Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
08-18-2010, 09:54 PM   #1
Veteran Member




Join Date: Jul 2010
Location: Oz
Posts: 408
A lens faster than the da f3.2 21mm limited?

Don't get me wrong I love the lens but at night it's way too slow without flash. I find myself at times having to reach for my A50mm f1.7. But sometimes it's just too long.
What I need is a f2 or faster. I could go manual cause I don't like the af lamp, so

08-18-2010, 09:59 PM   #2
Veteran Member




Join Date: Jul 2010
Location: Oz
Posts: 408
Original Poster
it's not like af is going to help me much. Besides, if lighting is good enough to not need the af lamp, most likely I'd use the da 21. I know about the Sigma 20mm f1.8 but would rather not get that. It's too big. Just a small 18-21mm f2 manual would do me
08-18-2010, 10:12 PM   #3
Site Supporter




Join Date: Mar 2008
Location: Israel
Photos: Gallery | Albums
Posts: 933
There is Pentax FA 20/2.8 that can be sharp even wide open. At least my sample seems to be. It is somewhat more useful than DA 21/3.2, but not by much. The only 20 mm lens that you can mount on Pentax camera that is faster that I am aware of is Sigma 20/1.8. But it is both big and has a reputation of being somewhat soft up until f2.8 or thereabouts... Pentax has FA* 24/2 and Sigma has 24/1.8 as well. Though slightly less wide, but perhaps it might be wide enough for you and also as fast as you need...

Personally, I had reservations about Sigma gear, but as of recently having acquired on this forum Sigma EX 24-60/2.8 I tend to change my opinion. It is big and heavy, but it is really well made and not bad optically. However, sample variation is significant and one should exercise caution whence hunting for Sigma optics...
08-18-2010, 10:14 PM   #4
Senior Member
scorpioh's Avatar

Join Date: Jul 2009
Location: Singapore
Photos: Gallery
Posts: 178
20-30mm is Pentax's weak spot in modern lineup. The 24mm f2.0 is the best choice but even so, its over a decade old lens.

08-18-2010, 10:31 PM   #5
Veteran Member




Join Date: Jan 2009
Location: Brisbane
Photos: Gallery
Posts: 1,421
I recently got the sigma 30mm f1.4, its a very fine lens, fast, sharp, not tooo big (still bigger than the pentax primes) but is obviously longer than your current lens.

a possible option if you are willing to go longer focal length
08-18-2010, 10:54 PM   #6
Veteran Member




Join Date: Jul 2010
Location: Oz
Posts: 408
Original Poster
I'm willing to go wider but not longer. I would like as small as possible. Is there a m42 lens like this?
I was searching and found a 21mm f2.0 Zuiko mount. There's an adapter which will allow Av mode. Don't know much about it and would be over $1000.
08-18-2010, 10:59 PM   #7
Veteran Member




Join Date: Jul 2010
Location: Oz
Posts: 408
Original Poster
If I had the bucks and liked range finders, leica has a 21mm f1.4. I can't imagine how wonderful that lens must be.
Also looks like there's a Zeiss compact 21mm f2, w/e that is. Can't afford either!
08-19-2010, 12:06 AM   #8
Pentaxian
philbaum's Avatar

Join Date: Oct 2007
Location: Port Townsend, Washington State, USA
Posts: 3,659
QuoteOriginally posted by troglodyte Quote
If I had the bucks and liked range finders, leica has a 21mm f1.4. I can't imagine how wonderful that lens must be.
Also looks like there's a Zeiss compact 21mm f2, w/e that is. Can't afford either!
trog,
let me give you an alternative view from my last 18 months of shooting live plays for promo shots. we're not allowed to use flashes for rehearsals so initially i went out and bought some zoom lenses with F2.8. But for some dark scenes, i still had problems with bluriness caused by either human motion, DOF with more than one actor on stage, or tungsten effects. Then i learned from another photographer to be fearless about using higher ISO, up to 3200 or 4000 with my K20. If i have noise problems, i just clean them up with LR3 or Topaz5. Actually the new generation of sensors such as with the Kx, probably the K5 and/or the Kr will no doubt make the higher iso less noisy.

With higher iso shooting, i can now use my F2.8 lenses at F4, F4.5 or smaller allowing me less discards due to slight AF problems because of larger DOF. Also with the higher iso, i am more likely to freeze human motion due to the ability to use 1/125 or higher shutters. I recently snapped 450 images with probably no more than about 10 blurred images due to AF problem. My acceptance rate has gone up with the use of high iso.

