Two Sigma Lens fails

[Contrast]

I guess I shouldn't be too amazed at the failure of the first, it was bought secondhand off ebay. This was a Sigma 70-300 1:4-5.6 DL and while it lasted (a few months) was superb, producing better/sharper pictures at 300mm than the kit Sony lens could at 200. Just started up the camera one day and was greeted by horrible grinding noises from the motor and no focus.

More annoying is my SIGMA 28-90mm F3.5-5.6 Mini Zoom Macro which is one day over 12 months old. Out of warranty anyway as it was bought as discontinued stock. This basic little lens produced incredible macro at 90mm for the price. Once again (turning the camera off this time) all I get out of it is masses of very loud constant motor noise and no focus. Got to admit it shakes my confidence in Sigma.

[David Kilpatrick]

Which camera? Both are old Sigma lenses and the 28-90mm is extremely old. My similar 24-70mm Sigma Canon lens failed after a few months. The problem with these lenses on any digital body except the KM 7D, 5D, Alpha 100 is that the AF motor has twice as much torque as Sigma allowed for - they also can fail on the 800si, Dynax 9, Dynax 7 all of which had very powerful fast AF motors. Sigma seem to have allowed only for the slower, weaker AF drive of the consumer level cameras. The grinding is stripped plastic gears and is caused by the fast infinity-stop 'startup' action of the KM/Sony AF design which cycles the lens focus when you switch on.

The 70-300mm is known for this, the 28-90mm is not because Sigma made and sold so few lenses. I've never even seen one. Sigma has been very good in the UK and USA about replacing or repairing lenses with stripped gears whether in warranty or not.

David

[Contrast]

This was on the A350. I doubt I'd get either lens repaired here in Australia, I know the "official" supplier here are sticklers for correct sales, no grey imports, and my "old stock, ex US" 28-90 would fall foul of that. I've been warned just to get a lens looked at by one repair place is at least $150 before repair and that means sending to Melbourne too. I'll just have to cut my losses on these. I didn't know about the torque thing. What is the excuse for the reported fails on newer lenses from Sigma?, I'm sure I read in other forums it affected their macro lenses and plastic gearing was involved. I'm a little confused by what you wrote, surely the motor is actually in each lens, not the camera. Do you mean the camera supplies higher voltage/current to the lens (and therefore lens drive motor) than the maker designed for? I'm sorry, plastic gears are just plain stupid..

[bossel]

I had one a Sigma 70-300 (non APO) that I got cheaply. Not too bad (for the money paid), used a few times on the A700 with slow AF. Later sold it off - pheeew

And the AF motor is in the camera! Check your lens-mount for a litte 'screw-driver'. Only for newer and high end lenses Sony moves to in-lens motors!

[Dr. Harout]

I had that problem with my former 50/2.8 macro DG EX. I don't/didn't have complaints for the IQ, but not for the inner construction/plastic gear. Mind you, the plastic type was awful, but yet there are plastic constructions which could bear your whole weight. I guess Sigma made a wrong "turn" somewhere and relied on cheap plastic.
Fortunately we have now HSM which quite probably/surely incorporates "tough" plastic. Cause if they don't they'll loose lots of customers with all these new high torque AF motored bodies.

[Greg Beetham]

I half suspected for a long time that it might not have much or anything to do with the 'gears' per se, but a lot more to do with correctly meshing in with camera protocols. There is a limit at either end of the focus travel in a lens where it comes too a stop, with OEM lenses the inbuilt encoder reports too the camera at what position the focus is 'at' so there is no danger of forcing the lens and the gear train against the stops. If a third party lens manufacturer don''t get it exactly right with lens chip ID emulation and deciphering the camera to lens comms, lens encoder/transponders, etc. there is a possibility of the very powerful stepper motor in the camera damaging the gear train in the lens I'd say.
That's my thinking on the 'why' some non OEM lenses suffer gear train damage, not so much because they use 'plastic' gears, but because the camera doesn't fully 'know' that particular lens after all. For one thing it wouldn't be on the in camera lens table, and using an emulated chip from a similar OEM lens might not work either, the length of travel, and rate of advance in the focus gears (ratio) might not be exactly the same as the emulated lens etc.
Greg

[Scooterman]

I have found that Sony in camera lens focusing motors, to be the most powerful of all the ones that use it, Pentax/ Nikon etc also very fast and the older Sigma lenses just cant cope with the power as they get older, the newer lenses have been up rated according to the Sigma service in the UK.

[Contrast]

I had one a Sigma 70-300 (non APO) that I got cheaply. Not too bad (for the money paid), used a few times on the A700 with slow AF. Later sold it off - pheeew

And the AF motor is in the camera! Check your lens-mount for a litte 'screw-driver'. Only for newer and high end lenses Sony moves to in-lens motors!

Found it thanks.. Hadn't actually realised that was there. I guess in that case the 100m28 macro is slow because of internal gearing, not the drive..

[Contrast]

That's my thinking on the 'why' some non OEM lenses suffer gear train damage, not so much because they use 'plastic' gears, but because the camera doesn't fully 'know' that particular lens after all. For one thing it wouldn't be on the in camera lens table, and using an emulated chip from a similar OEM lens might not work either, the length of travel, and rate of advance in the focus gears (ratio) might not be exactly the same as the emulated lens etc.
Greg

This makes sense too, I had noticed that the Sigma lenses tended to "jolt" when the camera is turned on, I also felt they tended to slam a little at the each end of focus range. For me they were optically far superior to the basic/kit Sony though. Trouble is genuine Sony is soooo pricey (Australia is paying a huge premium too) and my pocket is just not that deep at the moment. If I go overseas order, no warranty and I "should" get whacked for duty/tax if valued over $1000. Customs may assess value independant of invoices.

