Breathing of a Sigma 50mm Macro at F2.8

[Mark B.]

A breath test with a Canon 10D, Sigma F2.8 50mm Macro, and no concern for precision. I just wanted to get a general feel for the breathing, not the image quality or anything like that.

The macro ability of the lens isn't shown, because it's so breathy near 1:1 that there's really no point in even looking at those magnifications. Besides, it's hard to find something that will focus at 1:1 but still move out of the way to show objects in the distance. As it is now, the closest object in focus in this animation is probably at 1:2 mag or something like that... didn't look at the scale when I took the picture (see, no concern for precision).

Oh, and you've gotta love how the tree shadows were changing on the fence, making the picture that much more difficult to figure out.

http://www.reduser.net/forum/uploaded/406_1187418880.gif

BTW, IMO, this lens does not have bad breathing. It looks worse than it is because of the last frames, which I think are focusing closer than a non-macro 50mm normally would. If you shoot footage with this lens, you'd probably want to stay at least three feet from your subject to avoid obvious breathing.

[Stephen Williams]

Hi,

Compared with a modern motion picture lens, that breathes badly IMHO, if that does not bother you that's another matter.

Stephen


A breath test with a Canon 10D, Sigma F2.8 50mm Macro, and no concern for precision. I just wanted to get a general feel for the breathing, not the image quality or anything like that.

The macro ability of the lens isn't shown, because it's so breathy near 1:1 that there's really no point in even looking at those magnifications. Besides, it's hard to find something that will focus at 1:1 but still move out of the way to show objects in the distance. As it is now, the closest object in focus in this animation is probably at 1:2 mag or something like that... didn't look at the scale when I took the picture (see, no concern for precision).

Oh, and you've gotta love how the tree shadows were changing on the fence, making the picture that much more difficult to figure out.

http://www.reduser.net/forum/uploaded/406_1187418880.gif

BTW, IMO, this lens does not have bad breathing. It looks worse than it is because of the last frames, which I think are focusing closer than a non-macro 50mm normally would. If you shoot footage with this lens, you'd probably want to stay at least three feet from your subject to avoid obvious breathing.

[Evin Grant]

I'd have to agree that lens breathes pretty bad. But I think Macros will breath more in general because of the nature of their focus throw and design.

[Mark B.]

Doesn't look so bad to me, but maybe that's because I've seen the breathing near macro 1:1. If you saw THAT breathing, whoa, you'd suddenly realize this sequence isn't breathing at all. :turned:

[Stephen Williams]

Hi,

Just the first third of the the pull is fairly noticeable, hopefully the RED primes will be far better than that.

What was the F stop? bokeh is OK, I think Sigma make some good lenses for still cameras.

Stephen

[Jaime Vallés]

Wow, that breathing bothers you guys? I feel it looks fine. Yes, it's definitely there, but I don't think average Joe will ever think there's anything wrong with that shot. I imagine only DPs will look at it and go "eek!"

I've seen TONS of big Hollywood movies with "bad" breathing, and it never bothered me at all. Heck, I didn't even know what breathing WAS until all the threads on using SLR lenses on RED started popping up here.

To me, breathing is almost a non-issue, especially since it can easily be fixed in post if I'm really unhappy with a shot. A far more important issue (for me) is being able to actually focus properly using an SLR lens.

[Mr. Paul White]

To me, breathing is almost a non-issue, especially since it can easily be fixed in post How?... Sacrificing the frame, anyway.

[Jaime Vallés]

How?...
Zoom in or out of the image with keyframes in your NLE. If the breathing is making the image zoom in, compensate in the other direction with a digital resizing. Of course, you have to punch in to the shot a bit in order to have wiggle room, but since we're working with 4K resolution to begin with, it shouldn't make too much of a difference in image quality. Especially not if you're going to end up in 2K or 1080 as a final master.

[Don King]

Zoom in or out of the image with keyframes in your NLE. If the breathing is making the image zoom in, compensate in the other direction with a digital resizing. Of course, you have to punch in to the shot a bit in order to have wiggle room, but since we're working with 4K resolution to begin with, it shouldn't make too much of a difference in image quality. Especially not if you're going to end up in 2K or 1080 as a final master.

I'm not an editor but is this possible at Premiere with Cineform?

[Jaime Vallés]

I'm not an editor but is this possible at Premiere with Cineform?
I can't see why not. Can you digitally zoom in or out of a regular video clip in Premiere? If so, then you're set.

[Mr. Paul White]

Zoom in or out of the image with keyframes in your NLE. If the breathing is making the image zoom in, compensate in the other direction with a digital resizing. Of course, you have to punch in to the shot a bit in order to have wiggle room, but since we're working with 4K resolution to begin with, it shouldn't make too much of a difference in image quality. Especially not if you're going to end up in 2K or 1080 as a final master.


I'm not an editor but is this possible at Premiere with Cineform?


I can't see why not. Can you digitally zoom in or out of a regular video clip in Premiere? If so, then you're set.

If Cineform will provide 4K online editing... If...

[David Newman]

Yes, that will work fine. The RT motion support in CineForm's Prospect will allow real-time playback of your cropped/zoomed sequence.

