Help needed - Pentax-A 35-105mm f3.5

ScooterMaxi Jim · 01-13-2016, 07:36 PM

Originally posted by deepbluish

I probably should have mentioned this in the beginning, but I actually already own a fully functional 35-105mm f3.5 lens against which I compared the faulty one. On the proper one, the focus does change a bit with change in focal length, but nowhere near this much.

I double checked just to be sure, and I've just focused on a target at 105mm FL and distance scale showed around 1.5m. Then, I zoomed out to 35mm, refocused and the distance scale was on the infinity mark. That cannot be right.

It seems that more often than not focusing is not possible at all when zooming out from 105mm to 35mm. It just does not find the target.

Yeah, I would say you probably should have mentioned that... And did a little more testing to try to identify the obvious malfunction.

chmance · 01-13-2016, 08:47 PM

I have this lens and definitely it is parfocal in the non-macro mode. It does appear that the OP's copy has a mechanical problem. It is definitely not a "stack of primes" but pretty close to it. The only thing that prevents me from using it more often regularly is its heft. Otherwise, the image quality is amazing for such a zoom with so many elements.

**gofour3** · 01-14-2016, 09:20 AM

Originally posted by deepbluish

f anybody is familiar with this kind of a problem, I'd really appreciate any feedback whether this is something repairable.

If your zoom lens has no issues then note the following:

The A35-105/3.5 is a "two touch" zoom and is different from the "one touch" design used in the A70-210/4.

Here is an excerpt from the Pentax A Series lens manual for the recommended way to focus/zoom each type of lens.

Phil.

deepbluish · 01-14-2016, 03:05 PM

Thanks, Phil, but it's pretty much clear that I've bought a lemon.

**pepperberry farm** · 01-14-2016, 03:07 PM

Originally posted by deepbluish

Thanks, Phil, but it's pretty much clear that I've bought a lemon.

send it back for a refund?

**gofour3** · 01-14-2016, 03:41 PM

Originally posted by deepbluish

Thanks, Phil, but it's pretty much clear that I've bought a lemon.

Yep I would agree, my A35-105 and A70-210 work as described in the manual.

Phil.

**dadipentak** · 01-14-2016, 03:59 PM

Originally posted by kh1234567890

I hate its ergonomics

I can understand that: I just regard it as part of the len's "charm".

**monochrome** · 01-14-2016, 04:56 PM

Originally posted by deepbluish

Thanks, Phil, but it's pretty much clear that I've bought a lemon.

Send it to Eric. Maybe he can fix it for a reasonable sum.

TaoMaas · 01-14-2016, 06:41 PM

Originally posted by chmance

The only thing that prevents me from using it more often regularly is its heft.

It's definitely a heavy lens...but that's also what makes it a good match for my K10D, which is a bit of a large, heavy camera itself. I just pair the 35-105mm with my Tokina 80-200 f2.8, call it my 'heavy metal' kit, and resign myself to using them.

That kit isn't my walk-around choice, but it's definitely my choice when I can work close to my car.

fwcetus · 01-15-2016, 06:57 AM

Originally posted by chmance

The only thing that prevents me from using it more often regularly is its heft. Otherwise, the image quality is amazing for such a zoom with so many elements.

Originally posted by kh1234567890

One of these days I'll get round to selling mine since I hate its ergonomics so much ...

Originally posted by TaoMaas

It's definitely a heavy lens...but that's also what makes it a good match for my K10D, which is a bit of a large, heavy camera itself. I just pair the 35-105mm with my Tokina 80-200 f2.8, call it my 'heavy metal' kit, and resign myself to using them.

That kit isn't my walk-around choice, but it's definitely my choice when I can work close to my car.

Have any of you used the A 35-105/3.5's big brother, the A 28-135/4 (the "tower of primes")? It's larger and heavier (it has even more glass within), but it is constructed in the same fashion (it even has the exact same "macro shift" functionality). But, a couple of decades ago, the A 28-135/4 was my goto wedding lens of choice (on an LX).

deepbluish · 01-16-2016, 04:38 AM

Originally posted by monochrome

Send it to Eric. Maybe he can fix it for a reasonable sum.

I don't live in the US, so that really isn't an option.

Refund is also not an option anymore.

I'll try to send it for repair to a local repairshop. For some reason, I don't think it's anything major, it just feels like something is loose inside it. I wish I had the knowledge/courage to do the surgery myself. I've tried it before, but ended up with extra parts which did not seem to belong anywhere, yet came from somewhere.

35-105 is a heavy lens, but not that heavy. I always support it with my entire hand. My middle finger lands right on the zooming ring and index finger on the focus ring. What I do find cumbersome is that sometimes to obtain accurate focus you find yourself in that transition zone between normal focus and macro focus.

**pepperberry farm** · 01-16-2016, 04:49 AM

Originally posted by deepbluish

35-105 is a heavy lens, but not that heavy. I always support it with my entire hand. My middle finger lands right on the zooming ring and index finger on the focus ring. What I do find cumbersome is that sometimes to obtain accurate focus you find yourself in that transition zone between normal focus and macro focus.

agreed with the transition zone; I've learned to take a step, either towards or away from the subject....

