Sigma Super Wide Angle 20mm f/1.8 EX Aspherical DG DF RF Autofocus Lens for Pentax AF USA

Comments about Sigma Super W/A 20mm f/1.8 EX Aspherical DG DF RF AF Lens:

I have used this lens for some great razor sharp night shots, and good close ups in a crowd and it is pretty decent at up close macro like photos (this is not a macro lens but lets you focus pretty close to subject with a very wide angle perspective). I carry this lens and my 35 prime and for some events or larger venues my 85 prime. With this lens you get a very good wide angle perspective so it is great for a close up with the rest of what is going on in the background. Nice bokeh

Comments about Sigma Super W/A 20mm f/1.8 EX Aspherical DG DF RF AF Lens:

Excelent lens for outdoor in dawn and dusk. Or for people at parties or other social events.

Sharp and bright! A little slow in autofocusing.

Comments about Sigma Super W/A 20mm f/1.8 EX Aspherical DG DF RF AF Lens:

I read many reviews of this lens before purchasing. To be honest, I was skeptical of how sharp images would be between f1.8 - f2.7 after reading several reviews that images weren't coming out sharp enough.

After receiving this lens and playing with it at low aperture, it's an extremely sharp lens. However there is a little distortion around the edges, but your focus always remains as sharp as it gets. The distortion around the edges seems to go away around f4.0. The low aperture lets you get an amazing depth of field, especially shooting macro or with close ups. Overall, this lens is above what I expected. The 20mm is very universal, and I have been using it for video with my K7. One quirk about this lens that does bother me is that my Pentax K7 doesn't read the lens as an aperture of f1.8, it reads it as f1.7 which I think is an issue with the CMOS sensor. Besides this, this lens for exceeded my expectations, and would recommend it to anyone wanting a decent wide angle prime.

Comments about Sigma Super W/A 20mm f/1.8 EX Aspherical DG DF RF AF Lens:

I'll start with the only con...

82mm filters are so expensive.

Now...The pros:

1) Full compatibility with ASP-c and with 35mm full format. Checked this with K7 & K20d as well as the PZ-1p & MZ-S

2)Highly recomemded for any wide angle needs, but specially f1.8 will give you way more light than the zooms in that range

3) Consistent image quality at all apertures, withe the reserve of some purple fringe in the corners at f1.8 noticeable on very dark subjects against very bright whites like overcasty sky, as well as some softness also in the corners up to 2.8, from 2.8 to 16 I have no complain.

4) no noticeable distortion.

5) well build for a plastic lens

6) Fast accurate focus in good ligh (not so good in plain uncontrasted surfaces in lo light)

7) ergonomic well thought auto/manual focus shift

8)The easiest lens hood to install (that I have tried)

PUT A UV OR CLEAR FILTER, IT IS VERY EASY TO SCRATCH THE FRONT ELEMENT

Possible question: Why to keep this one while having an invaluable and superior in image quality Zeiss Distagon T* 3,5/18?

Answer: The f1.8 from this sigma's baby

Comments about Sigma Super W/A 20mm f/1.8 EX Aspherical DG DF RF AF Lens:

I love it for low light photography, indoors without a flash, and to isolate the subject from the background. Both the autofocus and manual focus work great and the image is fine. I like telephoto zooms but for wide angle I prefer bright primes, and this is becoming my favorite. Even if I didnt have a 35mm film SLR I would buy this because it seems like everyone is coming out with a Digital SLR that uses a Full Frame CCD or CMOS which have no lens factor (a 20mm will work like a 20mm instead of a 30mm)

Expertise: Advanced Amateur Shutterbug for 30 Years

Problems Encountered: You are limited to 1 normal size filter (for 35mm film or a full frame CCD cameras) So it's a good idea to buy a thin polarizing filter, however with a 1.5 or 1.6 lens factor you should be able to use 2 filters at the same time or a full size polarizing filter

Previous Equivalent Item Owned: Pentax A 50mm f:1.2 Lens

Items I Recommend: Sigma Thin Polarizing Filter & Sigma Thin UV Filter