!
When I finally slapped new smc on the k100d and started terrorize everyone around me, including neighbored pets and flowers, came to a satisfactorily conclusion: in full auto wide angle was given me more or less fair results even in crop, and as it has a very good DOF, infinity was not a critical issue at first! By the time I’ve got a hold of first old manual pentax mount glass, and tested - 30 days warranty from manufacture had long gone. As CS Pentax explained to my son, who called on my behalf, as a favor only, they found a rubber eye piece to replace one that was missing from a store and mailed it to me only after explaining to them, that Best Buy sales could not find any cameras in stock to pull it off of from for me. That along should have had being a “RED FLAG” for me, let along speck of white dust under the glass of top display and black dots and someone’s fingerprint on inside of the focusing screen. I am pretty sure they’re on inside, since would not come off at all after whet cleaning. Although Pentax did quite a bit to make old glass usable, manual focusing on this stock screen is not an option, at least for my eye site. I plan in the future to replace this screen for a double 45 split anyway. The auto focuses assist no help-missing constantly. All those discrepancies should have and probably would trigger my younger mind to connect all dots at once, and conclude that this unit may never have gone through re-manufacturing! It just would not pass QC on any stretch of imagination! Although I called and discussed this with Pentax ones, at the time I had to return lens on warranty repairs due to focusing group coming lose, but was not persisted enough to take care of all by warranty on the body (as over 30 days). Now, I come to believe, that my focusing problems comes from faulty set and never corrected manufacturing settings on top of all other problems. Acquiring and testing number of different used, and new as well lenses, does prove this conclusion of mine. I`d like to get all input from obviously experienced Pentaxiens the best way to deal with this problem.
As well as, what would be better lens out of this two? Opteka 500mm f/6.3 and Opteka 500mm f/8.0 on k100d Focusing those on perfect body is a challenge by itself. May be compare quality and other merits Optekas 500mm f/6.3 to 500mm f/8.0. I’ve ordered and got f/8.0 new to test on tripod gives me no clear focus on long distances and it goes past, the most best focused objects in infinity, to a full stop a few more degrees to a “full and terminal” out of focus. Tanks, Tony As well as, what would be better lens out of this two? Opteka 500mm f/6.3 and Opteka 500mm f/8.0 on k100d Focusing those on perfect body is a challenge by itself. May be compare quality and other merits Optekas 500mm f/6.3 to 500mm f/8.0. I’ve ordered and got f/8.0 new to test on tripod gives me no clear focus on long distances and it goes past, the most best focused objects in infinity, to a full stop a few more degrees to a “full and terminal” out of focus. Tanks, Tony

06-05-2011, 05:37 PM   #2
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Hi! Kind of a bunch of unrelated things here; you'd have been better off starting separate threads. But:

QuoteOriginally posted by tonybolo Quote
Hello to all!
someone’s fingerprint on inside of the focusing screen.
Not likely. You're probably seeing the texture of the screen itself. The more prominent texture of the Pentax screen compared to some others is designed to make it easier to focus. Consider, a completely transparent piece of plastic or glass would not even form an image.

QuoteQuote:
The auto focuses assist no help-missing constantly
You have to realize two things:

1) Only the center focus "point" is active with MF lenses.
2) The focus "point" is not a point at all. Thus when confirmation comes on, it is telling you only that something near that point is in focus, not necessarily the specific point itself.

Once you get accustomed to how it works, it can be useful.

