First Impressions: When I received the product, I was very impressed with the weight, the build quality, the smooth manual focus with just the right amount of resistance to make it easy to be precise. The weight was both impressive and at the same time, a little...
When I received the product, I was very impressed with the weight, the build quality, the smooth manual focus with just the right amount of resistance to make it easy to be precise. The weight was both impressive and at the same time, a little annoying - but there''s a lot of glass in this lens, and for a 50mm, it''s HUGE. One thing that I knew about in advance (but didn''t care for) was that the mounting ring isn''t sealed. On the other hand, the mount is steel, so it''s going to be much more durable than those plastic mounts we see on some lenses.
Of course, just like you would expect, I popped it on my D750 and took it out for a spin. Also like you would expect, I started shooting at F/1.4 - of course!
The images were... ok. No-where near as sharp as my images from my Nikon DX F/1.8 35mm... or my Tokina DX F/4 12-28mm... or my Tamron F/2.8 70-200mm. Nor was it as sharp (at the long end) as my Nikon kit DX 55-200mm.
While I found this disturbing, I started shooting at smaller F-stops... 6.3, 8, 9, etc. As you would expect, the quality improved quite a bit.
At the time, I figured I was facing an auto-focus fine tuning issue... and I was right. I''d gone through some similar issues with my Nikon kit lens, as well as my Tokina 100mm macro lens (when using it as a telephoto).
However... now I was faced with an interesting problem. Sigma sells a USB dock (about $59), but I usually used the on-camera auto-focus fine tuning settings to fix issues. The (free) software that uses the dock allows you to make auto-focus fine-tuning changes at - on a prime lens - four different distances.
I decided to use my Google-Fu to see if this was a worthwhile investment or not... and I came to the conclusion that it was after reading tons of reviews and forum commentary. Given the cost of the lens, I figured it was a minor investment if it really gave me what I was looking for.
So I bought the dock, and rather than using my traditional auto-focus tuning chart, I decided to just take shots at the different ranges at F/1.4 (to make focus issues VERY apparent) and adjust accordingly. This took me about an hour...
It was the best $59 and 60 minute investment I''ve ever made. :)
Once I''d tuned the lens based on my pictures, I took it out for a real-world spin... and it was EXACTLY as good as I''d read it to be. :)
Sharpness was incredible... not that sharpness is really the only criteria for lens choice, but it''s certainly something you have to consider, along with bokeh, focus speed, focus accuracy, F-stop range and so forth. (All of which this lens handles wonderfully well!)
Summing it up... once you fine-tune this lens, it lives up to it''s hype 100%. :) Having said that... if you''re not up for doing AF fine-tuning yourself, you can buy one and have Sigma do it for you. You''ll just have to ship it back to them to get it done. (If there''s a local authorized Sigma dealer near you, they might do it for you... or not.)
Just so we''re clear, not ALL the writings I found about this lens required AF fine-tuning. Some were perfect right out of the box, so your mileage may vary.
Having said that... if you haven''t learned to use your camera''s AF fine-tuning (pretty much all DSLR makers have this in their cameras), then you really, really, REALLY should learn how. Chances are you''ll find that some of your lenses aren''t performing quite as well as they could. :)
So, some general pro''s and cons:
Focus accuracy (single-point)
Focus speed (single-point)
Excellent color transmission
Professional build quality
Wonderful manual focus ring
Amazing picture quality overall
Very nice carrying case
Excellent lens cap, doesn''t pop off, etc.
Lack of dock seal
Need to purchase USB dock (perhaps)
Storage dock-cap on lens is a bit loose (can use a Nikon cap instead.)
This lens - after AF tuning - is absolutely amazing. I have to say that while I''ve spent more for a lens, I''ve never spent my money better.
Final Update 9/5/2015
A word about the auto-focus fine-tuning on this lens. First - doing auto-focus tuning at F/1.4 is very, very difficult at close ranges. Finding the focus (forward or back) can be very challenging - it gets easier at more distance (5 feet and up), but at 16 and 28 inches... seeing where the actual focus is can be tough no matter what chart you use. Stick with it, though - and read below, because there''s some very important information specific to Sigma Art lenses that you''ll need. :)
I had bought (via Amazon) a Datacolor SpyderLensCal SLC100, thinking it was time for me to finally move off my old free paper-printed focusing chart.
This focusing aid (the SypderLensCal) was and is good for LONG- DISTANCE auto-focus fine tuning. Do NOT use it for ranges of less than 3 feet - all my lenses on both my cameras (D750 and D7100) had a lot of trouble focusing on the target... something I found out later on after spending much time being frustrated by my tuning efforts on this 50mm Sigma Art.
Setting aside target problems, I had used the Sigma manual to do tuning for each of the ranges on the lens... while I was initially very pleased with the result, I found inconsistencies over time. After spending many hours re-doing and re-re-doing the settings on the lens with WILDLY varying settings according to each fine-tuning session, I finally called Sigma and asked them what (if anything) I was doing wrong.
I had followed their online PDF documentation to the letter - testing and adjusting focus on the closest setting first, followed by the next closest, etc.
Turns out their documentation left out one tiny detail, which the tech support guy provided within a minute of our discussion.
You have to reset all the settings to the default of ZERO before moving on to the NEXT RANGE. If you leave the closer range (or ranges) in place, it will skew the results of your front/back focus issue. Worse, (as I found out) if the numbers are big enough, you don''t really get a change in the adjustments of later settings - I had some of them up to +20 (the max) at one point!
Once I changed out the target and followed the proper procedure, I got some fantastic results. The adjustments on my lens copy were small: +1 at 16 inches, 0 at 28 inches, +6 at 60 inches, and +7 at Infinity. (All with a zero auto-focus fine-tuning on my camera settings.)
(Although I used a chart to set up infinity, I ended up increasing it from +6 to +7 when I did my real-world tests. My chart testing was inside, and even though I was beyond the 11 feet indicated by the lens, truly distant objects required a little more refining.)
Now the sharpness is outstanding and consistent at all ranges - no anomalies - and I''m 100% happy with my lens. :)
As stated, this is the last update... hope this helps!