Hi All - I have mentioned in a few posts about my problem with the EA50 easily blowing highlights but here I can give a clear example - In the first shot the exposure is pretty good and balanced but as soon as the woman's face comes out from the shade of the umbrella I get what looks like (or actually is) banding or posterisation on her facial highlights!

It reminds me of them old 256 indexed colour graphics on old computers. BTW I'm using PP3 unmodified in this shot. Is it a consequence of 8bit video? When highlights popped a bit on my old Z1 it just seemed smoother somehow and more graduated.

Any thoughts or am I just pixel peeping!

you can reduce the "blown-out" effect using a better profile for smoother highlights, and you can use the exposure compensation to tweak auto-iris/auto iso, based on the scene.

as a lot of parts on the image are black/dark gray, its a correct behavior. she was on the shadow, then came to the light. the image should be set around to 1 stop less than that (easily done with the scroll control to adjust EV +/-)

Apparently the FS100 has the same issue

http://www.dvinfo.net/forum/sony-nxcam-nex-fs100/520321-whats-up-those-highlights.html

Pete

Hi Pete

If you take the 2nd pic and blow it up 400% you can see that the posterisation on her face very clearly simply because PP3 profile does lift detail from shadows and you will get a bit of overexposure on bright light. Probably something like PP4 is a better bet as PP3 works for me indoors very well as well as in not so bright conditions. What you can do with PP3 is set an EV Value (negative just a tad) and assign that to button 2 (or any other) and that will autoset exposure to under-expose when selected.

That's why her face is "blown" a bit ... If you increase saturation however it exposes quite well.

Now, the posterisation is caused according to the experts is shooting in 50P ...It is said that 50P needs a bitrate of at least 50mbps not to do this on highlights and the EA-50 shoots at 28mbps at best. However if you expose correctly it won't happen and it tends to show up mainly on cheekbones and faces that are over exposed. It doesn't happen to me at all now cos I shoot in 50i not P ... I used to get terrible artifacts on closeups that were well lit on bridal party faces when shooting in 50P .... check the guys head..it's also a bit over the top BUT no posterisation on his bald bit at all. If you zoom the pic to 800% the lady's face is badly pixelated yet the guys bald patch is fine.

If you insist in shooting in progressive then watch your highlights carefully or change the PP3 profile or expose under a bit.

Personally the bride will never see it so yes, you are pixel peeping but the above is the reason why it does that. I wouldn't worry about it .... I cannot be bothered with progressive and trying to keep my shutter at 1/100th at 50P ...shooting interlaced I can rev the shutter to 1/600th without any issues and I really don't have time to micro-adjust stuff when I have bridesmaids tumbling out the limo!!

Chris

Chris that explains why I never had this issue with my Z1 as I shot interlaced!

Another example from the same shoot - well exposed but as soon as the tog's hand comes out of the shade (not even into the sunlight as it was overcast) - completely blown out! It is causing me an issue i need to address!

This can be easily fixed (the blown out area) in Adobe Premiere Pro using the Shadow/highlight filter.

Hi Pete

For purely the exposure issue I would copy the settings of PP3 into PP2 so you have two identical profiles (PP2 is for stills so I don't use it) ... Then lift the colour level on your new PP2 up two points. Finally set Knee to manual and set at 100% and leave the ramp at default. What this will do is compress any highlights in the image. You would have to try this before doing a wedding though as manual knee can be set from 75% to 105% and you have to decide where in the range suits you. If you push the knee level too much the image might look "plastic" ... which it will at 105% ... You might need to drop below 100% to avoid the artificial look so try shots at maybe 100%, 95% and 90% knee and see which looks best.

Set up a scene with something very bright white in the picture around duller objects ...maybe a white football in the garden so the camera will tend to over expose the light image and then shoot a bit on PP3 (as a reference) and then PP2 with the knee at 100, 95 and 90

Yeah I went back to 50i for weddings very quickly!!

Chris

Cheers Chris - It's a nice sunny day here so I'm going to spend an hour trying it out

Pete

Great Pete

Let us know the results ... according to Alastair Chapman (I think) if you set the knee manually too high the picture looks like it has been wrapped in clingwrap so I would suspect that setting the knee to 105% might give unwanted effects! Likewise 75% simply does nothing to compress the highlights.

Just for interest maybe shoot a few similar clips in 50i and see if the camera smooths highlights like your Z1??

Chris

Simple. Turn off your silly consumer orientated 'picture profiles'. (Audiophiles bypass tone controls on High Quality audio ampifiers - same thing) Set your 'Zebra' to 100% and NEVER see them!

PS: shooting 50i is a good idea. Conform to 25P with a professional transcoder, edit 25P and you'll be set.

