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mccririck · 04-06-2019, 04:05 AM

It's a Pentax-A SMC 28mm f2.8

It looks absolutely fine, but it seems to rattle inside a bit if I shake it. Is it broken?

**pepperberry farm** · 04-06-2019, 05:13 AM - **1 Like**

Originally posted by mccririck

It's a Pentax-A SMC 28mm f2.8

It looks absolutely fine, but it seems to rattle inside a bit if I shake it. Is it broken?

do the focus and aperture rings operate as intended?

have you shot anything with the lens yet?

Neuse River Sailor · 04-06-2019, 05:21 AM - **1 Like**

My SMC Takumar 35mm f/3.5 has a very slight rattle but otherwise is fine. It makes decent pictures. It cost me under $40 and I'm satisfied with it. If yours operates well, takes good pictures and didn't cost an arm and a leg, I'd say keep and enjoy it.

mccririck · 04-06-2019, 05:26 AM - **1 Like**

Originally posted by pepperberry farm

do the focus and aperture rings operate as intended?

have you shot anything with the lens yet?

Still need to test it. The focus and aperture work fine.

mccririck · 04-06-2019, 05:40 AM

I've just taken some photos on auto aperture and they look fine.

**pepperberry farm** · 04-06-2019, 06:10 AM

Originally posted by mccririck

I've just taken some photos on auto aperture and they look fine.

you could also contact the seller on eBay and ask if they noticed a rattle in the lens prior to shipping...

but if everything works properly, and you noticed no issues with the images produces, you may not have any worries then...

tvdtvdtvd · 04-06-2019, 07:14 AM - **1 Like**

At a guess, I'd say it is the linkage to the aperture actuator arm. Many of my older manual lenses rattle to a greater
or lesser extent. None of them have a problem. If the camera engages the actuator arm without issue then
there's nothing to worry about.

pschlute · 04-06-2019, 07:19 AM

My 31mm Ltd rattles like crazy if you shake it. Still takes super pictures. Test your lens out at various apertures and if the pictures are fine I would not worry.

vonBaloney · 04-06-2019, 07:26 AM

Hold the aperture lever in and shake -- still rattle? If it is glass rattling, something needs to be screwed down a bit (this is usually the front or rear and can be done without taking anything apart -- ring around the front element or the ring around the back element.) Glass has some weight to it so you can usually feel it if it is shifting at all, rather than just a pure rattle which is probably the aperture mechanism.

**aslyfox** · 04-06-2019, 07:42 AM

before " screwing around " [ pun intended ]

you may want to look at this thread

Cross-head screws - a caution: - PentaxForums.com

not sure if your lens has JIS screws or not

mccririck · 04-06-2019, 08:37 AM

Originally posted by vonBaloney

Hold the aperture lever in and shake -- still rattle? If it is glass rattling, something needs to be screwed down a bit (this is usually the front or rear and can be done without taking anything apart -- ring around the front element or the ring around the back element.) Glass has some weight to it so you can usually feel it if it is shifting at all, rather than just a pure rattle which is probably the aperture mechanism.

It does actually feel like it's glass shaking. It seems to be near the front as well, as it actually makes the noise if I just move the lens rather than actually shaking it.

**TwoUptons** · 04-06-2019, 09:52 AM

One of my old AF lenses (70-210?) did that, but it went away when I tightened the front ring. Easiest fix ever...

-Eric

mccririck · 04-06-2019, 11:26 AM

How do you tighten the front ring? Do you need a special tool?

vonBaloney · 04-06-2019, 11:48 AM - **1 Like**

You want to see if you can tighten the ring around the front element (within the filter ring -- usually the ring that says "28mm f/2.8" on most lenses but that's on the side of 'A' version so it is just that plain grey ring). You need a friction tool that you can apply pressure to the ring without applying pressure to the glass. Common household items that can often accomplish this are things like a rubber jar opening grippy thing (flat flexible piece of rubber) with the bottom of a coke can applied on top of it (bottom is curved so hopefully will only touch ring -- rubber needed for friction in the middle). The rubber feet on crutches is often the perfect size for this also if you've got any hanging around. If it is very loose, you'll be able to further loosen it with just finger pressure (counter-clockwise to loosen, clockwise to tighten) -- I recommend you see if you can loosen it easily with your hand or with a tool before you tighten it -- if it is easy to turn then that's your problem. And if you can't loosen it, it probably doesn't need to be tightened and it is some other thing. Once in a while those rings are actually glued and don't spin at all (probably not the case with that vintage lens though), so don't force it, but put some (safe) pressure on it and see what happens.

**goatsNdonkey** · 04-20-2019, 01:37 PM

There was an old Vaudeville doctor's office skit that had a part in it that went like this:

PATIENT: Doctor, it hurts when I do dat.
DOCTOR: Don't do dat!

Adapting it to this situation--

PHOTOGRAPHER: My lens rattles when I do dat.
FELLOW PHOTOGRAPHER: Don't do dat!

04-06-2019, 04:05 AM	#1
mccririck Forum Member Join Date: Mar 2019 Photos: Albums Posts: 81	Purchased a lens on eBay and it rattles It's a Pentax-A SMC 28mm f2.8 It looks absolutely fine, but it seems to rattle inside a bit if I shake it. Is it broken?

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04-06-2019, 05:13 AM - 1 Like	#2
pepperberry farm amateur dirt farmer Join Date: Dec 2014 Location: probably out in a field somewhere... Photos: Gallery \| Albums Posts: 41,781	Originally posted by mccririck It's a Pentax-A SMC 28mm f2.8 It looks absolutely fine, but it seems to rattle inside a bit if I shake it. Is it broken? do the focus and aperture rings operate as intended? have you shot anything with the lens yet?

