EMERGENCY!!! My lens stopped breathing!

Hunter Hampton

Carbonite Member
Ok, well it didnt stop breathing. I just learned how to choke it...

This is a tip that hopefully helps you out when you need to do some sort of rack focus with a lens like mine...

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So the famous cheap Fuji 17x7.6 CAC HD lens... Decent image for the price, but whoa!! it breathes heavier than your old uncle wally who smoked too many cigarettes.

If you are not familar with lens breathing, according to wikipedia...

[lens] Breathing refers to when a lens' optics change the apparent focal length slightly when shifting the mechanical focus. Some (often more expensive) lenses are designed to lessen the degree this effect. Lens breathing does not prevent one from racking focus or following focus with this lens, but it lessens the desirability of any type of focus adjustment, since it noticeably changes the perspective and composition of the shot.
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(the following files are highly compressed and do not reflect the actual image quality of the hpx500, its just to demonstrate the fuji lens breathing)

Here is a demo of the breathing from the fuji 17x7.6 CAC HD lens:
http://www.dvxuser6.com/uploaded/23459/1195861763.mov


Here is a demo of "choking" the fuji 17x7.6 CAC HD Lens in the exact same set-up & focal length:
http://www.dvxuser6.com/uploaded/23459/1195861984.mov

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Did you notice the difference?

I stopped the breathing by simply pulling focus with the macro ring in the back!

Here's how you do it.

1.Set your focus with the lens barrel on your object you plan on racking from/to, that is farthest from the lens.

2. Unlock your macro (you can gaff tape the button back if you want too)

3. Pull focus with the rear macro! (it takes some practice to get it down)



Its that easy and it will make the shots happen when you need that special rack focus! I wish I figured this out sooner!

It even looks like there is room to throw a focus gear around the rear macro ring, if you wanted to put connect a follow focus back there.

I hope this helps you hpx500 users with cheaper lenses.


-Hunter
 
that certainly looks like a good and very useful trick - prob only good for fairly easy racks since I suspect that being precise will be difficult - but great find - thanks for the tip
 
Yeah precision focusing with this method would take some care, but I bet with enough pratice you could easily do it. If my guess was right about gearing the rear macro ring, then you could hook up a follow focus with a drive gear that had a more gentle ratio as well. I like your work by the way! How is the post going on chasing the green?

-Hunter
 
thanks for the kind words. the film is going well. i wil prob be there for cc soon. again thanks for the tip. it wil come in handy im sure
 
Ok, well it didnt stop breathing. I just learned how to choke it...

So the famous cheap Fuji 17x7.6 CAC HD lens... Decent image for the price, but whoa!! it breathes heavier than your old uncle wally who smoked too many cigarettes.

Hunter nice post, Ive been looking at this myself. In my experience pretty much any lense will breathe, the new canons are pretty much the same as the cheap fujinon. The 2/3 inch beast so to speak. However the Fujinon HD Super Cine primes and zoom have got it pretty well sorted.

Its not always possible but sometimes repositioning subjects distance wise, and re framing to match can also help make breathing a little less obvious.
 
Been spearmintin' with Hunters find here and I think it's a usable solution. Not perfect, but better than what I had.

It's kind of hard to control, but if there was a gear available as Hunter suggests, this could be an even better solution.

I have heard others say they have figured out their own work-arounds, I would be very interested in learning more.

Thanks,
Brad
 
I've seen some nice trics being done with image stabilizers to choke breathing.

Far from an optimal solution, but if you have time and software, but not money to buy/rent a good lense, it does the trick.

I would trust this more to post, instead of risking to mess up the rack to avoid the breathing...

Gunleik
 
counterzoom breathing in post, will be the solution right?
Digital zoom in post if you have this option, just a few % zoom in or out. ("I think is new word counterzoom") and you wont see the breathing.
 
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