[Mr. Paul White]

Cropped with no substantial losses? Is it easy to crop/zoom at 4k with no hassles at all? Real time? Online editing at 4k?

I'd surely like to know if you have already a Cineform solution which we can order next October. Including Color Correction/Grading for direct output (film out). Sorry to post here. Maybe it is the wrong thread but since you've been replying myself about my doubts, I hope you can read this and I may have a direct response not just as slightly indication somewhere.

[Stephen Williams]

Zoom in or out of the image with keyframes in your NLE.

Hi Jaime,

I can see it's possible to zoom in, but how can you zoom out?

Stephen

[Jaime Vallés]

Hi Jaime,

I can see it's possible to zoom in, but how can you zoom out?

Stephen

You start by enlarging the image enough in your NLE (say 110%) so that when you zoom out digitally, the end of the zoom leaves you at the 100% size. It will compromise image quality a little bit (how much is yet to be seen), which is why I'd only use it in extreme cases of breathing, but I think it'll come in really handy for some shots.

[Stephen Williams]

You start by enlarging the image enough in your NLE (say 110%) so that when you zoom out digitally, the end of the zoom leaves you at the 100% size. It will compromise image quality a little bit (how much is yet to be seen), which is why I'd only use it in extreme cases of breathing, but I think it'll come in really handy for some shots.

Hi,

How do you get a bigger picture than you shot? If you enlarge the image before you start the framing won't be right.

Stephen

[Jaime Vallés]

If you enlarge the image before you start the framing won't be right.
That's exactly right. What you'd have to do is take this into account when shooting. If you're using a lens that breathes heavily and are doing an extreme rack focus, make sure you give yourself a little wiggle room in the framing if you need to zoom into the image in post. It's not a perfect science, but it would help minimize the breathing.

Granted, I'm thinking in terms of narrative feature use. You can set up shots and plan stuff like this well in advance. Run-n-gun or EFP would have a harder time dealing with post work like this, and it's impossible if at the end of the shooting day you have to hand in the tape (Hard Drive?) to your client.

[Stephen Williams]

That's exactly right. What you'd have to do is take this into account when shooting. If you're using a lens that breathes heavily and are doing an extreme rack focus, make sure you give yourself a little wiggle room in the framing if you need to zoom into the image in post. It's not a perfect science, but it would help minimize the breathing.

.

Hi Jaime,

Would it not be simpler, cheaper & of better final quality to rent a lens that did not breathe? As Michael Most would say Just because you can do something does not mean you should"

Stephen

[Jaime Vallés]

Would it not be simpler, cheaper & of better final quality to rent a lens that did not breathe? As Michael Most would say Just because you can do something does not mean you should"
Well of course it would! I'm just saying that if you want to own SLR lenses for RED, breathing shouldn't be too much of a concern.

Not to turn this into another Still vs Cine lens debate, but I personally am going to buy SLR lenses. If I'm in a big production, I'll RENT cine lenses. But I sure as heck won't spend my cash BUYING a cine lens, when an SLR lens gives me almost all the quality for a fraction of the cost.

Regardless, indie filmmaking has always relied on using the available tools in ways never thought of by the makers of those tools. It reminds me of the movie "Collateral". In the making-of section, they talk about how they simulated the Subway exterior with green screen and all sorts of FX. I just kept thinking "man, couldn't they just have simply jumped on a train at 3am and shot the thing and saved a bunch of money in the process?". Just because Hollywood has the money, doesn't mean they should waste it.

[Mark B.]

Hi,

Just the first third of the the pull is fairly noticeable, hopefully the RED primes will be far better than that.

What was the F stop? bokeh is OK, I think Sigma make some good lenses for still cameras.

Stephen

It was set for F2.8, which I figured would produce the most obvious breathing. I probably should have also taken a sequence at F8 for more of a real-world DOF, but I wasn't thinking about all the options when I was doing the shots.

[Stephen Williams]

Hi,

Not sure breathing will be very different. T4 is probably the most used stop outside IMO.

Stephen

[Mark B.]

Hi,

Not sure breathing will be very different. T4 is probably the most used stop outside IMO.

Stephen

Could be f4 is more popular with the video crowd, I wouldn't know because I'm more of a photography guy rather than a video guy. Photographers tend to seek out f8 since it's supposed to be the visual sweet spot for most photo lenses. I'd guess that f8 would be useful for video too, since the slightly deeper depth of field makes focusing a little easier than f4 and still shows some bokeh. Ultimately the decision will probably depend on what kind of light levels are hanging around and the level of separation that's needed in the shot.

I guess breathing might not change much with a change in f-stop, I haven't put much thought into the optics versus iris issue... I suppose they don't really have much to do with one another really, not where framing is concerned. What I did find though is that the shallow depth of field gives a better reference to where the focal point is, making it easier to figure out the focal distance and its relationship to the framing changes.

[Mark B.]

I take it back, I just tried a breath test using a really high dof and it's much easier to figure out than the shallow depth of field. With the dof high, you don't have to guess at where the border objects are located, trying to figure out where the bokeh blob ends and the object might begin. It's just more readily apparent what's going on with everything sharp.

And with that being said, I'm going to have to redo the breath test using a much higher f stop. I'm thinking that the lens is probably breathing worse than I thought.