Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-05-2016, 12:16 PM   #1
Senior Member
G.E.Zekai's Avatar

Join Date: Jul 2014
Photos: Albums
Posts: 199
DFA 70-200 f/2.8 Focus breathing

Hello Pentax forum how are you ?


I was wondering if we have any info about new DFA 70-200 and focus breathing.


Looking the specs of the lens and its competition their min focus are:

Canon 1.2m
Nikkor: 1.4m
Pentax: 1.2m
Tamron (VC): 1.3m
Tamron (PK): 0.95m


I first realised this issue/situation when i tried Nikkor 70-200 f/2.8 VRii. Side by side there was a huge difference when i wanted to zoom at 200mm for close headshots (Nikkor didn't looked like it was at 200mm). I only see this problem in 200mm and close to min focus distance.
Since i own the Tamron 70-200 Pk mount it didn't had this problem (probably having macro feature) but still there was minor difference with Canon lens.

I was wondering if new Pentax 70-200 loses few mm in zoom when you are trying to use min. focus distance at 200mm

Hopefully i explained what i mean, and hopefully this is the right term for this situation. Also why manufacturers doesn't disclose such an important info ?



Thank you all for reading and commenting ^_^

03-05-2016, 12:22 PM   #2
Imp
Pentaxian
Imp's Avatar

Join Date: Nov 2014
Location: Washington, DC
Photos: Gallery | Albums
Posts: 1,416
It's like that for the DA* 60-250, but I have no clue about the new DFA. Kenspo?
03-05-2016, 12:29 PM   #3
Site Supporter
Site Supporter
wtlwdwgn's Avatar

Join Date: Jan 2007
Location: Billings, MT
Photos: Gallery | Albums
Posts: 11,733
We won't see any reviews until it's released in April. Focus breathing is a concern. Tony Northrup says the only 70-200 without focus breathing is the Canon. The Nikon, Tamron, and Sigma all do have focus breathing.

03-05-2016, 12:33 PM   #4
Senior Member
G.E.Zekai's Avatar

Join Date: Jul 2014
Photos: Albums
Posts: 199
Original Poster
QuoteOriginally posted by wtlwdwgn Quote
We won't see any reviews until it's released in April. Focus breathing is a concern. Tony Northrup says the only 70-200 without focus breathing is the Canon. The Nikon, Tamron, and Sigma all do have focus breathing.
Thanks for the video. will watch it.

I am still curious why manufacturers don't disclose this. And so glad my Tamron isn't so bad in this area ( although much inferior build & optical quality)

03-05-2016, 02:53 PM - 1 Like   #5
Pentaxian
kenspo's Avatar

Join Date: Mar 2014
Location: Oslo
Posts: 2,192
QuoteOriginally posted by Imp Quote
I have no clue about the new DFA. Kenspo?
Sorry, i have no clue either. Will check this when i can.
03-05-2016, 03:29 PM   #6
Otis Memorial Pentaxian
Loyal Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 33,213
QuoteOriginally posted by G.E.Zekai Quote
I was wondering if we have any info about new DFA 70-200 and focus breathing.


Looking the specs of the lens and its competition their min focus are:

Canon 1.2m
Nikkor: 1.4m
Pentax: 1.2m
Tamron (VC): 1.3m
Tamron (PK): 0.95m
What does minimum focus distance have to do with focus breathing? My understanding is that most (all?) internal focus zooms have greater FOV at the long end at moderate distances than an external focus prime of the same focal length. This is true regardless of minimum focus distance.


Steve

Last edited by stevebrot; 03-05-2016 at 03:35 PM.
03-05-2016, 03:32 PM   #7
Otis Memorial Pentaxian
Loyal Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 33,213
QuoteOriginally posted by G.E.Zekai Quote
I am still curious why manufacturers don't disclose this.
Good question. I was quite disappointed to find that my Sigma 17-70 (C) has the same FOV at 70mm and 2m distance as my Pentax-M 50/1.7 and not that much different than the DA 18-55 kit at 55mm.

I think it would be a good thing for lens review sites to publish FOV data.


Steve
03-05-2016, 05:25 PM   #8
Senior Member
G.E.Zekai's Avatar

Join Date: Jul 2014
Photos: Albums
Posts: 199
Original Poster
QuoteOriginally posted by stevebrot Quote
What does minimum focus distance have to do with focus breathing? My understanding is that most (all?) internal focus zooms have greater FOV at the long end at moderate distances than an external focus prime of the same focal length. This is true regardless of minimum focus distance.


Steve
I though it might be related to min. focus distance somehow. I read on some forums that few guys discussing this issue and they were claiming it was because Nikkor having a further min. focus distance than others.

