DFA 90 2.8 Macro - AF motor goes to sleep

Fabian · 11-24-2017, 02:27 AM

I've had this happen every now and then over a 2 year period. The AF motor goes to sleep, sometimes in the middle of shooting or after the camera has been in "stand by" mode and it's woken up by a shutter half press (camera wakes up, but lens won't focus). A simple restart or un-/remount of the lens gets it going again.
Have seen it on two different copies of the lens. Firmware has been upgraded, no change.

Any ideas what might be causing this?

**shardulm** · 11-24-2017, 09:41 AM

Is there a DFA 90 macro manufactured by Pentax with a lens motor in it? I don't think any of their macro lenses have a built in AF motor. All their AF macro lenses are screw driven AF.
Are you sure it is a Pentax lens?

---------- Post added 11-24-17 at 12:03 PM ----------

Originally posted by shardulm

Is there a DFA 90 macro manufactured by Pentax with a lens motor in it? I don't think any of their macro lenses have a built in AF motor. All their AF macro lenses are screw driven AF.
Are you sure it is a Pentax lens?

Never mind if you are talking medium format. It is far beyond my reach even in terms of thinking

lytrytyr · 11-24-2017, 10:53 AM

Originally posted by Fabian

Any ideas what might be causing this?

Have your lenses been in extreme temperatures that might have messed with the lubrication?
Not necessarily when you have the problem, but previously.

Fabian · 11-25-2017, 03:37 AM

Nope, and with one of the lenses it happened already when it hadn't been used outside of studio.

11-24-2017, 02:27 AM	#1
Fabian Junior Member Join Date: Jul 2008 Posts: 49	DFA 90 2.8 Macro - AF motor goes to sleep I've had this happen every now and then over a 2 year period. The AF motor goes to sleep, sometimes in the middle of shooting or after the camera has been in "stand by" mode and it's woken up by a shutter half press (camera wakes up, but lens won't focus). A simple restart or un-/remount of the lens gets it going again. Have seen it on two different copies of the lens. Firmware has been upgraded, no change. Any ideas what might be causing this?

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11-24-2017, 09:41 AM	#2
shardulm Loyal Site Supporter Join Date: Jul 2013 Location: Cumming, GA Posts: 793	Is there a DFA 90 macro manufactured by Pentax with a lens motor in it? I don't think any of their macro lenses have a built in AF motor. All their AF macro lenses are screw driven AF. Are you sure it is a Pentax lens? ---------- Post added 11-24-17 at 12:03 PM ---------- Originally posted by shardulm Is there a DFA 90 macro manufactured by Pentax with a lens motor in it? I don't think any of their macro lenses have a built in AF motor. All their AF macro lenses are screw driven AF. Are you sure it is a Pentax lens? Never mind if you are talking medium format. It is far beyond my reach even in terms of thinking

11-24-2017, 10:53 AM	#3
lytrytyr Pentaxian Join Date: Nov 2011 Photos: Gallery \| Albums Posts: 4,310	Originally posted by Fabian Any ideas what might be causing this? Have your lenses been in extreme temperatures that might have messed with the lubrication? Not necessarily when you have the problem, but previously.

11-25-2017, 03:37 AM	#4
Fabian Junior Member Join Date: Jul 2008 Posts: 49 Original Poster	Nope, and with one of the lenses it happened already when it hadn't been used outside of studio.