Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-23-2016, 05:14 PM   #16
Site Supporter
Fenwoodian's Avatar

Join Date: Apr 2015
Photos: Gallery | Albums
Posts: 1,275
I own the Sigma 18-35mm lens and the highly rated SMC Pentax-FA 20mm F2.8 lens.

Over the last two days I have been testing the two.

The Sigma zoom at 20mm is better than the Pentax 20mm lens in overall IQ, especially sharpness.

The dynamic range of the Sigma is impressive. Similarly exposed shots with each lens on my K3ii demonstrated that most areas of highlights that the Sigma handled nicely were totally blown out with the Pentax 20mm lens.

Also, at most apertures, the Sigma was sharp and in focus over the entire frame, The Pentax 20mm lens at larger apertures was only in focus in the center, and even at the smallest apertures, the edges and corners on the Pentax 20mm lens were soft and blurry.

01-23-2016, 06:22 PM   #17
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,797
QuoteOriginally posted by WPRESTO Quote
Excuse on the basis of an aging film shooter who can only think of 28-35-50-55.
Or an RF photographer like me who mostly thinks of FL in regards to rangefinder framelines. 28~50 35~75 90~135

QuoteOriginally posted by Fenwoodian Quote
The dynamic range of the Sigma is impressive.
Dynamic range is not an optical property. The contrast range represented in an image is a result of accurate exposure and the inherent contrast range the sensor is able to record.

QuoteOriginally posted by Fenwoodian Quote
highlights that the Sigma handled nicely were totally blown out with the Pentax 20mm lens.
This indicates the sigma lens was transmitting less light than the prime lens was. Lower T. Stop, this is not a favorable property.
01-24-2016, 06:01 AM   #18
Loyal Site Supporter
dadipentak's Avatar

Join Date: Jul 2008
Location: Baltimore, Maryland
Photos: Gallery
Posts: 10,411
QuoteOriginally posted by MRCDH Quote
Dadipentak, what has your experience been with the 18-35? Didn't you have any autofocus issues?
No issues--but then, I'm not the sort who goes looking for them. I really fell in love with the lens when I took it for a walk along a local stream on a gloomy day last Spring.



01-24-2016, 02:33 PM   #19
Loyal Site Supporter
MRCDH's Avatar

Join Date: Nov 2015
Location: Scottsdale, AZ
Posts: 76
Original Poster
QuoteOriginally posted by dadipentak Quote
No issues--but then, I'm not the sort who goes looking for them. I really fell in love with the lens when I took it for a walk along a local stream on a gloomy day last Spring.


very nice shots; one can not find any faults with success. It appears you got a good lens which performs the way one would expect.


Last edited by MRCDH; 01-25-2016 at 08:08 AM.
02-14-2016, 02:08 PM   #20
Junior Member




Join Date: Dec 2015
Posts: 34
Any news?
There is a solution for bad focus or not?
02-15-2016, 09:03 AM   #21
New Member




Join Date: Jul 2013
Posts: 18
From what I have read the best technique is to focus using Live View, i.e. contrast detection instead of phase detection.

Last edited by GSWayne; 02-15-2016 at 05:34 PM.
02-15-2016, 09:43 AM   #22
Junior Member




Join Date: Dec 2015
Posts: 34
Ehhh
Thanks!
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
autofocus, calibration, capability, copy, dock, dslr, f1.8, fa, focus, job, k-3, k3, lens, mine, pentax, pentax k-3, pm, policy, primes, return, sale, sigma, sigma 18-35mm f1.8, time, video
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sigma 18-35mm f1.8 DC HSM Samples pentaxk3user Lens Sample Photo Archive 5 05-25-2016 10:34 PM
To the new owner of this Sigma Art 18-35mm f1.8, please provide some feedback. Stavri Pentax SLR Lens Discussion 2 10-06-2014 08:02 PM
Sigma 18-35mm F1.8 now available tjwaung Pentax Price Watch 10 07-03-2014 06:39 AM
is Sigma 18-35mm F1.8 DC HSM for pentax coming out? starjedi Pentax SLR Lens Discussion 23 04-29-2014 12:28 AM
sigma 18-35mm f1.8 Art or 35mm F1.8 ART ? Help needed ajaya Pentax SLR Lens Discussion 13 02-25-2014 08:11 PM



All times are GMT -7. The time now is 11:02 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top