DFA 70-200 f/2.8 Focus breathing

G.E.Zekai · 03-05-2016, 12:16 PM

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 ^_^

Imp · 03-05-2016, 12:22 PM

It's like that for the DA* 60-250, but I have no clue about the new DFA. Kenspo?

**wtlwdwgn** · 03-05-2016, 12:29 PM

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.

You Tube

G.E.Zekai · 03-05-2016, 12:33 PM

Originally posted by wtlwdwgn

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)

kenspo · 03-05-2016, 02:53 PM - **1 Like**

Originally posted by Imp

I have no clue about the new DFA. Kenspo?

Sorry, i have no clue either. Will check this when i can.

stevebrot · 03-05-2016, 03:29 PM

Originally posted by G.E.Zekai

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

stevebrot · 03-05-2016, 03:32 PM

Originally posted by G.E.Zekai

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

G.E.Zekai · 03-05-2016, 05:25 PM

Originally posted by stevebrot

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 ?

Shodra · 03-05-2016, 06:20 PM

Originally posted by G.E.Zekai

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.

**UncleVanya** · 03-05-2016, 09:47 PM

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.

**Digitalis** · 03-05-2016, 10:20 PM

Originally posted by wtlwdwgn

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.

pdo · 03-07-2016, 09:00 AM - **1 Like**

Youtu.be

Here's an excellent video on focus breathing on. Skip to 5 mins if you don't want to watch the whole video..

normhead · 03-07-2016, 09:14 AM

Originally posted by G.E.Zekai

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.

Kath · 03-22-2016, 10:57 AM

Originally posted by pdo

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.

**ffking** · 03-22-2016, 11:22 AM

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?

03-05-2016, 12:16 PM	#1
G.E.Zekai Senior Member 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, 03:29 PM	#6
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by G.E.Zekai 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, 10:20 PM	#11
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by wtlwdwgn 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.

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03-05-2016, 12:22 PM	#2
Imp Pentaxian Join Date: Nov 2014 Location: Washington, DC Photos: Gallery \| Albums Posts: 1,749	It's like that for the DA* 60-250, but I have no clue about the new DFA. Kenspo?

03-05-2016, 12:33 PM	#4
G.E.Zekai Senior Member Join Date: Jul 2014 Photos: Albums Posts: 199 Original Poster	Originally posted by wtlwdwgn 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
kenspo Veteran Member Join Date: Mar 2014 Location: Oslo Posts: 2,207	Originally posted by Imp I have no clue about the new DFA. Kenspo? Sorry, i have no clue either. Will check this when i can.

03-05-2016, 03:32 PM	#7
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by G.E.Zekai 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
G.E.Zekai Senior Member Join Date: Jul 2014 Photos: Albums Posts: 199 Original Poster	Originally posted by stevebrot 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
Shodra New Member Join Date: Dec 2014 Posts: 8	Originally posted by G.E.Zekai 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
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,454	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.

03-07-2016, 09:14 AM	#13
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	Originally posted by G.E.Zekai 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
Kath Site Supporter Join Date: Jan 2014 Location: Portland, OR Photos: Gallery Posts: 737	Originally posted by pdo 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
ffking Site Supporter Join Date: Nov 2015 Location: Old South Wales Posts: 6,039	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?