01-14-2016, 09:20 AM	#18
gofour3 Site Supporter Join Date: Oct 2008 Location: Vancouver, Canada Posts: 8,090	Originally posted by deepbluish f anybody is familiar with this kind of a problem, I'd really appreciate any feedback whether this is something repairable. If your zoom lens has no issues then note the following: The A35-105/3.5 is a "two touch" zoom and is different from the "one touch" design used in the A70-210/4. Here is an excerpt from the Pentax A Series lens manual for the recommended way to focus/zoom each type of lens. Phil. Attached Images

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01-13-2016, 07:36 PM	#16
ScooterMaxi Jim Veteran Member Join Date: Jul 2009 Location: Minnesota Posts: 1,520	Originally posted by deepbluish I probably should have mentioned this in the beginning, but I actually already own a fully functional 35-105mm f3.5 lens against which I compared the faulty one. On the proper one, the focus does change a bit with change in focal length, but nowhere near this much. I double checked just to be sure, and I've just focused on a target at 105mm FL and distance scale showed around 1.5m. Then, I zoomed out to 35mm, refocused and the distance scale was on the infinity mark. That cannot be right. It seems that more often than not focusing is not possible at all when zooming out from 105mm to 35mm. It just does not find the target. Yeah, I would say you probably should have mentioned that... And did a little more testing to try to identify the obvious malfunction.

01-13-2016, 08:47 PM	#17
chmance Veteran Member Join Date: Jan 2015 Location: Vancouver Photos: Gallery \| Albums Posts: 484	I have this lens and definitely it is parfocal in the non-macro mode. It does appear that the OP's copy has a mechanical problem. It is definitely not a "stack of primes" but pretty close to it. The only thing that prevents me from using it more often regularly is its heft. Otherwise, the image quality is amazing for such a zoom with so many elements.

01-14-2016, 03:05 PM	#19
deepbluish Senior Member Join Date: Jul 2008 Posts: 130 Original Poster	Thanks, Phil, but it's pretty much clear that I've bought a lemon.

01-14-2016, 03:07 PM	#20
pepperberry farm amateur dirt farmer Join Date: Dec 2014 Location: probably out in a field somewhere... Photos: Gallery \| Albums Posts: 41,660	Originally posted by deepbluish Thanks, Phil, but it's pretty much clear that I've bought a lemon. send it back for a refund?

01-14-2016, 03:41 PM	#21
gofour3 Site Supporter Join Date: Oct 2008 Location: Vancouver, Canada Posts: 8,090	Originally posted by deepbluish Thanks, Phil, but it's pretty much clear that I've bought a lemon. Yep I would agree, my A35-105 and A70-210 work as described in the manual. Phil.

01-14-2016, 03:59 PM	#22
dadipentak Site Supporter Join Date: Jul 2008 Location: Baltimore, Maryland Photos: Gallery Posts: 11,590	Originally posted by kh1234567890 I hate its ergonomics I can understand that: I just regard it as part of the len's "charm".

01-14-2016, 04:56 PM	#23
monochrome Loyal Site Supporter Join Date: Mar 2008 Location: Working From Home Photos: Gallery \| Albums Posts: 26,276	Originally posted by deepbluish Thanks, Phil, but it's pretty much clear that I've bought a lemon. Send it to Eric. Maybe he can fix it for a reasonable sum.

01-14-2016, 06:41 PM	#24
TaoMaas Pentaxian Join Date: May 2007 Location: Oklahoma City Photos: Gallery \| Albums Posts: 3,574	Originally posted by chmance The only thing that prevents me from using it more often regularly is its heft. It's definitely a heavy lens...but that's also what makes it a good match for my K10D, which is a bit of a large, heavy camera itself. I just pair the 35-105mm with my Tokina 80-200 f2.8, call it my 'heavy metal' kit, and resign myself to using them. That kit isn't my walk-around choice, but it's definitely my choice when I can work close to my car.

01-15-2016, 06:57 AM	#25
fwcetus Site Supporter Join Date: Sep 2006 Location: New England Photos: Gallery \| Albums Posts: 1,286	Originally posted by chmance The only thing that prevents me from using it more often regularly is its heft. Otherwise, the image quality is amazing for such a zoom with so many elements. Originally posted by kh1234567890 One of these days I'll get round to selling mine since I hate its ergonomics so much ... Originally posted by TaoMaas It's definitely a heavy lens...but that's also what makes it a good match for my K10D, which is a bit of a large, heavy camera itself. I just pair the 35-105mm with my Tokina 80-200 f2.8, call it my 'heavy metal' kit, and resign myself to using them. That kit isn't my walk-around choice, but it's definitely my choice when I can work close to my car. Have any of you used the A 35-105/3.5's big brother, the A 28-135/4 (the "tower of primes")? It's larger and heavier (it has even more glass within), but it is constructed in the same fashion (it even has the exact same "macro shift" functionality). But, a couple of decades ago, the A 28-135/4 was my goto wedding lens of choice (on an LX).

01-16-2016, 04:38 AM	#26
deepbluish Senior Member Join Date: Jul 2008 Posts: 130 Original Poster	Originally posted by monochrome Send it to Eric. Maybe he can fix it for a reasonable sum. I don't live in the US, so that really isn't an option. Refund is also not an option anymore. I'll try to send it for repair to a local repairshop. For some reason, I don't think it's anything major, it just feels like something is loose inside it. I wish I had the knowledge/courage to do the surgery myself. I've tried it before, but ended up with extra parts which did not seem to belong anywhere, yet came from somewhere. 35-105 is a heavy lens, but not that heavy. I always support it with my entire hand. My middle finger lands right on the zooming ring and index finger on the focus ring. What I do find cumbersome is that sometimes to obtain accurate focus you find yourself in that transition zone between normal focus and macro focus.

01-16-2016, 04:49 AM	#27
pepperberry farm amateur dirt farmer Join Date: Dec 2014 Location: probably out in a field somewhere... Photos: Gallery \| Albums Posts: 41,660	Originally posted by deepbluish 35-105 is a heavy lens, but not that heavy. I always support it with my entire hand. My middle finger lands right on the zooming ring and index finger on the focus ring. What I do find cumbersome is that sometimes to obtain accurate focus you find yourself in that transition zone between normal focus and macro focus. agreed with the transition zone; I've learned to take a step, either towards or away from the subject....