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02-12-2018, 06:34 AM   #1
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Stiff focus ring of my DA 70 Ltd

Hello,

Yesterday when I was playing with the DA 70 Ltd quick-shift, trying to take a photo of some sakura, I discovered that its focus ring was very stiff at close focus.

I wonder what could be the reason and if there is a way to fix it (though I'm not sure I'll have the courage to break down such a delicate lens, I did once with a S-M-C Takumar 135 trying to fix its infinity focus problem, and it never comes back to life again ) This is my favorite lens so I'm a bit upset, and also a bit worry it could get more troublesome later on.

I bought this lens over the Internet last summer, its physical status and image quality were great, and I almost never do manual focus or quick-shift with this lens, especially at close focus, so I don't know if it already had this problem by the time or not.

Thank you very much for any help

02-12-2018, 07:27 AM - 1 Like   #2
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There are a couple possibilities
a) There is dirt stuck in the focusing ring somewhere. If it is up top, you can maybe see it and use rocket bower to remove it. Rocket blower can remove dirt, dust and other particles that are causing friction. If the obtrusion is inside of the lens, then a blower might not be able to fix it. This would usually be fixed if you bring the lens to a repair shop for full cleaning (and notify them about this stiffness)
b) The lens is bent. This can happen to metal lenses if they get dropped or squished. If the focusing ring or barrel is not perfectly circular, it will have more friction at some focus points (where the ovals bump into each other). If this is the case, you can try bending it back into circular shape, but that is really tricky. In a repair shop, they should be able to fix this quickly, within an hour or two

If AF works normally around MFD, it is likely the blockage is up top and not deep inside of the lens barrel.

Whether it is a) or b), a repair shop should be able to fix it. I assume it would cost around 50-100euro over here to fix this. Most shops let you bring a lens in and they charge you a flat fee for diagnosis. If you decide to have them repair it, you don't have to pay the fee. If you decide not to do repairs, they keep the fee. If its a fine lens like that and you bought it used, the least you can do is take it to a shop, have it diagnosed and cleaned.
02-12-2018, 07:36 AM   #3
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Is quick shift normal when focus is farther away?
02-12-2018, 08:49 AM   #4
Bui
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Original Poster
QuoteOriginally posted by Na Horuk Quote
There are a couple possibilities
a) There is dirt stuck in the focusing ring somewhere. If it is up top, you can maybe see it and use rocket bower to remove it. Rocket blower can remove dirt, dust and other particles that are causing friction. If the obtrusion is inside of the lens, then a blower might not be able to fix it. This would usually be fixed if you bring the lens to a repair shop for full cleaning (and notify them about this stiffness)
b) The lens is bent. This can happen to metal lenses if they get dropped or squished. If the focusing ring or barrel is not perfectly circular, it will have more friction at some focus points (where the ovals bump into each other). If this is the case, you can try bending it back into circular shape, but that is really tricky. In a repair shop, they should be able to fix this quickly, within an hour or two

If AF works normally around MFD, it is likely the blockage is up top and not deep inside of the lens barrel.

Whether it is a) or b), a repair shop should be able to fix it. I assume it would cost around 50-100euro over here to fix this. Most shops let you bring a lens in and they charge you a flat fee for diagnosis. If you decide to have them repair it, you don't have to pay the fee. If you decide not to do repairs, they keep the fee. If its a fine lens like that and you bought it used, the least you can do is take it to a shop, have it diagnosed and cleaned.
I don't know of any camera repair shop in my region, I will try your suggestion first tonight Thank you

---------- Post added 02-12-18 at 08:50 AM ----------

QuoteOriginally posted by UncleVanya Quote
Is quick shift normal when focus is farther away?
Yes, quick-shift and manual focus work fine for 80-90% of the throw. Only from the start, where the lens is focusing at mfd, the ring is very stiff, when it passes a certain point, it becomes smooth as normal.

02-12-2018, 03:30 PM   #5
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QuoteOriginally posted by Bui Quote
Yes, quick-shift and manual focus work fine for 80-90% of the throw. Only from the start, where the lens is focusing at mfd, the ring is very stiff, when it passes a certain point, it becomes smooth as normal.
I think a question is: Does AF struggle at some point, or only MF?
You can search online for repair shops. There used to be a lot of film and camera stores some decades ago in any major city. Some of them still operate, but at a small tiny location. Hope you get what you need
02-12-2018, 06:43 PM   #6
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This sounds just like what happened with my DA 40 Limited. I ended up sending it to Pentax authorized repair center in the US. The focus ring was replaced under the extended warranty I bought with the lens. The lens has been fine since the repair.
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