Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-29-2012, 08:41 PM   #31
Pentaxian




Join Date: Nov 2011
Photos: Gallery | Albums
Posts: 3,736
QuoteOriginally posted by Digitalis Quote
The Pentax 50mm f/1.2 is the only lens that can beat the FA31 when it comes to bokeh.
Well, what about the Voigtlaender Nokton 58/1.4, or some of those old M42 preset Meyers?

03-29-2012, 09:22 PM   #32
Site Supporter
mikeSF's Avatar

Join Date: Jan 2009
Location: East Bay Area, CA
Photos: Gallery
Posts: 5,705
QuoteOriginally posted by Digitalis Quote
Pentax K-5 SMCP FA31mm f/1.8 Limited ASPH @ ISO 100 1/1250th f/1.8

Let me put it this way, there aren't many lenses that can produce smooth bokeh like that under those circumstances. The Pentax 50mm f/1.2 is the only lens that can beat the FA31 when it comes to bokeh.
and there ya go.
03-29-2012, 11:52 PM   #33
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,796
QuoteOriginally posted by lytrytyr Quote
Well, what about the Voigtlaender Nokton 58/1.4, or some of those old M42 preset Meyers?
This isn't a discussion over which lens has the best bokeh, that topic has already been debated ad nauseum on these forums and when it comes to lenses in the 30mm to 35mm focal length category there aren't many lenses f/2 or faster that can match the FA31*. Even the Leica 35mm f/1.4 Summilux-M - doesn't hold much of an optical advantage over the FA31 on full frame, despite its exorbitant cost. Speaking of full frame, I use the pentax FA43mm f/1.9 Special - which is basically an FA43 with a 39mm screw mount that can be used on Leica cameras. On the Leica M9 the FA43 is a pretty good lens* - the corners are soft at f/1.9 but at f/4~5.6 it is as sharp across the entire frame as the Leica 50mm f/1.4 Summilux-M ASPH - and the FA43 is also more resistant to flare.

*I prefer to use the FA43 Special on the Leica M8.2 because it behaves more like a 55mm lens on the 1.3X APS-H sensor.


Pentax K-7 Pentax FA31mm f/1.8 Limited ASPH - ISO100 1/250th @ f/1.8

Last edited by Digitalis; 03-30-2012 at 12:02 AM.
03-31-2012, 06:21 AM   #34
Site Supporter
germar's Avatar

Join Date: Apr 2007
Location: Austin Texas
Photos: Gallery
Posts: 728
Addressing the OP's original question, I own both and for me the true test is which one get's more "seat time" on my K-5. I use the 43mm more, because the FOV seems truly normal for me and it works with my style of shooting. The color rendering, IQ and bokeh is very much in line with the 31 Ltd, just amazing images. I think someone here has suggested that you look at your historically most favorite focal length and base your selection on that. If you've shot more wide stuff, the 31 is your choice, if more normal/long the 43 is the way to go. In regards to pure image quality concerns, these two amazing lenses are very very close.

Also another small point: The 31 Ltd is very large and heavy compared to the 43. The 43 is only a few millimeters bigger than a DA40mm, and you can get the 43 pretty tiny by "borrowing" the flat lens hood off a 40mm. It works fine and makes the K-5 pretty stealthy.

04-01-2012, 11:04 AM   #35
Veteran Member




Join Date: Jan 2007
Location: New Mexico
Photos: Albums
Posts: 1,125
QuoteOriginally posted by germar Quote
Addressing the OP's original question, I own both and for me the true test is which one get's more "seat time" on my K-5. I use the 43mm more, because the FOV seems truly normal for me and it works with my style of shooting. The color rendering, IQ and bokeh is very much in line with the 31 Ltd, just amazing images. I think someone here has suggested that you look at your historically most favorite focal length and base your selection on that. If you've shot more wide stuff, the 31 is your choice, if more normal/long the 43 is the way to go. In regards to pure image quality concerns, these two amazing lenses are very very close.

Also another small point: The 31 Ltd is very large and heavy compared to the 43. The 43 is only a few millimeters bigger than a DA40mm, and you can get the 43 pretty tiny by "borrowing" the flat lens hood off a 40mm. It works fine and makes the K-5 pretty stealthy.
I cannot see how anyone would find the standard hood for the FA43 too large. And remember, the main purpose of a hood is to shade the lens from stray light. If you use a hood that is too shallow, you may lose some of that shading.

Rob

Last edited by robgo2; 04-01-2012 at 07:51 PM.
04-01-2012, 12:58 PM   #36
Ash
Community Manager
Loyal Site Supporter
Ash's Avatar

Join Date: Mar 2007
Location: Toowoomba, Queensland
Photos: Gallery | Albums
Posts: 22,695
The FA43 lens hood appears alsmost inadequate it's so small - it's perfect for FF, and it's definitely nicely completenting the original lens cap.
For a 1.5x crop dSLR, a larger hood would ward of stray tangential rays a little better, but then why mess with perfection?
04-01-2012, 02:16 PM   #37
Veteran Member
rparmar's Avatar

Join Date: Jan 2008
Photos: Gallery
Posts: 8,783
QuoteOriginally posted by orangezorki Quote
Have to chime in for the 31mm as well - fantastic build and optics, but more importantly it seems to be a perfect 'normal' focal length.
Unfortunately for those who want a normal on APS-C, the FA31 comes in at close to 32mm focal length. That's a good way off the 28mm normal.

Everyone has different preferences, but I prefer 24-28mm or skipping up to 43mm -- the latter for obvious reasons!