Also after reading about this issue i found out Tamron 24-70 f2.8 is very horrible in this area. Hopefully pentax fixed it ?

03-05-2016, 06:20 PM   #9
New Member




Join Date: Dec 2014
Posts: 8
QuoteOriginally posted by G.E.Zekai Quote
I though it might be related to min. focus distance somehow. I read on some forums that few guys discussing this issue and they were claiming it was because Nikkor having a further min. focus distance than others.

Also after reading about this issue i found out Tamron 24-70 f2.8 is very horrible in this area. Hopefully pentax fixed it ?
I doubt it. Except for cheap fixes that Tamron would have thought of themselves, that would involve a fundamental change to the optical formula. At that point, they could have designed their own lens.

In any case, modifying one thing without changing much else should show up in some of the characteristics (like min focus distance) and it doesn't.
03-05-2016, 09:47 PM   #10
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 15,232
There are reverse focus breathing lenses out there as well. I'm not sure there is a marketplace for this level of deep info about a lens. But being a tech geek I would love to have this displayed and visualized somehow.
03-05-2016, 10:20 PM   #11
Pentaxian
Digitalis's Avatar

Join Date: Mar 2009
Location: Adelaide.
Posts: 9,540
QuoteOriginally posted by wtlwdwgn Quote
Tony Northrup says the only 70-200 without focus breathing is the Canon.
He's wrong*, The Canon EF 70-200mm f/2.8L IS II USM varies by around +/-10% throughout the focal range at 200mm. It is less than what the Nikon equivalent loses, but it is there.

*Hardly surprising, since he got his figures from DXO.

Last edited by Digitalis; 03-08-2016 at 03:09 AM.
03-07-2016, 09:00 AM - 1 Like   #12
pdo
Senior Member
pdo's Avatar

Join Date: Sep 2008
Location: Westminster CA
Posts: 264
Here's an excellent video on focus breathing on. Skip to 5 mins if you don't want to watch the whole video..
03-07-2016, 09:14 AM   #13
Pentaxian
normhead's Avatar

Join Date: Jun 2007
Location: Near Algonquin Park
Photos: Gallery | Albums
Posts: 33,132
QuoteOriginally posted by G.E.Zekai Quote
Thanks for the video. will watch it.

I am still curious why manufacturers don't disclose this. And so glad my Tamron isn't so bad in this area ( although much inferior build & optical quality)
There's video somewhere, that showed that the Tamron is just as good in optical quality. The build quality was not as good. Translation, if you're a working pro and you're using the lens often, the Tamron may not hold up, if you're an amateur and your use is occasional, in every aspect, IQ, CA, flare, AF, the Tamron is a match for the best Nikon and Canon have to offer. Maybe your Tamron got dinged and is out of alignment.
03-22-2016, 10:57 AM   #14
Loyal Site Supporter
Loyal Site Supporter
Kath's Avatar

Join Date: Jan 2014
Location: Portland, OR
Photos: Gallery
Posts: 728
QuoteOriginally posted by pdo Quote
https://youtu.be/vSuFrIYiINU
Here's an excellent video on focus breathing on. Skip to 5 mins if you don't want to watch the whole video..
Thanks for posting this video. I found it quite informative -- and reassuring -- on this issue. I'm glad that some people like to spend their time with these precision measurements and share them with us.
03-22-2016, 11:22 AM   #15
Site Supporter
Site Supporter
ffking's Avatar

Join Date: Nov 2015
Location: Poole
Posts: 4,114
I think we can all safely conclude that focus breathing and other such phenomena have more to do with the laws of physics and the trade-offs necessary in lens design than the competence of a given lens designer or company?
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!
200mm, 70-200, 70-200 f/2.8, dfa 70-200, dfa 70-200 f/2.8, distance, f/2.8, f/2.8 focus, focus, focus breathing, k-mount, min, nikkor, pentax, pentax lens, slr lens, tamron
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
FA 28-70/2.8 vs DFA 24-70/2.8? iht Pentax SLR Lens Discussion 44 12-24-2018 07:45 AM
Pentax DFA* 70-200 F/2.8 got delayed G.E.Zekai Pentax SLR Lens Discussion 4 06-17-2015 02:06 PM
For Sale - Sold: DA15*f/4, Tamron 70-200 f/2.8 - REDUCED AGAIN! Archaeologyag Sold Items 6 05-05-2015 02:14 PM
100-300mm f/4 or 70-200 f/2.8 + 2x TC BrianGriffin13 Pentax SLR Lens Discussion 10 05-15-2014 08:46 PM
Tamron 70-200 f/2.8 auto focus question stanjo Pentax SLR Lens Discussion 30 12-31-2009 07:51 AM



All times are GMT -7. The time now is 02:18 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