[bscott]

How bad is the focus breathing on the DFA* 70-200 f2.8 ?

[gatorguy]

How bad is the focus breathing on the DFA* 70-200 f2.8 ?

Less than on the Sigma 70-200. I've been meaning to post comparison photos and will try to get to it within the next day or so. Based on what I've personally observed it's not noticeable on the DFA.

[MarkJerling]

None of the user reviews mention it: HD Pentax-D FA* 70-200mm F2.8 ED DC AW Reviews - D FA Zoom Lenses - Pentax Lens Reviews & Lens Database

[gatorguy]

To be honest unless you're doing landscapes or macros and focus stacking I don't think it truly matters.

EDIT: Are you asking that question because of the one review by the Cameraville Guy? I think I remember him saying after-the-fact he determined he had a bad lens. Even then it was a single review whose opinions don't seem to be shared even on DPReview which has a reputation for being tough when it comes to expectations of Pentax gear.

I've owned the Tamron and (still own) Sigma 70-200's and IMO even considering the weight difference I prefer the Pentax DFA

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Last edited by gatorguy; 01-25-2021 at 04:45 PM.

[Paul the Sunman]

As someone who has shot around 8000 images with this lens, I neither notice it nor care. However, if you are thinking of using it as a stand-in macro, look elsewhere.

Here is some beading on a clothes line taken with the K1 about 5 minutes ago at 200 mm and minimum focus distance (about 1.2 m). So that's as close as you'll get.

[stevebrot]

How bad is the focus breathing on the DFA* 70-200 f2.8 ?

What is your specific concern?

All internal focus lenses work by reducing the effective focal length when focusing down from infinity. The most obvious effect for still photography is less magnification for a given subject distance than one would expect from an external/block focus lens at the same distance and nominal focal length. This is not something that most of us will notice unless we are doing a focus pull in video or doing some very involved focus stacking for near/far landscape or macro*. For example, I had been using my Sigma 17-70/2.8-4.0 for over a year before I noticed that what I saw in the viewfinder at 70mm and 1.0m appeared wider than what I knew it should be from experience. I was mildly peeved, but once I figured out was the compromise to allow cool stuff like lightning fast focus I was good with it.

Now if your concern is based on the evaluation of a particular YouTube vlogger, it might be good to review the evidence and if you are seriously uneasy about purchase, find a way to check it out in person either by the grace of a local owner or by renting.


Steve

* Actually, stacking for macro is best done by moving the camera/lens relative to the subject as a unit using a focus rail. One does not want to increase the reproduction ratio (magnification) from one end of the stack to the other.

[bscott]

Thanks for all of your comments. I was thinking of purchasing this lens since I really don't have a quality 70-200 lens. You are correct the Cameraville video did cause me to post this question. I do have a macro and focus rail for focus stacking but I would use this lens for landscaping when possible.

[BROO]

Focus breathing is an issue for videographers as you don't want the frame to change whilst shifting focus.
For stills not so much. In some cases it can be an advantage.
Be careful what YouTubers say. I haven't seen Li from Thecameravile show any professional grade images to date.

[Des]

All internal focus lenses work by reducing the effective focal length when focusing down from infinity. The most obvious effect for still photography is less magnification for a given subject distance than one would expect from an external/block focus lens at the same distance and nominal focal length. This is not something that most of us will notice unless we are doing a focus pull in video or doing some very involved focus stacking for near/far landscape or macro*. For example, I had been using my Sigma 17-70/2.8-4.0 for over a year before I noticed that what I saw in the viewfinder at 70mm and 1.0m appeared wider than what I knew it should be from experience. I was mildly peeved, but once I figured out was the compromise to allow cool stuff like lightning fast focus I was good with it.

Nice succinct description Steve.

There have been a few threads in which people have said that lens A is better than lens B for pseudo macro (ie at or close to the MFD) because lens B has a lot of focus breathing. Common nominees for the lens B category have been the DA 18-135 and the DA 55-300 PLM. The short answer is just to look at the specs: maximum focal length, MFD and maximum magnification. The screwdriven DA-L and DA 55-300mm f4-5.8 models (which are not IF lenses) have a maximum magnification of 0.28x and an MFD of 1.4m. The DA 55-300mm f4.5-6.3 (an IF lens) has a maximum magnification of 0.3x and an MFD of 0.95m. (I once did a field comparison of focus breathing between the DA-L and the PLM: One or the other need help on a 55-300 zoom lens?? - PentaxForums.com) Which is better for pseudo-macro? I'd take the PLM, not only because of the slightly higher magnification, but because the shorter MFD gives more options for framing the subject. True that if you move from 1.4m to 0.95m, the butterfly is more likely to fly off, but it is also more likely that you will be able to get a clear view from closer in. For things that don't fly off and don't bite, 0.95m is much more convenient than 1.4m.

Since the DFA 70-210 f2.8 has a maximum magnification of 0.13x, pseudo macro is rather academic, as Paul suggested. But the thread topic invites wider consideration.

[clackers]

The Cameraville guy again doesn't understand focus breathing.

It's 200mm at infinity, that's how these things are rated, it's not the closer you are to the subject.

With internal focus designs (such as the WR Pentax) it's inevitable.

[stevebrot]

The Cameraville guy again doesn't understand focus breathing.

Sad, but true. Near as I can tell, he may be conflating it with parfocal.


Steve

[mikesbike]

I have both types of lenses and don't often think about this factor. I never have thought about macro, but I can see how it could make a difference in terms of distance for making the shot. However, being as it comes into play as one closes distance to the subject, there can be other situations where it could make a difference. One example could be in getting a good, impressive rather close shot of a bird or other animal. Perhaps the animal will allow just a moderate distance without being disturbed, then grab shots along during the slow approach before the animal vacates. The non focus-breathing lens might provide larger images. Similarly, if trying to nail some candids of people in a fairly large room, one might be more successful when able to keep better distance.

Other than those special needs and at certain special distances, my IF lenses, as is the case with my DA 18-135mm DC WR lens, are great performers and deliver many keepers.

For those candids, my very favorite lens for that on APS-C is my FA 77mm Ltd. So inconspicuous and effective, and no worries about FB. If needing more reach, the DA 18-135mm is still compact and at distance beyond where the 77mm is effective, that distance will likely be where FB from the DA 18-135mm will be minimal anyway.

[DeKay]

The Cameraville guy again doesn't understand focus breathing.

He's also a YouTuber, so its all about the "click bait".

[Lowell Goudge]

I think the whole issue of focus breathing is largely overblown with zooms. The reality is that you will for the most part, zoom to frame the image you want, and unless you are specifically attempting to duplicate a shot from a prime, with a zoom in all details, you won’t notice.

As the effects of focus breathing is most noticeable at minimum focusing distance, I don’t worry about it. My concern when travelling is to simply have a single lens that can close focus, just in case, If I plan to do close up work, I use one of my macro lenses.

Note, if you want a real example of focus breathing, in the 1980’s sigma made a 135 mm close focusing lens, which had 2 focusing rings, the normal one, and then a second ring that allowed close focusing by changing the focal length to work from I think 1:10 down to 1:2.

Historically the phenomenon was I believed first noticed with the SMC Pentax 28/2.0 with fixed rear element

[bscott]

I just received my new K1ii and FA* 70-200 and I can't wait to go out and do some breathing.