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12-09-2010, 03:25 PM   #1
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K-5 slow focus on a Pentax macro 100 WR

Tested the K-5 with the Macro 100WR today and the setup have a lot of problems with the the focus. Sometimes the focus stop and I have to try to refocus several times. Is this a common problem with the Pentax autofocus or is this a problem with my camera?

12-09-2010, 03:39 PM   #2
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A little more information is required here.

What are you trying to photograph? How close are you from the subject? How much light is available where you're photographing? Are you using center point AF, selective AF, or auto AF?

- Jason
12-09-2010, 03:44 PM   #3
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I haven't tried my 100 on the K5 yet but what I noticed on the K7 was that at close range, AF was nearly useless. Unless you have a dead still subject (which I didn't) and you are using a tripod (which I wasn't), any slight movement will confuse the AF. Best to set to your desired magnification and use Catch In Focus to make your shot (if hand held). I somehow doubt that it's going to be any different on the K5.

12-09-2010, 04:00 PM   #4
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Macro mostly MF

A looong time ago I started macro with the FA100/2.8 macro and it was not long befroe I fond out that for macro manual focus worked best.... I sold it and was lucky enough to get just about the best macro glass ever, Voigtländer 125/2.5 and Pentax A*200/4 macro....

Although DA35/2.8 works fine in AF

12-09-2010, 04:15 PM   #5
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Yes, i tend to agree the 100mm WR is slow to autofocus regardless of the camera body, just based on the nature of the lens. I have tried it on the K-x, K-7, k-5, and always find manually focusing it to be much quicker.
12-09-2010, 11:28 PM   #6
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QuoteOriginally posted by inferno10 Quote
A little more information is required here.

What are you trying to photograph? How close are you from the subject? How much light is available where you're photographing? Are you using center point AF, selective AF, or auto AF?

- Jason
Autofocus mode Auto 11. Focus on a macro object ca 50cm and so changed to a object about 2 meter distance , then the lens will not focus on the new 2 meter object ( the lens is still in 50cm mode. I have to push the shutter several times before the focus motor react and focus on the new object ( also tried the AF button). This is an indoor picture in god light. AF.S mode on camera. ( No problem with other lenses like DA16-50 or FA43mm). All setup modes are the default on the camera and I work with the Aperture mode.
Tried the same macro setup with a Sony a900 with a Minolta 100mm macro and the Sony system have no problems with the focus.
Trygve

No problem with the focus with the 100mm WR in Autofocus mode Auto 5 - so why the problems in the the Autofocus mode Auto 11 ?

Last edited by Caddis; 12-09-2010 at 11:36 PM.
12-10-2010, 04:16 AM   #7
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QuoteOriginally posted by Caddis Quote
Autofocus mode Auto 11. Focus on a macro object ca 50cm and so changed to a object about 2 meter distance , then the lens will not focus on the new 2 meter object ( the lens is still in 50cm mode. I have to push the shutter several times before the focus motor react and focus on the new object ( also tried the AF button). This is an indoor picture in god light. AF.S mode on camera. ( No problem with other lenses like DA16-50 or FA43mm). All setup modes are the default on the camera and I work with the Aperture mode.
Tried the same macro setup with a Sony a900 with a Minolta 100mm macro and the Sony system have no problems with the focus.
Trygve

No problem with the focus with the 100mm WR in Autofocus mode Auto 5 - so why the problems in the the Autofocus mode Auto 11 ?


Not really sure why you would wish to use either the 5 or 11 autofocus modes when taking macro's. If you are going to AF rather than MF then center spot focusing is what you need.

Otherwise you have no control over where the camera is focusing (unless you manually select the focus point). When taking macro's you need complete control over the focus point because of the shallow DOF even at say F22.

Stick it on center point focus and try again.

12-10-2010, 05:04 AM   #8
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The problem is not the macro focus, but after a macro focus and if I try to focus on a different objekt in a longer distance from the camera it will not focus on that object. The lens will not operate to try the refocus. I have to rehit the shutter button several times before the refocus start to work in AF11 mode.
12-10-2010, 02:16 PM   #9
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QuoteOriginally posted by Caddis Quote
No problem with the focus with the 100mm WR in Autofocus mode Auto 5 - so why the problems in the the Autofocus mode Auto 11 ?
That sounds pretty much like you kept some detail from the 50cm plane in the region of interest of any of the 11 AF fields.

The idea of 11 point mode is that the camera focusses on the closest subject you see and that's possibly what you got.
12-11-2010, 01:07 AM   #10
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Minun Pentax K-5 toimii hienosti SMC PENTAX-DFA 1:2.8 100mm Macro. Macro kuvays tarkennetaan MF ainoa oikea tapa. Muotokuvauksessa voi olla AF.
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