Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
08-02-2010, 06:36 AM   #31
Veteran Member
Asahiflex's Avatar

Join Date: Jan 2008
Location: Netherlands
Photos: Gallery
Posts: 2,754
QuoteOriginally posted by goubejp Quote
Here is an example - very extreme, I must confess, and I have not set the proper settings for the lens - it is stopped down at f2.8 as it was have been possible to stop down at f5.6 for this completely static subject;
this is a 100 % crop so it is far less visible on the original shot; but ths issue is here; I don't have a A*85 to compare though.
Note that the clarity of the image and the excellent rendering on the stones anyway Regards
Many thanks for posting this sample! Indeed, the PF is easy to see and not unexpected for this type of shot. I believe there is a reason that our beloved portrait lenses have these abberations and that's because these add to the picture qualities we want in a portrait lens. This makes me wonder how the upcoming Sigma 85/1.4 will do in this regard (as it features ED elements; when the FA* 85 was made ED glass was already known, so why not use them in its design?).

08-02-2010, 07:35 AM   #32
Veteran Member
rparmar's Avatar

Join Date: Jan 2008
Photos: Gallery
Posts: 8,783
QuoteOriginally posted by goubejp Quote
If you understand french... look here :
Test_85mm
It compares Pentax A*85, FA*85, FA77, DA*50-135, Zeiss 85 and Samyang 85
Thank you so much for that link, one I had not seen before. Unfortunately it suffers from some of the usual irregularities in such tests. For example the FA77 is clearly mis-focused in "Test of resolution in landscape". Perhaps they were relying on AF? Hard to say, since they do not inform us.

The bokeh test is quite odd in that it does not provide a test bed for specular highlights, lights in background, reflections or any other common situation. In fact it seems that a less accurate lens might do better on their test.

Nonetheless, the advantages of the A* design over the FA* are plain. The Samyang is not usable unless stopped down significantly. And the Leica 80mm looks like the best lens to me. All results that conform with expectation.
08-02-2010, 10:44 AM   #33
Site Supporter
Douglas_of_Sweden's Avatar

Join Date: Apr 2008
Location: Stockholm
Photos: Gallery
Posts: 3,353
QuoteOriginally posted by 8540tomg Quote
Any other unused gems in your closet Jer? An A* 400/2.8 or a A* 1200/8 perhaps?
Not unused, but I got the A*85 and A*135 in my bag. Wish I had the A*400 and the A*200 macro, but the prices are tough. The ones I have was bought new from Pentax in the late 80's (the 85mm) or second hand. The A*135 second hand in 1992 for about 450USD (3500SEK), a bargain with todays prices since no one wanted manual focus back then (or so it seamed).

Give me a time machine...forget going back to solve the murders or prime minister Palme or president Kenedy, forget going back to solve the myseries of the vikings, romans, pyramids...I'd go back to the 90's to buy second hand A* lenses for almost nothing!
08-02-2010, 12:31 PM   #34
Site Supporter
Douglas_of_Sweden's Avatar

Join Date: Apr 2008
Location: Stockholm
Photos: Gallery
Posts: 3,353
QuoteOriginally posted by Asahiflex Quote
However, I have used the A* in the past (for a few weeks) and found it prone to CA in difficult conditions (but sharp it is). The FA* does not exhibit the same "problem". (BTW: the A* 135/1.8 is even worse in this regard).
QuoteOriginally posted by Asahiflex Quote
True; but the FA* does not show PF nearly as often as the A*. The A* even showed PF stopped down to f/5.6. I have used the FA* in numerous situations (even wide open) and I never saw any bad PF. However, the FA* tends to blow highlights easily, but that's about the only complaint I have. The FA* 85/1.4 at f/1.4 is sharper than the FA 50 at f/1.4 (I tried two copies of the FA50).
As far as I can see from the French shoot out, the only ~85mm with significantly less PF and/or CA problems at large appertures is the Leica, and that takes a Leitax conversion to put on a K body. All the others have their share of these problems. As for the A*135, I'm pretty sure my copy have less CA than my A*85.

