Sigma 70 200 sticky aperture blades?

maxxxx · 04-18-2015, 05:29 PM

It seems this week is trouble week. After having problems with the firmware update I have run into another problem:

Since I have had my Sigma 70 200 it sometimes overexposed pictures. Today I noticed this again and took a closer look: The overexposure got worse with higher apertures. I started looking into the lens from the front and I noticed that the aperture doesn't always open up fully between pictures. Sometimes it does and sometimes it stops in between. My 150-500 opens up fully every time on the other hand. After fiddling with lens for a while and taking a lot of pictures things got better.

Is this what "sticky aperture blades" means? Is there a way to fix this? The lens works really well (when it works) so I'd hate writing it off.

dane.dawg · 04-18-2015, 06:42 PM

Its probally the aperture arm.

wheelbuilder_25 · 04-18-2015, 06:49 PM

I ended up fixing an old (30 years) Sigma of mine that had sticky blades. Those were my symptoms as well, overexposed here and there, as the aperture wouldn't stop down to the correct stop. I fixed it myself after searching for some insight/direction on this forum. It was straight forward enough, and I'm OK with small detail type work. I had little to lose as well. I wouldn't do it myself if I had doubts about the sort of work. I believe that I searched for 'lens disasembly' here. There are also some folks that offer this as a service.

maxxxx · 04-18-2015, 07:30 PM

Originally posted by wheelbuilder_25

I ended up fixing an old (30 years) Sigma of mine that had sticky blades. Those were my symptoms as well, overexposed here and there, as the aperture wouldn't stop down to the correct stop. I fixed it myself after searching for some insight/direction on this forum. It was straight forward enough, and I'm OK with small detail type work. I had little to lose as well. I wouldn't do it myself if I had doubts about the sort of work. I believe that I searched for 'lens disasembly' here. There are also some folks that offer this as a service.

I am not afraid of taking the lens apart but I don't know what to do then. Did you clean the lens or lubricate it?

rawr · 04-18-2015, 09:23 PM

Which model Sigma 70-200? There are several.

maxxxx · 04-18-2015, 09:57 PM

Originally posted by rawr

Which model Sigma 70-200? There are several.

It's the HSM II. No OS.

rawr · 04-18-2015, 11:14 PM

Originally posted by maxxxx

It's the HSM II.

Aha. I have that one. No problems so far.

I wouldn't take the lens apart if I were you. With 18 elements in 15 groups, with HSM added onto that, it's a complex construction.

You should also consider your camera metering as a possible cause of the over-exposure you are reporting. Try using centre-weighted metering for a while.

And also perhaps invest in the Sigma HA 850-01 APS-C Lens Hood Extender (available on eBay). The HSM II is a FF lens, and using it on APS-C bodies with the standard hood means allowing more incidental light into the lens than it was designed for. Hence Sigma made the lens hood extender for the HSM II.

dane.dawg · 04-19-2015, 05:58 AM

My HSM ii had the same problem and it was the aperture arm.

wheelbuilder_25 · 04-19-2015, 07:03 AM

I ended up removing some corrosion from the blades. It was the last/worst step. I did check the arm, etc. first. Then again, this Sigma was pretty simple inside and I had little to lose.

maxxxx · 04-19-2015, 07:16 AM

Originally posted by dane.dawg

My HSM ii had the same problem and it was the aperture arm.

How did you fix it? The aperture arm on my lens works but it looks like the blades move too slow.

---------- Post added 04-19-15 at 07:19 AM ----------

Originally posted by rawr

Aha. I have that one. No problems so far.

I wouldn't take the lens apart if I were you. With 18 elements in 15 groups, with HSM added onto that, it's a complex construction.

You should also consider your camera metering as a possible cause of the over-exposure you are reporting. Try using centre-weighted metering for a while.

And also perhaps invest in the Sigma HA 850-01 APS-C Lens Hood Extender (available on eBay). The HSM II is a FF lens, and using it on APS-C bodies with the standard hood means allowing more incidental light into the lens than it was designed for. Hence Sigma made the lens hood extender for the HSM II.

It's definitely something with the aperture mechanism. I can see how sometimes the lens doesn't open fully and the blades get stuck in a middle position. And compared to my other lenses the mechanism isn't as snappy.

JimmyDranox · 04-19-2015, 08:34 AM

It is possible that some dust has combined with humidity, and make the movement harder. I would do this. Put the lens without caps in a box, with some desiccant, or some rice, if you don't have any other desiccant. I would let it there for two days, and then I will move the lever by hand 30-40 times, until the lens moves easily.

If this doesn't work, it means you had to disassembly the lens. Difficult job. Don't recommend to anyone without proper tools and manufacturer instructions. Better send it to service

04-18-2015, 05:29 PM	#1
maxxxx Veteran Member Join Date: Nov 2013 Posts: 385	Sigma 70 200 sticky aperture blades? It seems this week is trouble week. After having problems with the firmware update I have run into another problem: Since I have had my Sigma 70 200 it sometimes overexposed pictures. Today I noticed this again and took a closer look: The overexposure got worse with higher apertures. I started looking into the lens from the front and I noticed that the aperture doesn't always open up fully between pictures. Sometimes it does and sometimes it stops in between. My 150-500 opens up fully every time on the other hand. After fiddling with lens for a while and taking a lot of pictures things got better. Is this what "sticky aperture blades" means? Is there a way to fix this? The lens works really well (when it works) so I'd hate writing it off.

