[Serkevan]

It's funny thing this focus breathing. Extending the lens in and out while focusing inhales and exhales air, which is actually real breathing and will lead to dust getting sucked into and collected in the lens. Internal focus largely neutralizes this behaviour.

Dust is a non-issue.
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Also, if a fly can get in the middle of an internal-focus, internal-zoom lens, so can dust. And in general, modern lenses include dust filters, which would work well for years unless your entire portfolio is taken inside a flour mill.
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I agree with the rest of the post mostly - focus breathing is only an issue in so far as it reduces magnification, when that's something one wants. For normal stills, eh. No big deal.

---------- Post added 09-24-20 at 08:13 AM ----------

In a lot of professional photography work, there is a physical line (barrier) that a photographer cannot cross.
Example: You're a photographer at a music performance. The barrier would be the end of the stage, or a designated photographer area.
If your taking pictures with a 70-200 breathing lens next to a competitor who is using a 70-200 lens that does not breath, and you both try to sell your images, there will be noticeable differences between the two focal lengths of the two salable images. This focal difference may be the deciding factor for a client to purchase one image over the other.

In most hobbyist/enthusiast situations, sure breathing might not matter at all. You can just take a couple steps forward.

The effect is most pronounced near minimum focus distance, so in those situations it won't necessarily be an issue unless we're talking real exaggerated examples - and if you knew in advance (like a professional would, I guess?) then you'd know to bring a longer lens!

[FozzFoster]

Are you still looking for some "public lashing" or is this a serious discussion?

I know it's a hot topic - Pentax fans will ardently defend every aspect it seems.
Example: It seems one could say 'Pentax AF isn't that fast' and you'll get a choir of fans saying that 'AF isn't a concern and manual focus is the best thing in the world'...

I sorta feel like that's the same with Pentax 70-200.
A pro wedding go-to lens; and yes, a barrier exists at weddings - you can't get up on stage/podium or even get too close because you'll block the view and upset the people gathered to watch.

nah - if I see a problem with Pentax I don't have a problem talking about it. I'd rather fully understand the limitations rather than trying to sweep the problems under the rug.

And to circle back -- why would it be so wrong for Pentax to try and correct a known problem with their 70-200?
Someone asked "why would they need yet another 70-200?" and it could be conceivable that they wanted to tackle the breathing problem.

[Serkevan]

A pro wedding go-to lens; and yes, a barrier exists at weddings - you can't get up on stage/podium or even get too close because you'll block the view and upset the people gathered to watch.

As funny aside: the last wedding I attended (in India, for reference) had 4-5 photographers making such a barrier around the couple at all times. I was taking photos from a vantage point just to chimp and see the ceremony

[MMVIII]

No, I just don't agree with that take. That is just too simple.

I quoted someone out of the "Pentax-world" who claimed that it would not be a real problem for most use.

I assume you understand what your staged scenario would mean in worst case? If your subject is at the minimum focussing distance and you think the FOV is not narrow enough, then you can zoom in. If this happens at the longest focal setting of 200mm and your subject is really at the close focus distance of 1.2m the worst thing would be that you end up with a 36 Mp image where you have a slightly wider image than with a 3-times more expensive lens that gives up on some other qualities because it is optimised for minimal focus breathing.

There are scenarios where focus breathing might play a role, I pointed them out, but mainly this is something videographers are concerned about.
Could it be that in the Pentax camp this is just not a large groupafter all?

I know it's a hot topic - Pentax fans will ardently defend every aspect it seems.
Example: It seems one could say 'Pentax AF isn't that fast' and you'll get a choir of fans saying that 'AF isn't a concern and manual focus is the best thing in the world'...

I sorta feel like that's the same with Pentax 70-200.
A pro wedding go-to lens; and yes, a barrier exists at weddings - you can't get up on stage/podium or even get too close because you'll block the view and upset the people gathered to watch.

nah - if I see a problem with Pentax I don't have a problem talking about it. I'd rather fully understand the limitations rather than trying to sweep the problems under the rug.

And to circle back -- why would it be so wrong for Pentax to try and correct a known problem with their 70-200?
Someone asked "why would they need yet another 70-200?" and it could be conceivable that they wanted to tackle the breathing problem.

[normhead]

I guess all the other brands and lots of pro photographers are just nuttzos and they are all trying to solve a problem that doesn't matter........

