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Old Apr 11, 2009, 4:57 PM   #11
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Thanks, Lou. I'll be in touch privately.

The guy has written me back and said if I bring it back in the original packaging (which I do still have) he'll give me my money back. Says he never had any problems with it. I may be a sucker, but I want to believe him. I just know it's not working on either of my cameras. I'm almost tempted to ask him to show me how it works on his, but....

I'll probably go down one day after work this week it being Easter weekend and all.

Thanks for all the help. I looked around some on the internet to see if I could find anyone else having the same problem and couldn't find anything bad to say about this lens or the Tamron equivalent. I will definitely continue looking for one.

Keltech I saw the one you're talking about, but it's coming from Singapore. I usually stay away from anything on ebay from that area. Any comments?

Patty
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Old Apr 11, 2009, 6:39 PM   #12
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If it won't focus manually, the electrical contacts have nothing to do with it. I assume you have examined the front and back elements to make sure the lenses are clean - that is the only other thing I can think of other than an internal mechanical problem involving either the focusing mechanism or lens alignment/positioning? Take your camera along and try another example in the store, if they have one for an exchange. If they don't, you might want to consider the Tamron for its 6 yr US warranty after this experience! You are right to reject an overseas purchase because if anything goes wrong you probably can't get warranty service here - you would have to send it back to the country of origin.
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Old Apr 11, 2009, 8:03 PM   #13
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Thanks, Penolta. I can't imagine that it would be something on the lenses are clean since I've taken 400+ images with the camera and they are all clear.

Here are two other images one at 18mm and one again at 250mm. This one is a little closer. You can see the two short stones in the center of the first image. I'm a terrible of judge of distances so can't tell for sure how far this one was taken. But, it's definitely closer than the first images I posted.

The guy has agreed to take the lens back and give memy money back. Although, he did question that I might not realize this lens has a very small aperture at the long end. I told him if he can show me if I'm doing something wrong, I have no problem keeping it. We'll see.

Patty


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Old Apr 11, 2009, 8:05 PM   #14
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First one at 18mm, 1/13 sec, F22, AP, spot metering and focusing, SR on. This second one at 250mm, 1/100 sec, F9.0, AP, spot metering and focusing, SR on. These last two are hand held. The first one I was bracing myself on the car.
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Old Apr 11, 2009, 9:47 PM   #15
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Quote:
I can't imagine that it would be something on the lenses are clean since I've taken 400+ images with the camera and they are all clear.
Patty, in zoom lenses, internal lens elements move in relation to one another with changes in focal length and focus; effects of spots and smears (and lens imperfections) can be more obvious at some focal length/aperture settings (or even light levels) than at others.

You do realize that the longer the focal length, the shallower the depth of field? Also as magnification of the image increases, so does magnification of motion (which is why it is so much harder to hold high power binoculars steady than lower power ones). There is nothing wrong with the last image if you were focussing on the two stones in front (taken at 1/100 sec). For a 1/2 second exposure, some motion blur could be expected in number 3, where the headstone you are focussing on is the sharpest (as it should be with the shallow DOF) and may be correctable with post process sharpening. Number 2 could be motion blur, too, at 1/15 sec. I don't think this lens should be any harder to use than your Tamron 70-300, so what you need to do is to take the same pictures at the same time under the same lighting conditions with the two lenses (both set at 250mm) - that would be the acid test and rule out bad lighting with concomitant slow exposures as the cause. If the same problem appears, show the pairs of comparison shots to the salesman and he will have no reason to doubt you when you return the lens (and he will send it back to Pentax without selling to someone else first).
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Old Apr 11, 2009, 11:05 PM   #16
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The last picture you posted is pretty good for 250mm and 1/100. I know I can't hand-hold that without camera shake, even with SR on. But from your first post, it does sound like there could be a problem with the lens.
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Old Apr 12, 2009, 8:53 AM   #17
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Penolta, good point on the different focal lengths "seeing" different spots. I will check both ends and clean them up in case that's part of it.

I do remember from my photography class that the longer focal length yields a smaller depth of field. Although, I do admit to struggling with trying to remember everything I must when shooting. One of the reasons for a lot of my failed shots.:-) That was one of the reasons I was shooting at all f-stops. I will try again today using a tripod to definitely rule that out. Although, I had already done the test with the two lenses at the same time under the same conditions. Just not using a tripod. This image is with the Tamron70-300 at 300mm, F5.6, 1/400 sec, spot everything. I took three shots and did not have to even struggle with trying to find afocus point with it. Although, I will retry today at 250mm as you suggested. It is sunny here today, although cold and windy.

Harriet, I was impressed with that last photo, too, considering. But, the distance to those stones is about the same distance as the brown stone in the first photo. That's my problem. I can getcrystal clear shots at a close distance or at a lower mm, but not at 250mm at a long distance.

Keltech has offered to meet me and we'll experiment with his Tamron 18-250 and this Pentax one. That should give me a definite answer. I would think. Then there's no questioning whether the 70-300 is easier because of the larger aperture or what.

Patty

p.s. None of these images have had any cropping or adjustments made to them except to resize for viewing here.

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Old Apr 12, 2009, 12:12 PM   #18
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Patty, this last picture is not bad, considering the subject and lighting, and the DOF looks adequate given that both the very old worn stone in the foreground and the one with better raised relief are both legible. Compare with the earlier one posted and you can see the difference in focal length between 250 and 300mm - the larger stone in the central image is easier to focus on then the one in the smaller image. There is also the fact that you are trying to compare a 1/400 sec picture with one hand held at 1/15 sec - they are just not comparable. I have had occasion to take quite a few pictuires in cemetaries of gravestones new and old, and it is not easy, because many of the older stones are eroded and are hard to read, and lighting is seldom ideal on any particular gravestone, either being too contrasty or too flat, or else backlighted. Take a look at the type of pictures that Steve takes to evaluate cameras and lenses at the end of his reviews - you need to find a better test subject, perhaps a brick wall in full sunlight. There may well be something wrong with the lens - you have had enough experience by now to have a feeling for things not being right, but these pictures cannot be used to demonstrate it. If you are not comfortble with the lens, you won''t use, so there is no reason for you to keep - just return it and move on. Just my opinion. :roll:
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Old Apr 12, 2009, 8:16 PM   #19
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Thanks for the input, Penolta. I won't be able to return it until Wednesday. Idid some testing with the tripod and different subjects today and didn't have much better results. I'll meet with Keltech and see how it is supposed to work and decide if I'll pursue finding another one.

Patty
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Old Apr 12, 2009, 8:49 PM   #20
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I'll be interested in what you figure out with your lens. I played with the DA 55-300 today, taking pictures of surfers. I'm still undecided about this lens - it seems to have some significant problems at longer distances, too. Today I took an outstanding, sharp picture of a surfer that was relatively close, and some other ones at fairly far distance were good, but one that I took that was at 55 mm but included a very far distant shoreline was very poor. I'm about to send it back to Pentax and ask if the lens meets specifications (I suspect it is and that I've become really particular when it comes to lenses). It's way too late to return it for a different lens now - I'm beginning to believe that I should just skip the consumer zoom lenses and not buy anything but expensive primes. Too bad my budget isn't unlimited (sigh!).
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