Forum: Troubleshooting and Beginner Help
07-04-2020, 12:10 AM
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How does one control the aperture on lenses that do not have an aperture ring when using an extension tube. Does it default to the widest aperture which kind of defeats the purpose of photography using extension tubes - close focus with a wide depth of field.Thanks in advance for your input.
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Forum: Sold Items
07-03-2020, 11:50 PM
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Whats the lowest offer you would accept?
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Forum: Troubleshooting and Beginner Help
03-28-2020, 01:23 PM
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Had the same problem. It happenned when I tripped and fell. Camera or lens did not hit the ground but I guess it jarred it enough the the aperture was stuck wide open. Sent it to Advance Camera in Portland and they repaired it for what I thought was a very reasonable price. I believe around $75.
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Forum: Pentax SLR Lens Discussion
12-11-2019, 12:35 PM
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I had the 12-24 for a number of years. Thought its was a good lens and adequately sharp until I purchased the 11-18. The 11-18 is a far superior lens in both sharpness (center, corner and edge) and chromatic abberations. A little heavy but optically superior to the 12-24
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Forum: Pentax SLR Lens Discussion
04-24-2019, 08:34 AM
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Supplementary as in addition to the the manufacturers warrantee
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Forum: Pentax SLR Lens Discussion
04-24-2019, 07:21 AM
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Has anyone ever purchased the Square Trade protection plan that is sold by B and H? If you have, any experince(s) good or bad?
Thanks in advance for any info provided.
Jim
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Forum: Pentax SLR Lens Discussion
04-23-2019, 02:37 PM
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I recently purchased the new DA*11-18 lens and decided that I would test for any de-centering. I have never done this before so with the help of the internet I found a process for performing the test.The following is the process I used, the camera and lens settings, and the results.
Settings
Camera - K3 mounted on tripod
Exposure - Manual (Spot metered on the center of target on first (center) exposure)
Focus - Manual
Shake reduction - Off
Aperture - 2.8
Focal Length - 11mm and 18mm
Shutter speed - As need for correct exposure
ISO - 100
Process
Set the focal length to 11 mm. Positioned camera so the target (building about 120 yards away with sign"FISH CAMP") was in the center of the view finder. Focused on the "FISH CAMP" sign and adjusted shutter speed for proper exposure. Turned on the Focus Clamp (neat option on this lens) to ensure focus did not change between exposures. Took the first exposure using a remote shutter release in the mirror lock up mode. Loosened the tripod ball head and moved the camera so the target was in the upper left of the viewfinder. Tightened the ball head and made the second exposure. Repeated this for the other three corners. Changed focal length to 18 mm and repeated the whole process.
The attached images are 100% crops of the images. The top is the 11mm set and the bottom the 18 mm set. These are straight out of the camera images with no adjustments made. The only thing I did was crop them and make a collage in photo shop of the two different focal lengths
My observations - Upper left is the softest wth the bottom right the sharpest (There was a significant wind so don't look at the trees). Appears to have a little more vignetting on the top corners as compared to the bottom corners (top corners are darker than bottom corners). There is a little chromatic aberration in all four corners but could easily be corrected. CA on the 12-24 is much worse.
Since I have never done a de-centering test before was this the correct process and if so is this an acceptable lens regarding focus de-centering? I believe it is but for the price of the lens I just wanted to get a second opinion. Even though you want it to be there is probably no perfect lens.
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Forum: Site Suggestions and Help
04-23-2019, 01:00 PM
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Thanks Adam for your options. I went ahead and donated
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Forum: Site Suggestions and Help
04-23-2019, 10:45 AM
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Got to that page but cannot find a way to delete attachments. Can view them but not delete them
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Forum: Site Suggestions and Help
04-23-2019, 09:28 AM
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How do I delete attached photos. Have used up all of my attachment space and would like to add a couple of attachments.
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Forum: Pentax SLR Lens Discussion
03-09-2019, 07:36 AM
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Has anyone tried out the new 11-18mm 2.8 lens yet and if so what are your impressions?
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Forum: Monthly Photo Contests
10-16-2018, 12:00 AM
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Photo taken early morning at Lake Placids' Mirror Lake.
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Forum: Monthly Photo Contests
07-10-2018, 06:01 AM
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I would like to nominate this photo
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Forum: Monthly Photo Contests
07-10-2018, 06:00 AM
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I would like to nominate this photo
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Forum: Monthly Photo Contests
07-10-2018, 06:00 AM
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I would like to nominate this photo
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Forum: Winners' Showcase
07-10-2018, 05:58 AM
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I would like to nominate this photo
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Forum: Monthly Photo Contests
07-10-2018, 05:58 AM
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I would like to nominate this photo
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Forum: Monthly Photo Contests
07-10-2018, 05:58 AM
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I would like to nominate this photo
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Forum: Monthly Photo Contests
07-10-2018, 05:57 AM
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I would like to nominate this photo
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Forum: Monthly Photo Contests
07-10-2018, 05:57 AM
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I would like to nominate this photo
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Forum: Winners' Showcase
05-02-2018, 07:42 AM
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I would like to nominate this photo
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Forum: Winners' Showcase
05-01-2018, 09:44 PM
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Photo from a trip to Barcelona
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Forum: Monthly Photo Contests
07-14-2017, 11:54 AM
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Forum: Monthly Photo Contests
07-13-2017, 08:30 PM
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Glenwwod cemetery in Houston Texas
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Forum: Post Your Photos!
11-20-2016, 12:05 AM
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A pic I did a little experimenting with processing this image.
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