Forgot Password
Pentax Camera Forums Home

Show Printable Version Search this Thread
11-18-2013, 10:35 AM   #181
Veteran Member
i83N's Avatar

Join Date: Mar 2009
Location: Lithuania
Photos: Gallery
Posts: 1,203
QuoteOriginally posted by monochrome Quote
Link to PF Post for Hands-on opinion of the 20~40 at DFW PhotoExpo HERE
"The lens lineup included the 20-40 Limited; that lens on the K3 is just....solid. And fast. And solid. The combo reminds me of my classic Pentax stuff; the 135 1.8 ED on an LX, for example."
Link not working.

11-18-2013, 11:39 AM - 1 Like   #182

Join Date: Apr 2010
Location: Tennessee
Posts: 6,617
QuoteOriginally posted by tripodquest Quote
See my follow-up question above and please answer it if you can. I really want to understand all these things better, understand why my thinking is backwards. It doesn't seem backwards to me so I need someone to help me understand how and why it's backwards.
When I get back I will try to explain if someone hasn't already done it. There are a lot of points you can address with your question.

The simple answer is that APS-C lenses need to be sharper at wider apertures and faster in general to match the image quality of FF. To match FF you have to shoot at a wider aperture which means the lens needs to be designed for peak sharpness at a wider aperture. The Sigma 18-35 F/1.8 is the FF equivalent of a 27-53mm F/2.8. So the 18-35 has to be as sharp at F/1.8 as a 24-70 does at F/2.8.

There is a lot more too it, but that is one key reason.
11-18-2013, 12:01 PM   #183
Loyal Site Supporter
Loyal Site Supporter
monochrome's Avatar

Join Date: Mar 2008
Location: Working From Home
Photos: Gallery | Albums
Posts: 26,276
QuoteOriginally posted by i83N Quote
Link not working.
Fixed now - sorry.
11-18-2013, 12:11 PM - 1 Like   #184

Join Date: Jun 2012
Location: NY/Germany
Posts: 1,183
For those that don't want to click back to find that post, here's the link:

QuoteOriginally posted by monochrome Quote
Fixed now - sorry.

11-19-2013, 07:31 PM   #185
Veteran Member

Join Date: Dec 2010
Location: Manila
Photos: Gallery | Albums
Posts: 2,185
QuoteOriginally posted by Vylen Quote
Which is why I'm keen on getting the Sigma 24-70mm... a full frame lens with no-so-great edge performance and vignetting but looks fantastic on APS-C cameras haha
I considered that lens before, with with a front element and filter thread of 82mm and weighs like a couple of bricks in the bag, I decided to go with the Tamron 17-50 instead... (and foot zoom all the way, in case I have no time to switch to my 50-135!)

  • 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!
20-40mm, canon, da, filter, gr, nikon, oz, pentax news, pentax rumors, price, size, weight
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
Thematic By the numbers charliezap Mini-Challenges, Games, and Photo Stories 307 07-11-2020 08:42 AM
DA 40mm LTD. is the perfect walk-around lens tele_pathic Pentax SLR Lens Discussion 17 11-18-2013 10:40 AM
Is there a comparison between the DA 40mm LTD and the 40mm XS out there anywhere? ChopperCharles Pentax SLR Lens Discussion 9 05-07-2012 11:07 AM
For Sale - Sold: Brand New in Box: DA 15mm ltd, DA 40mm ltd, DA 17-70mm, DA 18-55mm WR chemxaj Sold Items 8 12-01-2009 02:16 PM
For Sale - Sold: DA 40mm ltd and DA 35mm Macro ltd (caution: large images) farfisa Sold Items 7 02-06-2009 07:21 AM

All times are GMT -7. The time now is 04:14 AM. | See also:, 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?
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]