QuoteQuote:
As well as, what would be better lens out of this two? Opteka 500mm f/6.3 and Opteka 500mm f/8.0
See the reviews in this forum (click Lenses above) and also the samples and discussion in the Mirror Lens Club thread in the Lens Club forum. Bottom line: most agree the f/6.3 is better. But neither is any better than one should expect from the price.
06-06-2011, 02:03 PM   #3
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Join Date: Jun 2011
Posts: 8
Original Poster
QuoteOriginally posted by tonybolo Quote
Hello to all!
Friend of mine, who had no photographic experience at all, where pressuring me to get back in to photography, to have a body to hang out with - him and his Canon 350, I guess. And, since digital came to somewhat more mature age I decided to give it a shot. First I picked up Fuji S700 and plaid with it for a year. Friend teased me a lot, pushing me to splurge on full frame but I went for Pentax k100D body, that came along refurbished by factory, supposedly, at Best Buy. Also, decided to order with it, one AF lens at very least as well. After some researching I chose its stock 18-55mm DAII brand new (based on Q/P ratio) lens, hoping to get use of old manuals later as well. Just try to imagine frustration of an old white-birded guy getting a hold of a "new" "body" a few weeks later and awaiting for weeks more for its lens to come! That was a new beginning - start of excitements and frustrations!
When I finally slapped new smc on the k100d and started terrorize everyone around me, including neighbored pets and flowers, came to a satisfactorily conclusion: in full auto wide angle was given me more or less fair results even in crop, and as it has a very good DOF, infinity was not a critical issue at first! By the time I’ve got a hold of first old manual pentax mount glass, and tested - 30 days warranty from manufacture had long gone. As CS Pentax explained to my son, who called on my behalf, as a favor only, they found a rubber eye piece to replace one that was missing from a store and mailed it to me only after explaining to them, that Best Buy sales could not find any cameras in stock to pull it off of from for me. That along should have had being a “RED FLAG” for me, let along speck of white dust under the glass of top display and black dots and someone’s fingerprint on inside of the focusing screen. I am pretty sure they’re on inside, since would not come off at all after whet cleaning. Although Pentax did quite a bit to make old glass usable, manual focusing on this stock screen is not an option, at least for my eye site. I plan in the future to replace this screen for a double 45 split anyway. The auto focuses assist no help-missing constantly. All those discrepancies should have and probably would trigger my younger mind to connect all dots at once, and conclude that this unit may never have gone through re-manufacturing! It just would not pass QC on any stretch of imagination! Although I called and discussed this with Pentax ones, at the time I had to return lens on warranty repairs due to focusing group coming lose, but was not persisted enough to take care of all by warranty on the body (as over 30 days). Now, I come to believe, that my focusing problems comes from faulty set and never corrected manufacturing settings on top of all other problems. Acquiring and testing number of different used, and new as well lenses, does prove this conclusion of mine. I`d like to get all input from obviously experienced Pentaxiens the best way to deal with this problem.
As well as, what would be better lens out of this two? Opteka 500mm f/6.3 and Opteka 500mm f/8.0 on k100d Focusing those on perfect body is a challenge by itself. May be compare quality and other merits Optekas 500mm f/6.3 to 500mm f/8.0. I’ve ordered and got f/8.0 new to test on tripod gives me no clear focus on long distances and it goes past, the most best focused objects in infinity, to a full stop a few more degrees to a “full and terminal” out of focus. Tanks, Tony As well as, what would be better lens out of this two? Opteka 500mm f/6.3 and Opteka 500mm f/8.0 on k100d Focusing those on perfect body is a challenge by itself. May be compare quality and other merits Optekas 500mm f/6.3 to 500mm f/8.0. I’ve ordered and got f/8.0 new to test on tripod gives me no clear focus on long distances and it goes past, the most best focused objects in infinity, to a full stop a few more degrees to a “full and terminal” out of focus. Tanks, Tony
Thank you for a prompt reply Marc!
I`ve red all related posts on Pf and, believe, you are the expert in focusing issues. Never the less:

QuoteOriginally posted by Marc Sabatella Quote
You're probably seeing the texture of the screen itself.
I did not noticed fingerprint until started cleaning sensor and attempted removing black dots on screen, closely locking at screen with lens removed.
I wish, I could come up technically with an idea to make snapshot of it, but it is a clearly a fingerprint.

QuoteOriginally posted by Marc Sabatella Quote
it can be useful.
I do have a few old and even brand new glass lenses that had to buy to test this problem. At first used ones, which gave me no certainty in problems origin, then I`ve got brand spanking new, but lower end "Hanimex" 135mm and still refused to believe in cameras fault, and now newest Opteka 500mm f/8.0.
I do realize in my eye sites maturity short comings and limitations, but in manual photography I did a few pix in my life. If center point is focusing point - you expect some thing in focus to be in the picture, at the very least! I like to use as little as I can flash and it makes even harder to focus.
On a tripod, with 5 different manuals, had hard time to green hexagon me most of the times. Even pangolin back and forth over its red position, but only occasionally, does give right focusing.
I do get an impression from you not to take this feature focus assists seriously, and, some what reluctantly, and unequivocally locking in to inexpencieve and more reliable eyeball assist focusing screen.
I would like some input in reliability of $20. like Double 45° Split Focusing Screen For Pentax K100D K200D K-M | Linkdelight.com or http://www.amazon.com/Double-Focusing-Screen-Pentax-CowboyStudio/dp/B004SO6MKQ[/URL]) rather then $120 Katseye, which, I am sure, exceptional quality and out of range of some of us, unfortunately.

Thanks again,
PS
I did not see reviews on Opteka 500mm lenses at all, may yet still dig it out later.
At this point I did prove to myself: The newest lens did not make a squat of difference in my focusing struggle with k100D. I will have to make a best choice I can of f8.0 (weight quality of one) to a f6,3 (double weight and larger size of other) - is the last one noticeably better?
I realize 10x cost, like $1000. lens will be 2 or 3 times better then $100. one, but will you see any difference with $150-$200. Vivitar Rokinon lenses?
Love Denver!
06-06-2011, 04:26 PM   #4
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The Opteka lenses are actually made by Samyang and are sold under a variety of other names, including Vivitar, Rokinon, Kenko, and others. They are the only mirror available new that I know of, so pretty mcuh any review of a new mirror lens, that's the one.

06-10-2011, 11:35 PM   #5
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Thanks for the info Marc.
Wonder, if quality changes with label.
Yet, Opteka the lowest priced of all and I could not find any comparisons between F6.3 and f8.0 latest models. That exact decision I have to make now and appreciate any input.
06-11-2011, 06:20 PM   #6
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No direct comparisons, but there are plenty of examples and opinions in the Mirror Lens Club thread I mentioned.
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