Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
08-08-2011, 01:45 AM   #1
Veteran Member
sany's Avatar

Join Date: Mar 2011
Location: Dubai, UAE
Photos: Gallery | Albums
Posts: 428
85mm lens and teleconverter

Has anyone used teleconverters with 85mm lens and how was the experience, any disadvantages?
Some buying advice-will any k mount tc work with any lens and how effective will it be on my 85 f2?

08-08-2011, 04:56 AM   #2
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
The disadvantage is loss in image quality, unless you have a very good and rather costly TC. Your 85/2 with a 1.5x TC becomes 127/3.5 -- but many good inexpensive 135/2.8 lenses are available. With a 2x TC it becomes 170/4 -- but many good inexpensive 200/3.5 lenses exist, and even a used 180/2.8 may cost less than a good TC. TC's are usually best when matched with long fast lenses.

Last edited by RioRico; 08-08-2011 at 06:52 AM.
08-08-2011, 06:38 AM   #3
Veteran Member
sany's Avatar

Join Date: Mar 2011
Location: Dubai, UAE
Photos: Gallery | Albums
Posts: 428
Original Poster
Thank you sir!
08-08-2011, 06:39 AM   #4
Veteran Member




Join Date: Dec 2007
Location: Prague
Photos: Gallery
Posts: 1,198
I hate the results obtained with FA*85 on AF1.7x TC. In theory is should be good 135/2.8 but in practice there is too much purple fringing.

08-08-2011, 07:00 AM   #5
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
I have used my vivitar (Samyang) 85/1.4 with the pentax SMC-F 1.7x AF TC as a reasonable 145mm F2.5 lens

I did not experience a lot of fringing, or other problems and it makes for a compact option for a tele if yuou don't have one.
08-08-2011, 08:14 AM   #6
Veteran Member




Join Date: Dec 2007
Location: Prague
Photos: Gallery
Posts: 1,198
AF 1.7x won't give you any better than f2.8, no matter how fast lens you attach. Not much fringing you say? Could you share a samle picture with me please?
08-08-2011, 09:07 AM   #7
Pentaxian
Cambo's Avatar

Join Date: Dec 2007
Location: Vancouver, BC
Photos: Gallery | Albums
Posts: 864
Me too...

QuoteOriginally posted by elho_cid Quote
I hate the results obtained with FA*85 on AF1.7x TC. In theory is should be good 135/2.8 but in practice there is too much purple fringing.
a shame to destroy the impeccable image quality of that lens with ANYTHING....I don't even like putting a high-quality polarizer on it, let alone a tele-converter.

And it's already a 127mm on digital....sort of...so 127 x 1.7 = 216mm f=2.8....

Cheers,
Cameron
08-08-2011, 11:57 AM   #8
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
QuoteOriginally posted by Lowell Goudge Quote
I have used my vivitar (Samyang) 85/1.4 with the pentax SMC-F 1.7x AF TC as a reasonable 145mm F2.5 lens

I did not experience a lot of fringing, or other problems and it makes for a compact option for a tele if yuou don't have one.
QuoteOriginally posted by elho_cid Quote
AF 1.7x won't give you any better than f2.8, no matter how fast lens you attach. Not much fringing you say? Could you share a samle picture with me please?
true, it will not show F2.5 but only F2.8, however, that does not change the reality that the TC when added to an F1.4 lens gives you optically an F2.5 lens regardless of the aperture the camera sees.

Where this can be important is most likely with PTTL flash exposure. where you may have confusing results because of the 1/2 stop difference between reality and reported.

08-08-2011, 01:53 PM   #9
Veteran Member




Join Date: Dec 2007
Location: Prague
Photos: Gallery
Posts: 1,198
QuoteOriginally posted by Cambo Quote
a shame to destroy the impeccable image quality of that lens with ANYTHING
True, but I like to play with my equipment. I even tried some extension tubes on the FA*85.

QuoteOriginally posted by Lowell Goudge Quote
true, it will not show F2.5 but only F2.8, however, that does not change the reality that the TC when added to an F1.4 lens gives you optically an F2.5 lens regardless of the aperture the camera sees.
Well by theory 1,7x1,4=2,38 but the AF1,7 TC is made as f2,8 tops. Check it's user manual, if you don't trust me. I guess it is due to smaller diameter of the lens in it...
08-08-2011, 07:36 PM   #10
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
QuoteOriginally posted by elho_cid Quote
True, but I like to play with my equipment. I even tried some extension tubes on the FA*85.
Tubes are clean. TC's add more glass between subject and frame, and so introduce at least *some* IQ loss. And unmatched and other less-than-stellar-quality TC's do worse than that. Whether that's important is up to each individual togger. If content is more important than quality, go for it! I heartily recommend TC's for surveillance, blackmail, criminality, and photojournalism.

Last edited by RioRico; 08-08-2011 at 08:32 PM.
08-08-2011, 08:04 PM   #11
Veteran Member
sany's Avatar

Join Date: Mar 2011
Location: Dubai, UAE
Photos: Gallery | Albums
Posts: 428
Original Poster
cheers, everybody I will not be going for it
08-08-2011, 08:13 PM   #12
Senior Member




Join Date: Jun 2010
Location: San Diego
Photos: Gallery | Albums
Posts: 166
I tried my -F 1.7X AFA TC with a Samy 85 f1.4, did not care for it.

I may be in the minority, but I use the 1.7X all the time. Only use it with Macro lenses, though. Very useful to extend my reach and still hand-hold. Macro lenses can really withstand extra glass with some minor loss in IQ--but Macro IQ is so high to begin with... and of course they excel stopped down (f/8-22).

-W
08-08-2011, 08:29 PM   #13
Loyal Site Supporter
dadipentak's Avatar

Join Date: Jul 2008
Location: Baltimore, Maryland
Photos: Gallery
Posts: 10,406
I've often had very good results using Pentax TCs with Pentax lenses. As Lowell says, a TC can expand your range while keeping cost &/or weight down.
10-09-2017, 02:43 PM   #14
New Member




Join Date: Feb 2016
Location: Moab, Utah
Posts: 22
For anyone interested..

I've used the M series 85mm f2 with Pentax 1.4-s rear converter and it lends excellent results. The rear converter works well on the 13 3.5 and especially well on the M* 300mm f4. There's slight quality loss, but not nearly as bad as off-branded and quality 2x converters I tested.
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!
85mm lens, 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
85mm lens carljmi Pentax SLR Lens Discussion 45 11-11-2011 11:13 PM
For Sale - Sold: a Bevy of 85mm lenses: pentax-m 85mm f2k and Rokinon 85mm f1.4 gscara Sold Items 3 06-07-2011 07:56 PM
ROKINON 85MM F1.4 LENS NEBULA_ONE Pentax SLR Lens Discussion 7 03-12-2010 10:51 AM
Vivitar 85mm MF lens Leya216 Pentax SLR Lens Discussion 4 10-03-2009 06:31 PM



All times are GMT -7. The time now is 02:20 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