You have to love this site. You propose a technical explanation, you get a non-technical answer based on popular perception. I'd put up some technical diagrams, but, I'm not getting paid for this.

Bottom line, it doesn't matter to me whether or not you understand, but, I'd appreciate responses in kind. As in when I propose a notion based on my knowledge of lens design and function, the response be either in kind, or not at all. Anecdotal evidence is the start of an investigation, but it's a long way from the end.

I base my observations on using the F-70-210 and DA* 60-250. What lenses are these "pros" basing theirs on? At least give me that much. There is a very good chance that they could nullify the loss of magnification by using image scaling software to enlarge the image to achieve the same result in the "focus breathing" lens. Maybe suggest it to some of those guys who complain about focus breathing and see what they come up with.

My suggestion being that the native resolution of the lens is spread over a wider and wider area as the front lens element moves forward. By keeping the element in the same place and moving the inner elements, you should be able to maintain the same resolution throughout the focussing process.

[FozzFoster]

than with a 3-times more expensive lens that gives up on some other qualities because it is optimised for minimal focus breathing.

Since other brands have R&D'd a lens that is 3x more expensive to compensate for breathing... and it sells... clearly this breathing problem takes more consideration than you are giving it credit for.

not be a real problem for most use.

I think therein lies the issue. 'Most case uses' are not what camera companies are gearing towards, it seems.
They are specializing equipment for the pro photographer - think the 50mm and 85mm that were just released. 'Most case uses' don't warrant a $2500 85mm lens.
It would seem to me that the 70-200 and 70-210 are nearly flawless, but the public feedback is that they breath.
So, it would make sense for Pentax, gearing toward the pro shooter, to try and mitigate that negative public feedback.

---------- Post added 09-24-20 at 09:52 AM ----------

you get a non-technical answer based on popular perception.

Sorry normhead I didn't mean to be terse. And I am far from technical so I can't really meet you there.
But there is clearly a market demand for non-breathing lenses - popular perception correct or not.

[pres589]

An even better D-FA*70-200 would be a very surprising turn of events from my cheap seat but perhaps it's something they feel would sell, get good attention to the system, and further establish Pentax as a premier camera brand.

I would be curious what an 18-100 f2.8 lens would be like to use. Seems like a clear step up from my 18-135... It would probably be more than 2x the physical size.

Where's the patent for the high-perf 28mm that was talked about over the past year??

[normhead]

Since other brands have R&D'd a lens that is 3x more expensive to compensate for breathing... and it sells... clearly this breathing problem takes more consideration than you are giving it credit for.

That would be in line with my expectations. I never said it couldn't be done. I said focus breathing was the best technical solution. It doesn't surprise me at all that people would go through technical gymnastics to solve a problem, that isn't a problem, in most circumstances.

Focus breathing for zoom lenses is only relevant when you can't zoom in enough to compensate for focus breathing. SO, not relevant in every circumstance. With my DA*60-250, if I need 135mm or less I can zoom in to 250mm or less, and get the framing I'm after. so limiting focus breathing is really only relevant at full reach, for other circumstances you can at least partially compensate. If I need better than I can get, I change lenses, just like any other time. Paying 3x the amount for a lens to me is just stupid unless you have income coming in to cover the cost of the expenditure. After all, I can use my DA*200 with the 1.4 or 1.7 to achieve breathing free images if I desire. And I can buy all of them and have 200 2.8 for the same money as paying 3x for a lens that doesn't breath. So while there may be demand for such lenses, the circumstances for which they are needed needs to be defined. I doubt it's relevant to most of us. I'd be fine with no focus breathing, when it can be produced for the same price. Why not? You expect to pay more for more magnification. Personally, I put my 1.4 ( or 1.7) TC on my DA*60-250, problem solved. If that isn't good enough, I put the 1.4 or 1.7 on my 300 2.8. Problem solved.

But I agree, if you just want to throw money at it, buy a 3x as expensive lens. I prefer my own solutions for the same problem that don't involve new glass, so no it is not imperative to spend that much. There are other solutions.

Don't like the focus breathing on a DA*60-250, use the DFA 100 macro with a 2x TC. You get a lot more magnification at close to the same field of view at nowhere near 3x the price. Or the 200 2.8 with the 1.4.

[FozzFoster]

What lenses are these "pros" basing theirs on? At least give me that much.