Hi Craig

Exactly what I do but if you set the profiles to "off" the saturation goes crazy on indoor shots! Way too much saturation once you get indoors .... Most audiophiles prefer a flat response for audio right?? The flattest profile as far as I can see is the PP3 which conforms to a natural colour tone and ITU709 gamma and in audio terms it seems to me to be the flattest profile of all. I have no idea what "off" sets the camera to but skins tones under lights or indoors look very harsh whilst PP3 seems the most neutral and very easy and natural to boost in post.

I shoot 50i with 100% zebras and edit progressive and have no exposure issues. Even on auto exposure you have a good range of EV settings to compensate if the ceremony background is exceptionally dark or badly backlit and even pushing to EV 1.7+ is bad backlighting my correctly exposed foreground areas are dead even and accurate (of course the bright sky/water is blown out but in those cases you have little option!) It's like an adjustable (+ and -" ) "backlight button like the old camcorders used to have and is an essential tool when stupid brides insist on standing against very bright light!

Funny, a few years ago I was shooting on Panasonic AC-130's also in AVCHD and had the same pixellation issues on faces (especially cheek bones) when using 50P so it doesn't seem to be restricted to one brand so it must be a format restriction or a bitrate restriction. In 50i it never was an issue so I have been doing the edits as progressive and never had any major problem ... Doing it that way you are supposed to have only half the vertical resolution but my eyes have yet to see any difference between the formats despite videophiles (correct word?) insisting that 50P is the only format to shoot in.

Chris

Hi Chris,

Of course my 'reference' is for the Vg20 which (according to my extensive test chart analysis) shoots a 98% perfect colour balance at the tungsten or daylight presets (only 2% colour shift) so for the EA-50, you would be correct. I really urge users to get hold of some test charts, shoot at the various presets and look on their NLE's waveform and vectors to see what is actually going on.

PS: I'm flying to Kyoto, Japan on Sunday for a week's music video shoot and contrary to popular trends, I'll be shooting exclusively in 50i!

Nice Craig

Have a great time and I'm assuming the weather will also be a tad warmer in Japan than in the Blue Mountains in May.. snow must be pretty close to arriving now?

Safe trip

Chris

Well I had an interesting one yesterday - A wedding In the middle of a very dark forest with shafts of hot sunlight - what an exposure nightmare - I was shooting with PP3 (colour level up 2 points) but at 100% zebras It was hard to expose so they never showed - what happened was half the wedding party was in the darkness and the other half in bright sunlight - I kept it so the Zebras just creeped in on the highlights and it's sort of ok but I need to boost the mids in Premiere

I also find without using a profile indoors is way too contrasty and saturated.

Hi Pete

With zebras at 100% (I actually have mine at 90% as well) if you stop down to eliminate all zebras you will definitely be under-exposed. I almost always get zebras on bright sections like sky and it won't ruin the exposure at all. Just ignore those zebras and make sure that faces/skin tones have no zebras and you will be pretty much spot on. Just for interest, did you change the knee setting? My PP3 is currently just like yours with the colour level two points up. I find that it's almost correct for indoor shots but a bit under saturated for outdoor. Most of the time I tend to lift indoor shots just a tad and quite a lot more for outdoor. If you watch the facial skin tones and make sure they don't start turning orange but stay warm the saturation will be pretty close! I'm not sure how the graduations work in Sony Vegas but it goes from zero to 3 (positive and negative) and my indoors are set at 1.166 and outdoor at 1.333.

Did the exposure correction sort out the posterization problem as well??

Chris

Hi Chris - Yes I find 100% Zebras in most situations is the best indicator - at the weekend woodland wedding, the bride was quite often stood in a shaft of light where the rest of the wedding party were in darkness - had I ensured that the white dress was completely free of zebras then the rest of the scene would pretty much be in complete darkness.

I try not to let highlights blow but when faced with such stark contrasts it's pretty impossible not to. The other time when I'm happy to do this is when I have too much sky in shot - I'm happy to let that blow out in favour of getting bride/groom/guests etc correctly exposed.

I did a few tests using manual knee settings - I filmed a white toaster in the sun on dark tarmac (god knows what the neighbours thought) and with standard PP3 there was a nice gradation between the shades but using any manual knee setting the highlight area flattened out! (from 75% to 105%) so I've kept it on auto. To be honest when things such as the bride's dress blows out it's not too bad as the gradation seems more natural - I seem to get this awful posterisation on skin tones - strange

Pete

Hi Pete

Don't beat yourself up over the huge contrasts we get at weddings! You want to try and film a bride I did from Sierra Leone! Her face was really dark with bright eyes and then the snow white wedding dress. Digital media struggles still when faced with a nearly 100% contrast ratio ..I just live with it. We don't have TV studio conditions where Soapie weddings are filmed and everything is controlled so we just have to make the best of what we have. I bet the bride would never see any highlight blowout in her video no matter how obvious it is to you. We just get too technical..it's our nature as videographers!