I used my DA 21 f3.2 at F3.5 and even up to F9 recently for a wide angle picture of an evening play outdoors. Came out great!!! So what i'm trying to tell you is, you may want to spend your money on a camera with a more capable low light sensitive sensor than spend money on ultra fast lenses. I found that the DA 21 f3.2 is plenty fast for me for the kind of DOF i need. And i often dark scenes. IMO, low light camera first, fast lenses second. unless you are doing an entirely different kind of shooting. just food for thought :-)

best wishes with your selection,

08-19-2010, 12:52 AM   #9
Veteran Member




Join Date: Jul 2010
Location: Oz
Posts: 408
Original Poster
phil,
I have the k7. Anything past iso 1250 in shadows looks horrid with lr3 NR. I usually try shooting 100 for shadows and 200 for highlights if I can. With my A50 f1.7, f2 is the sweet spot.
I only want another lens for super dark candle light only
08-19-2010, 12:57 AM   #10
Veteran Member




Join Date: Jul 2010
Location: Oz
Posts: 408
Original Poster
so IQ isn't that important. I already have the da 21 which gives canon L glass a run for the money. I'm just looking for basically what I can do with the a50 but wider. IQ wise my da21 beats my a50 by leagues but for low light it is quite special.
08-19-2010, 12:58 AM   #11
Veteran Member




Join Date: Jul 2009
Posts: 1,296
QuoteOriginally posted by Boris Quote

Personally, I had reservations about Sigma gear, but as of recently having acquired on this forum Sigma EX 24-60/2.8 I tend to change my opinion. It is big and heavy, but it is really well made and not bad optically.
Big and heavy compared to what? Compared to other standard-range f/2.8 zooms it's quite compact.
08-19-2010, 02:06 AM   #12
Veteran Member
blende8's Avatar

Join Date: Feb 2007
Location: Bremen, Germany
Photos: Albums
Posts: 1,484
Sigma 20/1.8 is s great low light lens.
This lens often needs a focus correction, but then it is sharp at f1.8.
08-19-2010, 04:00 AM   #13
Forum Member




Join Date: Feb 2009
Location: Vienna
Posts: 96
I think I recently mentioned this in a different thread: MC Mir-47 Pentax K 2.5/20 Lens

At 20mm f/2.5 it may well fit your needs. Haven't found a whole lot of feedback about it, but at that price, you may want to just give it a shot. Try doing some research online. I think there are some sample shots floating around.

EDIT: Oops, I think I missed this part:
QuoteOriginally posted by troglodyte Quote
f2 or faster
In that case, I guess the Sigma is the way to go.
08-19-2010, 05:05 AM   #14
Pentaxian
bdery's Avatar

Join Date: Mar 2008
Location: Quebec city, Canada
Photos: Gallery
Posts: 5,826
I have tried several options, including the Sigma 20 and 30 mms on an Olympus body and some 28s Pentax. The problem with most wide lenses is that they are not really usable wide open. They get the job done butcontrast and sharpness are lacking. Not so with the 21 mm, and I suppose that's one reason why it's slower than other lenses.

The Sigma 20 mm is definitely softer wide open, and picks up about where the 21 mm starts. I haven't used the Pentax 20 and 24 variations, but from comments they seem to be about the same. Some 28s are usable wide open, but are not as wide, and not terribly faster at f2,8.

For me the 21 mm was the best choice. I use it with my F50 f1,7 and together they make a great combo. I suggest humbly that with a little practice, and with SR, using the 21 wide open should work even in very low light. It does for me.
08-19-2010, 05:18 AM   #15
Veteran Member
blende8's Avatar

Join Date: Feb 2007
Location: Bremen, Germany
Photos: Albums
Posts: 1,484
QuoteOriginally posted by bdery Quote
The Sigma 20 mm is definitely softer wide open, and picks up about where the 21 mm starts.
This is a common myth, probably caused by wrong AF.
With a correctly adjusted AF the Sigma is fine at f1.8 (see below).
The contrast is a bit weaker at f1.8, but this is normal with all fast lenses.

100% crops:





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!
k-mount, lens, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale - Sold: Pentax Limited 21mm / f3.2 DA lens dkreithen Sold Items 2 11-07-2008 08:38 AM
For Sale - Sold: Pentax DA Limited 21mm f/3.2 lens wiyum Sold Items 2 10-12-2008 12:43 AM
For Sale - Sold: Pentax SMC DA 21mm F3.2 Limited Pancake Lens frank Sold Items 11 09-07-2008 07:15 PM



All times are GMT -7. The time now is 10:07 PM. | 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