With a quick google search Nikon released their 70-200 f/2.8 E FL ED VR which is, apparently, tack sharp and does not breath compared to the predecessor 70-200 f/2.8 G VR II.
Also breathing just isn't restricted on the short end, it can be on the long end too. The Nikon 70-200 G was laughed at because on the long end it appeared closer to a 120mm rather than a 200mm.
Nikon heard the laugh and mitigated the issue on future releases.

I've heard similar Canon stories too.

[kokol]

After a tack sharp 11-18 f/2.8 and a tack sharp 16-50/f.28, which always felt too short, I am really curious to see what an 18-100 f/2.8 would look like. It could be a fantastic astrophotography lens! Though "probably" bulkier and pricier than the 18-135...

[MMVIII]

Sorry normhead I didn't mean to be terse. And I am far from technical so I can't really meet you there.
But there is clearly a market demand for non-breathing lenses - popular perception correct or not.

There are always good reasons the 70-200 range could get another contestant. But seriously, this - if you think I dont give this "issue enough credit" - are the words of Tony Northrup:
"Focus breathing isn’t typically a problem for photographers. However, it can be an issue with some professional videography."

So you are basically saying that Pentax should, after all, produce a cine lens, just because there was a video of a guy who showed an "issue", that actually exists in any system and systems that want to attract videographers beside photographers are taking care of that, even if they have to compromise on other aspects, but it would help with public perception?

This leaves me breathless ;-)

[FozzFoster]

This leaves me breathless ;-)

Nice one

"Focus breathing isn’t typically a problem for photographers. However, it can be an issue with some professional videography."

I entirely agree that a regular photographer would probably not notice this issue. And I entirely agree that a regular videographer would probably notice this issue more easily.

But I am trying to argue from the not-so-regular shooter perspective. (I am not claiming that I am pro, but rather trying to see it from their POV)
The photo industry seems to be gearing towards a not-so-regular shooter who is competing professionally against other photographers with images that are nearly identical - where these sort of 'minor' problems can make or break a sale.

And no, I do not support a cine lenses at all, maybe some could perceive that as an added benefit, but I am arguing the fact that breathing is noticeable in stills too. When compared against a competitor. Pro work.

---------- Post added 09-24-20 at 11:00 AM ----------

Tony Northrup:

Found your reference... but he further states:
"For still photography, however, you can simply adjust your focal length or distance to the subject to get the composition you need".

I am claiming that you are using one lens. a 70-200. and needing a shot at 200mm that looks like 200mm when compared to other shots at 200mm
I am claiming that you have a barrier. a stage in my previous examples.

So, I do not agree with Mr. Northrup that those are the simple adjustments needed to fix all stills photography.


Imagine:
Trying to sell a picture, against a competition of photographers, you're one of many reporters at the White House - Variable focal range is preferred as people walk into the room to take their seats... but then, a close up (needing ~200mm) shot of, say, the Presidents facial expression at a specific moment in a speech!!
The individuals who have lenses with focus breathing problems are like "shoot, guess I gotta lower my camera, exchange my 70-200 for my 300 f/2.8... oh dear Mr. President please hold that expression please!"

Most likely, the individual who used a non-focus breathing lens to take the shot, and got the best close up of that facial expression, is going to make the sale. over the peers.

Just seems silly to ignore that other brands recognized the issue and made efforts to fix it.

[reh321]

When compared against a competitor. Pro work.

Both of our daughters got married in the past two years.
I know for certain that they looked at the work, not at the equipment.
I was surprised that the first 'pro' used only a Nikon 85mm lens - she provided all needed 'zoom' with 'her feet'.
Not how I would have done it - but her customer was happy with the results.
The second 'pro' used a Canon - but I have to admit I noticed neither the model of the body nor of the lens
{she wanted a photo of herself with the bridal party, so she asked "the other photographer" (me) to take it}.

[reh321]

IMHO for stills it doesn't matter.

You just use a lens with a "longer" focal length - if a 70-300mm is actually 250mm at maximum length, use one which claims to reach 500mm {but actually only reaches 430mm}??

[Cynog Ap Brychan]

With regard to focus breathing, I recall a YouTuber who said they could not use Nikon because the standard portrait lens, the 70-200 focus breathed to quite a large degree. At that time, the main Canon portrait camera was the 5d Mark III with 22 Mpx, while NIkon had the 36 Mpx D800. Had he not heard of cropping?