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11-02-2014, 03:52 PM   #1
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Any K-3 owners use the DA 17-70?

There are multiple reviews in the database stating the DA 17-70 struggles to focus from 50 mm and up. However, it's never clear how the camera body has influenced this. Can anyone comment on how reliably this lens can focus using PDAF when married to the K-3? Thanks.

11-02-2014, 11:30 PM   #2
HYS
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I use 17-70 with K-3 and I faced the same problem.
Initially the lens worked very fine. And this problem began to repeat progressively.
At 17 it focused, but at 70 refused. And finally stopped to focus. The problem was the SDM motor.
In the local service the motor was exchanged with a new one (~ $120).
Now the lens is perfect. I have the feeling that it works better then ever.
11-03-2014, 12:27 AM   #3
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QuoteOriginally posted by IchabodCrane Quote
There are multiple reviews in the database stating the DA 17-70 struggles to focus from 50 mm and up. However, it's never clear how the camera body has influenced this. Can anyone comment on how reliably this lens can focus using PDAF when married to the K-3? Thanks.
I didn't write a DA 17-70 review, but if I had, I'd have said it was an okay f4, 17-70 lens. Got mine used a few years ago from KEH. Worked fine on my K-5 bodies and its works fine on my K5IIs bodies.
Very useful in small studios and it's my Santa Claus lens, really handy zoom range. Also have a 5 year old 50-135 and no SDM issues with either lens. My gear is heavily used and I don't baby it.

If I needed one, I'd buy a used from KEH.com for $313, comes with a 6 month warranty. KEH is the first place I check when I need something.

17-70 at 63mm.


17-70 at 39mm


17-70 at 43mm
11-03-2014, 12:45 AM   #4
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The 17-70 is really sharper in almost all lengths than 18-55. The f4 is not a problem for me.

11-03-2014, 03:13 AM   #5
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This is funny - I was just going to post a Q on the 17-70 focusing

I do a lot of photography from high altitude - example: Trip from Shoreham to Corsica and Greece, September 2014

The 17-70 was originally bought for a K200, then used on a K5.

I don't know when I first noticed the focus issue but it was probably when I got the K3.

The camera focuses pretty well on the ground - see the Spanish architecture here: Flight from Shoreham EGKA to Salamanca LESA, Spain, November 2014

(in fact all the daytime pics in the last link above were done with the K3 and 17-70 and that is the only lens I carry around; the first link above used a mixture of cameras and only most of the airborne shots were K3)

But in the air it really struggles. The autofocus works but it doesn't work accurately. However when I tried the Live View a few times on the very last flight, that worked much better. I know Live View uses a different focus principle: it drives the lens back and forth so as to maximise the high frequency video spectrum components. The sharpest image contains the highest frequency components.

So I think there is a problem with the combination of the K3's focus sensors and the 17-70 lens, when shooting through the aircraft windows.

The bizzare thing is that I used to get really sharp airborne pics with the K5 and the 17-70.

The 17-70 had a problem about 6 months ago, apparently with the SDM. It focused but didn't quite get there the last millimeter (or whatever). Amazingly I still had a few weeks left on the extended warranty so I got it fixed. The K3 went for repair at the same time (!!) due to its infamous "machine gun mirror" problem. So both items should now be fixed to spec.

I plan to do a focus check using the special target, but obviously this can be done only on the ground And anyway I am pretty happy with the ground focus performance.

BTW the K3 pics in the 2nd link above (Salamanca) were done in RAW (DNG) and converted to jpeg using Lightroom (90% jpeg quality setting). The 1st link was also done that way but only for the airborne pics (because I didn't have a raw-capable camera on the ground; the K3 is just too heavy to carry around unless you are on a dedicated photographic trip).

Last edited by peterh337; 11-03-2014 at 03:39 AM.
11-08-2014, 12:11 PM   #6
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Well I am having the same issue. I gave lens to service and they replace the sdm motor. After a year problem happened again. Previously I was using Pentax k100d super and now it's k-3. What I found is that focusing works perfectly with the live view. After getting back to normal mode it works ok for some time and the stopped working again. So weird. But I am not going to replace sdm motor again, too expensive to have it not working again.
11-08-2014, 05:48 PM   #7
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QuoteOriginally posted by peterh337 Quote
This is funny - I was just going to post a Q on the 17-70 focusing

I do a lot of photography from high altitude - example: Trip from Shoreham to Corsica and Greece, September 2014

The 17-70 was originally bought for a K200, then used on a K5.

I don't know when I first noticed the focus issue but it was probably when I got the K3.

The camera focuses pretty well on the ground - see the Spanish architecture here: Flight from Shoreham EGKA to Salamanca LESA, Spain, November 2014

(in fact all the daytime pics in the last link above were done with the K3 and 17-70 and that is the only lens I carry around; the first link above used a mixture of cameras and only most of the airborne shots were K3)

But in the air it really struggles. The autofocus works but it doesn't work accurately. However when I tried the Live View a few times on the very last flight, that worked much better. I know Live View uses a different focus principle: it drives the lens back and forth so as to maximise the high frequency video spectrum components. The sharpest image contains the highest frequency components.

So I think there is a problem with the combination of the K3's focus sensors and the 17-70 lens, when shooting through the aircraft windows.

The bizzare thing is that I used to get really sharp airborne pics with the K5 and the 17-70.

The 17-70 had a problem about 6 months ago, apparently with the SDM. It focused but didn't quite get there the last millimeter (or whatever). Amazingly I still had a few weeks left on the extended warranty so I got it fixed. The K3 went for repair at the same time (!!) due to its infamous "machine gun mirror" problem. So both items should now be fixed to spec.

I plan to do a focus check using the special target, but obviously this can be done only on the ground And anyway I am pretty happy with the ground focus performance.

BTW the K3 pics in the 2nd link above (Salamanca) were done in RAW (DNG) and converted to jpeg using Lightroom (90% jpeg quality setting). The 1st link was also done that way but only for the airborne pics (because I didn't have a raw-capable camera on the ground; the K3 is just too heavy to carry around unless you are on a dedicated photographic trip).
Great flights and trip reports.

Cheers,

RM-
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