Lens Distortion on the BMPCC

In some of the lens threads here and elsewhere, I've seen others cautioning against lenses like the Panasonic 7-14mm and the Olympus 9-18mm due to the distortion these have and the lack of in-camera correction that you would get with a Panasonic or Olympus camera.

However, although it's always great to have a lens that is as pure and distortion-free as possible, isn't this essentially a non-issue? When shooting RAW, can't you just perform the lens correction in, say, Lightroom on the raw image data and come out with an image that is just as good if not better than what you would get with any in-camera correction?

I understand that ProRes might be a bit harder to correct, so if anyone has any tips on the best workflow to correct for lens distortion with ProRes, that would be great.

Bottom line: I need an ultra-wide option on the BMPCC that is comparable to the Tokina 11-16mm (@11mm) on an APS-C sensor. The Panasonic 7-14 seems to be the best option, although others have said that it has too much distortion that isn't corrected. However, I fail to see why you couldn't just correct that in Lightroom. Am I right?

P.S. The only other decent option <9mm that I've found is this bad boy, but I'm not about to drop $9k on a lens for a $1k camera:

We have some Illumina lenses at school for our ArriFlex cameras:
https://www.samys.com/p/All-Products//I ... 6DB93EA7E0

Their image quality is quite good.

Thanks, that's another option that I didn't know about. Do you know if it comes in a 6mm variety? Doing the math, a 6mm on the pocket camera (100.07° diagonal FOV) is closer to the Tokina 11-16 on a 600D (98.63°) than an 8mm (83.66°). For reference 7mm would be a 91.29° diagonal FOV.

The distortion correction in Lightroom might work (if they have a profile for that lens, it is complex distortion rather than simple barrel distortion) but you are working with a much lower resolution image (1920px wide) that a still from the Panasonic or Olympus (>3500px wide) camera that the tool was designed for. So you may loose more resolution in the process as Lightroom stretches the image to remove the distortion.

That's not to say it can't be used just that your image might become a little softer in the process.

For ProRes you convert the file to an image sequence tho the latest version of Lightroom might actually support distortion correction on video files (not tested it).

Other options for wide:
1) Tokina 11-16 with a Metabones SpeedBooster. That would give you 7.8-11.3mm which on the BMPCC would give you a similar FOV as a 22.4-32 on a Full Frame DSLR.
2) Sigma 8-16 with a Metabones SpeedBooster. That would give you 5.7-11.3mm which on the BMPCC would give you a similar FOV as a 16.3-32 on a Full Frame DSLR.

Both with less distortion, sharper and brighter.

Thanks, that's another option that I didn't know about. Do you know if it comes in a 6mm variety? Doing the math, a 6mm on the pocket camera (100.07° diagonal FOV) is closer to the Tokina 11-16 on a 600D (98.63°) than an 8mm (83.66°). For reference 7mm would be a 91.29° diagonal FOV.

I don't know if there is a wider lens than that available. We were using it on an ArriFlex 16mm (not super 16), and even on that its field of view was huge. Having used it I'm pretty certain that it's about as wide as I'll ever need to go for the vast majority of my work, but so far even the 12mm has been serving me extremely well.

I would like to get an 8mm lens sometime, though I'm undecided between the Illumina and the Tamron zoom lens. I'll get one eventually I suppose, but it's not critical. I might instead just get a PL mount and use the school's lenses for a while.

Other options for wide:
1) Tokina 11-16 with a Metabones SpeedBooster. That would give you 7.8-11.3mm which on the BMPCC would give you a similar FOV as a 22.4-32 on a Full Frame DSLR.
2) Sigma 11-16 with a Metabones SpeedBooster. That would give you 5.7-11.3mm which on the BMPCC would give you a similar FOV as a 16.3-32 on a Full Frame DSLR.

Both with less distortion, sharper and brighter.

