[icypepsi]

I have a habit of buying lenses with optical defects, fungus included. The fun part is that I almost never saw any image degradation. About the only time I got bad results was with a lens that had a completely crystallized back group.

Based on your photos I could understand why you exchanged it (because it's a new lens) but I would gladly buy one with such a "defect" at a discount price.

Wow, the crystallization part is a jaw dropper!
I'll have to agree with you. I don't think you'll see too much of image degradation. Yes, mostly that it is a new lens and it shouldn't have it. But if you think deeply, there may be shooting situations someday when that thing could (I'm totally guessing here) add/multiply to some flare, or reflect certain incident light and make it visible in the picture, or at least slightly color cast some part of it. I will even agree that it may not be very significant and/or consistent, even if visible at pixel peeping levels. But, with the software-testing-thought-process-mind that I have, what if that region of the lens starts to give away more coating, or accumulate microdust that may build onto itself because it is uneven, or something else that I'm not able to guess? Or maybe it is all impossible for the next 5 years! I don't know. At that point, to me it was more like being able to trust a known devil than an unknown angel So, I'll say I'm seeing it as a "half glass empty" thing, because it should ideally be sold as a "seconds" item. If you notice, a similar thing happens in so many other industries. Like for instance, when a H0nda car has practically unnoticable paint problems during manufacturing, it is sent off as a "defective" one. H0nda does it for it's brand name. I've personally seen this happen all the time when I worked with them.

Nice to know that your experience sees no major hassle. Thanks for sharing.

[Pentaxor]

I have a habit of buying lenses with optical defects, fungus included. The fun part is that I almost never saw any image degradation. About the only time I got bad results was with a lens that had a completely crystallized back group.

Based on your photos I could understand why you exchanged it (because it's a new lens) but I would gladly buy one with such a "defect" at a discount price.

what happened to your love for the FA*85? traitor !

[Asahiflex]

what happened to your love for the FA*85? traitor !

Heehee! It's sitting right here, next to me, in my photo backpack. I have no plans of buying the Sigma, but if I come across one for 500 euros... I'd gladly take it.

[icypepsi]

Physical:
I took a hesitant peek into the copy 3 lens last night, and... yes... copy 3 has a speck too. But this time, in one of the front elements. The inner part of the lens body (that part that holds the glass), towards half of the outer circumference of that same element, had such jagged edges, like they were cut by a hacksaw blade and not sawed off to smoothen before giving the body to the "glass" department for fitting the glass!!! And another long "speck" was even left over off that jagged circumference and was quite peeping onto the glass element! Looked exactly like the shiny "speck". All clearly visible. What can I say? I must say I have never seen a lens like this. So I know that the speck was not some coating problem, but the manufacturing remnant of the inner glass-holding body. This should have ideally been cleaned up. And the jagged circumference shows that there could possibly be a misalignment of the element, because it feels like that part should have been a lot more inside.

Focus ring
The focus ring was tighter to operate, just like my copy 1. When I was playing with it, at one point, suddenly, the focus ring became loose just like copy 2!! And immediately after that happened, it tightened back like it was. Again, such variation from copy to copy! I noticed there was a lot less dust inside the lens (unlike copy 2). The mount appeared brand new, like it should be (unlike my copy 2).

Disclaimer:
1. When I say the focus ring was tight, it is in relative terms of the other lens copy. It was not as smooth as, say the Pentax DA* 50-135 SDM's focus ring (which was buttery!). A little tighter than that. Nothing that would require a spanner!
2. When I say dust inside the lens, I don't mean it is a trash can. My copy 2 had like maybe 10 dust particles distributed around. Copy 3 had like 3-4. In comparison, when I look into my other lens that I've used for more than a year now, it has about 20-25 particles. All roughly speaking and all this with careful observation held towards a light source.

Focusing:
I haven't yet done test-chart-testing. As far as AF is concerned, copy 3 seems to be consistent too, requiring a +1 microfocus adjustment. Sharpness, as sharp as the other copies.

Resultant image:
So, like I said, because of those "specks", either copy 2 or copy 3, I don't think there will be any visible degradation. Practically it may, but I'm sure undetectable by human eyes.

Conclusion:
I'm afraid this is how Sigma is. Being a precision lover, I have not seen such horrid manufacturing of such a delicate optical instrument. They really need to straighten out their manufacturing process/line that is leaving specks around in their lenses. Maybe just a batch of them have this problem. But, after all, we are talking about precision optics here for which they are even charging big money (although, smaller than the "others" ). It's not a plastic toy. Ofcourse, my copy 2 was better I'm going to give myself some time to see how the whole thing is and then decide what to do.

[Pentaxor]

Physical:
I took a hesitant peek into the copy 3 lens last night, and... yes... copy 3 has a speck too. But this time, in one of the front elements. The inner part of the lens body (that part that holds the glass), towards half of the outer circumference of that same element, had such jagged edges, like they were cut by a hacksaw blade and not sawed off to smoothen before giving the body to the "glass" department for fitting the glass!!! And another long "speck" was even left over off that jagged circumference and was quite peeping onto the glass element! Looked exactly like the shiny "speck". All clearly visible. What can I say? I must say I have never seen a lens like this. So I know that the speck was not some coating problem, but the manufacturing remnant of the inner glass-holding body. This should have ideally been cleaned up. And the jagged circumference shows that there could possibly be a misalignment of the element, because it feels like that part should have been a lot more inside.