QuoteOriginally posted by fmerges Quote
At the end I bought the 43mm, the 100mm macro was not the WR one. The 43mm I got is a silver one with serial number #0004338 Made in Japan.
You are going to enjoy that lens. But do consider manual focus for greater control and accuracy.

QuoteOriginally posted by fmerges Quote
Have to get now a silver filter, any recommendations?
Filters kill IQ. The hood will protect the lens.
04-01-2012, 03:30 PM   #38
Site Supporter
Ex Finn.'s Avatar

Join Date: Nov 2007
Location: Southern Maryland.
Photos: Gallery | Albums
Posts: 6,298
QuoteOriginally posted by rparmar Quote
Unfortunately for those who want a normal on APS-C, the FA31 comes in at close to 32mm focal length. That's a good way off the 28mm normal.
Say what?. I must be missing something here so my apologies up front.

04-01-2012, 04:11 PM   #39
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,796
QuoteOriginally posted by Ash Quote
why mess with perfection?
because we can?

QuoteOriginally posted by rparmar Quote
Unfortunately for those who want a normal on APS-C, the FA31 comes in at close to 32mm focal length
depending on where you are focusing. A lenses focal length can vary quite substantially at closer distances especially IF lenses, but it is usually within 1mm*/- tolerance.

QuoteOriginally posted by rparmar Quote
Filters kill IQ. The hood will protect the lens.
scare words, if you have a high quality Hoya pro-1Digital or Schneider (B+W) you should be fine image degradation is kept to imperceptible levels.
04-01-2012, 04:51 PM   #40
Pentaxian




Join Date: Nov 2011
Photos: Gallery | Albums
Posts: 3,736
QuoteOriginally posted by Digitalis Quote
A lenses focal length can vary quite substantially at closer distances especially IF lenses, but it is usually within 1mm*/- tolerance.
As I understand it, the focal length is defined to be
the lens center to focus plane distance,
when the lens is focused at infinity.
04-01-2012, 05:08 PM   #41
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,796
QuoteOriginally posted by lytrytyr Quote
As I understand it, the focal length is defined to be the lens centre to focus plane distance, when the lens is focused at infinity.
But as you focus closer, the optical centre of the lens moves further away from the sensor.
04-01-2012, 05:11 PM   #42
Pentaxian




Join Date: Nov 2011
Photos: Gallery | Albums
Posts: 3,736
QuoteOriginally posted by Digitalis Quote
But as you focus closer, the optical centre of the lens moves further away from the sensor.
True, but that increasing distance is not what is normally understood as the "focal length" of the lens.

See http://en.wikipedia.org/wiki/Focal_length
04-01-2012, 06:52 PM   #43
Veteran Member
rparmar's Avatar

Join Date: Jan 2008
Photos: Gallery
Posts: 8,783
QuoteOriginally posted by Digitalis Quote
scare words, if you have a high quality Hoya pro-1Digital or Schneider (B+W) you should be fine image degradation is kept to imperceptible levels.
Scared? Who me?

You add a piece of glass to the front of your lens with two surfaces, neither of which were anticipated by the lens designer. By doing so, you also include an new air gap. The only result of this will be image degradation. Especially at night or when flare might be at risk. Yes, if you pay a lot for high-priced glass this effect might be minimal, but why bother? (And I emphasise "might" since many expensive filters are crap. This has been objectively tested and proven.)

In extreme environmental conditions (salt water, wind-born sand) it may be worth bothering with a filter. For day-to-day use you're wasting money.
04-01-2012, 06:53 PM   #44
Veteran Member
rparmar's Avatar

Join Date: Jan 2008
Photos: Gallery
Posts: 8,783
QuoteOriginally posted by Digitalis Quote
But as you focus closer, the optical centre of the lens moves further away from the sensor.
This is obviously some new definition of "focal length" of which I was not previously aware. Seems to me you're talking about "focus distance" or "subject distance".

But regardless of whether we are talking 31mm or 32mm, that's not "normal" for APS-C.
04-01-2012, 08:38 PM   #45
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 8,796
QuoteOriginally posted by rparmar Quote
You add a piece of glass to the front of your lens with two surfaces, neither of which were anticipated by the lens designer.
Then why do they put filter threads on the front of lenses if they do not anticipate photographer to use filters? why does the Pentax D-FA 645 25mm f/4 - a lens designed for medium format, have a built in 40.5mm filter drawer?

QuoteOriginally posted by rparmar Quote
By doing so, you also include an new air gap. The only result of this will be image degradation. Especially at night or when flare might be at risk. Yes, if you pay a lot for high-priced glass this effect might be minimal, but why bother? (And I emphasise "might" since many expensive filters are crap. This has been objectively tested and proven.)
With modern multi-coating techniques the air gap is less of a problem than it was for uncoated lenses. If you use a quality multi-coated filter there shouldn't be any observable difference, however at night times when there are many point light sources in a scene it will be beneficial to remove filters because ghosting and filter flare can become serious issues.
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!
43mm, k-mount, kit, lens, ltd, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
43mm... sell my 50mm and 35mm for a 31mm? krypticide Pentax SLR Lens Discussion 60 08-01-2011 01:37 PM
For Sale - Sold: Pentax FA 31mm/1.8, FA 43mm/1.9, DA 35mm/2.8 Macro, DA 12-24mm, AF160 flash (U farfisa Sold Items 15 12-10-2010 02:00 PM
For Sale - Sold: FA Limited 31mm, 43mm, 77mm and Metz 48 AF-1 (US) jpfisher Sold Items 17 08-05-2010 07:22 AM
For Sale - Sold: Pentax Limiteds 43mm/31mm/77mm, FA * 200mm, K10D, TC Dave Sold Items 20 06-17-2010 09:08 PM



All times are GMT -7. The time now is 10:21 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