Hey Ray, thanks for your quick answer :-) Yes, up until now i've always used the colour option.

and i have selected a big portion of the green screen as well

@kate-m

Hi Kate.

Then there is not much more you can do within Movie Edit Pro (MEP) as far as I'm aware.

Daylight is seldom perfect despite being even and a higher frame rate does not always mean a shorter exposure time for each frame, so movement within each frame is still possible if you are not able to use a wide aperture. Any shadow no matter how light, cast to the screen is potentially going to give you problems. Professional green screens outside tend to be huge with additional even floodlighting on them and some distance from the performers. Adding additional lighting for the performers and then using ND filters on the cameras to get the correct exposure times. Studios tend to be easier to set up but you need space and very even lighting.

And from the Mr Selfridge outdoor sets.

While there are some video editing packages out there that may do a better job now than there used to be, it still pays to know how to reduce post production work.

@kate-m

Hi,

Can we assume that you played around with the sliders Threshold, Fade range, Antispill?

One test that you can do is to export 1 frame from your video, without the effect, and open the image in something like PaintShop Pro or PhotoShop and try to do the same thing. Zoom in on the subject. Do you see a green tinge around the edge of the subject? If, so, then the problem is at the source.

John CB

@kate-m

Hi Kate.

I'm not sure what third party plugins you have with your version but I just found this alternative in my version.

Not sure which New Blue package it came with though. Magix changes offers so often it's hard to keep up.

[Edit] The pack is New Blue elements three. Here are the rest of the controls.

I've no idea if it is better than the standard offering or not.

Ray.

@kate-m

Hi

. . . .  i can't get rid of the green or grey fringe . . . .

A green fringe is where you would use the Antispill control. If you are getting a grey fringe or areas then if the green screen you are using is not evenly illuminated it will appears as different shades of green, some of which the effect cannot remove totally as the shade is outside the acceptable range - see the image in this comment

The sequence I use for adjustment is:

1. Threshold - adjust until most of the green screen is removed without taking away part of the subject
    
2. Fade range - adjust to fine tune threshold without taking away part of the subject.
    
3. Antispill - adjust to remove residual green in areas where it show through - see this comment for clarity. See the video in this comment for an example of Antispill in use

There are a couple of assumptions:

• the green screen background of uniform colour, and not creased or unevenly lit.
• the Stamp green option is being used.

HTH

John EB
Forum Moderator

Hey Ray,

thanks for all those good new thoughts!

I'll look into ND filters, i haven't heard of them so far :-)

Also i'm just getting used to my camera Sony alpha a7ii. And since i'm filming myself, i have my aperture on at least 8, this way i stay in focus better when i move around a little (i focus the spot i will stand on first by focusing my camera on something as tall as me, so i know i will be in focus).

Thanks for the good pictures, too.

Hey John,

good idea :-)

Would the software gimp also do the trick? If not, i'll see that i get PaintShop Pro or PhotoShop to try it out.

Yes, i have played around with the the sliders Threshold, Fade range, Antispill, but that didn't help enough yet.

Hey Ray,

the New Blue elements three looks really good. I will see that i get it right away, because that has a lot of the features Premiere Pro and Da Vinci Resolve have, that i have seen on tutorials online. I'm psyched :-D

@kate-m

Hi Kate.

When using a DSLR or mirror-less camera that uses interchangeable lenses, using f stops of above f5.6 can increase exposure times in less than bright sunshine. Also when you get above f5.6 on a lot of cheaper zoom lenses you can get coloured fringing around thin or sharp edges such as hair due to diffraction. That would exacerbate any problems when working with a green screen. All my lenses either tend to be prime lenses or constant aperture lenses with a widest setting of f2.8 or wider on the primes. Widest is f1.4. They tend to have much less problems when stopping down but even then I'm not happy going above f4 but really should only effect hair in this instance and not so much hand movement which would be down more to exposure times of the frames.

Ray.

Hey John EB,

thanks for the clarification on the Threshold, Fade range and Antispill, that helps, too.

Is the stamp green better than the stamp color?