04-19-2015, 08:34 AM	#11
JimmyDranox Veteran Member Join Date: Oct 2012 Location: Ploiesti, Romania Photos: Gallery \| Albums Posts: 1,632	It is possible that some dust has combined with humidity, and make the movement harder. I would do this. Put the lens without caps in a box, with some desiccant, or some rice, if you don't have any other desiccant. I would let it there for two days, and then I will move the lever by hand 30-40 times, until the lens moves easily. If this doesn't work, it means you had to disassembly the lens. Difficult job. Don't recommend to anyone without proper tools and manufacturer instructions. Better send it to service Last edited by JimmyDranox; 04-19-2015 at 08:45 AM.

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04-18-2015, 06:42 PM	#2
dane.dawg Veteran Member Join Date: Aug 2011 Location: B.C. Photos: Gallery Posts: 1,436	Its probally the aperture arm.

04-18-2015, 06:49 PM	#3
wheelbuilder_25 New Member Join Date: Dec 2014 Location: upstate, ny Photos: Albums Posts: 14	I ended up fixing an old (30 years) Sigma of mine that had sticky blades. Those were my symptoms as well, overexposed here and there, as the aperture wouldn't stop down to the correct stop. I fixed it myself after searching for some insight/direction on this forum. It was straight forward enough, and I'm OK with small detail type work. I had little to lose as well. I wouldn't do it myself if I had doubts about the sort of work. I believe that I searched for 'lens disasembly' here. There are also some folks that offer this as a service.

04-18-2015, 07:30 PM	#4
maxxxx Veteran Member Join Date: Nov 2013 Posts: 385 Original Poster	Originally posted by wheelbuilder_25 I ended up fixing an old (30 years) Sigma of mine that had sticky blades. Those were my symptoms as well, overexposed here and there, as the aperture wouldn't stop down to the correct stop. I fixed it myself after searching for some insight/direction on this forum. It was straight forward enough, and I'm OK with small detail type work. I had little to lose as well. I wouldn't do it myself if I had doubts about the sort of work. I believe that I searched for 'lens disasembly' here. There are also some folks that offer this as a service. I am not afraid of taking the lens apart but I don't know what to do then. Did you clean the lens or lubricate it?

04-18-2015, 09:23 PM	#5
rawr Veteran Member Join Date: Jun 2009 Posts: 11,913	Which model Sigma 70-200? There are several.

04-18-2015, 09:57 PM	#6
maxxxx Veteran Member Join Date: Nov 2013 Posts: 385 Original Poster	Originally posted by rawr Which model Sigma 70-200? There are several. It's the HSM II. No OS.

04-18-2015, 11:14 PM	#7
rawr Veteran Member Join Date: Jun 2009 Posts: 11,913	Originally posted by maxxxx It's the HSM II. Aha. I have that one. No problems so far. I wouldn't take the lens apart if I were you. With 18 elements in 15 groups, with HSM added onto that, it's a complex construction. You should also consider your camera metering as a possible cause of the over-exposure you are reporting. Try using centre-weighted metering for a while. And also perhaps invest in the Sigma HA 850-01 APS-C Lens Hood Extender (available on eBay). The HSM II is a FF lens, and using it on APS-C bodies with the standard hood means allowing more incidental light into the lens than it was designed for. Hence Sigma made the lens hood extender for the HSM II.

04-19-2015, 05:58 AM	#8
dane.dawg Veteran Member Join Date: Aug 2011 Location: B.C. Photos: Gallery Posts: 1,436	My HSM ii had the same problem and it was the aperture arm.

04-19-2015, 07:03 AM	#9
wheelbuilder_25 New Member Join Date: Dec 2014 Location: upstate, ny Photos: Albums Posts: 14	I ended up removing some corrosion from the blades. It was the last/worst step. I did check the arm, etc. first. Then again, this Sigma was pretty simple inside and I had little to lose.

04-19-2015, 07:16 AM	#10
maxxxx Veteran Member Join Date: Nov 2013 Posts: 385 Original Poster	Originally posted by dane.dawg My HSM ii had the same problem and it was the aperture arm. How did you fix it? The aperture arm on my lens works but it looks like the blades move too slow. ---------- Post added 04-19-15 at 07:19 AM ---------- Originally posted by rawr Aha. I have that one. No problems so far. I wouldn't take the lens apart if I were you. With 18 elements in 15 groups, with HSM added onto that, it's a complex construction. You should also consider your camera metering as a possible cause of the over-exposure you are reporting. Try using centre-weighted metering for a while. And also perhaps invest in the Sigma HA 850-01 APS-C Lens Hood Extender (available on eBay). The HSM II is a FF lens, and using it on APS-C bodies with the standard hood means allowing more incidental light into the lens than it was designed for. Hence Sigma made the lens hood extender for the HSM II. It's definitely something with the aperture mechanism. I can see how sometimes the lens doesn't open fully and the blades get stuck in a middle position. And compared to my other lenses the mechanism isn't as snappy.