I believe you meant the Sigma 8-16, but yes, I've thought about these options as well. I already own the Tokina, but the EF-S variety, and since I also own a 600D (for video and stills), I don't really want to have to buy the lens again in Nikon F/G format.

Meanwhile the Canon EF to MFT Speedbooster seems to be on indefinite hold, and since it's an EF and not EF-S speedbooster, I'm not sure if the Tokina would even work with it.

Which was why I was hoping to find a good native MFT or affordable adaptable PL lens for an ultrawide option on the Pocket.

Also, for reference, there is a Zeiss 6mm T1.3 Ultra 16, but I can't find it for sale currently (likely to be just as expensive as the 8mm).

EDIT: Does anyone have any data on the distortion for the Panny 7-14 or Olympus 9-18? E.g. uncorrected photo samples or metrics? I would like to know how bad the distortion really is. Thanks!

I believe you meant the Sigma 8-16

Yeah. Sorry. Fixed.

but yes, I've thought about these options as well. I already own the Tokina, but the EF-S variety, and since I also own a 600D (for video and stills), I don't really want to have to buy the lens again in Nikon F/G format.

Makes sense.

Meanwhile the Canon EF to MFT Speedbooster seems to be on indefinite hold, and since it's an EF and not EF-S speedbooster, I'm not sure if the Tokina would even work with it.

When it does come (a lot of electronic info to reverse engineer) I'm pretty sure the EF-S lens will work on the BMPCC.

Which was why I was hoping to find a good native MFT or affordable adaptable PL lens for an ultrawide option on the Pocket.

PL ultra wides ain't cheap tho. Probably cheaper to buy a Nikon Tokina 11-16 and a speed booster.

We need to see some test footage with the wide Panasonic

Photozone is always showing the uncorrected distortion too in their reviews.

They have both the 12-35mm 2.8 Panny and the 7-14mm 4.0 tested. Judging from that, it is quite massive.

It's not really the cameras fault.

Lens makers are cheating by having the camera do the corrections they used to do optically. of course the advantage is that it makes it MUCH cheaper to make these extreme lenses, but the down side for motion is that the corrections don't apply.

There is a reason you get what you pay for...especially with lenses.

(i'm pretty sure the dSLR's like the GH also don't apply correction in their video either...)

jb

We need to see some test footage with the wide Panasonic

Just found this...

woodybrando July 27
Ok just posted it to my google+ I think the jello effect is exaggerated by the gh3 I shot it on.

https://docs.google.com/file/d/0B-J8MGO ... sp=sharing

(via personal-view.com)

Photozone is always showing the uncorrected distortion too in their reviews.

They have both the 12-35mm 2.8 Panny and the 7-14mm 4.0 tested. Judging from that, it is quite massive.

Bear in mind that the Pocket CCs sensor is rather small, so it "cuts" out only the middle portion of the image circle. You don't need to worry about distortion in the outer parts of the image, only in the (enlarged) center.

The distortions are proportional, so the enlargement of the center crop enlarges them as well. I'd say their percentage is constant.

@ JB
I wouldn't call it cheating, since all classic lenses are a compromise between different parameters, like sharpness, chromatic (and other) aberrations, speed, distortions and so on. Optimization of one factor is quite often pulling other factors down.

If you can correct some of them electronically (which is done in real-time even for video in cameras like the GH2), you ca go further with those you can only control optically. A lens like the 12-35mm 2.8 from Panasonic would be very hard to do the traditional way, even at a higher price.

OTOH, for a smaller image circle you can make quite good lenses with less effort, that's why I'm always suggesting wide lenses calculated for S-16 or one inch. They are generally much faster for the same angle.

The distortions are proportional, so the enlargement of the center crop enlarges them as well. I'd say their percentage is constant.

I don't think so, because most of it comes from the projection of a spherical image onto a flat sensor, and the distance between a flat plane and a spherical surface grows faster than linear. Still i may be wrong, and it's just wishfull thinking... we'll see in a few weeks, when the Pocket CCs reach the public.

