[Ash]

Decided to try my hand at a new Sigma 70-200 II to replace the Tamron 70-200 I had that developed a sticky aperture lever.

Many testimonials praising this lens gave me some hope that it would be a winner. In my hands, build quality's great. Good feel and smooth AF action. I had the background knowledge that it was 'somewhat' softer at the long end, and particularly wide open.

Performance? Good, but not excellent.
I bought it for the ability to capture sharp images, esp. in the centre, wide open at all FLs.

The apparent softness at the long end was not expected to be as bad as I found it with this one, and coupled with a halo effect and significant drop in overall contrast wide open I'm now questioning whether others have experienced this same phenomenon... some of my examples:

All images are at 200mm, 100% crops.

Centre, f/2.8:


Slightly off-centre, f/2.8:




Corners, f/2.8:


Now at f/5.6, images were beautifully sharp in the centre, but fell apart towards the corners:


These are but a few I've taken, more to come later...

But before someone criticises my technique in testing this lens, I'll convey that centre shot crops contain the subject aimed for focus, confirmed numerous times by repeated focus lock checks, in calm conditions with stabilised hand-held captures with Tv faster than 1/200. Furthermore, all corner shots were captured using a flat coloured poster/printed paper with sharp details exactly perpendicular to the lens axis, using a tripod when necessary to keep ISO <800. Still not a scientific test, and I'm not trying to make it out as such, however I do know I have not had this sort of issue recurring with the Tamron 70-200 I had, nor even my DA 55-300 wide open.

Another significant issue I had with the lens is its compatibility with the Tamron SP 1.4x TC...
HSM works fine at 70mm, but absolutely will not lock focus at or anywhere around 200mm, and I tested it in full sun - very high contrast conditions. Hunts back and forth, whether at infinity or close focus, and gives up the ghost after a second - to use it at these FLs with the TC one has to manual focus. The Tamron on the other hand locked on focus swiftly at each attempt, regardless of FL or lighting conditions (OK, perhaps a little slow or not consistent in low light, but in concerts it was simply magic).

Would anyone like to comment on this short and non-representative test on this EX lens that hasn't quite pleased me as I wished it would?

Thank you for reading.

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Last edited by Ash; 09-04-2009 at 07:08 AM. Reason: typo

[kjellhar]

Hi, are you sure the AF system is not off a bit. How about trying to do some focus bracketing to see if you get a sharper image slightly offset from what the AF system settles on.

[Ash]

I've not needed to adjust focus as images are sharp centrally from f/5.6 onwards.
I assume that if I can manage to get an image sharp somewhere at one aperture, it should be maximally sharp at other apertures.
I will try adjusting AF in any case to see if it makes any difference, though.

[Ash]

Did try AF adjust - marginal, probably indistinguishable improvement on -5 adjustment.
Images remain soft and poorly contrasted throughout at f/2.8-4.

Found the biggest Achilles' heel of this lens (according to this copy anyway):
Close focusing (anything closer than 2.5m) at any FL, between f/2.8-5.6.
Unfortunate...

[kenyee]

Can you try another copy? I don't think mine had that issue at 200/2.8 (I've attached crop and original...taken at iso 100 and 200/2.8 with a flash handheld to freeze motion).
I did have an issue w/ bubbles on the front lens coating, so I'm sending it back for an exchange.

I'm surprised it doesn't focus faster as well...thought it'd be much faster than my Tamron 70-300 butt only feels slightly faster and still hunts from end to end at times w/ a swoosh noise instead of slamming the lens from side to side like the Tamron ;-)

[Ash]

No-one else with this lens care to comment?
Happy owners, do you not get the same softness in your images at these settings?

To illustrate my issues further here are some more samples, again with multiply-confirmed AF lock:
Centre, f/2.8 - focusing distance 8m:




Centre, f/2.8 - focusing distance 4m:


Centre, f/2.8 - focusing distance 1.2m:




Corner, f/2.8 - focusing distance 8m:






Corner, f/2.8 - focusing distance 3m:


These are 100% crops taken at ISO 200, fast shutter speeds - in RAW -> JPEG by ACR.
AF adjustment does not improve any of these results.
Softness, poor contrast and haze seem consistent with the images, worse with close focusing.

Same results with your copy?

[Ash]

Can you try another copy? I don't think mine had that issue at 200/2.8 (I've attached crop and original...taken at iso 100 and 200/2.8 with a flash handheld to freeze motion).
I did have an issue w/ bubbles on the front lens coating, so I'm sending it back for an exchange.

I'm surprised it doesn't focus faster as well...thought it'd be much faster than my Tamron 70-300 butt only feels slightly faster and still hunts from end to end at times w/ a swoosh noise instead of slamming the lens from side to side like the Tamron ;-)

Thanks for the comment kenyee.
From your sample, there does appear to be some softness and low contrast clearly evident in the crop.

The AF is only marginally faster but only when it's focusing from near to far - the quiet HSM motor has a fast acceleration mid-cycle, which screw-AF motors don't have. Other than that, I don't see significant differences.

I don't have access to any other copies of this lens around - I'm in a regional town with NO Pentax dSLRs let alone lenses being sold within 150km of me. I bought the 70-200 from B&H.

[Ash]

Uncropped (but compressed) images used for the above crops are here for perusal:

200mm, f/2.8:




















200mm f/5.6:




Perhaps I am asking too much from this lens?
Comments are greatly appreciated.

[OrenMc]

I am now just headed out the door with my copy. I will do some close focus tests ( non-technical ). I am not taking a tripod but a monopod to help a little.
I am also testing my Kenko 1.5 that I just received yesterday so hopefully I will have something for you later.
I have not used this lens much since I received it but initial impressions were good. I believe you comment in that thread.

[Ash]

I remember Oren.
Your f/2.8 images looked reasonably sharp and well contrasted at the resolution posted.
I look forward to your results.

[Alfisti]

Is it new?

Man any time you see that halo going on the lens is screwed together wrong.

[krypticide]

That looks about right to me, Ash. The softness I mentioned wide open includes a bit of haloing. Again, I haven't handled the Tamron or 50-135mm, but I'm still quite happy with this lens. Maybe it's just the benefit of not having anything firsthand to compare with...

[Alfisti]

Almost anyone that has used the older, first generation 70-200 siggy prefers it.

[simdavid]

If you have adjusted your sharpness setting stronger, could you put it to normal and try again?

[Ash]

Is it new?

Man any time you see that halo going on the lens is screwed together wrong.

Brand new from B&H.