DA 15 losing AF ability at infinity

DeadJohn · 01-31-2015, 07:45 PM

I just received a DA 15 from KEH. Optics are in good shape. I seem to be having problems when the focus ring hits the infinity stop.

Symptom 1: manual focus and Av mode. At infinity my K5 calculated shutter speed 1.5". The speed changed to 0.5" as soon as I quick shifted a little closer than infinity. Jumps back to 1.5" at infinity. Test images confirm different exposure brightness.

Symptom 2: camera set to AF.C or AF.S. If I quick shift to infinity the rear LCD displays the focus mode as "MF", goes back to "AF" if I quick shift closer than infinity.

Symptom 3: turn camera off, focus to infinity, turn camera on, rear screen prompts for focal length.

Note that I don't get the "F--" display and I can continue to control the aperture even when the camera thinks my DA 15 is a manual lens. I've already tried mounting and unmounting the lens, cleaning contacts (will try more thorough clean later), changing camera battery.

Anyone ever experience something like this? Suggestions?

lytrytyr · 01-31-2015, 08:19 PM

Originally posted by DeadJohn

Suggestions?

Are you within the time frame to return the lens to KEH?
If so, it doesn't seem worthwhile flogging a dead horse.

DeadJohn · 02-01-2015, 12:45 AM

I am well within the KEH return period. I just want to make sure I don't return a lens unnecessarily. This DA 15 seems broken but maybe there's some nuance that I've missed.

j2photos · 02-01-2015, 01:34 AM

My DA 15 LTD behaves nothing like this on my K-3. If all your other lenses behave appropriately I would say there is something wrong with this lens and I personally would return it.

Na Horuk · 02-01-2015, 04:44 AM

Hey, too bad you are having those problems.
a) Dismount the lens, make sure camera and lens contacts are clean and free of particles.
b) Make sure the lens' mount looks good - that it is not bent, cracked, missing screws, etc.
c) Try other lenses on your camera, see how they behave
d) When the DA 15mm is off the camera, try focusing from near to infinity and observe the mount. Does anything odd happen?

Either way, unless this is actually a camera defect (it happens with other lenses as well), I would have this lens sent back and either have them repair it at no cost, or return the money. I think keh has some warranty, but be sure to notify them as soon as possible. Notify them by email before you send the lens, so that you definitely notified them within the warranty period.

01-31-2015, 07:45 PM	#1
DeadJohn Pentaxian Join Date: Jan 2011 Location: New York Posts: 4,833	DA 15 losing AF ability at infinity I just received a DA 15 from KEH. Optics are in good shape. I seem to be having problems when the focus ring hits the infinity stop. Symptom 1: manual focus and Av mode. At infinity my K5 calculated shutter speed 1.5". The speed changed to 0.5" as soon as I quick shifted a little closer than infinity. Jumps back to 1.5" at infinity. Test images confirm different exposure brightness. Symptom 2: camera set to AF.C or AF.S. If I quick shift to infinity the rear LCD displays the focus mode as "MF", goes back to "AF" if I quick shift closer than infinity. Symptom 3: turn camera off, focus to infinity, turn camera on, rear screen prompts for focal length. Note that I don't get the "F--" display and I can continue to control the aperture even when the camera thinks my DA 15 is a manual lens. I've already tried mounting and unmounting the lens, cleaning contacts (will try more thorough clean later), changing camera battery. Anyone ever experience something like this? Suggestions?

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01-31-2015, 08:19 PM	#2
lytrytyr Pentaxian Join Date: Nov 2011 Photos: Gallery \| Albums Posts: 4,310	Originally posted by DeadJohn Suggestions? Are you within the time frame to return the lens to KEH? If so, it doesn't seem worthwhile flogging a dead horse.

02-01-2015, 12:45 AM	#3
DeadJohn Pentaxian Join Date: Jan 2011 Location: New York Posts: 4,833 Original Poster	I am well within the KEH return period. I just want to make sure I don't return a lens unnecessarily. This DA 15 seems broken but maybe there's some nuance that I've missed.

02-01-2015, 01:34 AM	#4
j2photos Veteran Member Join Date: Jun 2010 Location: Manteca, CA Photos: Gallery \| Albums Posts: 1,653	My DA 15 LTD behaves nothing like this on my K-3. If all your other lenses behave appropriately I would say there is something wrong with this lens and I personally would return it.

02-01-2015, 04:44 AM	#5
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	Hey, too bad you are having those problems. a) Dismount the lens, make sure camera and lens contacts are clean and free of particles. b) Make sure the lens' mount looks good - that it is not bent, cracked, missing screws, etc. c) Try other lenses on your camera, see how they behave d) When the DA 15mm is off the camera, try focusing from near to infinity and observe the mount. Does anything odd happen? Either way, unless this is actually a camera defect (it happens with other lenses as well), I would have this lens sent back and either have them repair it at no cost, or return the money. I think keh has some warranty, but be sure to notify them as soon as possible. Notify them by email before you send the lens, so that you definitely notified them within the warranty period.