Hey Ray,

thank you for all your good detailed information :-)

I'm filming at 1/100 with 50 frames/sec, because i've heard on a green screen tutorial, that that's a good idea. And it has improved things.

The lighting on the green screen and on me (as the subject) outside is nice and even, so i hope i don't need to employ extra lighting. So maybe then i don't need an ND filter, because it just blocks out too much light, is that right? Or how does it help achieve the correct exposure times? (By reducing the f stop which brings in more light maybe?) It actually doesn't get that bright here where i live.

Since i'm filming myself (i have to set one focus point where i will stand) i will experiment to see if i still stay in focus when i go below f8 with my aperture, and i will go under f5.6 to avoid colored fringing, as you have advised, because my hair has also been a challenge.

And for movement (which i do a lot in my video) i could try to decrease the time exposure? I have maybe misunderstood you, because i'm still learning how to use my camera :-) So from 1/100 to how high? It goes up quite high on my sony alpha 7ii (1/8000), so i'm unsure if i should go up to 1/1000 or higher?

I will just fiddle around with the shutter speed and see if things get better :-)

i have a lense from Sony FE 1.8/50

Is that good enough, or would you recommend another one?

Thanks so much :-D !

Kate

@kate-m

Hi Kate.

I'm out to work again in a short while. I will give a much more detailed reply to your questions later this evening, (in around 5 to 6 hours) along with some example pictures. Basically though everything is compromise. Reduce one problem normally causes another. Decreasing the exposure time too much may cause other problems as it would introduce noise if it adjusts the ISO to a higher setting (Hence the need sometimes for more lighting} and may produce a stuttery unnatural looking moving image. Or it may just be under exposed.

Ray.

@kate-m

I don't know the Sony FE 1.8 50mm lens. Still has some chromatic aberration problems when stopped down according to this review.

Look at this review page. You will just have to try it and see. For a prime lens it is still quite cheap so there may be problems.

Ray.

@kate-m

Hi Kate.

The Sony Alpha II is a full frame camera and good at both stills and video. The problem for video is it is it being full frame. Meaning that compared to an APS-C sized sensor (the next sized sensor down for Digital interchangeable lens cameras.) an f2.8 stop on a lens would be the equivalent of an f1.4 stop on the smaller sensor. So you have to stop down any lens you use more than if you used a smaller sensor for video shooting. This is why the Panasonic 4/3rd framed cameras became so popular for video.They have to be stopped down even less to get more depth of field. Stopping down not only gives a greater depth of view but also sharpens edges within the available depth. That in turn means the lens has to be quite high quality to avoid chromatic aberration or (colour fringing) that can change hue depending on the amount of fringing. Also for a given amount of pixels assuming all sensors have the same amount of photo sites (pixels) and are of the same generation sensor, the larger sensor needs less light because each photo-site is larger, and hence shorter exposure time for a given ISO value.

This is where compromise kicks in. You can add more frames per second but the larger sensor will need less exposure time than the smaller one to get the exposure correct. So say for a given amount of light a larger sensor with the same amount of pixel may need half the time a smaller sensor would need to get the same exposure.

All well and good you may think but that means if the exposure only takes a tenth of the time the frame lasts for before the next frame is taken, then sure, the image will be much sharper due to the lack of movement within the frame.But then you have to wait another nine times that amount of time before then next frame is taken. During that time movement will occur that is not recorded. So the next frame could have a 'micro jump' in movement that the eye will pick up on as seeing two images at once. This happens to high speed movement within the frame and can look unnatural in those parts of the frame it occurs in.

Look at the first few seconds of my video below and look at the staffs the people are using to see the effect.

Please view it full frame via YouTube.

If that is not too off-putting then that could be a solution that may help. If on the other hand it looks bad to you (most people don't notice) then you need to prolong the exposure. That can be done either by narrowing down the aperture or using a Neutral density filter (ND Filter). Allowing less light through making the exposure longer but again a good ND filter can be very expensive if you don't want further degradation to the image by adding additional glass to your lens. You could stop down the lens but you need a very good lens. On average my prime lenses start at around £450 and constant aperture zoom lenses about £1,400. That tends to keep them at about the same quality as the sensor is capable of reproducing the images. Even then I tend to avoid going above f8 if I can avoid it. Also bear in mind that on average a wider lens needs less stopping down than a narrower one for the same depth of view.