Focus ring
The focus ring was tighter to operate, just like my copy 1. When I was playing with it, at one point, suddenly, the focus ring became loose just like copy 2!! And immediately after that happened, it tightened back like it was. Again, such variation from copy to copy! I noticed there was a lot less dust inside the lens (unlike copy 2). The mount appeared brand new, like it should be (unlike my copy 2).

Disclaimer:
1. When I say the focus ring was tight, it is in relative terms of the other lens copy. It was not as smooth as, say the Pentax DA* 50-135 SDM's focus ring (which was buttery!). A little tighter than that. Nothing that would require a spanner!
2. When I say dust inside the lens, I don't mean it is a trash can. My copy 2 had like maybe 10 dust particles distributed around. Copy 3 had like 3-4. In comparison, when I look into my other lens that I've used for more than a year now, it has about 20-25 particles. All roughly speaking and all this with careful observation held towards a light source.

Focusing:
I haven't yet done test-chart-testing. As far as AF is concerned, copy 3 seems to be consistent too, requiring a +1 microfocus adjustment. Sharpness, as sharp as the other copies.

Resultant image:
So, like I said, because of those "specks", either copy 2 or copy 3, I don't think there will be any visible degradation. Practically it may, but I'm sure undetectable by human eyes.

Conclusion:
I'm afraid this is how Sigma is. Being a precision lover, I have not seen such horrid manufacturing of such a delicate optical instrument. They really need to straighten out their manufacturing process/line that is leaving specks around in their lenses. Maybe just a batch of them have this problem. But, after all, we are talking about precision optics here for which they are even charging big money (although, smaller than the "others" ). It's not a plastic toy. Ofcourse, my copy 2 was better I'm going to give myself some time to see how the whole thing is and then decide what to do.

don't worry, Pentax also some of those. imperfect aperture blades, wobbly focus ring, SDM inconsistency, etc... in today's age, QC seems to be more tolerant to such small imperfections. brought about by costs and other things. if the lens works, keep it. if something like that deters you from loving it, send it back or sell it for $500.

[icypepsi]

don't worry, Pentax also some of those. imperfect aperture blades, wobbly focus ring, SDM inconsistency, etc... in today's age, QC seems to be more tolerant to such small imperfections. brought about by costs and other things. if the lens works, keep it.

Reassuring. Thanks. This is what I wanted to see.. whether positive or negative, but more people's experiences, helping me avert a possible wrong decision. Please share more experiences.

..or sell it for $500.

You might as well steal it away!

[MaK5]

I'm afraid this is how Sigma is.

Well, this is how Sigma is. For the price they charge, some corner has to be cut for them to be profitable.

[robgo2]

Physical:
I'm afraid this is how Sigma is. Being a precision lover, I have not seen such horrid manufacturing of such a delicate optical instrument. They really need to straighten out their manufacturing process/line that is leaving specks around in their lenses. Maybe just a batch of them have this problem. But, after all, we are talking about precision optics here for which they are even charging big money (although, smaller than the "others" ). It's not a plastic toy. Ofcourse, my copy 2 was better I'm going to give myself some time to see how the whole thing is and then decide what to do.

The Pentax 77/1.8 is a thing of beauty and not much more expensive. Sorry to bring it up, but you may want to consider it.

[Pentaxor]

You might as well steal it away!

may I?

[icypepsi]

The Pentax 77/1.8 is a thing of beauty and not much more expensive. Sorry to bring it up, but you may want to consider it.

Don't be sorry. I definetely had it on my mind too. The HSM and the good optical quality seen all over the net sways me. If I'm sending this back I'm surely going to look at it too. I love the 85mm perspective and wanted it a little wider and hate that it would have been wider had I an FF. I don't think 77mm is too different from 85mm + its wider and so makes up for what I miss. Thanks for the suggestion.

[icypepsi]

Sorry to be reviving this old one up again, but I have to give the good news...

Finally, I got my perfect (well almost!) copy!! I got it from amazon. Like a lens expert, I ripped open the delivery package and examined both the lens ends under different lights. And, wow... no uneven coating!!!

- AF was spot on... albeit with a +2 microfocus adj. (and with a K7, I don't give a damn!). It even gets the focus correct in considerably low light conditions (yes, I think it's a lens behavior, maybe in combo with the cam).
- Colors are very saturated (with the right exposure)
- Absolutely no lens flares under direct sun even without the hood!!!! But I just keep the hood extension on to protect the front element (and to make the lens look bigger than it really is )
- Sharp sharp images! We all know that by now.

The only problem I had was non-optical. There was a serious dent in the plastic portion (where the cap fits) of the mount. Am I going to return it? Sorry! I don't mind the physical stuff as long as the optics are excellent.

So to summarize my problems:
Copy 1: BH - In consistant AF
Copy 2: BH - Coating had specks.
Copy 3: BH - Coating had specks.
Copy 4: Beach cam - AF was a bit noisy, like it was running against gravel!
Copy 5 (keeper): Amazon - Plastic portion of mount was badly dented.
But, to note, in all copies, the optical quality was just jaw dropping-supperb!

So with everything else fine, I rushed and bought a Marumi made UV filter.. about $30.

With something this wide of an aperture, I had great difficulty getting the DoF I want outdoors in this summer sun. But, only until I bought a pack of .3, .6, .9 ND filters

Aaaw.. aaw.. aaaawwwwwoooooooooooooooooooooooo!!!!!

Cheers...
Anil