[Greg Beetham]

Yep and that's the great pity of it, the Sigma optics are gererally very good by all accounts, some give fabulous quality and bang for the buck, but I'm fairly certain that the whole escapade of making compliance with the camera so complex nowdays is no accident. It all started back when camera cos. decided it'd be really good if they got rid of the f-stop ring off the lens and relegated setting the f-stop onto the camera body. That made aperture control the responsibility of the camera body and not the lens, opening up a whole other can of compliance worms, I'm sure it was all in part or in total aimed at reducing the inroads into OEM lens sales by third party lens manufacturers, not as a first thought convenience for 'us' at all.
Greg

[Contrast]

I'm fairly certain that the whole escapade of making compliance with the camera so complex nowdays is no accident. It all started back when camera cos. decided it'd be really good if they got rid of the f-stop ring off the lens and relegated setting the f-stop onto the camera body. That made aperture control the responsibility of the camera body and not the lens, opening up a whole other can of compliance worms, I'm sure it was all in part or in total aimed at reducing the inroads into OEM lens sales by third party lens manufacturers, not as a first thought convenience for 'us' at all.
Greg

I had already realised there was a major drawback to Aperture only controllable from "in" camera, I'd be tempted to play with reversing rings and extension tubes if I could just manually set the aperture on a recent lens, without they seem to default to smallest aperture. Weird thing is a lot of big brand camera manufacturers are getting lenses rebadged from sigma/tamron and the likes anyway, you'd think there would be a little more cooperation. Isn't there a license issue with making a lens with a particular mount? I'm fairly certain it is of great benefit to Sony DSLR to have as many lenses as possible available out there, it should increase camera sales but admittedly at the cost of their own lens sales. As an aside I'd like to think it would keep their lens prices honest, but no sign of that here in Australia, they won't even match their own US pricing on MySony US, never mind competitors lenses.

[Greg Beetham]

I get the impression that Sony in particular isn't too keen for the universal approach in 'their' domain, they still try too create a 'captive' audience wherever possible...memory stick and so on. And yeah we get reamed in Oz and not just by Sony either, it's likely that most of the difference is import duty, you know all those taxes and charges the GST was supposed to replace, a politician's promise, well they 'forgot' duty and added GST on the top, after adding the duty on items over $1000 on non locally manufactured imported items.
I think there is some relationship between Tamron - Sony but I don't know the exact details. Sigma has some sort of (or used too) relationship with Nikon I think.
Greg

[Contrast]

I've just managed to pick up a Minolta 28-100 f3.5-5.6 supposedly new (with warranty) off ebay for $54 inc postage. At that price it'll do to replace the failed Sigma 28-90 but I'm sure macro won't be anything like as good, I just hope it is better generally than the kit Sony 18-70 which I don't rate at all. I'm not sure how warranty will work on my purchase though, can't be that many "new" Minolta items to replace it with. Long term thinking is to start buying some serious glass, This cheapo stuff is OK for my college assignments but there is no doubt it is basically doggie-doo. I'm still not convinced I'll be long term Sony, hence my reluctance to invest now (not that I have the cash), I'm waiting to see what they bring out Pro/Semipro. I'm following Canikon just as closely atm. I'm very impressed by Image quality on Nikon, and the Canon 5d/7d cameras.

Adds - lolz at your filter replacing the cr word with doggie-doo !

[Contrast]

And yeah we get reamed in Oz and not just by Sony either, it's likely that most of the difference is import duty, you know all those taxes and charges the GST was supposed to replace, a politician's promise, well they 'forgot' duty and added GST on the top, after adding the duty on items over $1000 on non locally manufactured imported items.
Greg

This got me thinking, I wondered exactly what the premium was we are paying on "official" stock here. Taking the HVL-58AM flash as an example, it is $799 here from Sony website. The Battery pack is $399. On MySony US (Sonystyle.com) the same flash is $449 US (~$505 Aus) and the battery pack 249.95 US (~$280 AUS). Interestingly I could get a solid and good looking battery unit out of China for a mere $28 Aus inc p&p (see http://cgi.ebay.com.au/ws/eBayISAPI.dll ... K:MEWAX:IT ).

So we are looking at $294 extra on the flash here in Australia. I can't believe the American price has no Duty or Tax component at all but even if it doesn't the numbers don't add up (IF it did it would make it worse). According to this page;- http://reviews.ebay.com.au/The-A-Z-of-I ... 0015634691 The duty is only usually 5% plus 10% GST on the lot. That would make our $505 flash around 583.30 with a little rounding. We are still $215.7 (over 42% on $505) adrift. I don't think transport into Australia would be any more expensive than going to Europe or America.

This excercise wasn't to question your statement at all, it was purely about understanding what we have to put up with here. Bottom line is, doesn't matter who is taking the extra, we are paying it...

[bfitzgerald]

This must be mostly a Sigma problem you don't hear much about Tamron stripping gears or even many Minolta lenses (even cheap kit ones). I've 0 Sigma lenses and I'm not crying about it either! If I remember pulling apart a few old Minolta ones they have metal gears.
28-100 is no macro champ watch out for the blooming though..it's better on a film body being honest.