08-02-2010, 12:36 PM   #35
Pentaxian
builttospill's Avatar

Join Date: Jun 2009
Location: Utah, Idaho
Photos: Gallery
Posts: 1,675
QuoteOriginally posted by Douglas_of_Sweden Quote
Give me a time machine...forget going back to solve the murders or prime minister Palme or president Kenedy, forget going back to solve the myseries of the vikings, romans, pyramids...I'd go back to the 90's to buy second hand A* lenses for almost nothing!
When you go back can I give you my shopping list too?
08-02-2010, 02:00 PM   #36
Pentaxian




Join Date: Jul 2009
Location: Seattle
Posts: 7,103
slrgear.com has tested the Zeiss 85mm and you can see it's performance over its aperture range. It's a nice lens, readily available, don't have to compete for it and cheaper than the rare A* 85mm when you get lucky enough to find it. My copy has chromatic aberration well under control.
08-02-2010, 02:27 PM   #37
Veteran Member




Join Date: Oct 2007
Location: France
Photos: Albums
Posts: 804
QuoteOriginally posted by Douglas_of_Sweden Quote
As far as I can see from the French shoot out, the only ~85mm with significantly less PF and/or CA problems at large appertures is the Leica, and that takes a Leitax conversion to put on a K body. All the others have their share of these problems. As for the A*135, I'm pretty sure my copy have less CA than my A*85.
Not exactly (I am native french so may be the automatic translation induced some errors that I have not seen). The better result for CA/PF is obtained with the DA*50-135 which is the most recent design of all these lenses; if I can make a parallel, the DA*300 which is a brand new design if absolutely free of PF, the DA*200 which seems to be a copy of the FA*200 optical design is prone to PF (even if both lenses uses ED elements); I only think that this design parameter was not taken in account in the design of lenses in the film days because it was not relevant. My FA 31 limited also suffers slightly from PF too at large apertures. Knowing the flaws and the strength of my lenses and "personality" of each lens was part of my personal learning curve. I love the FA*85 which is one of my favorite lenses (err... I have many great Pentax lenses, which one is my favorite ? Hard to choose)
08-02-2010, 02:48 PM   #38
Veteran Member




Join Date: Oct 2007
Location: France
Photos: Albums
Posts: 804
QuoteOriginally posted by Asahiflex Quote
Many thanks for posting this sample! Indeed, the PF is easy to see and not unexpected for this type of shot. I believe there is a reason that our beloved portrait lenses have these abberations and that's because these add to the picture qualities we want in a portrait lens. This makes me wonder how the upcoming Sigma 85/1.4 will do in this regard (as it features ED elements; when the FA* 85 was made ED glass was already known, so why not use them in its design?).
I don't know, but I have read somewhere that spherical aberration was not completely corrected on these kind of lenses to achieve a better bokeh - smoother specular highlights - because spherical aberration caused a smooth transition between light and darkness; aspherical elements are also avoided in these design as they have reputation to lead to harsh bokey. Otherwise for a portraiture lens this kind of PF should not be a problem otherwise you have a severe problem of light in your studio !
As I have written in another post, if I compare the DA*200 and the DA*300 which both have ED elements, the DA*200 is prone to PF wide open as the DA*300 is completely free of PF even wide open. The main reason I think is that the DA*200 has the same optical design as the FA*200, on the contrary DA*300 is a new optical design. Old design from film days did not take PF in account because it was not relevant, it is induced by the sensor itself
regards

08-02-2010, 03:14 PM   #39
Veteran Member
rparmar's Avatar

Join Date: Jan 2008
Photos: Gallery
Posts: 8,783
QuoteOriginally posted by tuco Quote
slrgear.com has tested the Zeiss 85mm and you can see it's performance over its aperture range. It's a nice lens, readily available, don't have to compete for it and cheaper than the rare A* 85mm when you get lucky enough to find it. My copy has chromatic aberration well under control.
I would be well happy with the Zeiss. Anyone got an extra?
08-02-2010, 07:42 PM   #40
Site Supporter
Douglas_of_Sweden's Avatar

Join Date: Apr 2008
Location: Stockholm
Photos: Gallery
Posts: 3,353
QuoteOriginally posted by goubejp Quote
Not exactly (I am native french so may be the automatic translation induced some errors that I have not seen). The better result for CA/PF is obtained with the DA*50-135 which is the most recent design of all these lenses; if I can make a parallel, the DA*300 which is a brand new design if absolutely free of PF, the DA*200 which seems to be a copy of the FA*200 optical design is prone to PF (even if both lenses uses ED elements); I only think that this design parameter was not taken in account in the design of lenses in the film days because it was not relevant. My FA 31 limited also suffers slightly from PF too at large apertures. Knowing the flaws and the strength of my lenses and "personality" of each lens was part of my personal learning curve. I love the FA*85 which is one of my favorite lenses (err... I have many great Pentax lenses, which one is my favorite ? Hard to choose)
Oui, les résultat de la DA*50-135 est tre bon à f1.4 et f1.8 ouverture...
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!
guy, k-mount, pentax a*, pentax lens, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
NEW Pentax 85mm/1.2 vindrum Pentax SLR Lens Discussion 14 12-18-2016 11:33 PM
Rumored SAMSUNG 85mm 1.4 could be a 85mm FA rebrand omega leader Pentax News and Rumors 19 09-07-2009 03:05 PM



All times are GMT -7. The time now is 07:21 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