If you understand hyper focal lengths, that can help a lot with wide apertures vs focal length. Worth looking into.

So even a frame with a high shutter speed can still end up with some edges being fuzzy or blurry or worse still with no definition at all for the chrome key effect to work with.

Even fine hair or a fur edged item can be a challenge to green screen as it will end up being seen as a colour block rather than a separate part within the image.

This gets worse as the shutter speed slows or the exposure time increases.

So as I said. Sometimes it is a compromise. The best results need experience first and an ability to analyze what the problem is. Then perhaps the correct equipment that can get quite expensive for the best results. Even pro green screens and lighting can cost as much as the investment into a camera depending on how invisible a result you need.

There are some programs out there now that use Artificial intelligence that can separate any object from its background when recorded through a camera but they often need very expensive graphics cards to process the information in real time.

Zoom is capable of doing just that but at lower resolutions.

Getting quite good results with less fast motion within the frame is more easy and less expensive to accomplish. Like everything it takes practice.

Ray.

@kate-m

Hi

. . . . And for movement (which i do a lot in my video) i could try to decrease the time exposure? I have maybe misunderstood you, because i'm still learning how to use my camera :-) So from 1/100 to how high? It goes up quite high on my sony alpha 7ii (1/8000), so i'm unsure if i should go up to 1/1000 or higher? . . .

If your movement is as fast as an F1 racing car then using shutter speeds of 1/500 or faster are necessary.

In your case 1/100 sec would, IMO, be plenty fast enough and will allow you to use an aperture of about f8 or higher (f16 in bright sunshine), at an ISO 100. This should eliminate a lot of the colour fringing Ray was referring to.

Ray has mentioned hair, which can be very problematic, if it is loose and/or volumous/flyaway then it is going very difficult to remove the spillover, you may want to try a hair style that reduces loose/flyaway hair, also avoid fine striped or check clothing and avoid wearing anything of a green shade - there are plenty of green screen 'bloopers' on Youtube.

HTH

John EB

Hey Ray,

thank you so much for all your great advice, your clear examples and all those new insights for me :-D !!!

I will go through it deeply, as soon as i find he time in the next few days :-)

Kate

Hey John EB,

good to know, yes, i'm not as fast as a racing car :-D

My Sony alpha a7ii camera only goes down to ISO 200 for video, but that's most likely not an issue. I have a dumb question: What does IMO stand for? I looked on the internet but i couldn't find the right meaning. Sorry, i'm really wet behind the ears when it comes to cameras and filming :-)

Kate

Hey John EB,

yes, my hair is loose and flyaway, which looks good for the characters i'm playing in front of the green screen. But now that you mention it, i may buy a wig to avoid this problem.

@kate-m

IMO = In My Opinion

thanks, got it :-)

@emmrecs @johnebaker @kate-m @browj2

Hi Kate.

I wish it were as simple as to why you suffer fringing more than John would if he tried but it basically boils down to your camera having a much larger sensor than Johns with many more photo sites and the inevitable binning and amalgamating of pixels as your high resolution image gets squashed down to a 4K or lower resolution video image.

Sensor sizes exaggerated for demo purposes.

Any movement of your hair is going to go across many more photo-sites in a given amount of time than on Johns camera. Effectively speeding up the motion by comparison. How that information is then collated, reduced down, and reproduced inside the cameras processing engine may vary greatly. There are also other differences because of sensor size differences such as depth of field for a given aperture and amount of exposure time needed for a given ISO that should not change but may do by up to a third of a stop because your camera is not using a T lens which has much more accurate exposure calibration.

I'm sorry if I'm making this sound more complicated than it first seems but there are many variables at work that none of us can predict, so some of the suggestions here to improve things for you may work or may not.

Fingers crossed but don't be disappointed if results are not as perfect as you would like.

Ray.