Home Photography Focus Breathing: TEST & FIX IT

Focus Breathing: TEST & FIX IT

Advertisement canpers.com

Your lens might not be the focal length you think it is… Your 200mm lens might only be 135mm! Your 70mm lens might be 45mm! In this video, I’ll show you why …


Facebook Comments
Advertisement canpers.com


  1. Take this HEAVILY into consideration if you ever want to look at a superzoom. The new Tamron 18-400mm appears to be TERRIBLE in regards to this, and that is SO IMPORTANT since it is advertised as a MACRO lens. C'mon Tamron, be honest with the shortcomings of your new $600+ lens.

  2. Great video. Only I thought "focus breathing" means that the focused lens goes out of focus when you zoom in or out. When shooting a video in autofocus mode and zooming in or out you then get the effect that the picture becomes shortly defocused and then focused again. This gives the "breathing" effect, hence the name. (Many lenses do that, esp. when designed for stills, not videos, but some don't.) Am I wrong?

  3. Do macro lenses suffer less or more from this or is it irrelevant? I use a DX Tamron 18-200mm f3.5-5.6 Macro lens and I have noticed it looks more like 135mm when shooting >=170mm up close and I mean it won't make the slightest difference between 170mm and 200mm, it's like it caps there. For landscapes no such issues.

  4. Focus breathing? You find the same smoke and mirrors in binoculars, where the "field of view" is always different–in FIXED power binocs with supposedly identical objective lenses and powers. And no one will explain it.

  5. extension tubes don't fix focus breathing. They fix it the same way cropping the image would fix it. Essentially what you are doing is putting the lens further away so the image circle is bigger. Your sensor would now only line up with the inner parts of the image circle and thus you are throwing away light. Cropping the image would essentially do the same thing. Its like using a teleconverter.

    You should just buy a lens that doesn't focus breathe if you really cared that much. The Sony 70-200 GM has the lowest focus breathing of any 70-200 lens because of its dual focus group with dual focus motor design.

  6. a question:
    i thought the focal length of the lens was the distance between the lens and the image sensor when the subject is in focus.

    But that would mean (in the example of the first camera lens shown in the video), that the focal length is increasing drastically when focusing to a close subject?!
    but that isn´t happening (or is it?)?????

    if it does, that would also mean, that the f number would increase and the picture would be less bright when focusing closer. And i don´t think changing the focus has ever changed my exposure.
    would be cool if someone could help me out here!!

  7. Tony, according to my tests Tamron 70-200 G2 is around 150mm at the closest focusing (not 130-135mm as you mentioned).
    Here are the tests I did a while back:
    – Closest focusing set at "200mm": https://www.flickr.com/photos/93201726@N03/32896183890/in/dateposted-public/
    – Infinity focus with exact same framing at 150mm: https://www.flickr.com/photos/93201726@N03/32896182570/in/dateposted-public/
    – Here is what you are actually looking at: https://www.flickr.com/photos/93201726@N03/32896184520/in/dateposted-public/

  8. does this phenomenon ever work by increasing magnification of the subject the closer you focus (same issue but in reverse)? I read a review about the 105mm sigma that states the magnification increases by 13% at the closest focusing range from infinity. The closer you are the tighter it crops would actually be okay in my book having less distance to walk. Or would that likely be a mistake by the reviewer?

  9. As an engineer I get this. As u say, why not say? Marketing Sir. They want competition planned their way. Maybe this can work in our advantage. Does a 200 focus to 270? Then you'd have to maybe mark coorrecctly on lens? Happy shooting

  10. Huge thanks for bringing light to this issue. This, along with a few other things, are features that camera and lens makers frustratingly “cheat” us on.

    Luckily big players like yourself advocate for the consumer. I hope more people catch on too.

  11. So they can't just lengthen the lens and give us a little extra length? This sucks, I was going to buy tamron 70 200mm, but want that 150 to 200, if I'm not getting it, forget it. Extra 1000 to nikon.

  12. So am I better served by buying lenses that extend when they zoom? I just bought my first (used) 70-200 Sigma but I guess it's a good thing I mostly shoot landscapes with it.

  13. In fact, I hate they don't tell us a whole lot of pretty important things about lenses, and we must guess or try to try them before buying them… I think we should complain about that.

  14. When referring to the Canon in this video, I'm assuming this is the IS II version, correct? What about the non-IS and the original IS versions? How do they perform in this category? Anyone?

  15. so I remember watching this 2 years ago and thinking, "wow I am certainly not gonna buy the tamron G2" and here I am now realizing that the focus breathing isnt that big of an issue 90% of the time. if I need a 200mm its because I need that extra reach. if I wanna shoot something closer, id probably get a macro lens anyways. Here I am in 2019 buying a tamron g2 because its dirt cheap and nobody cares about focus breathing haha.


    Prime lenses: Yes, focus breathing can impact them.

    Light loss: According to our testing, focusing up-close causes light loss, regardless of whether you use extension tubes. We don't see any light loss in this scenario with extension tubes, presumably because you're not changing the focusing distance.

    For those who've seen Matthew's video where he calculates that the focal length of the Canon is greater than 200mm: I worked closely with Matthew and discovered he had an error in his formula; he measured distance from the sensor rather than the origin of the cone of the field of view. As a result, his math exaggerated the focal length the closer he focused. So; he accurately measured the focal length at infinity at 200mm because his fixed error (a few inches) was insignificant compared to the focusing distance. But up close, the error caused by those few inches becomes more significant. If he had continued to focus closer, the focal length he calculated would have approached infinity.

    The Canon 70-200 f/2.8 is 195-200mm at the long end, whether you're focusing up close or at infinity. But you don't have to take my word for it–just test it with extension tubes, as I describe in this video. If it actually gets longer at close range, then adding extension tubes will make the image *smaller*. BTW, I've never seen a lens that does "reverse focus breathing" thing at close range, and it would require a very odd design to do that. It seems like that concept only exists because of the error in Matthew's formula.

    Some people have seen Matt Granger's excellent review of the new Tamron 70-200 and misinterpreted his results. Matt did a great job of pointing out the severe focus breathing of the new Tamron. The fact that the new Tamron does provide for high magnification (filling the frame for a very tight headshot) is unrelated to focus breathing.

    Magnification determines how big your subject can be in the frame. Focus breathing relates to effective focal length (which in turn controls the compression of facial features and the background) as well as the working distance from your subject (which is critical for weddings and events, where you can't always control the distance).

Leave a Reply