04-06-2019, 05:21 AM - 1 Like	#3
Neuse River Sailor Pentaxian Join Date: Mar 2018 Location: North Carolina Photos: Gallery Posts: 531	My SMC Takumar 35mm f/3.5 has a very slight rattle but otherwise is fine. It makes decent pictures. It cost me under $40 and I'm satisfied with it. If yours operates well, takes good pictures and didn't cost an arm and a leg, I'd say keep and enjoy it.

04-06-2019, 05:26 AM - 1 Like	#4
mccririck Forum Member Join Date: Mar 2019 Photos: Albums Posts: 81 Original Poster	Originally posted by pepperberry farm do the focus and aperture rings operate as intended? have you shot anything with the lens yet? Still need to test it. The focus and aperture work fine.

04-06-2019, 05:40 AM	#5
mccririck Forum Member Join Date: Mar 2019 Photos: Albums Posts: 81 Original Poster	I've just taken some photos on auto aperture and they look fine.

04-06-2019, 06:10 AM	#6
pepperberry farm amateur dirt farmer Join Date: Dec 2014 Location: probably out in a field somewhere... Photos: Gallery \| Albums Posts: 41,781	Originally posted by mccririck I've just taken some photos on auto aperture and they look fine. you could also contact the seller on eBay and ask if they noticed a rattle in the lens prior to shipping... but if everything works properly, and you noticed no issues with the images produces, you may not have any worries then...

04-06-2019, 07:14 AM - 1 Like	#7
tvdtvdtvd Veteran Member Join Date: Jan 2010 Posts: 1,665	At a guess, I'd say it is the linkage to the aperture actuator arm. Many of my older manual lenses rattle to a greater or lesser extent. None of them have a problem. If the camera engages the actuator arm without issue then there's nothing to worry about.

04-06-2019, 07:19 AM	#8
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,219	My 31mm Ltd rattles like crazy if you shake it. Still takes super pictures. Test your lens out at various apertures and if the pictures are fine I would not worry.

04-06-2019, 07:26 AM	#9
vonBaloney Pentaxian Join Date: Oct 2011 Location: Albuquerque, NM Posts: 6,029	Hold the aperture lever in and shake -- still rattle? If it is glass rattling, something needs to be screwed down a bit (this is usually the front or rear and can be done without taking anything apart -- ring around the front element or the ring around the back element.) Glass has some weight to it so you can usually feel it if it is shifting at all, rather than just a pure rattle which is probably the aperture mechanism.

04-06-2019, 07:42 AM	#10
aslyfox Seeker of Knowledge Join Date: Aug 2016 Location: Topeka, Kansas Photos: Gallery \| Albums Posts: 24,583	before " screwing around " [ pun intended ] you may want to look at this thread Cross-head screws - a caution: - PentaxForums.com not sure if your lens has JIS screws or not

04-06-2019, 08:37 AM	#11
mccririck Forum Member Join Date: Mar 2019 Photos: Albums Posts: 81 Original Poster	Originally posted by vonBaloney Hold the aperture lever in and shake -- still rattle? If it is glass rattling, something needs to be screwed down a bit (this is usually the front or rear and can be done without taking anything apart -- ring around the front element or the ring around the back element.) Glass has some weight to it so you can usually feel it if it is shifting at all, rather than just a pure rattle which is probably the aperture mechanism. It does actually feel like it's glass shaking. It seems to be near the front as well, as it actually makes the noise if I just move the lens rather than actually shaking it.

04-06-2019, 09:52 AM	#12
TwoUptons Loyal Site Supporter Join Date: Nov 2015 Photos: Albums Posts: 4,227	One of my old AF lenses (70-210?) did that, but it went away when I tightened the front ring. Easiest fix ever... -Eric

04-06-2019, 11:26 AM	#13
mccririck Forum Member Join Date: Mar 2019 Photos: Albums Posts: 81 Original Poster	How do you tighten the front ring? Do you need a special tool?

04-06-2019, 11:48 AM - 1 Like	#14
vonBaloney Pentaxian Join Date: Oct 2011 Location: Albuquerque, NM Posts: 6,029	You want to see if you can tighten the ring around the front element (within the filter ring -- usually the ring that says "28mm f/2.8" on most lenses but that's on the side of 'A' version so it is just that plain grey ring). You need a friction tool that you can apply pressure to the ring without applying pressure to the glass. Common household items that can often accomplish this are things like a rubber jar opening grippy thing (flat flexible piece of rubber) with the bottom of a coke can applied on top of it (bottom is curved so hopefully will only touch ring -- rubber needed for friction in the middle). The rubber feet on crutches is often the perfect size for this also if you've got any hanging around. If it is very loose, you'll be able to further loosen it with just finger pressure (counter-clockwise to loosen, clockwise to tighten) -- I recommend you see if you can loosen it easily with your hand or with a tool before you tighten it -- if it is easy to turn then that's your problem. And if you can't loosen it, it probably doesn't need to be tightened and it is some other thing. Once in a while those rings are actually glued and don't spin at all (probably not the case with that vintage lens though), so don't force it, but put some (safe) pressure on it and see what happens.

04-20-2019, 01:37 PM	#15
goatsNdonkey Site Supporter Join Date: Jan 2016 Location: Fulton County, Illinois Posts: 3,736	There was an old Vaudeville doctor's office skit that had a part in it that went like this: PATIENT: Doctor, it hurts when I do dat. DOCTOR: Don't do dat! Adapting it to this situation-- PHOTOGRAPHER: My lens rattles when I do dat. FELLOW PHOTOGRAPHER: Don't do dat!

Purchased a lens on eBay and it rattles

Win a Pentax Limited Lens: Raffle Now Live!