Did you try a shot using 50P and then 50i on the same subject and drop both onto a timeline but de-interlace the 50i so you have 25P ?? I have always done it that way and to be honest I haven't used my Sony's in 50P mode when faces are involved ...I had too much posterisation with all my Panasonics in 50P ... It only seems to affect faces (mainly the cheekbone area) but I also found it on a nature shot of a multi-branched bush and the centre branches pixelated quite dramatically, it's also evident in closeups

Then again if you really need (or like) 50P then once you have written the data down to 720x576 I also doubt that the bride would even see it. Because 50i technically has a slightly lower vertical resolution (although I cannot see it) I also add just a touch of sharpening in post on the track but it probably not necessary.

When I get a free moment I might also give 50P a spin on closeup faces and see if it pixellates but I can bet it will on my cameras too ...it's the AVCHD format that really needs a faster bitrate to handle double frame formats like 50P

Chris

I think I'm narrowing down my problem a little - I'm noticing more that certain colours over expose more than whites - I definitely have more issues with skin tones than white wedding dresses - also look at this shot - the little girl's white dress is correctly exposed but her yellow top has lost all detail - what am I missing here?

Pete

Hi Pete

What technical specs did you shoot on there?? Format, Picture Profile, Lens and Settings and what was in Manual and what was on Auto on the camera ??? That yellow top looks like it has been "coloured over" with a yellow highlight pen.. it's really smudgy indeed yet the dress is razor sharp.

It looks to me like the knee setting has gone crazy right up to max or the camera has tried to apply smoothing of some sort to the image BUT only to the yellow top ...very strange indeed.

Maybe a list of your cam settings might solve the issue... I'm not sure? Is that frame grab straight off the raw footage BTW??? I can honestly say I have never seen an issue like that in any of my footage.

Chris

Standard PP3 (colour level 2 steps up) with stock lens, Shutter 100, Gain 0, Iris (not sure but probably F5.6) I do use a Genustech Eclipse variable ND filter so I need to conduct a few tests with and without. The framegrab is straight from the Premiere timeline.

It seems to be saturated colours and skin tones mainly :/

It's not always the case though because here's a still from the same wedding - very strange as this yellow seems fine!

Just another opinion here on what I see. I have no idea what you guys see in that photo/frame grab when you say the white part of the dress is in but the yellow is out? On my monitor it looks like it is exposed for the shadows and all highlights in the filtered sunlight are blown out. Her white dress and the ribbon around her waist are severely blown out on what I see? So are some other areas, all consistently, I don't see any color isolation problems. I am on a Mac Book Pro I am not crazy about at the moment.

Steve

PS Shafts of light coming through trees in a forest? You drew an unlucky straw on that one!!! Especially since viewers are now accustomed to that scene being exposed like it is in the Hobbit movies, 100% CG!!! You might as well turn the groom into a toad to impress them!

Hi Pete

To be perfectly honest I don't have an answer as it looks fine to me apart from the yellow that's gone crazy!! Yep the roses in the second grab look quite normal with no smearing so I have no idea why.

Nothing has occurred in your NLE? That screen grab was actually 1024x576 so it's not the native 1920x1080 but an SD still .... I would just double check the raw footage and pull a full size still from the footage just to make sure than it's not occurring during the downsizing to SD

I rarely use ND's but have only had bad colour casts from them over the entire image (supposedly IR contamination?) so I wouldn't think that the filter is causing any issues unless you accidently put a fingerprint smear on the ND exactly over the yellow top??

Any reason why you edit in SD and not HD ??? Look at the image on the time line in 1920x1080 as well and also check if it occurs from start to finish of that clip.

Chris

No Chris I edit in HD 50p - I resized the image for a quicker upload - I'm testing some 50i footage today with a mix of whites and bright colours!

Ok no problem there! It however doesn't explain the weird yellow top does it? Shooting some footage in 50i probably won't show up anything.

However I have noticed one thing quite different with my footage! I also have PP3 with the colour level up two points and my 50i footage is a LOT more desaturated than your still pics are. Assuming your footage is uncorrected and as it comes out the camera, first check your 50i footage and maybe do a similar shot again (same scene) in 50P and see if your 50i seems to have less colour overall ??? Maybe 50P boosts primary colours whilst 50i is flat ... My footage outdoors even on a cloudy day still needs a saturation boost in the NLE so maybe it is a 50P thing ... I have no idea??

If you can maybe include a garment that was the same sort of yellow as the wedding and see if you can determine if the camera maybe doesn't like it ??? If it goes away in 50i then remember you can also correct colour components in the profile ...if yellow is the issue you can give it a negative profile?

Your results will be interesting to see!

Chris