Also, for reference, there is a Zeiss 6mm T1.3 Ultra 16, but I can't find it for sale currently (likely to be just as expensive as the 8mm).

EDIT: Does anyone have any data on the distortion for the Panny 7-14 or Olympus 9-18? E.g. uncorrected photo samples or metrics? I would like to know how bad the distortion really is. Thanks!

Erik, look on the German site for Photozone. They will show you the distortion charts for those wide lenses with correction in-camera and without correction. The sample photos aren't usually helpful but the chart is. Just remember they use charts that are for the true micro four-thirds sensor so the distortion won't be quite as bad on the edges as they show. Even with correction, some of these Panasonic and Olympus lenses can have significant distortion that might concern you or not depending upon what you are shooting and what is acceptable.

I've never had personal experience with their micro four-thirds cameras or lenses but after looking at many lenses in Photozone, I'm not enthusiastic about their performance. There are other sites that also do a great job of reviewing those lenses in their uncorrected format such as Lens Tip. You may not be concerned at all if you are primarily shooting landscapes or people, but definitely not the best choice for architecture or interiors with build lines near the edge of your frame. I think John Brawley is quite happy using some wide Panasonic lenses on the BMPCC as illustrated in his sample footage. So they are fine for some purposes. I think I'd prefer to put a prime like the SLR Magic 12mm T1.6 on the BMPCC for wide, but that may not be wide enough for some needs, hence the appeal of these Panasonic wide zooms.

Rick Lang
Sent from my iPad using Tapatalk HD

There is a reason you get what you pay for...especially with lenses.

John, have you by chance tried the Panasonic 7-14 on the Pocket? I know you've used the SLR Magic 12mm, which looks very nice, but I would consider that "wide" (61.6° diagonal) when I really am looking for an "ultrawide" option.

Just found this...

Thanks. FOV looks great but we'll need some actual footage before we can tell how the image quality/distortion is.

OTOH, for a smaller image circle you can make quite good lenses with less effort, that's why I'm always suggesting wide lenses calculated for S-16 or one inch. They are generally much faster for the same angle.

Any specific suggestions? The C-mount lens thread at EOSHD doesn't look promising; almost all the lenses <10mm have problems and even if they cover they look awful.

I don't know if there is a wider lens than that available. We were using it on an ArriFlex 16mm (not super 16), and even on that its field of view was huge. Having used it I'm pretty certain that it's about as wide as I'll ever need to go for the vast majority of my work, but so far even the 12mm has been serving me extremely well.

Yeah, 8mm would probably wide enough for 95% of what I would want to shoot, but I'm a sucker for ultrawides and sometimes you just want that extremely wide image. Here are two frames from a music video I shot with the Tokina 11-16 on a 600D.




If I could get something that wide on the BMPCC I would be a very happy man.

Erik, look on the German site for Photozone.

Thanks. I did, and although it looks like it isn't much more than simple barrel distortion, it is pretty severe.

John, have you by chance tried the Panasonic 7-14 on the Pocket?

In his second video ("pocket in kurnel", in his blog article "shooting from the hip pocket") there are some shots taken with the 14-42 panasonic lens that have the sea horizon in them - even at 14 mm there quite a nasty amount of distortion, i don't want to think about what we'll see from the 7-14 panasonic, or the 9-18 olympus! (actually i won't think about it, yet test it myself once that elusive camera finds its way to europe...).

Could always try a 0.7 wide angle converter on a prime like the SLRMagic.

Been done for years on 2/3" cameras with pretty good results.

Could always try a 0.7 wide angle converter on a prime like the SLRMagic.

Been done for years on 2/3" cameras with pretty good results.

I find it hard to believe a wide-angle converter on top of another lens would have less distortion/vignetting/etc. than a native wide lens like the Panasonic 7-14, but maybe I'm wrong.

Do you have a link to such a product that would work on the SLRMagic?